Preparations for winter fumigation for the citrus white fly


Material Information

Preparations for winter fumigation for the citrus white fly
Physical Description:
Morrill, A. W ( Austin Winfield ), 1880-
Yothers, W. W ( William Walter ), 1879- ( joint author )
Government Printing Office ( Washington, D.C )
Publication Date:

Record Information

Rights Management:
All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 29649746
oclc - 27899729
System ID:

Full Text


United Staite' 1, IclC f irfjuturc,
L. 0. HOWAHI Lioi.r,,i *o: and Chwe f Hurau.

By A. \\. NI it i mi I \k 'I < YUIIIII ,
I \ il~l >l ll I !< l i\ .

As at result of invii.le-tiLliiiii- conducted Iny the P1ii ri ,,f Ento-
nimoliiy luring Hli- pii-( three yiiar-, I'lriii1nii1i'ii for t he citrus white
fly has been phliw-d upon a priit i,.ul li,.i-i. and the ri ,,- has been
6< siinplified that 1ny citrus grim.r" ca-n undertake the trea Imnnt of
his grole .ithl ltn driprndiiiug upon experienced friii-n ilrs to con-
duct the iperation-. i. I'nder preeiit cndildions i iini.,iiiLli,,ii is the
most sattisfi(ictor\ arid profitable iii,.liid 'If contr,,llini'- the I white l1Y
in hundreds of infested -r,,vvs in the ( il if coai-- i r-lI r, i',' iii r I, .'in ,-
alnd its usfuilness will h1b extelnd,,l to niea'l\ ail l liii \r'
when the practical ri'roiiiniendlii fill, in N f,,ill I,'.,,iiuiLi- Iiillli l ii
the wliite flyv have been put into fir. ['li T.ii[>,.rir c'ii\iiin Jf
Floriila cilirus fruit, when grown in L.''e- tr,,,r ftrin injuiir fr ,'-ii
insect pest- aind the iiwikcnin- of iir,-',.--i e -,rI",T- i., tin wiirc--
sity for ,rgauiziti0,ion- for (oiii' itniiin~ sin ect '.-I :iuil f,,r niiirk' lin-
the fruit point to the general adoption of Ill,, iNiIri I e.:n-ilir. to
be recommend ndedl in the puiihlica ion referred i,.
At the present time the aiutliors wild reuiiiimniid f iu uii fuir
the white llv under tlit, fIloi,\ini circiilii-liai v- Ill n u.r,\u i,-i.'iii
b% a dlistiince of at least 2'( viyards from aill ,ilir ilifT st,',l r 'rr ,-,
in citrus groves 4or inii fi rlis-rI,\% in- sections i i in NIc W hit, ll\ liN :i
recently appenarid and is still of ihitned ili-trilvi:n i.ii.;il in -,ciii
wluere cooperation Can be secured iiil ,ii- rr" in iiinitiiruill i.-vI.Iiil
groups. In mianyv leases t owner ,f an .\lliii\v M ildi N',llileh
grove which is isolated except for a small ,'r,\,,f ai f,,\ ,,.re, fromi
other infested ,.rves cain wll afford t ai la ii-n hi, iiiipenl. or. if
necessary, fuiiiniatt the nelilghlolr-i ri , tirIn .at hii-'i, n i exIp n...,
.' F.x rience *- l'.ir ha -hiwni th.iIr a a riulb ill .i- .l i. .ri 1 11ii, ii ~,i -- 4i ril
fumiluation c Ibe pra Ii r.i d without ir-1 ii, r-, -l 'l.ii.l # Ihrn, hi.
migrali in of i.di1r I -
937- ci r. II --4,9
.... -

rather than to permit the presence of such grove to interfere with
his results.
Full directions concerning equipment, chemicals, and methods of
procedure in inmigat iig for the citrus white fly have been publihlied
in a bulletin of this Bureau.a This bulletin is based upon results
obtained in January and February, 1907. Extensive field experi-
ments have been conducted (during the last two seasons and the
additional results obtained will be embodied in a supl)pleentary
report now in preparation by the authors of this circular. It is
hoped that before the bIeginning of the next fumigating season,
extending from December 1 to March 1, a publication in the Farmers'
Bulletin series of this Department will be available. This bulletin
will contain only such advice and directions as are of practical
importance in fumigation work against the white fly, limitingg the
details of experiments published elsewhere as the necessary basis
for establishing practical conclusions. The present circular aims to
call attention to the desirability and in most cases necessity for
early preparations where fumigatioff work is planned for the coming g
winter season; also to give full directions for such preparations.

