• TABLE OF CONTENTS
HIDE
 Front Cover
 Table of Contents
 Errata
 Introduction
 Beetles attacking green or freshly...
 Beetles attacking seasoned wood...
 Conclusions






Group Title: Bulletin - Union of South Africa, Dept. of Agriculture and Forestry - no. 247
Title: Wood-boring beetles in South Africa
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00023274/00001
 Material Information
Title: Wood-boring beetles in South Africa preventive and remedial measures
Series Title: Bulletin Union of South Africa, Dept. of Agriculture and Forestry
Physical Description: 2, 37 p. : ill. ; 24 cm.
Language: English
Creator: Tooke, F. G. C ( Francis Gwinnett Constans )
Scott, M. H
Publisher: Dept. of Agriculture and Forestry
Place of Publication: Pretoria
Publication Date: 1944
 Subjects
Subject: Wood borers   ( lcsh )
Forest insects -- South Africa   ( lcsh )
Beetles -- South Africa   ( lcsh )
Genre: non-fiction   ( marcgt )
 Notes
Statement of Responsibility: by F.G.C. Tooke and M.H. Scott.
General Note: Errata slip included.
Funding: Bulletin (Union of South Africa, Dept. of Agriculture and Forestry) ;
 Record Information
Bibliographic ID: UF00023274
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: African Studies Collections in the Department of Special Collections and Area Studies, George A. Smathers Libraries, University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: aleph - 001597066
oclc - 13511910
notis - AHM1196

Table of Contents
    Front Cover
        Page i
    Table of Contents
        Page ii
    Errata
        Page iii
    Introduction
        Page 1
    Beetles attacking green or freshly felled wood
        Page 2
        The pinhole borers or ambrosia beetles - Family platypodidae
            Page 2
            Page 3
            Page 4
    Beetles attacking seasoned wood only
        Page 5
        The bostrichidae
            Page 5
            Page 6
            Page 7
            Page 8
            Page 9
            Page 10
            Page 11
        The lyctus powder-post beetle - lyctus brunneus
            Page 12
            Page 13
            Page 14
            Page 15
            Page 16
            Page 17
            Page 18
            Page 19
            Page 20
            Page 21
            Page 22
        The anobiidae or death-watch beetled
            Page 23
            Page 24
            Page 25
            Page 26
            Page 27
        The european house borer - hylotrupes bajulus l.
            Page 28
            Page 29
            Page 30
            Page 31
            Page 32
            Page 33
            Page 34
            Page 35
            Page 36
    Conclusions
        Page 37
Full Text
PRICE 6ds


/r / '<^ ;^/,^' ^(^
BULLETIN No. 247
(Entomology Series No. 14)



UNION OF SOUTH AFRICA,


DEPARTMENT OF AGRICULTURE AND FORESTRY





WOOD-BORING BEETLES

IN SOUTH AFRICA

Preventive and Remedial Measures

BY

F. G. C. TOOKE, M.Sc.,
Forest Entomologist, Division of Entomology, Pretoria

AND

M. H. SCOTT, B.Sc.,
Chief Forest Products Officer, Forest Products Institute, Pretoria










'PRINTED :N THE UNION OF SOUTH AFRICA BY THE GOVERNMENT PRINTER, PRETORIA


G.P.-S.857 -1944-5 --4,000


UHWftIVSITY OF FLORIDA LIBRARIES
















TABLE OF CONTENTS
PAGE
INTRODUCTION ...................................................... .-- .--.
INSECTS CAUSING DAMAGE ............. .... ............... ........ --.........
A.--BEETLES ATTACKING GREEN OR FRESHLY FELLED WOOD.
The Pin-hole Borers or Ambrosia Beetles ................................... 2
Life Cycle .............. ........ ...... ............ ... ..... .
Economic Importance.............................................. 4
Species of Wood Attacked ....................................... 4
Preventive Measures against Pinhole Borers .......................
R epellents... ......................... ............... 5
B.-BEETLES ATTACKING SEASONED WOOD ONLY ....................... .............. 5
(1) The Bostrichidae............. ...... ........................ 5
Heterobostrichus brunnes ...................................... 9
Sinoxylon ruficorne........ ................... ........... .... 1 I
(2) The Lyctus Powder-Post Beetle-Lyctus brunneus ......................... 12
Life Cycle .................... .......... ................. 13
Seasonal History ............... ............. 18
Timbers Attacked and Conditions Suitable for Attack................ 18
Timbers Susceptible to L. brumneus Attack in South Africa............. 19
Methods of Control and Eradication :-
Removal of Sapwood............... ..................... ..- 19
General Hygiene........ ... ....... ........ ...... ...... 19
Sterilization by Heat ........ ... ................... ..... 20
Preservative Treatment................... ....... -.......... 20
Selection of Preservatives ..... ......... ........... 21
Treatment of Infested Timber ........................... ..... 22
(3) The Anobiidae or Death-Watch Beetles.
Common Furniture Beetle-AAnobium punctatum.......................... 28
Life Cycle ......................... ............ .. .... .. .--.. 23
Timber Attacked and Conditions Favourable for Attack:.......... 25
Methods of Control and Eradication...................... -.. 28
(4) The European House Borer-Hylotrupes bajulus................... ..... 28'
History in South Africa .................. ..................---- -
Life Cycle ............... .. .......
Nature of Attack and its Im;ications ............................... 33
Preventive and Control Measures :-
(a) Out of Doors :-
(1) In Plantations ..........................- :-- 3&5
(2) Pine Fences............ ............. ..... ..... 35
(b) Indoors ....... ................ ............... ....-- --- -- 3
Preservative Treatment of Timber for Replacements or for New Buildings 36
CONCLUSION .................. ... ....... ...... 3T
6-'





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LMPORTANT: Please paste this in Bulletin 247

Further research has led to the discovery of tIh
following mixtures which, for several reasons, are
superior to the solvent naphtha-diesel oil mltares
listed within. See page 21 and 35.
20% seal oil -or linseed oil plus 76% white
spirit (Mineral turpentine) plus 4%
pentachlorophenol.


16% Sostrol (dehydrated castor oil) p3lusA (i
White spirit plus 4% penteohloropHimao
gAY soevemt for pentachlorophenol aay be W~ ~
provided a 44 solution is maintained, but the tse to White
spirit as a penetrant should be strictly adhered to.
It should be noted that the above mixtures ard
highly inflammable and are irritating tb the ecia,







WOOD-BORING BEETLES IN
SOUTH AFRICA.


INTRODUCTION.
BEFORE the war, comparatively little was heard in the Union of
the damage and destruction to woodwork in houses and other
structures by various wood-boring beetles. This does not imply that
they were not active; the Division of Entomology and the Forest
Products Institute were frequently called upon for advice and to
investigate damage to stocks of ash, oak and hickory handles, floor
blocks of syringa and other woods.
The main damage by these insects was, however, at that time
confined mostly to round poles of gum and wattle and to a lesser
extent to wood such as marula which was used for brushes and brooms.
The question of preventive treatment was made the subject of
special investigation by the Forest Products Institute at Pretoria,
and large volumes of wood were treated in various chemical solutions
and exposed to attack over long periods. As a result of these experi-
ments it was possible to select two or three preservatives which were
particularly suited for the various forms of protection desired. To-day
many thousands of electric transmission poles, telephone poles,
fencing and building poles, as well as thousands of cubic feet of
furniture timber, flooring, and aircraft timbers of non-durable species
thus treated with preservatives are- giving entirely satisfactory service
in the Union, well protected against insects and decay.
With the advent of war, however, and the cutting off of many
of the accustomed sources of timber supply and the heavy reduction
in supply from other sources, the Union has been importing tropical
timbers from Central and West Africa, as well as others from
Portuguese East Africa.
Among these timbers are a number which are of excellent quality
and extreme usefulness. At the same time, as is well enough known,
there are some which are very susceptible to insect attack at various
stages of their manufacture.
S It so happens that among the latter are some of the best substi-
tutes for the general purpose timbers previously imported from
Europe, Canada and America, and they have been available in com-
paratively large quantities.
Furthermore, the prevailing timber shortage has resulted in the
greatly increased use. of certain highly susceptible untreated locally
grown timbers, particularly for structural purposes.
The.present position is then, that a large number of houses, flats
and offices 'throughout the Union have been furnished or fitted
with untreated, susceptible wood already actually infested before
being brought into these buildings, and as a result considerable
damage has been caused with consequent considerable financial loss.
Various pamphlets .have been issued by the Department from
time to time in connection with the preservation of timber, and
special attention has been drawn to insect attack in gum and wattle
poles and in certain tropical woods.
r' The question is now regarded very seriously by the Government
and this bulletin is written to give the matter greater publicity and
to indicate what can and has been done to meet the present position.





2

INSECTS CAUSING DAMAGE.
The number of species of insects which attack and destroy
seasoning and seasoned wood is very large, but fortunately in this
country only a few have become sufficiently important to merit
mention here. These are contained in the two insect orders, the
Isoptera, the termites, and Coleoptera, the beetles.
As this bulletin deals only with wood-boring beetles and as full
information on termites or white ants is to be found in various
departmental publications, only a passing reference is made to them
here. Termites normally only attack timbers in close proximity to
the ground but wood which has been given a full treatment in creosote
and one or two other tested preservatives is fully protected against
them.
For the purpose of convenience the wood-boring beetles may be
placed into two main groups: (A) those that attack green or freshly
felled wood and (B) those that confine themselves to dry or almost
dry wood. This grouping is purely arbitrary and while it serves
the purpose for the species dealt with in this publication, it cannot
be generally applied.

