The arsenates of magnesium as insecticides


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The arsenates of magnesium as insecticides
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Dearborn, F. E
United States -- Bureau of Entomology and Plant Quarantine. -- Division of Insecticide Investigations
U.S. Dept. of Agriculture, Bureau of Entomology and Plant Quarantine, Division of Insecticide Investigations ( Washington, D.C )
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Table of Contents
    Front Cover
        Page i
        Page ii
    Table of Contents
        Page 1
        Page 2
    Occurrence of magnesium arsenates in nature and chemistry of magnesium arsenates
        Page 3
        Page 4
        Page 5
    Patented methods of preparing magnesium arsenate insecticides
        Page 6
    Analyses of magnesium arsenate insecticides
        Page 7
        Page 8
        Page 9
    Compatibility of magnesium arsenate with fluosilicates and cryolite, and adhesives and carriers for insecticidal dusts
        Page 10
    Application of magnesium arsenate as an insecticide
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
        Page 19
        Page 20
        Page 21
        Page 22
        Page 23
        Page 24
        Page 25
        Page 26
        Page 27
        Page 28
    Literature cited
        Page 29
        Page 30
        Page 31
        Page 32
        Page 33
        Page 34
        Page 35
        Page 36
        Page 37
        Page 38
        Page 39
        Page 40
        Page 41
        Page 42
    Back Cover
        Page 43
        Page 44
Full Text

E-451 October 1938

United States Department of Agriculture
Bureau of Entomoloe, and Plant Quarantine


By F. E. or.or Division of Irnsecticide Investigations

A. Occurrence of marnosium arsenates in nature .................. 3

B. Chemistry of jnan;rsium ar'sen-tes 3........................ 3
1. lc.nciar-nesium orthcarsenate, ':CE4(As04)2 ................. 3
2. D.. 2xncsium orthoarsiates
(a) The compound. Lg:A~sOA.l/'21W) .......................... 4
(b) The compound. MgIEA~s0%..ooO ................................ 4
(c). The compo.x..d ::ns0. l/2E20 ........................ 4
.(d.). The compound. IC~iAsO4.*7E2O ............................ 4
3. Marnusium pyroarsenate, L':r2As20? ............... 4i
4. .Trimag-nesium orthoarsenates
(a) The co4pound 'g3(As04) 17H20 4
(b) The compoud Ig3(As428H2. ........ ..... ........... 5
(c) The compoud.rd .M.,3(AsO452.10H20.. ...................... 5
(d) The compound :g3(AsO4)2.22H20....... .................. 5
5. Baic mag:,esium orthoarsenates............................ 5
6. .Magnesium ammonium orthoarsenate.......................... 6
7. Double salts of mwgncsi-nm arseiate ....................... 6

C. Patented methods of preparing, marnecsium -trscnate insecticides 6

D. Ana.lysos of m-.:r-.osium insecticides ................... 7

E. Compatibility of ':r 2-i.sium arscnate ',ith fluosilicates
and cryolite .................... ......... ........... .... 10

F. Ad-hesi-es and cPrriers for insecticidal dusts ................ 10

G. Applic 'tion of mag.esimn arsenate as an insecticide ........... 11
1. ;'-"exican bean beetle (Epi1achna va;i'. .stri.(Mul s.) ......... 11
2. B-,n le:\f beetle (Cerotoma trifurcltE'. (Forst.))............ 19
3. Coding moth (Ca:'rocrs2" pomonella (L.) ... ........... 19
4. Plum curculio (Conotf-c-ljus nonuphzjr (Hcrbst) ............ 22
5. Japanese beetle (Popillia .japonica (@ewm.) .................. 23
6. Rusty tussock moth (-otolophus antirua (L.))............... 23
7. Cra,.berry fireworm (Phopobota vacciniana (Pck.l)).......... 24
8. Potato flea,-beetles (Epitrix cucumeris ,HarrLs and
E. subcrinita leconrite)........... ....................... 24