Orders for tents should be placed as soon as possible after it is
decided to fumigate a grove. Tent makers do not always have on
hand a sufficient quantity of desirable grades of canvas to fill large
orders. Delays in filling the order may necessitate shipment by
express, at a cost several times the expense of shipment by freight.
The first step is the determining of the sizes of tents required. It
is a more common mistake to underestimate the size of a tent required
than to overestimate it. Some allowance should be made for the
growth of trees, in consideration of the future use of the tents. If
the trees are nearly uniform in size, the largest trees should be selected
for osiurinrg. A tape measure attached to a reel is used in meas-
uring trees to determine the size of tent required. Standing a few
feet from the outside branches of the tree to be measured, enough
of the tape is unreeled to extend over the top of the tree and about
half way to the ground on the other side, the free end of the tape is
held in one hand and the reel is thrown over the center of the tree
and unreels the tape by its own weight until it reaches the ground.
Two or three attempts may be necessary in order to have the tape
pass over the center of the tree. It should be borne in mind that the
weight of the tent will reduce the extreme height of the tree and that
a Bul. 76, Bur. Ent., U. S. D>-l. .\k.'r Fumigation for the Citrus White Fly as
adapted to Florida conditions. By A. W. Avorrill.
[dCir. 111]

it is tli 1-f1,, unne essary f ir t ihe tale I\ p..-- o-er the li-.-i. -t t ._'-.
"11Ir Iii' I ., tt I '( t 0t -iih I e ad) l d etdI tI Iti Il(llll f of feet I l
thle top i"1 the trlee, as sho n In ie Ii* il i wr m iit t, 1i1l fte tllt ni
4 to 6 ) ',', I shoI ld ln added. In ','I" ii. j I'r+ fI 111 t 4) 1.+5 fet
liili rei1 uire teiit' hl weeni if nt ; I fe,(i in ize": t res fron I I I'11,1
l'l-t II: i' 1 iquirc t1i 1 t > feel in siz,: trI'uI I 21 to 25 feet hIugh
r,.,1lin> t,'le ts i-ii t 7i feet in sitt': hnlu tlIse?1 2 to I11 fet4t li .i r(I( ire<
tents TI to 7'; fet in si..
Ill i,... ,,I to tin, n mini elMr of t its rp(|inri'(l, it is sufe l,) "touiiiut,
* tha it with ie trent fulr ei(h! fi ) t1re s th1* o1rlk- of ,iiii ., c iI <(u Ild
be (omph1ted i ten to four- _Itt'__
ten 1i i. I ,I Iork. (woe ,,,,+ '

fmat't ill sise ah smaller, aoiil--
fr~ i,_. t tit l te t G

so spaced as to oo~ inte iinter-
fiani e, ith the l- oif k t| f *hift i
In.ii the tent .
id' iign't decidedI upon the
Staiui ulor a n yd iz lts lif theste t is tr el
f t~ll t'd t~d I h I uhi 5
fl ie I as soI A( II I ... l I,,

should be obtained ti,,ri tent
tdi lu iitiauo makers s idho are
Sa 1osit ion to furnih the 11
t Int.-. Si l sez Iction of t ent 1
tnerial is a t ntter of I 47 .i e itiep _.A euto
In k IIrIi p t (I krituII
etn I be (.)I I ,t'12(lftl v inI

r*eg. (t to fi'.Jtiii-s i t the ,',' T.I ,I t ttilac tii v ha t ,-le l ,,. of
imltr' '> i,,it-i., to diret of 1ass of lhigh t x h n h ld i et .en th- e e and
tha sun, or aniy 1rigl t light. Neither of th, methls i entirely
s;tn t, v howi ever, in sfhcl i m,+u riil for f,,ni-..,iiI,. tents.
\Vithi a slihnlbihar .ll'lgelaiaemlt lldevbise b~y the authoiNs for te-I ill. the
tight n,.-+ of material submit ted to the halorhtorv ait ( )rha anlo, Fla., for
ex,,nit I t I i,, it has been found that sactihvs of ,luck r trv nI Irl j0
per cent in their ',,,, ,:trative I. :t i--, ....
regure illustrates tl o extreme samples of s-oln(e duck hinh
ditrt,, to the extent of 47 wer cent in this respect. As a result of
aTHe size of tents isexpreed in terMn el the all ta w, i-utw unrlel c-ids u11
t ae Simp, ile sheet of canvas of whiYch thoe tent is., i...... I
cUk. 1111