BEETLES ATTACKING GREEN OR FRESHLY FELLED
WOOD.
THE PINHOLE BORERS OR AMBROSIA BEETLES- FAMILY
PLATYPODIDAE.
Pinhole borers or Ambrosia beetles are the names shared by the
members of the family Platypodidae with certain groups of the
Scolytidae, or true bark beetles, having similar habits. It is damage
caused by various species of Platypodidae that we are mainly con-
cerned with in this country, but as members of this family are almost
entirely restricted to tropical and sub-tropical areas, little damage is
done to locally grown timber in the Union and for this reason little
is known of the identity and biology of our local species. A certain
amount of damage has been reported at times, usually in the East
coast areas, notably in Zululand. One species, Platypus various
Samp. has been recorded boring in wood of Milletia sutherlandi in
the Transkei.
Pinhole borers are serious pests of timber in all the Central
Africa States where they cause considerable damage, and imported
African hardwoods frequently show pinhole borer damage which is
often confused with Lyctus-beetle damage.
The beetles range in size from j to inch and are usually dark-
coloured insects, cylindrical in form. (Fig. 1.)
The mature larva is soft-skinned, nearly straight and cylindrical
in shape. It fits closely into its tunnel, touching the whole" circum-
ference when a body segment is expanded; being legless, it crawls by
alternating expansion and contraction of the segments in a pro-
gressive ripple. The young larva is ovoid in outline, too small to
span the width of the tunnel, and forced to crawling by adhesion to
one side of the wall. Larvae feed entirely on the Ambrosia-fungus
growing on the walls of the tunnel and do not eat wood.
LIFE CYCLE.
The life cycle is very uniform throughout the family; this
generalised account applies to most of the species.
The life cycle commences with the flight of the beetles from the
timber in which they were bred to new breeding material, such as
susceptible living trees or newly felled and fallen logs. It is probable





2

INSECTS CAUSING DAMAGE.
The number of species of insects which attack and destroy
seasoning and seasoned wood is very large, but fortunately in this
country only a few have become sufficiently important to merit
mention here. These are contained in the two insect orders, the
Isoptera, the termites, and Coleoptera, the beetles.
As this bulletin deals only with wood-boring beetles and as full
information on termites or white ants is to be found in various
departmental publications, only a passing reference is made to them
here. Termites normally only attack timbers in close proximity to
the ground but wood which has been given a full treatment in creosote
and one or two other tested preservatives is fully protected against
them.
For the purpose of convenience the wood-boring beetles may be
placed into two main groups: (A) those that attack green or freshly
felled wood and (B) those that confine themselves to dry or almost
dry wood. This grouping is purely arbitrary and while it serves
the purpose for the species dealt with in this publication, it cannot
be generally applied.

BEETLES ATTACKING GREEN OR FRESHLY FELLED
WOOD.
THE PINHOLE BORERS OR AMBROSIA BEETLES- FAMILY
PLATYPODIDAE.
Pinhole borers or Ambrosia beetles are the names shared by the
members of the family Platypodidae with certain groups of the
Scolytidae, or true bark beetles, having similar habits. It is damage
caused by various species of Platypodidae that we are mainly con-
cerned with in this country, but as members of this family are almost
entirely restricted to tropical and sub-tropical areas, little damage is
done to locally grown timber in the Union and for this reason little
is known of the identity and biology of our local species. A certain
amount of damage has been reported at times, usually in the East
coast areas, notably in Zululand. One species, Platypus various
Samp. has been recorded boring in wood of Milletia sutherlandi in
the Transkei.
Pinhole borers are serious pests of timber in all the Central
Africa States where they cause considerable damage, and imported
African hardwoods frequently show pinhole borer damage which is
often confused with Lyctus-beetle damage.
The beetles range in size from j to inch and are usually dark-
coloured insects, cylindrical in form. (Fig. 1.)
The mature larva is soft-skinned, nearly straight and cylindrical
in shape. It fits closely into its tunnel, touching the whole" circum-
ference when a body segment is expanded; being legless, it crawls by
alternating expansion and contraction of the segments in a pro-
gressive ripple. The young larva is ovoid in outline, too small to
span the width of the tunnel, and forced to crawling by adhesion to
one side of the wall. Larvae feed entirely on the Ambrosia-fungus
growing on the walls of the tunnel and do not eat wood.
LIFE CYCLE.
The life cycle is very uniform throughout the family; this
generalised account applies to most of the species.
The life cycle commences with the flight of the beetles from the
timber in which they were bred to new breeding material, such as
susceptible living trees or newly felled and fallen logs. It is probable


































SFIG. 1. A typical Pin-hole Borer of the Family Platypodidae. X16.

that the adult life spent in the open is very short, a few hours to 1
or 2 days, and they soon bore into another tree or log to found a new
home. During this period the fructifications of the Ambrosia-fungus
are transported by means of special devices such as tufts or baskets of
long bristles, secretary pores, pits, etc. These spores germinate in the
new tunnels, giving rise to a new growth.
The arrangement of tunnels varies greatly with different species
of pinhole borers, Some species construct simple galleries in which
the eggs, larvae, pupae and adults are found living together; others
construct compound tunnels with numerous branches, along the sides
of which are constructed niches known as larval ar pupal cradles.
With such species the eggs are deposited in these niches and also the
larvae develop and pass through the pupal stage in them. These
larvae are fed by the adult beetles who insert plugs of the Ambrosia-
fungus into the cradle entrances. In the species where no cradles
are formed by the adult, the larvae shift for themselves, feeding upon
the Ambrosia-fungi growing on the tunnel walls.
The Ambrosia-fungus, Monilia or Penicillium, grows readily on
the walls of the tunnels spreading its hyphae into the wood tissues
and staining them back. This black stain on the walls of the tunnels
is characteristic, of the group of beetles, and distinguishes their work
S from all other wood-boring insects. (Fig. 2.).
The life cycle from the time of boring in by a pair until the off-
spring begin to swarm may be from 5 to 6 weeks in some species, up
to 6 months to a year in others. The period of occupation of a log
by colonies of pinhole borers is determined by the rate of seasoning








or desiccation. When the moisture content has fallen to about 40
per cent., the wood is vacated by the beetles. The total emergence
period of the occupation may last for 6 months and all broods escape
through the original entrance tunnel of their parents or that of an
adjacent colony if linkage has connected them. New exit tunnels
are not made.


FIG. 2. Pin-hole Borer Damage in Tropical Hardwood. Natural size.

ECONOMIC IMPORTANCE.
While few species bore into standing living trees, the greatest
damage is to newly felled boles, logs and branches which are attacked
within a few hours of felling and they continue to be liable to further
attacks so long as they remain moist enough. Dry or seasoned timber
is immune. The timber is spoiled by disclosure of pinholes, and
streaks on sawn faces owing to the trans-section of the galleries on all
aspects. Structurally the timber is scarcely weakened at all by the
presence of pinholes, unless they are very abundant.
SPECIES OF WOOD ATTACKED.
The following species of wood are susceptible to a greater or
lesser degree to pinhole borer attack: African Mahogany, Agba,
Brachystegia sp., Chamfuta, Essenhout, Fuma, Iroko, Kiaat, Lauan,
Limba, Mafamuti, Marula, Mucarala, Mugongo, Oak, Obeche,
Okoume, Panga-Panga, Parana Pine, Rooi-essenhout, and many
others.





5

PREVENTIVE MEASURES AGAINST PINHOLE BORERS.
The best means of combating I these insects are rapid conversion
of the log into boards and rapid drying of the latter.
If logs cannot be sawn immediately, they should be stored
(a) in dense shade, the object being to keep the timber moist, sool
and dark, (b) in the open in full sun, to heat the bark and dry the
wood out quickly and (c) the best and most effective method, in a log
pond which has the advantage of protecting them against splitting as
well as against insect attack.
At the saw-mill or sales depot the usual hygienic principles
should be enforced, i.e., prevent only local breeding of borers by
constant inspection and destruction of breeding material produced
by milling operations or the importation of infested timber.
Preservative treatment of logs is not as a rule practicable nor
should it be necessary if they are sawn up within a reasonable time
and the boards either dried in a kiln, or if of a species like Obeche
which will stand such treatment, racked for rapid sun drying for a
week or two before being stacked in the ordinary way for seasoning.
Once the moisture content has fallen below about 40 per cent. the
boards are safe from attack by pinhole borers.
*REPELLENTS.
A very large number of chemicals have been tested overseas with
*a view to preventing attack by pinhole borers. Boards were either
dipped or sprayed with the chemical, but no substance has yet been
found which will repel pinhole borers entirely. The best results
were obtained with a mixture of benzol (75 per cent.) and orthonitro-
diphenyl (25 per cent.), but it is doubtful whether this method will
ever have a practical value.
In conclusion it should be emphasized that if the type of bore-
hole described above is found in dry boards, it is perfectly safe to use
them and the only disadvantage will be in the marred appearance of
the board, unless the attack has been exceptionally severe when the
mechanical properties of the wood may be affected; but this is very
unusual.

BEETLES ATTACKING SEASONED WOOD ONLY.
r .The second group of beetles to be considered are those which
attack seasoned or dry wood. These are by far the more important
and are responsible for practically all the damage done to hard- and
softwoods in this cqintry. All the most important pest species can
be placed in four families, the Bostrichidae, or shot-hole borers or
auger beetles, the Lyctidae, or powder post beetles, the Anobiidae, or
death watch beetles, and the Cearmb Ycidae, or long-horned beetles.

(1) TH7 E BOSTRICHIDAE.
TUnfor.tunately up to the present our knowledge of the biology
of South African timber boring Bostrichid beetles is very meagre and
mainly limited to observations on the:economic- aspect.
Bostrichidae are essentially polyphagous but prefer well-seasoned
hardwoods. It is exceptional for the food-plants of one species to be
restricted to one genus or one generic group of plants. The majority
of species emerge most abundantly at periods in the spring and
summer "and are inactive in the winter. The adults are nocturnal or
'at least crepuscular. The -newly transformed beetles emerge, mate,
lay eggs and:migrate during the dark hours. After mating the male
assists the female in gnawing a hole into the wood. This is usually
cut straight into the wood to a depth about equal to thelength of the





5

PREVENTIVE MEASURES AGAINST PINHOLE BORERS.
The best means of combating I these insects are rapid conversion
of the log into boards and rapid drying of the latter.
If logs cannot be sawn immediately, they should be stored
(a) in dense shade, the object being to keep the timber moist, sool
and dark, (b) in the open in full sun, to heat the bark and dry the
wood out quickly and (c) the best and most effective method, in a log
pond which has the advantage of protecting them against splitting as
well as against insect attack.
At the saw-mill or sales depot the usual hygienic principles
should be enforced, i.e., prevent only local breeding of borers by
constant inspection and destruction of breeding material produced
by milling operations or the importation of infested timber.
Preservative treatment of logs is not as a rule practicable nor
should it be necessary if they are sawn up within a reasonable time
and the boards either dried in a kiln, or if of a species like Obeche
which will stand such treatment, racked for rapid sun drying for a
week or two before being stacked in the ordinary way for seasoning.
Once the moisture content has fallen below about 40 per cent. the
boards are safe from attack by pinhole borers.
*REPELLENTS.
A very large number of chemicals have been tested overseas with
*a view to preventing attack by pinhole borers. Boards were either
dipped or sprayed with the chemical, but no substance has yet been
found which will repel pinhole borers entirely. The best results
were obtained with a mixture of benzol (75 per cent.) and orthonitro-
diphenyl (25 per cent.), but it is doubtful whether this method will
ever have a practical value.
In conclusion it should be emphasized that if the type of bore-
hole described above is found in dry boards, it is perfectly safe to use
them and the only disadvantage will be in the marred appearance of
the board, unless the attack has been exceptionally severe when the
mechanical properties of the wood may be affected; but this is very
unusual.