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9. Oriental peach moth (Grapholitha molesta (Busck))....... 24
10. Boll weevil (Anthonomus grandis (Boh.))................. 24
11. Cabbage insects ...... ....................... ... ..... .. 24
12. Strawberry root weevils (Brachyrhinus oyatus (L.)
and B. rugifrons (Gyll.)).......................... 5
13. 3Beet webworm (Loxostcge sticticalis (L.))............. 25
14. Turnip webworm.... ..6.................... 26
15. Spotted blister beetle (Epicauta maculata (Say))........ 26
16. Black vine weevil (Brachyrhrius sulcatus (F.)) .......... 26
17. Ev.',opean corn bores (Pyrausta nubilalis (Hbn.))....?.... 26
18. Bluoberry maggot (Rhagoletis pomonella (Walsh))......... 26
19. Squash beetle (Epilachna borealis (F.))................. 26
20. Plum web-sawfly (Neurotoma inconspicua (iTorton))........ 27
21. Grape berry moth (Polychrosis viteana (Clem.)).......... 27
22. Green clover worm (Plathypena scabra (F.)) .............. 27
23. The pyralid Maruca testulalis (Geyer)................... 27
24. Colorado potato beetle (Leptinotarsa dec-mlinreatq (Say)) 27 ,
?5. Red-legged grasshopper (Melanoplus femur-rubrum (Deg.)). 28
26. Lima bean pod borer caterpillars (Maruca testulalis
(Geyer), Fundella cistipennis (Dyar), and Etiella
zinckenella (Treit.)) .............................. 28
27. Gypsy moth (Porthetria dispar (L)................... 28
28. Miscellaneous .............................................. 28

Literature cited ........ ............................................ ...... ........ 29

A. Occurrence of Liagnesium Arsenates in 173tnre

vAA.-nc sium compounds are widely distributed in nature, the arsenates
occurring as the following minerals:

Adelitc, Ca(:gC.:-)As04
Berzeliitc, (Ca,Mg,.Mn,.iTa2)3(AsO4)2
Cabrerite, (i:i ,;.:, Co)3(As0 4)2.8H20
Hornesite, 'tg13(AsO4)2Q.H20
Zaryinite, (-: .n, Ca, Pb, Hg) (As04) 2
Picropharmacolite, (CaLig.13(As04) .~620
Roselite, (Ca,:g,Co)3(A.s04)2.2H20
Rosslerite, :.:HKAsC4.1/2H20
Tilasite, Ca(l.'FZ)AsO4

u. Chemistry of La::riesium Arsenates

Tr.e author does not vouch for the accuracy and results obtained
in the prep"'-ation and --roperties of the various compounds given below.
The result- given are abstracts taken from the literature. Ordinary or
orthoa-senic acid (H_3Aso04) is a trib-sic acid, and theoretically is
c-pable of forming three magnesium arsenates (1, 113, 116) the monc.magnesium
orath':arsenate [::iA(Asc4)2], the dimagnesium orthoarsenate (.g_-IAs04), and
the trimagiiesium ortho'arsenate [g.3(As04)2]. All these magnesium arsenates
are known, t'Vo of them -ith.various amounts of 7ater of crystallization,
the number of moles of water deendrAir- upon the conditions under which
the compound is forced. In general the compou-ids formed at low tempera-
tures and from more dilute solutions contain the larger amount of water
of crystallization, while those forrc,_d at high temperatures or from more
concentrated solutions contain the smaller amount of water of haydration.

1i. :-.:cnromagr.esiIm orthoarsenate

Lo.icmaa.,';esium orthoarsenate (62, 64) has the formula .:g-14(AsO4)2.
Schiefer (133, 160) prepared the compound by heating a solution of
magnesium oxide in arsenic acid, and obtained very hydroscopic crystals,
soluble in water.

2s Dimagniesium orthoar senates

The general formula for the dioag.iesium orthoarsenates may be
written as i:giAsO4.-H2O, in which (X) represents the moles of water of
crystallization. Salts have been prepared containing 1/2, 5, 6 1/2,
and 7 moles of water of hydration. The gei-3ral method of preparing the
dimagnesium salt is to allow disodium ar-'-- te (---a HAsO4) to react with
magnesium sulphate (62, 63) in water solution, or 1y treating a solution
of disodium arsenate (i!apAs04) with acetic acid, and adding the calcu-
lated amount of magnesium sulr.hate. The precipitate that first forms is
amorpThous, but soon crystallizes in leaflets.