the examinations made so far, the authors strongly advise against
the use (of drills of ;inY kind. Thie ipl;i'rIni.e of these is much more
ii.oh.;iiiig than that of clucks, and it seems impossible to estimate
their comparative tightness except by tests with special apparatus.
Our experience up to the present time leads us to reconimend closely
woven (luck we ighing 8 ounces per yard, when 281 or 29 inches wide,
or about 10 ounces per yard when the material is :3 inches wide.
The more expensive grades of cloth are not always the most nearly
gastight. In the case of two leading concerns which have supplied
large orders of tents for use in Florida, the medium grades of mate-
rial, as shown by the prices quoted, have been found to be superior
in gas-i,,hiling qualities to either the cheapest or the most expensive
of the three grades upon which prices were quoted.
The form of cover which is at present almost exclusively employed
is the flat octagon. Frequently those who have never seen a tent of
this kind fail to realize its simplicity. A square piece of canvas
would answer the purpose as well as the octagon, but to save material
and the lhndtling of extra cloth the corners of the square are left off.
A perfectly circular cover would be more economical in respect to the
amount of cloth required, but the saving would not cover the extra
expense of construction in this form.
For specifications tentmakers may be referred to Bulletin 76 of
this bureau.a In general these specifications are simply that the
form is approximately octagonal, of anmy desired size, made of par-
allel strips of goods overlapped three-eighths or one-half inch,
double stitched, and all raw edges hemmed. In the case of tents
50 feet or more in size a reinforcement is desirable across the middle
section near each end, as described in the bulletin referred to. It is
desirable that allowances be made for shrinkage, otherwise a tent
after becoming wet and later drying may not be sufficiently large to
cover trees of the size for which it was intended. The following
published statement by the senior author is of importance in this
connection and is quoted in full:b
Shrinkage of the goods after being thoruuhly wet is an important consideration in
the economical construction of fiiinigating tents. In order that the tents approxi-
mate a r, .ul., r octagon, after having been used for fumigating purposes, it is necessary
either to have the goods thoroughly shrunk bl1wf,,re 'utting or to make allowance for
subsequent -hrintka.e by cutting the strips lng,''r. A test made with a brand of
8-ounce duck commonly used in California for fumigating tents showed that the shrink-
age lengthwise of the goods amounted to 7.5 per cent and crosswise 0.9 per cent.
This means that in a 1O0-,i,,t tent the shrinkage would result in the full-lenath strips
shortening 31 feet, while the tent would shrink less than 6in, h<'r,-.wi-e of thestrips.
Such irr..,ul.irii might be remedied by a skirt of 6-ounce drill, but it is simpler to
a For sale by the Superintendent of Documents, Government Prinling Office,
\\,-,iiiiL'in. 1). C. Price, 15cents.
b Bul. 76, Bur. Ent., U. S. Dept. k-,r pp. 17-IS
[Cir. 111]