BEETLES ATTACKING SEASONED WOOD ONLY.
r .The second group of beetles to be considered are those which
attack seasoned or dry wood. These are by far the more important
and are responsible for practically all the damage done to hard- and
softwoods in this cqintry. All the most important pest species can
be placed in four families, the Bostrichidae, or shot-hole borers or
auger beetles, the Lyctidae, or powder post beetles, the Anobiidae, or
death watch beetles, and the Cearmb Ycidae, or long-horned beetles.

(1) TH7 E BOSTRICHIDAE.
TUnfor.tunately up to the present our knowledge of the biology
of South African timber boring Bostrichid beetles is very meagre and
mainly limited to observations on the:economic- aspect.
Bostrichidae are essentially polyphagous but prefer well-seasoned
hardwoods. It is exceptional for the food-plants of one species to be
restricted to one genus or one generic group of plants. The majority
of species emerge most abundantly at periods in the spring and
summer "and are inactive in the winter. The adults are nocturnal or
'at least crepuscular. The -newly transformed beetles emerge, mate,
lay eggs and:migrate during the dark hours. After mating the male
assists the female in gnawing a hole into the wood. This is usually
cut straight into the wood to a depth about equal to thelength of the







beetle, after which the excavation is parallel to the surface. The
waste wood is always expelled from the burrow which is always kept
open. The main burrow may have several lateral galleries and often
a terminal chamber where the beetle can turn around. The eggs are
laid at the end of the main galleries and in the lateral tunnels. The
adults are usually found dead in the passage or at the original
entrance which is very effectively plugged up by their dead bodies.
The larvae, as they gnaw their way through the wood, pack
their tunnels tightly behind themselves with excrement and wood
particles.
Prior to pupation the larvae of the final instar begin tunnelling
towards the surface, and form a cell close to the surface of the wood
wherein they transform to pupae.
All species exhibit as a normal characteristic delayed develop-
ment of part of a brood, that is to say some of the brood of a species
with an annual generation may not mature until the second or third
year. The factors responsible for delayed development are competi-
tion for food in crowded infestations, and variation in the moisture
content of the wood and greater or lesser amounts of starch which
is an essential constituent of the food of these beetles.
The following is a list of the most important Bostrichids found
damaging seasoned wood in the Union, The list of wood species
attacked by each is by no means complete, only those woods being
recorded which have been brought to the notice of the Division as
being seriously damaged.


























FG. 3. Bostrycholites cornututs 01. Male. X8.
Bostrychoplites cornutus, 01., attacking bamboo and eucalyptus
logs. and poles, particularly Eu. saligna. Widely distributed
throughout Southern Africa.






























Fla. 4. Dinoderu8 minutes, Fabr. X26.

Dinoderus minutus, Fabr., causes severe damage to bamboo,
cane chairs and wicker work generally. Particularly bad in Natal.
Heterobostrichus brunneus; Murr., recorded from Rhodesian
teak (Baikiaea plurijuga) and kiaat (Pterocarpus angolensis, D.C.)
as well as many species of Eucalyptus; widely distributed throughout
Southern Africa.
Sinoxylon ruficorne, Fahr., a frequent borer in Eucalyptus and
Acacia, probably attacks logs. of all Leguminosae, widely distributed
throughout Southern Africa.





















FIG. 5. Sinoylon trtsvaalense,s esae. 'X14.







Sinoxylon transvaalense, Lesne, same as the previous species.
Xylion adjustus, Fahr, frequently attacks Rhodesian teak and
also common Eucalyptus, e.g., E. globulus, as well as several species
of Acacia, widely distributed in Southern Africa.
Xyloperthodes nitidipennis, Murr., attacks many species of
Eucalyptus, restricted to East coast areas. (Figs. 3 to 7.)


FIG. 6. Xylion aduatus, Fahr. Male. X15.


F'l. 7. Xyloperttode nitidtpennis Murr. X12.


~Q8c~~






9

As it is the purpose of this bulletin to enlarge on those species
of beetles which are causing the most concern to members of the
timber trade and to the house-owner and as these Bostrichids are not
of serious consequence as compared with other wood boring beetles
discussed later, a short note on the biology of two typical species will
be given. Illustrations of all the species listed, will, however, be
found in this bulletin. (Fig. 8.)


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1.
a


FIG. 8. Holes bored by Bostrichid Beetles. Natural size.

Heterobostrichus Brunneus, MURRAY.
A rather slender cylindrical beetle, dark brown to almost dull
black in colour, measuring 2/, to J inch in length. The body is
covered with a pubescence formed of very short fine hairs. The
pro-thorax depressed in the front, fringed with stout spines on either
side, the first projecting beyond the margin, finely punctured on
the sides and granulated on the hind margin. Legs smooth, dark







:reddish ,brown.. Wing-covers finely striated with somewhat irregular
:idwOw of 'distinct punctures; the tips rounded slightly depressed in
.the'cent.re'. .:(Fig. 9.)







/ \






-4.











FIG. 9. Heterobostrichus brunneus, Murr. X10.


H. brunneus, which is found over the whole of Southern Africa,
is one of the commonest Bostrichids in packing cases and boxes as
well as the sapwood of logs and boards of hardwood species.
The female beetle may lay eggs on the rough surface of sawn
timber and of logs from which the bark has been removed or may
penetrate inside natural cracks and crevices or may bore a short
tunnel into the wood for the purpose of feeding and oviposition. Eggs
are deposited singly and the larva bores away from the surface a
gradually widening tunnel which may reach a diameter of J inch.
In heavy infestations these larval tunnels twist and turn in all
directions intersecting tunnels of other larvae. The tunnels are
tightly packed with moderately fine wood dust. The full-grown larva
measures about J inch in length; it is a white, fleshy, curved grub
with three pairs of thoracic legs. (Fig. 19.)


ImG.. 10. brunneua, Mature Larva. X7.








; When mature the larva works towards the surface of .the wood
where it forms a cell in which it pupates. The immature beetle,
remains inside the wood for a variable period towards the end -f
S which it is occupied in further boring and feeding among larval
tunnels, finally emerging by an exit hole on the surface.' (Fig. 11.)









FIG.. 11. .brunnes, Pupa. X3.

The life cycle from egg to emerged beetle requires a minimum
period of one year, but it is usual for a large fraction of the larval
brood resulting from eggs laid at one season to take two or three
years to complete development.
H. brunneus is capable of causing considerable damage to timber,
In logs and poles it often reduces the wood to powder to a depth of
two to three inches. Sapwoodonly is attacked.

Sinoxylon ruficorne, FAHR.
This is a small beetle about I inch in length, short and broad.
in proportion. It varies in colour from black to dark brown, mature
specimens are nearly black, often with a reddish brown blotch on the
side of the basal portion of the wing-covers. The head is small with-
prominent round eyes and reddish antennae. The prothorax is broad-
rounded in front and covered with fine spines. The wing-covers are,
more or less finely punctured at the base, the punctuations becoming-.
coarser towards the posterior end. Fig. 12.


Fia. 12' Sinozylon rfaicorne, Fahr. X12;







The apical declivity bears 3 pairs of definite tubercles which
project slightly beyond the margin, and on each side of the elytral
suture' is a pointed triangular spine.
The life history of this species is very similar to that given for
H. brunneus. *
The beetles bore a short tunnel into the wood which runs radially
through the bark to the inner sapwood, and then turns and runs in
the same plane in a curve parallel to the outer sapwood circum-
farence. It is used as an oviposition tunnel and is kept clean of all
wood dust. The larvae bore ever widening galleries in the sapwood.
Pupation takes place at the extreme end of the larval tunnel in a
cell and the beetle bores out by a direct route to the surface.
The insect takes about a year for its development. It is primarily
a borer of the sapwood of logs particularly Leguminosae but its
-range of food-plants is probably wide and varied.
The adult beetles sometimes bore into green shoots and twigs of
Acacias for the purpose of feeding, making axial tunnels, as a result
the leaders of seedlings or young sapling may be girdled ar killed.
They also at times bore into the stems of sickly or dying trees with
more or less success.
For control measures see under Lyctus powder-post beetles.

(2) THE LYCTUS POWDER-POST BEETLE-
LYCTUS BRUNNEUS, STEPH.
Beetles of the family Lyctidae are close relatives of the Bostri-
chidae, and indeed some authorities group them together under one
large family.
The Lyctus beetles are popularly called powder-post beetles in
that the larvae which fortunately attack sapwood only, reduce
attacked wood to a fine, flour-like powder. They are probably the
most dangerous pests to untreated hardwood products. It has been
estimated that these beetles cause an annual loss in the United States
of approximately 4,000,000 and at the moment they are causing an
annual loss in this country which must run into thousands of pounds.
Although -there are several species of Lyctus beetles in the world,
only one species appears to be responsible for damage in the Union;
this is Lyctus brunneus, Steph.
This Lyctus beetle has been the cause of the recent wholesale
damage to woodwork of limba, marula, etc., in flats and houses, and to
roof timbers of wattle and eucalyptus. Limba (Terminalia superba)
is one of the most generally used of East coast timbers. It is a wood
of light to medium weight, easily worked and is similar to oak in
colour though lacking the wide ray.
Lyctus brunneus is not a new introduction, but has been known
in this country for many years, but the damage it has caused in the
past has been on a comparatively small scale. Careful observation
indicates that the increase and spread of the insect during recent
years has been due, firstly, to the importation of certain highly
susceptible hardwoods from Central Africa, such as limba and fuma
(in the past) often already infested with the insect, and secondly, the
greatly increased use of such susceptible home-grown woods as gum
and wattle for roofing and building purposes because of the shortage
of more suitable wood.
It is realized that the above statement is likely to have consider-
able repercussion with, regard to the Central African timber trade.
We should like to qualify this statement, therefore, by adding that
although the Department has definite proof that stocks of Central
African hardwood, more particularly limba, are reaching this
country in a heavily infested condition, this is not to say that all







stocks are so infested and that all exporters are to blame. It is
probable that owing to the unprecedented demand for timber due to
war conditions many new producers have set up business recently in
the Belgian Congo and neighboring states and are exporting timber
of a dubious quality, while the older established firms are more
particular in this respect. Unfortunately this does not help matters
much if infested and uninfested timber is stacked in close proximity
at the sales depot to await shipment or is exported in the same ship
or truck. Under such conditions all stocks are liable to arrive at
their destination in an infested state.
At the same time, importers in this country cannot be held
entirely blameless in importing such inferior timber.
Whatever the contributory causes may be, the country is now
faced with a very serious situation and the Government is very much
alive to the dangers of Lyctus attack in timber and is specially con-
cerned with preventive measures to be taken.
The matter of the preservative treatment of woods susceptible to
Lyctus attack has been discussed with the Belgian, French and
Portuguese authorities and definite steps towards this end have
already been taken by some of them.
Attention is drawn to Section 32 in Chapter 4 of the Forest and
Veld Conservation Act and to Clause 66 of Government Notice No.
1292 of 1942 in the above connection. It is also possible that the
maximum price allowed for various susceptible timbers will- be
increased if it can be proved that the suppliers have rendered the
wood immune to insect, attack.
LIFE CYCLE.
The adult of L. brunneus varies from one-tenth to one-sixth of
an inch in length. It is of a uniform dark reddish brown colour.
The head is short and broad; the large rounded eyes project on the
sides; the last two segments of the antennae 'form a flattened club.
The prothorax overhangs the back of the head, is rounded in front,
swelling .out on the sides behind the eyes, then arcuate and rounded
Son the hind margin. 'The dorsal surface convex, not. shining, covered
with fine shallow punctures and lightly clothed with short scattered
hairs. Body and wing-covers long, of uniform width,. the latter
