- 4-

(a) The compound I.TgH1Ls04.l/2H20O
This compound occurs in nature as the mineril Rossierite. De
Schulten (38, 39) prepared it by heating magnesium carbonate in an
excess of arsenic acid in sealed tubes, at 225" C. It crystallizes in
colorless monoclinic leaflets, and has g density of 3.155 g/cc. at 15C.

(b) The compound MgHAsO4. 5H0 2

Schiefer (62, 133, 160) obtained this compound by dissolving
magnessi-ii pyroarsenate in acetic acid and allowing the salt to
crystalline from the solution.

(c) The compound MglAs04.6 1/2H20

In various handbooks (1, 75, 120) is described a compound contain-
ing 6 1/2 moles of water of crystallization. It is a white crystalline
corTround, insoluble in cold water; 0.15 part dissolves in 100 parts of
waI,:r at 100 C. It is soluble in nitric acid, but insoluble in ammonium

(d) The compound Mg1HAs04.7E20

This compound was prepared (39, 62, 96) by'dissolving the ignited
residue of ammonium magnesium arsenate (magnesium pyroarsenate) in acetic
ac-J, and allowing the salt to crystallize. It crystallizes in monoclinic
leaflets (71, 72, 129) and is stable in air. Dried over sulphuric acid,
4,5 to 5.5 moles of water of crystallization are removed. Dried at 100
C., the ccoaound loses 5 to 6 moles of water; and at 200 C. 6 moles of
Water: of -7.j ration are removed. On igniting, the compound is converted
into magnesium pyroar senate (Mg2As207).

3. Magnesium pyroarsenate, Mg2As20O

This compound is produced (62; 64) by igniting the dimagnesium
orthoarsenate or the ammonium magnesium orthoarsenate compounds.

4. Trimagnesium orthoarsenates
The general formula for the trinuj.-n-sium orthoarsenates may be
written, Mg3(AsO4)2 .XH20, in which (X) represents the moles of water of
crystallization. Compounds have been made which contain 7, 8, 10,. and
22 moles of water. The usual method of preparing the trimagncsium
orthoarsonates (10, 62, 64) is to allow arsenic acid to react with mag-
nesium hydroxide in the- proper proportions, as -illustrated by the follow-
ing equation:

3'g(OH)2 + HgAs04 Mg3(AsO4)2 +6H'0

(a) The compound '.:g3(As04)2.7H0

This compo.uid was prepared by Chevron and Droixhe (26, 62), using
monosodi-um arsenate (NTaH2As04), magnesium sulphate, and sodium bicarbonate.

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(b) The compound :"'.3(As042.820

This compound occurs in nature as the mineral Hornesite (114).
It crystallizes in monoclinic prisms of light rose color. The density
of the native comrnound is 2,474 g/cc -,t 15 C,, while that of the
prepared compound is 2.609 g/cc at 15u C.

It is prepared (40, 62, 64) by mixing at room temperature a
solution of 20 grams m'a:1 esium sulphate (.SM)4.7T20) dissolved in 1 liter
of water with a solution of 16.9 grams disodium arsenate (i'a2- s04.H20)
and 4,5 :rarrs sodium bicarbonate dissolved in 800 cc of water. The
precipitate that first forms is amorphous, but after standing 24 hours
or more at 20-25 C. the crystalline salt is fcri.ic.

(c) The compou id i, 3(Az0) 2" 1H20

This compound (40, 62, 94) is -prepared by digesting ammonium
magnesium arsenate (nLh.:A=C,.) or potassium magnesium arsenate (O4kAsO04)
for a lorng time in water. It is also produced by the action of water on
the compouU Mg3(AAs04) T2?2K20.