IA ln to have ecm h -I rip ilt hr 1, r I,? a j i i, l lu i i iil ,tutm :" r ceL.t I, ILi. r. ,..
lit the I. ,,- h ir -%% mul wiw w lriika II tI + h. n-++'rr.++l t+ ulmv- tIin *I ,,. I
,ii'e iw 6 6 p +r i l amIl eahII jI r i ,t ri Iri 'f it.tan t ii, i I I ; f I U tn' +++ A
.",4l it,'t.. tent f++itiriirtrdc+ in this- ltiitittfr wou+ld tihT i.rlor niit~rixi h.,+r|'i +rr h nk w
.21 feet (19 I eft I ,t irar ++I I I: I I t i in lo h n. 1.thwtit r +Is th + ++tri, tlr ili tr
,iiilt,' section, andi -1t f' t I ,'. i hiIt, n' rrn wi r+ i ti + the 'ri. A t+r Ihriir kiii the
,~lliii'h l,,ll- W hllll I t'q ai~l roxillttfly 4 + t I i ch ih I I h dir. tilt
On atcc unI t ,, tlt< variation in tIi<, >h: iil,.,.'c f .liil,',,'i, l)rnnIs of
(lurk it is necessary to test the crt-osswise it'l i, I.'1li-, thi sltiiiik.i,: inll
t.Oi sanmpile selttUtl. TVlis Imiy lIt I"ne liy nu, ii\,\.:. witi a lead
Iwncil, lihws 1 foot or IniOw in ,ii.tlh, kith ctroswise and Ii,_th-
wise if tlihe strip of L('>*,I Tlhe saminpilfe should be shiirunken \i,,
rech time etillin-. by -iil'miim.'iii.: inl water for two or three hours
and dvlinlg in the Stillu. "I' alnltnt of the l hil.. can then he
uli ri.iiin ,l 1> b iiyi..-,ii iuin_ the pencil lines just ilfi.jd to.
Ti'e ni, irkiii, of thi tents w ith ,.,miunted swri|es. which is 1 part
of the process of det,'iiiliiiirl- ,'.i'.,'!' requtirements ., i-'iln.ied by the
w'nior author,' requires less than ain hitir for each Itent. The ne4e--
wiry l|re)arliations for t his, therefore, tonsist illn 1i111,1 i ll suitable
paiint and arr..igiti." for a patch (,f ope lield where the tents Ilnlv be
spre'aiid flat to become satuirated within rain or dlew. thus loi nii i, the
desired slWrink.',e. The importance of the tents l'iiir- llviric.Lily
slirunkevn before the ifi':.'iiiriL for the LI.1111,:tions is obvious.
Directions for nmihlew-irii,,,fI i" tlie tents will be given in publi-
cations now in preparation and it is not necesmar"y to include them
in this. connection. Tents should be !li !."l ilv dried in the suni
bef,,re 1win-. f,,Idhd, foIr sti.i,_,, and in l,.iii iir" them fo f field u-e
tlhe v should not be exposed to rains or dews any more than is neces-
sory to shrink as advised above.
In the (wlf .mlarl.. seasoned cypress is pr,,bablly tile best material
available for thlie manufacturer tf I,' Aind derricks used in shifhi,.
tents. The-,' serve practically\ thle sime lurpi)ose, tlie former biing
used in li.iii.dliniii tents up to 50 fri in size and the litter in Iniillii'.
tents Ai feet in size and l.,ii.. The poltles have no other attmach-
nient than a rp e. while thle derricks each consist of a pole with a
erosspiece and braces at the base and e\ -i.)olt attachllnent for p)ully
And tackle at tihe small end. These poles and derricks can be pre-
plared fIr use in a short tiiie. but it is very important that the poles
he cut and peeled l,., .r+iiii..l before they are needed for use to
permiit them to become well seasoned. P,,i,-. should be carefully
selected in order to have them as -tr.izht anid free from knots as
possible. While only two poles or two derricks are needed for use
1At oine time. an extra :-Upply of both should always be in ,.in,-.
AI >. cit., 32-;3
l[.'ir 111]