>- II


Ftd. 13. Lyclua brunneua, Stepb., X13.







bearing very shallow parallel striae, small irregular punctures, and
scattered long recumbant brownish hairs. (Fig. 13.)
The beetles are sexually mature when they emerge. Mating
takes place immediately after emergence either at dusk or during
the night, but it has also been observed during the daytime. Indivi-
dual males may fertilise several females. During daylight the beetles
usually conceal themselves in cracks or holes in the wood but become
active at dusk and fly readily; they are attracted to light. They
feed on the surface of the wood by gnawing the torn fibres and by
this means the females are able to detect the suitability of the timber
for oviposition in relation to its food value for the larvae.
The length of the life of the females when free to mate and
oviposit averages about six weeks; the males live for only two to
three weeks.
Oviposition takes place mainly at the period of the greatest
activity, i.e., at dusk, but may also occur during the day. The eggs
are inserted in the open pores or vessels exposed on transverse or
longitudinal surfaces of sawn wood. More than one egg may be
deposited within the same vessel. They are never deposited in cracks
or on polished surfaces.
The diameter of the vessels in which oviposition occurs may be
greater than the normal diameter of the egg or slightly less; in the
latter case the vessel diameter must be great enough to allow the
introduction of the ovipositor.
The susceptibility of timbers to Lyctus attack is thus governed
primarily by the relationship between pore-diameter and ovipositor-
diameter.
As the average diameter of the ovipositor of L. brunneus is about
80 (-M=1/1,000 mm.) it is theoretically possible for any timber
containing pores large enough for the introduction of the ovipositor
to be attacked, i.e., any timber having some vessels with a minimum
average diameter of about 90/u. But timbers which are regularly
susceptible to Lyctus damage are those having an abundance of pores
of much greater diameter. Natural infestation has been recorded in
timbers, the largest minimum pore sizes ranging from 104,/ to over
300ju.
The egg is translucent white and cylindrical, with rounded ends.
It is about one-thirtieth inch in length and not more than one-third
of the length in diameter, and bears at the one end a thread-like
attachment. (Fig. 14.)




FIG. 14. Lyctu brunneus, Egg. X46.

The larvae or grubs hatch out in from two to three weeks. At
this stage they are straight-bodied, white in colour and very minute,
measuring about 0-026 inch in length. The grub or larva steadily
grows and after moulting assumes a curved form. When full-grown
it barely measures one-fifth inch in length and is fleshy white in
colour, the forepart of the body is much thicker than the hind end,
and the head is deeply sunken. The head bears two short 4-jointed
antennae. The body is without spinules (hair-like structures) and
of the nine spiracular apertures along each side, the hindmost pair
are nearly four times as wide as the others, and can be seen much
more easily. There are three pairs of thoracic legs, the front pair
being much .stouter than either the middle or the hind pair. (Fig. 15.)



















FIG. 15. Lyctus brunneus, Mature Larva. X15.


The sapwood tissue eaten by the larva is reduced to a very fine
powder and is packed closely in the tunnel behind it. This fine
flour-like frass, which is a conspicuous sign of Lyctus damage, has
given the name powder-post beetles to these borers. In the
early ,stages the young larva usually tunnels with the grain of the
wood. In the later stages the larval tunnel takes an irregular course
often recrossing its earlier track or intersecting the tunnels of other
larvae. Tunnels approach the surface of infested wood but do not
penetrate it, leaving a thin unbroken skin.
The chief source of food of Lyctus larvae is the starch in the
cell-contents of the wood; the substance of the cell wall is
not digested. Besides starch it has been shown that certain sugars,
disaccharides and a polysaccharide as well as protein are necessary
constituents of the larval food. The larva is unable to digest cellu-
lose and hemi-cellulose; the relative proportions of cellulose, pento-
sans and lignin in sapwood are not changed during the passage of the
wood particles through the intestine of the insect.
SThe, presence of starch in sapwood is essential for infestation by
Lyctus to occur and although starch is not its sole food the greater
the,starch content the greater the possible extent of damage. Below
a minimum concentration of starch no attack occurs. In addition to
starch a water-soluble substance is necessary for the normal growth
of the larva.
Moisture is also necessary for the normal development of the
larva. It will thrive in wood with a moisture content between 30
and 8 per cent., the higher moisture content being the more favour-
able; wood with less than 8 per cent. moisture is not attacked, or at
least if it is, the larvae are not able to develop.
The grub continues to excavate its tunnel and grows chiefly
during the spring and summer and becomes very much less active if
temperatures fall low enough becoming almost completely dormant
during the winter. If in heated rooms, however, it may continue
active work for some months longer, with a consequent speeding up
of its development.
Normally, the larva remains in the wood for about ten months,
but this time varies with, the condition of the wood and the tempera-
ture. When fully matured, it bores its way near to the surface of
the wood in order to huild a pupal chamber where it rests preparatory
to changing its -forim and becoming a beetle. In some cases, the
grubs at this period will extend their tunnels through heartwood or
Softwood lying adjacent to the hardwood sapwood in which they have
lived up to this stage.
-When the larva has reached maturity and prepared its pupal
chamber, it lies stationary and inactive and gradually changes its








form and becomes a beetle. The period
change in about one month. (Fig. 16.)


necessary for the complete


FIG. 16. Lyctu brunneu, Pupa. X7.


FIG. 17. Lyctua brunneu Damage. Outer skin of Wood on left removed showing how
the Larvae have reduced the Wood to Powder. Natural size.







IThe beetle may remain inside the wood for a variable period,
particularly if the transformation takes place in the late autumn or
in the winter months, when it is apt to await the onset of warm
weather before emerging.
Normally, as soon as it is developed, the beetle begins to cut its
way to the surface. On emerging it generally pushes some of the
fine dust in front-of it and, as a result, small piles of dust can often


-,.0
,


















18. Showing exit holes made by emerging Adults of Lytu brunnus. Natural size.




be .een in the vicinity of new holes. This is usually th first external
ig o o t h -
I a S *
./, ?r.. *i .




time where the beetle has o other means of readily coming free,
Sh a b b t a t s t
i Rt.' "




'*

'





," '"i ', ; i "l ', "

^*^t i-1 d i';'' 11 "' :


4' 3 ||' .,'' 'i.."

:.,'.i_ .;i .. i *,' '



Fia. 18. Showing exit holes made by emerging Adults of Lyctua brurneu. Natural size.

be seen in the vicinity of new holes. This is usually the first external
sign of attack. The size. of the holes which are known as flight-
holes, varies from one-thirty-second to one-sixteenth inch and some-
times, where the beetle has no other means ,of readily becoming free,
the holes may be bored through heartwood, through softwoods and in







exceptional cases even through asbestos and lead sheeting and plaster.
(Figs. 17 and 18.)
SEASONAL HISTORY.
Under conditions of normal temperature and humidity the com-
plete cycle, from egg laying to the development of a mature beetle
with subsequent egg laying, takes from 9 to 12 months. Under
exceptionally favourable conditions such as constant high tempera-
ture and humidity, and high starch and moderate moisture content
in the wood, the life cycle may take from 7 to 8 months, while any
adverse conditions may prolong is from 21 to 3 years.
The period of greatest emergence of the beetles is during -the
summer months, i.e., from October to December but stragglers may
continue to appear long after this. Inside buildings, where any sort
of heating apparatus is fairly constantly used, for example kitchens,
active beetles are likely to be found during any month of the year.

TIMBERS ATTACKED AND CONDITIONS SUITABLE FOB. ATTACK.
It must be emphasised that Lyctus beetles attack only the sap-
wood of certain hardwoods.
Unfortunately in some African timbers as well as many of the
exotic eucalypts, it is very difficult to distinguish sapwood and heart-
wood, especially when the timber is seasoned. Also some woods
contain a large percentage of sapwood. Limba is particularly badly
attacked for, this reason.
However, once 'the sapwood of a piece of timber has been
destroyed, the Lyctus beetle abandons the timber and all attack
ceases. Further, although it is commonly believed otherwise, timber
need not be thoroughly seasoned before infestation can occur. As
soon as timber is sawn surface drying commences, and it has been
shown that material sawn only two or three weeks has become infested.
It is probable, however, that the beetles do not reach their maximum
development under such conditions and that air-seasoned timber of
about 15 per cent. moisture content is more suitable for their growth.
They have been found living and developing in timber as low as 8
per cent. moisture content, but not lower. However, it is not possible
to maintain timber below 8 per cent. in general use in South Africa.
The two main sections of the timber industry affected by Lyctus
are the building and furniture trades. In the latter, furniture may
be manufactured and delivered in sound condition, but after a few
months flight-holes may appear in the furniture. If such attacks
occurred for the first time within eight to nine months of receipt,
it is almost certain that the timber was infested before the furniture
was delivered, such infestation having occurred in the raw material
before receipt by the manufacturer, in the manufacturer's storage
yard from nearby infested timber, or in a storage shed after the
furniture was manufactured. The responsibility for Lyctus infesta-
tion rests as much with the timber merchant as with the manufac-
turer, and both should take adequate means to prevent or eradicate it,
thus reducing the spread and increase of the trouble.
A list of some of the woods more commonly known to be attacked
by powder-post beetles is given below, which also indicates the degree
of susceptibility to attack.







19

TIMBERS: SUSCEPTIBLE .TO Lyctus Brunneus ATTACK IN SOUTH AFRICA.


Species.
African mahogany (Kkaya sp.).............
' Agba (Gosweilerodendron balsamiferum)......