(d) The compound ,.'.r3sO04) 2.22H20

; -As cr ". '.... (., ::, 6 is prear.d .similarly to the corn-
pound contlininj7- C moles of <'ater of hydration, ..ith the exception that
a lower te-'j.erature (10 C.) and more dilute solutions are employed. After
strnl.i : 2.- hours, crystals of the salt ar'. collected. It crystallizes
in monoclinic plaes (7].), of density of 1.788 gicc at 15 C. The salt slow-
ly decomposes in the ail, Under water it is converted into the salt con-
taining 10 .!oles of vwater of hyr:ation, I ssicated over sulphuric acid
the salt remains 6 mol:s of water. Dried at 100 C. it retains 5 moles
of water, and at 200 C. it retains only 1 mole of rater of hy.1ration.
Recent chemical handbooks (75, 120) describe this compound as being
insoluble in hot and cold watEir, but -olu'le in acids and amr,....lure

5, Basic magnelitn orthc arsenates

Earstow and Cottringer (9) patented a method of making magnesium
arsenate insecticide which they believe produces two basic magnesium
arscnates. To one of the compound's they assign the formula
dg3(As04)2.1gO.yH20,, in w'tich the value for (Y) was not determined. This
compound occurred either as long needle-shaped crystals; as elongated
pointed-end crystals; or as short, flat prisms, having parallel extinction
and a positive principal zone, with 1> = 1.580 and )-, 1.E05. To the
other basic compound they gave the fo2 iiula Mg3(As04)2.2rj0.ZH20, in which
(Z) represented the moles of water of crystallization, but wr.s not
determined. This compound occurred as excecdin-ly small lens-sh-aped crystals,
having parallel extinction and a positive principal zone, with } -= 1.566
and Y = 1.575.

-...6 -

6. Magnesium ammonium orthoarsenate .

This compound crystallizes in tetr-qonal prisms with 6 moles of
water of hydration. Its formula is M1 ",THA.04.oH.20 It may be prepared
in a number of ways (41, 62, 64). It is precipitated under ordinary con-
ditions when arsenic acid or a water-soluble arsenate. is addled to a
solution of a water-soluble magnesium ccmp.1ound, in the prese-ce of
ammonium chloride. and., ammonium hydroxide. It i-s a white compzour.d (62,
75, 120), having a density of 1.932 g/cc at 150 C.; 0.035 part is soluble
in 100 part.s of water at 20o0 C. It is soluble in hot. water and in acids,
but insoilQ--,Ie in alcohol. When ignited it is converted into the magnesium
pyroar senate (egg2As2O7)4

7. Double salts of magnesium arsenate (62, 96).

Magnesium orthoarsenate forms double salts with other elements, but
their properties and method of preparation will not be described in this

C. Patented Methods of Preparing Miagnesium
Arsenate Insecticides

The first United States Patent issued for the manufacture of
magnesium orthoarsenate as an insecticide wasissued to Barstow (8). This
patent covered both the di- and tri-orthomagnesium arsenates. The compounds
were produced by the reaction of arsenic acid on magnesium hydroxide in ,
the proper proportions, or by the reactions of the normal and acid arsenates
with the water-soluble salts of magnesium.

Dow (43) a little later took out a patent for the manufacture of
an insecticide consisting of a mixture of lead and magnesium arsenates.
The product is formed by reacting a suitable lead salt with anr excess of
arsenic acid, and neutralizing the residual acid with an excess of
magnesium hydroxide.

Dow (44) patented the manufacture of diingnesium arsenate as an
insecticide. He formed the product by the reaction between magnesium
hydroxide and arsenic acid.

Barstow and Cottringer (9) made an improvement in the manufacture
of uatnesium arsenate as an insecticide, producing thereby a product in
which the content of water-soluble arsenic (As205) is claimed to be much
lower than in other magnesium arsenates. They precipitated the compound
by neutralizing arsehic acid with an excess of magnesium hydroxide, and
subjecting this mixture to temperature of approximately 145-175 0. in
an autoclave uhder pressure. They claimed that the magnesium arsenate
may exist in'one 'or all of three forms; first, the dimagnesium orthoarsen-
ate, MgHAs04.XH20; second, the basic magnesium arsenate, Mg3(Ac04)2hMg0.YH20;
and third, another basic arsenate, Mg3(AsC4)2.2MgO.ZH20.

Cullen (34) patented a method of making a calcium or magnesium
arsenate insecticide, in which he causes arsenious oxide (As203) to react

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with lime or magnesium hydroxide and roasts the arsenite so formed in a
furnace, thus oxidizing it. By using an excess of lime or rnagresium
hydroxide, basic arsenates are produced which contain less wvater-soluble
arsenic than otherwise. The reactions involved may be illustrated by
the following equations:

MgO + As203 + H20 = Mg3(AsO ) 2 + H`20

On roasting Mg3(As03)2 + 02= 'L3(As04)2
and 2Mg(OH)2 + As203 = Mg2As20 + 2H20

on roasting Ig2As205 + 0- = Mg2As207

Heath (73) improved upon Barstow's patent (8) and the Barstow and
Cottringer patent- (9) in producing a less soluble magnesium arsenate as
well as improving its fluffiness.