so that in case of breakaige the work can be continued with
little interruption. The length of the shifting poles should be
about 2 feet more than the height of the average trees, and the small
end should be about 11 inches in diameter. The poles for derricks
should be about 3 or 4 feet more in length than the height of the
average tree, and when ready for use should be between 3 and 4
inches in diameter at the base and between 2 and 3 inches in diam-
eter at the top. The method of itt t.chling the crosspieces and braces
is described and illustrated in Bulletin 76 of this Bureau. If ordinary
three-eighths or one-half inch bolts are at hand, a pair of derricks'can
be prepared for use in less than half an hour, and this need not there-
fore be considered a necessary part of the early perparations for
fumigation. Cypress poles should be seasoned in a barn or packing
house, or if out of doors they should be in the shade. Straight poles,
while bring seasoned, should be so supported as to prevent bending
or warping. If, after cutting, a pole is found to be crooked, it may
perhaps be made practically straight by the proper arrangement of
the supports when seasoning.
In generating the gas earthenware crocks are used. In general,
trees 5 to 8 feet high will require crocks of 14 gallon- capacity; trees
9 to 12 feet high, crocks of 2 gallons capacity; trees 13 to 16 feet high,
crocks of 4 gallons capacity; trees 17 to 20 feet high, crocks of 4 or 5
gallons capacity; and trees 21 to 30 feet high, crocks of 5 or 6 gallons
capacity. For trees up to about 18 feet in height one crock will be
needed for each tent, but for larger trees two crocks should be used,
dividing the dosage into two equal parts. Crocks with straight sides
can be used with more cyanide for each gallon of capacity than crocks
which narrow at the top, and it is to the former style rather than to
the latter that the preceding statements refer.
The foregoing directions should enable anyone preparing to fumi-
gate to determine the actual number and sizes which will be needed.
It is always advisable to have several extra crocks at hand, so that
delays will be avoided in case of breakage.
Crocks of more than 2 gallons capacity can not be readily obtained
as a rule and frequently even the smaller sizes can not be obtained
of local dealers in sufficient numbers to equip a large outfit. It is
important, therefore, that orders for crocks be placed as soon as
possible when preparing to fumigate. As the tops or covers are not
needed, dealers should take this into consideration in quoting prices.
When not purchased of local dealers and no allowance is made in the
price on account of the covers of the crocks, instructions should be
given not to include the covers in the shipment, in order to avoid
unnecessary freight or express challrges.
[Cir. Ill]


('invi.nii.iiI handlules for thei crocks caI be ma dI o If a lilt'i., of
wiie, If properly Ii ,._'el th Ie eInds of ti. handle ii ti' held in
lit-l ,1 n (il ipIll ,-ile sides of tIin 1r"ck. 1t, erwtise tI I ey maY cauttse
l, i21111a|l\ annoya re.

{)f lhe nlUlmerouls articles of m~iliorl impor +~ltance. which somet(liimeS
,' ii' ,L easily obtained and I l sh.oIld therefore be aIII .i,., I fr Iis earlI
i',. it-.siblt are rubber I1, ,. ant Il l.. I I .' lIIt1s. Two I, r liree
i mn I ,," rubber ,'1'\ Irliou l be 11 gained for a ul '' I out lit. ( )Ie
pair iw. needed for thIe one lho Ii ea-sr,'s tIn, acid and -l.'.ri il'., the
l..a. ,iid one pair should be avail 1able for use by tlie helper ',ho
ellji,'S thi' contents ,,f the crocks after f,,,iii-.iri,-'. The tlird pair
..lIll be on hand in case onei o(f the, pairs in use is lost or ,lestr1o, ed
b1 anu\ means. RlIlubber --,I,'- all be ptlrl'hesdp of or ordered
l'irm rlg electrical -'id l liy houses or lechtricili-ht ,oijtimiies. lack
ri-il)lr L-l"'\rI. with c(lotith lirniiL are l )referabIle to the red rubber
,_l|V,\- It without lini! ..' which are soivi liues used. The litter are not
en-ln1 removed from the hands, especially after tlhe become wvet on
tl li, iiidI'. anid are on this accton t very trohublesomte. )One sh tuhld
iv,'nl1 ,'-ove,, which are s,, thick tliat a wet eIt -l :i`iduate can not be
eIn.Li handled when weani ii,'... them.
.\ .i 111-. iri aii t, of Hi ounces cIapa'ity is neeIdedl for each inlilit.
andl if not obtainalhble of local dealers ione or tw o extra ones shIoild
lie always on hand. The' cian be purchused tlhr,,_'li local di._..i.
,r dir,'ectly of wholesale tli-. houses. It is important that the num-
ber- on the gi :1l i:it,, be plairi and easily readable.
"lr les are preferable to lanterns, and if p 1ossile three or four
of thl. former should be obtained.
IBni lanes, stoneware pitchers, dippers, water buckets, nip,-. pul-
le'Ys. and other articles can -usuallv Ibe obtained of local merchants.
The cheni'cals retquiretl in f,,i._':ii nion w ith hyVtlrocvanic-atcid L-'aIs
arte potassiumr cvanid (KCN( an suNtlphurit' acid (II IS( )
1oTASStt'+, M i XNlint
Tlhe cvanid ordinarily usedl in f'iin -'!,i i citrus trees is put uip in
21i i- it ii nIl cases and costs bet weeni 21 amlI -' 2.: cents a pot i Id int t on
lot- It should )e 1 uaranteetl to be '' to o'' per cent pure. In
''al''nlat ing' tihe aliountt of cvanitl rf,.jir ,i ', a tree shou tl be selectedl
wIlicl rpre-.mi as nearly aIs can be estimated thle avri_', size of tIhe
t re.. in the i"r ,v Ti1', distance over the top can be obtained by
(hlie t in pe measure in t he samIe mIanner as described in connect't ion wit It
e-t mInt in,'- the sizes of tents required. In addition to this measure-
ment the circumIference of the tree should be mieaisured w ith the