Ash (Fraxinus sp.) ......................
Brachystegia sp........... ............
Black wattle (Acacia mollissima)............
Blackwood (A. melanoxylon)...............
Chamfuta (Afzelia quanensis) ............
Essenhout (Ekebergia capensis). ............
Eucalyptus sp............................
Eucalyptus maculata..............'........
Eucalyptus macrrorhyncha. .................
Eucalyptus microcorys .....................
Eucalyptus paniculata .....................
Eucalyptus viminalis.....................
Fuma (Ceiba pentandra)....................
Grevillea robusta...........................
Iroko (Chorophora excelsa)..................
Jalhalsbessie (Diospyros mespiliformis)......
Kiaat (Pterocarpus angolenss) ..............
Lanan (Shorea sp)........................
Limba (Terminalia superba). ..............
Mafamuti (Piptadenia buchananii)...........
Marula (Sclerocarya caffra) ...... ..........
Mucarala (Burkea africana)...............
Mugongo (Ricinodendron rautanenii) .........
Oak (Quercue sp) .........................
Obeche (Tripochiton scleroxylon) ............
Okoume (Aucoumea klaineana) .............
Panga-Panga (Albizzia versicolor)...........
Rooi-essenhout (Trichilia emetica)...........
Stinkwood (Ocotea bullata) ............... ..
Wattle (Acacia sp.).......................


Degree.
Occasional.....
Common ......

Common ......
Very common.
Very common.
Common ......
Not seen......
Very common.
Very common.
Very common.
Common ......
Common ......
Common ......
Common......
Very common.
Common .....
Occasional.....
Common......
Very common.
Occasional.....
Very common.
Occasional.....
Very common.
Common ......
Common... ..
Very common.
Common ......
Not seen......
Common .....
Very common.
Occasional.. ..
Very common.


'Remarks.

Sapwood gummy and
usually removed.




Wood, mostly sapwood.





Wood, all sapwood.



Wide sapwood.

Wood, mostly sapwood.

Wood, mostly sapwood.


Especially American oak.


In addition the following wood species are listed as being attacked by L. brunneus in Australia
by Wilson and Cummings: Acacia dealbata, Acacia implexa, Aleurites molucanna, Angophora baker,
Angophora intermedia, Angophora lanceolata,'Angophora subvelutina, Baloghia lucida, Cedrela australia,
Embothrium'wickhami, Ficus macrophylla, Flindersia bennettiana, Grevillea robusta, IAtsea reticulafa,
Nothofagus moorei, Orites excelsa, Panax elegans, Panax murrayi, Schizomeria ovata, Sterculia acerfola,
Symnarpia laurifolia, Tarrieta peralata, Tarrieta acinophylla, Tristania sauveolens, and the following
species of Eucalyptus : Acedes, aggregate, amplifolia, angophoroides, australiana, baileyana, bancrofti,
baurinana, bicolor, bicostata, bakeleyi, bosistoana, botroyoides, bridgesiana, calophy.la, canaliculata,
einerea, coriaceae,eorymbosa, erebra, dalrynpleana, deanei, de beuevillei, diversicolor, dives, eleaeophora.
esemia, fastigata, frazinoides, gigantea, globulus, gomphocephala, goniocalyx, r a, leuccozylon,
longifolia, macarthuri, maerorrhyncha, maculata, maideni, melliodora, microcarpa, mirocorys, nitens,
oblique, baniculata, parramatensis, patents, perrineana, pilularis, piperita, .polyanthemaos, regnans,
resinifera, robertsoni, robusta, rostrata, rubida, seeana, siderozylon, smithii, stelllata, stuartiana,
tereticous, tesselaris, trachyploea, umbra, viminalis.
Beeson lists the following wood species attacked by L. brunneus in India : Albizzia odoratissima,
Artocarpus integrifolia, Bonabas malabaricum, Canarium eup~hyllUm, Dipterocarpus pilosus, Erythrina
indica, Greville robusta, Kydia calycina, Mangifera indica, Michelia champaea, Michelia oblonga,
Quercus sp., Bed Pine. Terminalia belerica, Terminalia bialata, Terminalia myriocarpa, Terminalia
toenentosa.





careful removal offers the first method for prevention of attack or
spread of the insects. For some timbers, particularly some furniture
woods, this is economically impossible, and it is then advised that
the timber be treated by one of the methods given below.
General Hygiene.--If it is necessary to use sapwood, then parti-
cular care should be taken that waste pieces are not left around the
yard or in storage sheds. Such pieces are a breeding place for Lyctus
and will act as sources from which infestation of sound timber may
occur. In all cases waste should be burned. Care should also be
taken that yards are kept clean, and if it's at all possible timber
Containing sapwood should be isolated and kept in separate stacks.
I Even if sapwood cannot be segregated, frequent inspection of stacks,
particularly in spring and early summer, will do much to help to
minimize the damage by early discovery of the attack. In practising
methods of yard and storage hygiene, there must be co-operation







between neighboring firms, as the Lyctus beetles are capable of
flying some distance, and so infestation can spread from one yard
to another.
Sterilization by Heat.-This is the most satisfactory and effective
method for killing all stages of Lyctus. Experience in the United
States of America and England has shown conclusively that, if 1-inch
timber is heated to a temperature of 1300 F. and maintained at this
temperature at 100 per cent. relative humidity for one and one-half
hours, all infestation will be killed. If lower humidities are used,
the temperature must be increased or the time of treatment consider-
ably lengthened. The correct method for the treatment of infested
timber is to place it properly stripped in the seasoning kiln, raise
the temperature to 1300 F. and hold it there for periods depending
on the thickness of the stock. For 1-inch stock, the time to heat the
timber throughout to 1300 F., once the kiln has attained this tempera-
ture, is about half an hour; for 2-inch stock, two hours and for
3-inch stock four and one-half hours. To these times should be added
the sterilization period of one and one-half hours mentioned above.
Thus after reaching 1300 F., 1-inch stock should be heated at 100
per cent. relative humidity for at least two hours, 2-inch stock for
at least three and one-half hours, and 3-inch stock for at
least six hours. In the heating period particular care should be
taken with certain types of stock. Comparatively green stock can be
heated immediately with live steam without trouble, as can also
partly seasoned quarter sawn stock. In the case of plain sawn
seasoned stock, particularly if checks are already present, the heating
up period should be carried out at a relative humidity slightly lower
than that giving an equilibrium moisture content corresponding with
the moisture content of the timber. For timber of from 12 to 15 per
cent. moisture content, a humidity of 70 per cent. is recommended
with a temperature of 1500 F. These conditions would be suitable
for any seasoned material and the temperature should be held for at
least an hour for each inch in thickness of the boards once the kiln
has been thoroughly heated. This will in no way damage or affect the
timber.
If all timber is kiln-dried either green from the saw or after
being partly air-seasoned, the kiln conditions used for drying South
African woods will be found to be severe enough to kill all Lyctus
infestation. No further sterilization treatment is, therefore, neces-
sary. Tests carried out with wooden air screws exposed to a tempera-
ture of 1500 F. have been completely successful. Humidities of
between 70 and 74 per cent. were used.
Timber which has been sterilised by suitable heat treatment or
kiln drying is not immune from further infestation, and should be
immediately treated by one of the methods outlined below.
PRESERVATIVE TREATMENT.
For complete protection against Lyctus the wood must be
thoroughly penetrated with a preservative and for this purpose a full
chemical treatment of the sawn boards is usually necessary. Dipping
or brush treatment are measures which will give some temporary
protection to the wood, the degree of protection depending on the size
of the piece, the preservative used and the condition of the timber.,
But as soon as the protective coat is ruptured by planing or resawing
or simply by handling, thb untreated wood is again exposed to attack.
If the wood is already infested this superficial treatment is of little
value since up to date no preservative is known which will penetrate
sufficiently below the surface of the wood to kill all the beetles, larvae
and eggs, except in the case of 1-inch stock, and short pieces of wood
where end penetration plays an important part. The nearest approach







to a satisfactory preservative of this kind is to be found in (a) the
lighter creosotes, (b) mixtures of creosote. and heavy or medium
solvent naphtha or extraction naphtha, whichever is available, (c) a
mixture of 2 parts diesel gas oil and 1 part white spirit, and (d) a
5 per cent. solution of pentachlorophenol in a mixture of equal parts
medium or heavy solvent naphtha or extraction naphtha and diesel
gas oil or in one of the solvent naphthas alone. This last mixture
or extraction naphtha (d) has exceptional penetrating properties, but
must be used with care on account of its very inflammable nature.
Once the naphtha has evaporated there is no further danger.
"The use of mixtures containing solvent extraction naphtha on
parquet flooring is not recommended as the naphtha dissolves the
bitumen in which the blocks are set. In this case heavy and repeated
applications of a mixture of equal parts of paraffin and turpentine
may be advised. As the fumes of heavy solvent naphtha have
caused headache and nausea in some few cases it is as well to keep
rooms well ventilated during treatment and for several hours after-
wards.
Uninfested or sterilized timber previously made up and dipped
in one of the. above mixtures, is very unlikely to be attacked, how-
ever, especially if covered with paint or varnish or a wax polish on
all surfaces, thus closing the pores of the wood and preventing ovi-
positing by the beetle.
The difficulty in this case is to know whether the timber is free
from attack or not and this cannot generally be determined from a
visual examination. The only certain and practical way of sterilising
finished material would be by means of' a heat treatment in a kiln.
SBy a full chemical treatment is meant the immersion of partly
seasoned boards in the preservative, heating to about 1800 F. and
allowing the preservative to cool to about 900 F.
Alternatively the boards may be transferred rapidly in a hot
condition after the heating period to a tank of cold preservative. This
S shortens the total time for treatment considerably.
Recent tests carried out with metallic salts at the Forest Products
Institute on limba indicate that a satisfactory absorption of preser-
vatice can be obtained by means of a two-hours hot and a two-hour
cold treatment.
-The treated timber has, of course, to be redried, but this is a
comparatively rapid process.
In this connection it should be noted that when treating with
water-soluble salts as a result of the tannin contained in many woods
coming into contact with iron either from the tank or from impurities
in preservatives a bluish discolouration appears in the sapwood of
treated boards. If this is to be avoided wooden tanks and copper
heating pipes must be used in conjunction with preservatives con-
forming to certain specifications.
SELECTION OF PRESERVATIVES.
Creosote.-For wood exposed to the elements creosote is most
generally suitable and effective not only against beetle damage but
also against termites and decay. It is also an excellent preservative
for weather boarding, bearers, joists and other similar building
timbers. Since it discolours the wood and remains oily to the touch
for some time,. it is not used for interior work .except for rafters under
thatch. A minimum absorption of 5 lb. per cubic foot of wood is
S generally sufficient but'for special purposes this is increased to 8 lb.
The treatment is improved if from one lb. of fuel oil is added for
every 5 lb. of creosote. Wood treated in this way may be put into the
ground or exposed to the worst possible conditions for decay and
termite and borer attack without ill-effect and may last 20 to 30years
or longer.