No. ~i hat'. Ueeri used by rht' aurht.r'I for uhi'~

I Ir itl

tape line. This can be done by atta.niling the free end of the tape to
a t\\ ig and passing around the tree, hanging the tape on the outer
tVig. as it is unreeled. If the grv-e consists of two sizes of trees, as,
for example, large seelliing and medium-sized buddedl trees, an aver-
age specimen of both kinds should be measured. The amount of
vcyanid required for these averLage specimens can be determined from
the disage table given herein. Tli following examples illustrate tlie
method of ulinig the table after the distance over and the circum-
ference of the tree have been obtained.

An iuiilI of
I. v.'. ilrl I -l iiii.1 I I r, uiiif r- 1.,jr .-,iiurn,
No. over tree. eneeOflrr cyanid

Feet. Feet. OUncs.
1 24 40 9
2 38 5 26
3 52 72 58
4 66 79 96

The amount of cyanid in ounces having been obtained for the aver-
age tree in the grove, this amount is multiplied by the total number of
trees to be treated and divided by 16 to reduce to pounds. It is advis-
able to obtain from 5 to 10 per cent more cyanid than the amount esti-
mated, in order to avoid delays in case of underestimation. The
cyanid, being put up in air-tight tin cases inclosed in stout wooden
boxes, may be stored for months without deterioration. Excess
evanid can usually be disposed of without difficulty.
Sulphuric acid can be purchased in iron drums containing about
1,500 pounds at about 1 f- cents a pound. One drum of acid is required
for about 4 cases of cvanid. The acid should be guaranteed 66:'
Baume or 93 per cent pure. It is advisable to have a sample tested
with an acid hydrometer, an inexpensive instrument which can be
obtained through ;any druggist. Acid should not be stored for more
than two or three weeks in the drum. Unless it is to be used at once
the entire contents should be emptied into carboys, the mouths of
which should be closed with wooden plugs, strips of burlap, and plaster
of Paris. Empty carboys can be purchased for $1.50 or $1.75 each,
and 9 are required to contain the contents of an acid drum. Only
ca rl, vYs in good condition should be used, since the container is made
of thin glass and breaks easily if the bottom of the wooden case becomes
weakened and fails to supptirt the contents. Great care should be
used in handling the acid. Probably the quickest and safest way of
emptying acid from the large drum into carboys is a method which
has been used on several occasions by the authors. The drum is
mounte(l on two heavy planks resting on the ground and is arranged
so that it can be rolled forward and backward easily. At one end of
[Cir. Ill]

tlie planks at pit aiiout :; fe t deep is :,li'. 'II ',sho ldieml ,l I _' 4,., .ii.'2i
fuIr tIwo men tsta.l.d in and place I h. empty urlov in i' '-iliii i n
lift it out whe linll ,,-d. A l:. _' r ,ii'iit l icd funnel Inlmad' of shelt lead is
aced I in the onolth of the carAo,. A piece of cast-iron ji r,-1 about
I ir S i nches Ic l'_I awd plopi l)'l IhrehIded is a C.on\eniIce, but not a
re,,uire lent. This, if \a ailaule. is screwei ini t lie '11I iii,- in thle
iniii. w which is i 1.iL:- (.l sI lIh t I ihe ll -if I ill l our inib ti funnel le('nd-
11ng to the carl oy. A piee of iif)v Il ,il or 1r the ti r sui i l'e liiiier
.Aliiill e I i I'wi,,II'. l -,ikidl across t InI evId s f tlh (wo plank '\uppIrts of
lI drum to prevent its 1 II,, rolled too fur forw ardt. \hel ne V er there
i. I a suitable platform available, or timber is av ailalle for i,,: i.'
1 ri,' ii_ one, the trouble of .lil-'-rll.. Ihlie pit tinn l e 1 b) ) ileld. It is not

9 I -
0 I

7 -----~- --------..^ ---t-
7 x x

?__ 4 5 __Z5 .

17 7 10'2 181 I I
2 30-36 40 61 33-40 3-54 ; | X
10'/2 2 5 13 ?'''___ ^_______
S38,-44 38 0 37 1 j 6-4

A C D E F 6 H I i K
2 ii. r ii u ry I e I Io P 1 O tr s
1 !t !_- I ', .. M orrll
adivisalle to emipil drums front railroad st at iont I orjpat kip, '-1-v p'lit-
formih. as more or less acid is 1.imilI spilled. No one hiouhld stand
nearthe car)o when the acid is1'iii poured, and care /houl he taken
to prevent til spatti riii of the acid from reial11 ii i_ thie face. WIhen
iaiil'lit^ acid, it is always w ell to have water at hand for use in case
of accident. With pr 'per care sulphuric acid can le haiidled w1 without of anv kind.
01 V'.i:lM- OF ,(i\- F". ANDM)OSA(;K ABLES.
While it is not always iiuuaru V that 11i:17r1iiiii of br"\i- be
it Is always advisable as a matter of nrcerld and to prevent errors.
Ai-Ure.. 2 and :1 illustrate Mutho-,( of ikiin- itw 'iall rniX when trees
('io. ii ,'

are set in the square and in the alternate system, respectively. The
figure, in the squares represent the records of the trees fumigated,
the two upper figures separated by a dash representing the dimen-
sions of the tented tree and the lower figure the amount of cvanid
given.~ These records are made at the time each tree is fumigated.
In pr(.-)e1t ing the dosage table recommended in Bulletin 76 it was
stated that the amounts of cyanid could be incren'.seil from 10 to 25
per cent with adv;niigi, under certain conditions. At the present
time the authors advise for general use a table (fig. 4) representing



7 ------ ---------

W, -- X --

___42-54- 43-62
39-47 24 40-49 29
3 X 21 41-51
42-50 47-60 23

2 23 40-47 34 43-48

32-38 20 42-50 24
13 23 I
A B C D E F 6 H

FIG. 3.-Diagram of grove with .alierniiig trees; first tour rows in process O)f funmipiiti with four tents;
three sets of trees fumigated, the tents being moved from south to north: X, X, X, trees missing. I From
,,riM ll I1

an increase of 25 per cent over the minimum requirements previously
given in tabular form. This seems desirable, owing to the wide
variations in the weave of various tenting materials and to the fre-
quency with which slight winds might interfere with the results.


With the gradual extension of the process of fumigation in the
control of the white fly in Florida and other citrus-growing sections
of the Gulf coast, the value of a citrus grve will be consid(erablv

a The amount is according to the doi-age table given in Bulletin 76 of this Bureau,

[C('ir. 111]

all'erll liv the d il1iilli ii.s ill fi Iii, I--ii.,lin presentied hi e\CCesive t ,,f I rI.I'- closeiiss tf plant i ,. un'evcnu't uf I_',."n, am oilter
co('Ii hmin. "'l, systeatit tratIt en t oi ,f _''"\ tI or I\ trcomell I theseC
X illhiiilli i-. so that t th e' I t'' lI Im '.I' I .i I i::i_':.l< i, will f it o, ly
ie.. of value in tils respect, but wsill co1nst itlutlt a '_" I culii ur!l prazi 'e.
Tr.e- planted too clos ei for f'ii,,i'n l ioii to Ih' jwavthinllt' art' too
hxlW pruniX nt+ot only hl+essen (lie e'xpense1 +f f'ii..l'_/:.lh~ ion. bu reduces+
the. eMlxpense of mili.i'.z tuit' fruit \itihonil rmm, ;im tl-r qftuant it.