Even a dipping treatment of a few minutes in hot creosote for
sterilised wood, affords definite protection against the beetle in the
case of joists and bearers, if they are not afterwards resawn or their
surface is not broken in any way.
Creosote is now manufactured in South Africa and is likelylo be
produced on a considerably larger scale in the near future. It can
be supplied to various standard specifications.
Metallic Salts.-For wood protected from the weather and where
it is desirable to paint, varnish or polish the surface immediately, a
cheaper and yet effective preservative may be found in one of the
water-soluble salts such as borax, boric acid, copper sulphate, zinc
chloride and zinc.sulphate. All of these are toxic to Lyctus, the latter
two having been used for many years in the Union where they are at
present easily available. Tests with borax and boric acid are planned
in the near future but stocks are not available in the Union. Copper
sulphate must be used in wooden tanks with copper heating pipes to
avoid its corrosive action on metals. For permanent protection
against Lyctus a minimum absorption of I lb. of dry salts per
cubic foot or one gallon of 5 per cent. solution is recommended for
both zinc chloride and zinc sulphate.
Pentachlorophenol-solvent Naphtha.-This new mixture was
devised for treating infested timber but it has such remarkably good
penetrative properties that it is highly probable that very good pro-
tection will be conferred on uninfested timber if it is given a 10-
minutes cold dip in this mixture. It must be remembered that
planing or resawing will expose untreated surfaces which should then
be given a brush coating. The mixture recommended is a 5 per cent.
solution of pentachlorophenol in medium or heavy solvent naphtha or
preferably 5 per cent. pentachlorophenol, 45 per cent. solvent naphtha
and 50 per cent. diesel gas oil or 5 per cent pentachlorophenol, 30 per
cent. extraction naphtha and 65 per cent. diesel gas oil.
Much can be done by both exporters and importers in practising
this rapid and comparatively simple process more often. It would
save endless loss and trouble and subsequent confusion.
It is hoped that by the time this article is published considerable
stocks of pentachlorophenol will be in the country. The solvent
naphthas are obtainable from Steel Sales, Escom House, Johannes-
burg, and the diesel gas oil is obtainable from any oil company. The
mixture should not cost more than ls. 9d. to 2s. per gallon.
TREATMENT OF INFESTED TIMBER.
If timber is badly attacked it will show a large number of flight-
holes, small circular apertures from one-sixteenth inch or smaller
for Lyctus, to about one-eighth inch diameter for Bostrichidae. On
opening up the wood in the area affected, it will be found to be
powdered and all such material should be destroyed by burning.
If the number of holes is small and the wood is to all intents still
sound, it may be safely treated by one of'the methods before described
for rough sawn boards.
If the wood is already in position in a building a mixture of
equal parts of heavy or medium solvent naphtha and diesel gas oil
or 2 parts diesel gas oil and 1 part extraction naphtha should be
applied by means of a brush or spray. Unless this mixture is very
liberally applied and the wood completely drenched with the liquid
good results will not be obtained. It should be applied at the rate
of not less than 1 fluid ounce to 1 square foot or 1 gallon to 80 square
feet.
This mixture has been evolved to meet the constant demand for
a highly toxic and non-staining wood insecticide which will not
affect subsequent polishing or staining. This mixture meets all these








requirements and has such excellent penetrative properties that often
-only one application is, necessary for wood 1 inch and less in thick-
ness. .For woods, of greater dimensions -several applications may be
S necessary.
the. addition of 5 per cent. pentachlorophenol to the above
mixtures increases the toxicity of the mixture and affords permanent
protection against further attack. The same results can be obtained
by applying paint, varnish' or a wax polish to the surface after treat-
ment with the naphtha-diesel oil mixture.
Alternative mixtures to the above are (a) a 5 per cent. solution
of paradichlorobenzene in paraffin mixed with an equal volume of
pure spirits of turpentine, or (b) orthbdichlorobenzene used pure or
diluted equal parts with paraffin. These mixtures have not the same
penetrating powers as the above but are given in case the first mixture
is not readily obtainable.
If the infested wood is varnished or painted, the only method of
dealing with the pest is by means of individual treatment of the
flight-holes' with a large hypodermic syringe. One of the above,
mixtures is injected into the flight-holes, both recent and old, with
a large hypodermic syringe, the needle of which is made to project
about one-eighth inch beyond the end of a rubber stopper. The
needle -point is placed in a flight-hole, the rubber pressed firmly
against the wood and as much liquid as possible forced in. The
treatment should be repeated at intervals of two to three days, until
powder no longer exudes. The wood must be kept under observation
for some time, so that any further outbreak can be dealt with without
delay. The flight-holes should be plugged with wax.

THE ANOBIIDAE OR DEATH WATCH-BEETLES.
Abonium Punctatum, DE G.-THE COMMON FURNITURE BEETLE.
Only two members of the family Anobiidae have so far been dis-
covered in South Africa; these are the common furniture beetle,
Anobiun punctatum, and the bark-feeding Anobiid, Ernobius mollis,
L. The latter is of only secondary importance and will not be con-
sidered here.
A. punctatwm is common throughout the world and of all the
furniture beetles causes the greatest damage to wood used inside.
-Up to the present it has been found doing extensive damage to wood-
work of houses in the George, Riversdale and Port Elizabeth districts
of the Cape and has also recently been recorded from the Harrismith
district, Orange Free State. From the nature and extent of the
damage it is apparent that the attacks are of several years standing
and that the insect was introduced into the Union quite a consider-
able time ago.
Unlike the Lyotus beetles, Anobium beetles attack both sapwood
and heartwood, hardwoods as well- as softwoods. Peculiarly, the
beetles do not appear to attack timber freshly seasoned but prefer it
to be some years old. As a result, most damage occurs in private
homes, museums, etc., and in furniture and other warehouses where
wooden articles may be retained over periods of some years, or where
antique furniture is stored. The appearance of holes on the surface
is usually the first sign that the wood is infested.,
S LIFE CYCLE.
The life cycle of A. punctatum is very similar to that of Lyctus
,brunneus. The very small white, oval-shaped eggs are laid in cracks,
in openings between joints, on rough sawn surfaces or in old flight-
holes.







These hatch in from three to four weeks into the larvae.' The
young larva immediately commences to bore into the wood, often
boring its tunnel at an angle to the grain of the wood.
The full-grown larva is white, soft-bodied, curved and wrinkled
and measures about one-quarter inch in length. It has three pairs
of five-jointed legs, and a pair of rudimentary eyes, with whicTi it
cannot see, but which appear to permit it to distinguish the light so
that its borings do not approach too closely to, or break through, the
surface of the wood. (Fig. 19.)



















FIG. 19. Anobium punctatum, De G. Larva and Pupa (larva XI2).

Superficially the larva resembles that of Lyctus but differs from
it in that the large brownish breathing pore spiraclee) near the end of
the body is absent. On the folds of the body are rows of reddish-
brown spinules (hair-like structures). These spinules are absent on
newly hatched grubs, but develop in the later instars. They
apparently assist the larva in its progress through the wood.
The borings of the larva tend to reduce the inside of the wood
to a honeycomb structure, and its work can be distinguished from
that of Lyctus by the' fact that the holes left behind by the grub are' not
tightly packed with dust. The dust also is much coarser than Lyctus
dust, and when rubbed b between the fingers has a distinct granular'
feel as compared with the floury texture of Lyctus dust. It also lies
more freely in the tunnels, and can be displaced relatively more
easily..



pupal stage.
The pupal stage lasts about a month, giving rise to the beetle.
The beetle remains in the pupal chamber until its body hasof
become firm and hard, when it immediately commences to bore its
way out of the wood. The emergence holes are from one-thirty-second
to one-slxteenth inch in diameter, and in appearance are similar to
Lyctus holes. The beetle is of small site, usually from one-tenth to
one-quarter inch in length. It is elongated, more or less cylindrical
one-quarter inch in length. It is elongated, more or less cylindrical







in shape and, compared with the Lyctus, its body is shorter in pro-
portion to its width. The colour varies from red brown to dark brown.
The appearance of the body is characteristic, the head being more or
less withdrawn inside a hood or cowl-shaped thorax. The head is
provided with a pair of antennae or feelers, the last three joints of
which are much enlarged. The wing-covers appear striped, due to
more or less parallel lines running lengthwise along the body and
consisting of fine pits or punctures. (Fig. 20.)






/ 1 d



















FIG. 20. Anobium punctatum, De G. X12.

The time from the laying of the egg to that of the emergence of
the beetle and its subsequent egg laying is normally one year, and
seldom appears to be less even in heated buildings. Sometimes, how-
ever, the complete life cycle may take two years or more.
The beetles emerge principally in spring and early summer,
and may be found from October to January. They can fly consider-
able distances, and it is possible, therefore, for an infestation to
spread rapidly over a large area. They are most active at dusk and
during the night.
TIMBER ATTACKED A14D CONDITIONS FAVOURIABLE FOR ATTACK.
For preference, Anobium attacks wood which has been in use and
seasoned for some years, and timber which has been free from attack
) -for twenty or thirty years may suddenly be extensively infested.
.Unlike Lyctus, Anobium attacks both the sapwood and heartwood.
Where both sapwood and heartwood are present, attack is at first con-
fined to the sapwood, but the infestation soon spreads to the heart-
wood, which may become extensively damaged.







The articles attacked vary from flooring boards and building
construction timber to the finest of furniture. Large numbers of
European and American timbers are susceptible to attack, and the
common furniture woods such as oak, beech, birch, walnut and maple
are often badly attacked, as are also various pines and spruces.

As Anobium prefers old seasoned timber, old furniture stores
may often contain infested articles. The infestation rapidly spreads
to other articles in the store and distribution of these to places pre-
viously free is probably a very common method of spreading the
insect.


Iw *'Kt:?;~*
6... ~r. ~ Mn ff2F.I~i .1r


FiG. 21. Showing Exit Holes made by emerging Adults of A. punwatum. Natural size.

Generally, once attack starts, Anobiumi causes more damage than
Lyctus which, as previously mentioned, confines its attack to the
sapwood only. The article attacked is reduced in value, and as attack
increases with length of time, the article may eventually be destroyed
or rendered worthless if no remedial measures are taken. (Figs.
21 and 22.)




































































Ie. 22. Showing Damage to Wood by A. p2nctatum. Top-Damage with the grain.
Bottom-damage across the grain. Note honeycomb-like appearance of the
Wood. Natural size.







METHODS OF CONTROL AND ERADICATION-
For methods of control and eradication the reader is referred to
the measures advocated for Lyctus beetles which will apply equally
well for this insect.
The presence of this Anobiid, widely spread throughout the
Union, must be viewed with great concern. It is one of the most
serious pests of woodwork in houses and if its ravages are allowed to
go unchecked, it will cause untold damage.
Its presence should be an added incentive to building contractors
and house-owners to demand and to use only treated wood.

(4) THE EUROPEAN HOUSE BORER-HYLOTRUPES
BAJULUS L.
The long-horn beetles (family Cerambycidae) normally attack
only green timber, but there are a few exceptions to this general
rule. Of these, the most important is the European house borer,
Hylotrupes bajulus.
This beetle, which has popularly become known as the Italian
beetle in this country, is a native of Europe and is found in all
northern European countries, particularly those round the Baltic
Sea, where it is of considerable economic importance. It has also
been recorded from Russia, France, Spain, Turkey and North and
South America.
The destructiveness of this pest in Europe is well illustrated by
the following reports culled from the literature on the subject. The
final statistics of a survey of buildings in Germany discussed at a
meeting in Berlin on 27th June, 1938, of the Association for the
Scientific Advancement of Measures against H. bajulus, showed that
infestation by this Cerambycid was even more widespread than had
been feared by experts. Infestation was recorded in 54,957 or 41-46
per cent. of the 132,377 buildings examined, and the percentage in
some regions was 70 to 80. In about 33,000 buildings, large portions
of the structural work were threatened.
In May, 1938, another official survey of about 140,000 buildings
in Germany showed that H. bajulus occurs in the attics of about 40
per cent. of all German houses.
In an investigation in Stockholm, 195 of 340 houses were
infested.
In Copenhagen and its surroundings more than ten churches,
several factories and 1,000 houses have been infested; in some cases
the roofs have been in danger of falling in.
HISTORY IN SOUTH AFRICA.
About 10 years ago a single specimen of H. bajulus emerged
from a floor of a house in Claremont. Remedial measures were
advised and as no further report of damage was received, it was
concluded that this was an isolated infestation which had been
eradicated.
In 1941 the beetle was found doing extensive damage to a school
in Port Elizabeth; doors, window frames, window sills, door jambs
and even kitchen tables in daily use had all collapsed or were on the
point of collapsing. A few months later it was discovered in a large
advertisement hoarding and a pine paling fence in close proximity to
the school. An intensive survey was then made and the beetle was
discovered breeding actively at ten further points. These included a
grand stand and several pine fences, pergolas and palm houses in the
city parks as well as in the basement of another school. Since then
two houses have been found badly infested.







From the evidence there can be no doubt that it is widely dis-
Stributed through Port. Elizabeth and reports of further cases of
damage to buildings and houses can be expected in the future.
In March, 1943, the roofs of two houses in Cape Town were
discovered to be so heavily infested as to have almost reached the
collapsing stage. Further investigation in this city has revealed an
appalling state of affairs. Several scores of houses and building in
the southern .suburbs have been found infested to a greater or lesser
degree. This is not all, however; Hylotrupes has been found actively
breeding in old stumps and logs in the pine forests on the slopes of
Table Mountain and the Cape Flats and even in dead branches high
up on living trees. It has also been found breeding in pine slab and
pine pole fences. The survey is still continuing and new infesta-
tions are of almost daily occurrence, so that the total area infested
cannot as yet be demarcated -but up to the time of writing it includes
the greater portion of the southern suburbs.
From the area and the intensity of the infestation it is apparent
that the insect was introduced into Cape Town many years ago,
probably fifty or more. This idea is -confirmed by reports of roofs
having had to be replaced in the past because of what was then
attributed to dry rot ".
That its presence has not been detected before may be ascribed to
ignorance of the presence and potentialities of this insect.
Recently is has also been discovered in a wooden tower on the
roof of a church in Tlittnhage.
LIFE CYCLE.
As the discovery of H. bajulus in South Africa is of recent date,
much -investigational work still remains to be done. A certain amount
of information and facts have already been obtained, however, and
these are given below.
The beetles vary considerably in size, ranging from half to one
inch in length, the females usually being larger than the males and
further distinguished by the presence of a short tubular ovipositor
proiectin- behind the wing covers. The mature beetles are black,
but .thick grey- pubescence covers most of the prothorax and forms
four, spots on each wing-cover; these spots may, however, become
fused so as to give' rise to two transverse grey bands. The antennae
are about one-half the length of the insect and are relatively slightly
longer in the male than in the female. A very characteristic feature
of HyTotralie.s is the presence upon the prothorax of two smooth,
shniing blar k prominences, one on either side of the median dorsal
line. (Fig. 23.)
The adults pair shortly after they emerge from the wood and
after a day or two the females start ovipositing. The active life of
the male lasts from 7 to 44 days with an average of 17-4 days, and
the females from 7 to 60 days, with an average of 26-2. The beetles
are very active and strong fliers, but tend to hide away during the
day. The period of greatest activity is probably at dusk but this
point has not yet been established.
Over4sas workers state that the eggs are laid; often singly, in
cracks and erevires of the wood. Beetles up to the present have only
been studied in captivity in this country, and these laid eggs in com-
paratively iar,'e fanshaped batches anywhere oh the surface of the
wood, as well as in vra,-ks and crevices in the wood. There is a great
divergence of opinion as to the total number of eggs laid by a single
female, the number given by various workers varying from 40 to 300,
the average varying from 63 to 105. The females may oviposit one to







seven times, usually one to three, the usual period between successive
oviposition being two to three days. The males usually preponderate
slightly in numbers and mating takes place more than once.


FIG. 23. The European House Borer, Hylotrupes bajulus, L. Adult X4. Larva X2j.

The eggs are white .and semi-opaque, flat and mussel-shell-
shaped in appearance and measure from 1 to 2 nmm. The incubap-
tion periods depend largely on temperature and may take from 6 to
19 days.
The small larvae which hatch out of the eggs may crawl about
the timber before boring in, but usually they commence to-bore in
immediately, and continue to live in the wood for several years. The
larvae are typical long-horn grubs, white, fleshy, somewhat flattened
above and below, having the legs. but slightly developed, and when
full-grown attaining a length of j to 1 inches. The head is sunk in
the prothorax so that only the brown mouthparts are visible and has
on either side three very small ocelli which are characteristic of this
genus.





31

There appears to be a great variation in the length of the larval
period which for overseas conditions is given as varying from 2 to 17
years. Here in South Africa, observations indicate that out-of-doors
they take about 2 to 3 years to mature, while indoors the period is
somewhat longer, possibly 3 to 6 years. The development of the
larva is particularly influenced by temperature and humidity;
,moderately high temperatures and high humidity being particularly
favourable.
Only. coniferous timbers are attacked and the larvae usually bore
into the sapwood and avoid the heartwood although it is not immune,
The larvae destroy the wood so thoroughly as to threaten the very
existence of the buildings involved. Their tunnels extend in the
sapwood up to just beneath the surface, a skin about J mm. thick
being left, and the interior of the wood being rendered spongy in
appearance. Sawdust falls to the outside only now and then; usually
there is no sign of the damage being done until the wood has reached
collapsing point. (Fig. 24.)


FiG. 24. Damage by H, bajdlua to structural Roof Pine Timber. Xi.







When mature, the larvae bore to a point just beneath the surface
and then turn back and pupate at some depth. Pupation usually
occurs in the spring but sometimes in autumn or winter. If pupa-
tion takes place in the spring, the pupal period lasts only about three
weeks, after which the adults emerge and gnaw through the thin
surface left by the larvae.
Beetles start emerging from the wood in October and continue
to emerge in great numbers during November and December. These
three months are the period of greatest emergence but stragglers
probably continue to emerge throughout the summer. (Fig. 25.)


FIG. 25. Damage to Pine Fence Pole by H. bajulus. Note exit holes. X.

The beetle, in emerging, cuts an oval-shaped emergence-hole
which, due to the great variation in the size of the beetle, varies
considerably in size. On the average it measures about one-quarter
by one-sixteenth inch. The number of exit-holes made by the young
beetles affords little indication, however, of the severity of the
infestation, as several adults often emerge from the same hole. The
appearance of exit holes in the wood is often, though, the first indica-
tion of the presence of the insects. As previously mentioned, the


N(







beetles are strong fliers and can' thus disperse widely and rapidly
over any given area.
NATURE OF ATTACK AND ITS IMPLICATIONS.
As stated above, Hylotrupes attacks only coniferous timber,
particularly pines and spruces; there is no evidence to show that
hardwoods have ever been attacked. All locally grown pine timber
is probably susceptible; so far the following species have been found
attacked: Pinus canariensis, Pinus halepensis, Pinus insignis, Pinus
pinaster and Pinus pinea. Oregon pine or Douglas Fir appears to be
immune for it has never been found attacked although frequently
deal timbers in the same roof have been heavily infested.
Susceptibility tests with this and other selected wood species are now
under way.
The larvae destroy'the sapwood from the time of felling to long
after the timber has been seasoned and used.
In Europe Hylotrupes confines its attack to the roof timbers of
houses, and very rarely attacks interior woodwork or furniture. There
are records of its breeding out-of-doors, however, in telegraph poles
and pine fences.
In South Africa, while it does seem to prefer to attack roof
timbers, its attack is by no means confined to them for it 'readily
attacks flooring, doors, windows, picture rails, and even furniture
made of deal "..
Referring to its attack in roofs, an interesting theory is put
forward by Danish workers. Although it has been known in
Denmark since 1763, Hylotrupes has become a serious pest in
buildings during the past thirty years only, owing, it is believed to
the use of slates for roofing. Prior to 1875, all houses with roofs of
straw, wood or burnt tiles, all poor conductors of heat, and with the
last two, attics were sufficiently moist to prevent the timber from
developing cracks. With slates, the attics become very hot in
summer, and this shortens the larval period of H. bajulus, which
also finds the cracks very suitable for oviposition. Infestation
develops quickly under a slate roof and new breeding places are
constantly sought, whereas there are tiled houses in which H. bajults
has been present for a great number of years, and only a little of the
timber has required replacing.
This point is mentioned here because in South Africa the exact
opposite seems to be th'e case. Hylotrupes has been found mainly
under tiled, thatched or shingled roofs; in only one or two cases have
the roofs been of iron. It is possible that in our much hotter climate
temperatures under iron roofs become too high for the borer and that
in this country optimum conditions for development may exist under
a roof with material which is a poor conductor of heat such as tiles
or thatch.
In Cape Town and Port Elizabeth Hylotrupes breeds as readily
out-of-doors as indoors. It attacks stumps and logs and dead branches
on living trees in the forest and pine pole and slab fences within the
city limits. It would seem that such wood is attacked almost imme-
diately after felling and give rise to two to three generations of
beetles before becoming too rotten for breeding purposes.
This fact not only complicates and aggravates the whole problem
of control,, but also makes the task of eradication a hopeless one.
The -position at Cape Town particularly is most serious and compli-
cated. Hylotrupes is actively at work over a large area of the pine
forests on the slopes of Table Mountain and the Cape Flats, and while
every effort will be -made to do away with breeding material such as
logs and small branches, the. task of clearing the whole area -of
2