C Inc C/,9CUMAfErEN C __ M_
OW' 10;il5 2025 3035 4045 50 5255 57 606265 67' 702'7275 '7' 80,, 875' 90 .1M*
10 2 2 2, "
12 3 ;J 3 121
1 14 3" 3 '3' 3 ... .
16 4'4 4':4 4 .4
18 5 5 5 5 5 _l
I0 152025 30g35 40.45 5052- 55571 60621 65672 70 72f 75 r" 0-2'.85 87' 90
20 .5' 5-' 5' 5 ;' 60
,22 5'6. 6''V6 7 22 4'
224 6'" 7 8 9 97 24
26 9 9 9 919' i f i 26
28 1 0 II I 1J3' __________ 28
10Q15 2025 30 354045 50522 555? 6062- 65677 70 72-''5 771' 80&.8587' 90
312 3 13 4 15 30
:323 m14 15.16 18.19 32
.3 34 15 5 16 18 192r'23 34 3
!36 t i '9 21' 22' 23'25 36
30 9 20 2 23'Z24'26'2' 28 ." 38
2: 30_35 4045 5052'55 57' 6062' 656 '07' 75 77-'805265 87' 90
22 23 26 2' 28 30 31 32 40
2326 2830 3132 33 35 36 42'
4 E44 _ 30 3' 33 35 36 3"'39 40 42' 444
-46 33 34'36.3' 39"4,4243 45 4' .9 46
35 37 38 39 42 43 45 4' 48 50 5 53 8'______ _
4045 50 555 57R 60 62, 65 6-'-'0 "O2 7 5 ,77e 9082'85 887- 90g
39,41 43 45 4649 51'53 55 5158 6-D 50
52 [ 43 45 4 49 53 56 58 6- 62 64 F.- 52
5__ 4 -.46 48 50 53 .38 60 62 64 66 68 "V 73. 545
156 5 6 53.56156' 63.66 68 71 '3 '5 '7.-9 56
'58 - 53 56 59'61 64 6' -0 '2 15 '8 80 82 84 58
S ~ 150"52255 57' 60 62 65 67z '0 Z' 75 .77S'O W 85 Vf' 9g
60 60 63 65 68 0 3 '6 5'9 82 L5 85' 91 94 60
6 4 66 69 '2 '6 "9 82 85 89 92 95 98 01, :A 64 6
1"9l 8 J4 3 89 93 '0' 9; 04 66
'--'Ki 14 3- 9+0 93 9'[ ,,l 0 1316 6
60 Up 65 67O 70 ?72 75 77- 80 8 65 872 50
70 50 83. 9. 9- 9 8 102 '06 il' I:l;4 1 i 23 70
72 . 86. 90 94. 98 03'07 ill '5'i19'23 '2' 72
7 74 848' 89 94 98 103 0'"112 rl6'1Ol024jl28 133 s4,7
76 1 I 1 87'90'94'98 102 i0''ii1'1'17 121 125 29134 1327,
FIm. *t.- os a shritiih fur ixr ni (ii tiiii'dilti [or tln' rHrit.<'+ whitr fly.++ (Cirit't:iil

In Jif.j)r'irilIi_ for the ftniiirati n oi f a L'._rl,,te, if tlie' lriin.hlt hilt'r-
hIrk to any extent, either p ur:nlir'' ,,f hranctlh illternate trees or rowt oi' trt't'e is ndvi+.inhte. I 'andw.(ill (in ti'i {illte r
purts of the trees should Ihe til,,r,,.t-lily remuoxve'd in :Ill eases to avoiil
tle enriii,, of tents. Watershot is should le lii,,',in'.,_'.i1v remove%\+td
at I lie same time, sinte about 1 per cent of tine white tof pip,. pre "ent
during the winter mnionths survive fniniiiation and the reistate an I'
I ie insects on watershoot leaves is muih 'i'r',:,ier than els\wherei ol
tilt trees.
[i ir. I 11



12 U 1111111111 111 lIIll111lll
1 3 1262 09216 5579

If possible, the cultivating and fert ilizing of groves to be fumigated
should follow fiiiigtioii m. It is muchi more difficult to handle the
fiiii-.iii,: tents on newly cultivate(l ground, and the dust arising
in the -1ift ilg of the tents is sometime a matter of considerable dis-
comfort to the men ciii;ig(,d in the %work.
W. M. lT.A-. A
.1- tI ; ,/ Secretary i' .- l r. i, It i,ire.

WASHINGTON, D). C., A.uq.,s 10, PJ'Wj.
[Cir. 111]