34


stumps and dead branches on living trees is an impossible one, and
thus material will always remain as food for the beetle.
Further, householders have at their very doors ideal breeding
material in the shape of pine fences which have been found literally
riddled by the insect in the southern suburbs. The number of beetles
which can emerge from such fences is enormous; 180 beetles emerged
in the laboratory from a pine pole 4 feet long and 4 inches
in diameter. The solution as far as these fences go, lies in the hands
of the public; they must either stop using them or insist on the wood
being treated.
These few facts should be sufficient to indicate that while much
can be done to limit the breeding points of the beetle out-of-doors,
these cannot be entirely eliminated and that the threat to houses from
beetles breeding in outside material will always be present.
There still remains, of course, the danger of beetles breeding
indoors and spreading from house to house and this applies to all
centres where Hylotrupes is at work. It must be realized, therefore,
that the solution of the whole problem boils down to one of house
protection for such houses which have not been invaded, and eradica-
tion and future protection for houses already infested. It is here that
the active co-operation and support of the public is needed. Every
man's house is his castle and it is by no means the wish of the Depart-
ment to interfere with this right by promulgating and enforcing
onerous regulations, such as official inspection of houses and enforce-
ment of control measures, but the situation is most serious and unless
every householder is prepared to safeguard his own as well as his
neighbour's property, such regulations will. doubtless have to be
enacted.
Co-operation by the house-owner is not sufficient, however;
timber merchants and suppliers, particularly those handling pine
structural timbers and pine slabs and poles for fences must realise
that, unless they are prepared to treat timber, they are merely adding
fuel to the fire; architects, building societies, municipalities and all
associations, institutes and bodies connected with the building trade
should specify and insist on the use of only treated wood in all future
building programmes. The use of treated timber only for all
building purposes in the future will have to be enforced unless the
co-operation of all concerned make this unnecessary.
Another aspect must be mentioned here and that is the danger of
Hylotrupes spreading to other centres. It is known to be present only
in Cape Town, Port Elizabeth and Uitenhage and a recent Union-
wide survey has failed to reveal its presence anywhere else. So far
as can be ascertained, the optimum conditions for this borer are
moderate temperatures with consistently high atmospheric humidities.
The moisture content of the timber is, of course, largely dependent
upon the humidity of the air. High atmospheric humidity, such as
prevails in the coastal areas, prevents timber drying out beyond a
point where it becomes unsuitable for larval development. Its effect
upon the eggs is also very pronounced; humidities from 50 per cent.
upward are generally favourable, but at 28 to 36 per cent. there is a
large mortality in the egg stage and at 18 per cent. the mortality is
very high. It seems probable, therefore, that. Hylotrupes will not
readily establish itself outside the coastal belt, on accountof the high
temperatures and low humidities which it will encounter. Experi-
ments are now under way to prove this point, and if it should be
found that the borer can exist in inland centres, as Johannesburg and
Pretoria, control on pine timber traffic from the infested areas to
inland centres will probably become necessary.








PREVENTIVE AND CONTROL MEASURES.
(a) Out-of-Doors.
(1) In Plantations.-As Hylotrupes breeds readily in pine
plantations in stumps, logs and general debris, every effort should be
made to keep pine plantations in close proximity to cities as clean as
possible. Timber which is not of merchantable size should be sold
as firewood or otherwise disposed of. In felling operations trees
should be sawn or cut as close to the ground as possible so as to leave
the smallest possible amount of stump above ground. Drenching
stumps with creosote, tar, crank-case, oil, etc., would undoubtedly
prevent ovipositipn by the beetle, but it is doubtful if this will prove
,either economical or feasible from a management point of view.
(2) Pine Fences.-On no account should untreated pine fences
-erected in the infested areas. Fences already erected and known
to be free of borer, should immediately be given a thorough brush
treatment with creosote, which should be repeated at four-yearly
intervals. Infested fences should be immediately removed and burnt.
A11 pine fences should be inspected immediately.
(b) Indoors.
It must be emphasized that the control of H. bajulus in timber
in buildings is an extremely difficult matter. To commence with,
it is almost impossible to detect the presence of the insect in timber
in the early stages of the attack as the larva generally throws out no
frass but packs the digested wood in the burrow behind as it pro-
gresses through the wood. In certain cases, however, careful inspec-
tion may reveal what appears to be a slight corrugation on the surface
of the wood caused by the yielding of the fine layer of wood over a
very superficial boring. The presence of flight-holes is a sure indica-
tion of the presence of the borer.
,Heat treatment by means of specially devised machines which is
very effective; in Europe is being experimented with in this country,
Sbut there are so many practical difficulties with the, type of house
built in South Africa that this method at the moment does not hold
out too much promise.
Should heat treatment prove effective and 100 per cent.
sterilisation of infested wood in a roof be obtained, such sterilised
timber would still be liable to reinfestation and the subsequent treat-
ment of all roof timbers with some toxic preparation is indicated.
'If the heat treatment should prove impracticable, all that can
then be done is to remove all timbers showing signs of infestation or
-suspected of being infested, replacement with treated timber, and the
thorough treatment of all roof timbers with a toxic preparation.
The question not only of a toxic chemical which will protect the
wbod from further attack but also of a solvent and penetrant which
will carry such a chemical well into the tissues of the wood is, there-
fore, of the utmost importance. Pending the results of further inves-
tigations, the Division of Entomology has been recommending the
thorough. treatment of all timbers, either by means of a brush or
pressure sprayer, with one of two mixtures.
(a) 50 per cent. creosote plus 50 per cent. heavy solvent naphtha.
It is hoped to substitute this mixture with (b) 50 per cent. diesel
gas oil plus 45 per cent. heavy solvent naphtha plus 5 per cent. penta-
chlorophenol, when expected shipments of pentachlorophenol arrive.
Unfortunately several practical difficulties in' the use of heavy
solvent naphtha have arisen. Brush coating of all timbers in a roof
ILas been found to be impracticable and ineffective and, therefore,
. 3








pressure spraying only has had to be resorted to. Using this method
the fumes of the heavy solvent naphtha have proved noxious not only
to the operators but in some cases to the inmates of the house. This
is most unfortunate,'as the solvent naphtha is a material with excep-
tional powers of penetration and on this account its use in the penta-
chloroph'enol mixture was much to be desired. For the present,
however, its use has been discontinued, but where operators can be
properly protected against the fumes and where the inmates can
vacate the house during and for several hours after treatment, or in
untenanted buildings, its use is still to be recommended.
There is no reason at all, however, why mixture (a) or (b) cannot
be used for treatment of wood before such wood is put into a building-
As both medium and heavy solvent naphtha are now in short supply,
the following mixture is now recommended: 5 per cent. pentachloro-
phenol in a mixture of 2 parts diesel gas oil and 1 part extraction
naphtha. This mixture is inflammable. All mixtures containing
solvent naphtha are inflammable and the necessary fire precautions
should be taken. As soon as the solvent naphtha has evaporated,
there is no further danger.
For use in roofs the following mixture has temporarily been
substituted for mixture (a): (c) 70 per cent. creosote plus 30 per cent.
diesel gas oil. Owing, however, to its poor powers of penetration and
the staining property of the creosote, this mixture has not given
satisfactory results.
At the time of writing, therefore, the question of treatment of
roofs timbers in situ remains unsettled, but with thearrival of penta-
chlorophenol (stocks should be available by the time this article is
published) undoubtedly comparatively innocuous and non-staining
mixtures will have been devised, for investigations on other less
noxious solvents and penetrants are being intensified.
For the present where roofs are found infested, the following
action is advised:--
(1) Remove all heavily infested timber and replace with timber
treated with mixtures (a) or (b) or with some standard
preservative.
(2) Lightly infested timber should be thoroughly scraped and
the larvae removed by cutting out the infested parts.
(3) Thorough treatment of all timbers with mixture (c).
(4) The timbers should be inspected every six months there-
after for signs of further activity.
PRESERVATIVE TREATMENT OF TIMBER FOR REPLACEMENTS OR FOR
NEW BUILDINGS.
Timber fully treated as described previously in this bulletin
under the heading Lyctus-Powder-Post Beetles, i.e., creosote or
metallic salts, is perfectly safe against attack by Hylotrupes whether
it is previously infested or not. Roofing timber may be given a
creosote treatment but for interior woodwork or wood which is to be
painted a treatment in metallic salt such as zinc chloride is recom-
mended. If the wood has been sterilised in a kiln a good dipping
treatment in the pentachlorophenol-solvent naphtha mixture would
be of value.
It must again be stressed here that unless the use of treated wood
for building purposes is made a standard specification for all future
constructional work, regulations enforcing such a measure will have
to be created and enforced.







CONCLUSIONS.
Woods susceptible, to Lyctus and Hylotrupes should, in general,
be treated as near the source of supply as possible. Not only would
this mean reduction in costs due to mass production but it would
minimise the risk of infestation and of untreated material getting
through. It would obviously be better for saw-millers to supply the
treated material than for a number of wholesalers or a still greater
number of distributors to have to put up plants for the purpose.
It is a short-sighted policy for suppliers to adopt the attitude
that so long as the wood leaves the saw-mills free of attack, it does
not matter to them what happens afterwards. Treatment should be
sufficiently thorough to ensure that any subsequent sawing or planing
does not expose untreated wood. It follows that it would be best to
supply consignments in boards as near the thickness in which they are
to be used as possible. This is, of course, sometimes difficult to do
and may mean an increase in the price, but it has many obvious
advantages such as shorter time required for drying, more thorough
treatment and often less wastage.
Local merchants could, however, avoid much trouble for them-
selves and householders if they adopted the necessary simple precau-
tions and generally gave timber more careful inspection.
Of the various insects mentioned in this paper the most impor-
tant at the present time is Lyctus brunneus. Hylotrupes bajulus,
although of very considerable potential danger, is as yet restricted in
its operations, while the pinhole borers and Bostrichids are of .minor
importance.
In conclusion is may be said that the Government is very much
alive to the dangers of insect attack in timber and is especially con-
cerned with preventive treatment. As already inentioned, the
question of Lyctus attack in Central African timbers'has already been
discussed with the Belgian, French and Portuguese authorities and
it is hoped that the danger from this source will soon be done away
with.
With'regard to the domestic situation, the position is being care-
fully watched and all possible steps are and will be taken to cope with
the problem.
Further tests are being undertaken at the Forest Products
Institute and by the Division of Entomolcgy to prove the value of
many proprietary and other preservatives and to improve, if possible,
the methods already in use against all destructive agencies.
Promising results have been obtained in many cases but the thorough
testing of new ,preservatives without which none can be confidently
recommended unfortunately takes a considerable time.
If in the meantime the methods and recommendations suggested
for the prevention and control of the pests mentioned are adopted,
this will go a long way to eradicating the trouble.
Municipalities, architects, building societies, saw-millers, timber
merchants and the general public are urged to co-operate in seeing
that these recommendations are put into effect.




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