The product is produced by mining a slurry of magne-isium hydroxide
in water with the required amount of arsenic acid solution. Then approx-
imately 15 percent of caustic alkali equivalent to the arsenic acid used
is added, as calculated from the molecular proportions in the following

(1) 3:aOH + H As0O4 -- Ta3ASC4 + 3H20

The resulting slurry is heated in an autoclave to 180 C., and held there
until a sample on analysis shows less than 0.2 percent of soluble arsenic

Seaton (134) patented an ii.secticide consisting of di- or tri-
magnesium arsenate in which is incorporated appro::imr.tely 4 percent of a
casein compound or an equivalent deflocculating agent, such as gelatin.

D. Analyses of IKA-resiun Arsenate Insecticides

iagnFesium arsenate as an insecticide was first offered for sale
(122) in 1919. The early product contained 32.13 percent of arsenic oxide
(As205) and had a water-soluble arsenic content of 1.25 percent (As205).
This material caused severe injury to apple and peach foliage when applied
as a spray. Patten (122) showed that the arsenic content of the early
magnesium arsenate insecticide was rendered soluble in water by the action
of carbon dioxide. He determined the water-soluble arsenic content,
using water saturated with carbon dioxide, and found that 41.7 percent
of the total arsenic had gone into solution. By passing carbon dioxide
for 2 hours through water (1,000 cc) in which magnesium arsenate insecti-
cide (1 gram) was suspended, he found that 96 percent of the arsenic
oxide had been dissolved. Barstow and Cottringer (9) state that in practice
when magnesium arse-n-Lte is made by directly reacting magnesium hydroxide
with arsenic acid, the product is apt to contain more arsenic in soluble
form than is desirable,


Patten and 0'Mjr., (123) in 1919 analyzed 'tv o s'mpl&s of
magnesium arecnate insecticides then on the market. One sample
was .r'gnosiun orthoarsenate, while the other scrmple was magnesium
pyrocrscnate. The orthoarsenate contuLined 32.13 percent arsenic
oxide (As2C5) and had a water-soluble crsonic content of 1.25 percent
(As205). The pyroarsonate contRind 38.05 percent arsenic oxide
(As205) and hb.d a w.-ter-soluble arsenic content of 0.23 percent
(As205). They found that the water-soluble arsenic content of the
pyroarsenpte, using water saturated with carbon dioxide, was only
3.0 percent (As205), and whjn carbon dio,:ide was bubbled for 2-1/2
hours through water (1,000 cc) in which it (1 grem) was suspended,
only 11.28 percent of the total arsenic was rendered soluble.

Cook and Mclndoo (27) in 1922 mrde a eher.ical, physice,6
and insecticidal study of the arsenical insecticides on the
market. Below are the results of their analysis on magnesium

Total arsenic (As205)
Water-Soluble arsenic (As2O-)
Magnesium oxide (M0)
Carbon dioxide (C02)
Under t e rmi ne d

2.96 percent
33.60 "
1.56 "

Leach (99) in 1926 analyzed a magnesium Ersenate used in
experiments as soil insecticides. Below are his results.

Total arsenic oxide (As205)
Mg3(As04)2 equiv. to total As205
W.ter-soluble arsenic oxide (As205)
MgO in excess of arsenic oxide
Calcium oxide

Insoluble in acid (SiO2)
Loss on ignition




Cathcart and: Willis (23) reported the total arsenic and the
water-soluble arsenic contents of commercial m-'gncsium rrsonato
insecticides on the market for the years 1930-1933 inclusive.
Their results are tabulated below.


___________________ Magnesium xrsenate_________________

Nemne of


teed not
less than

arsenic Water-soluble
Found Guaranteid
(percent)not more


Dow Chem. Co.
Mechling Bros.
Chipman Chem. Co.
Dow Chem. Co.
Mechling Bros.






gMagnesium arsenate dust

Dow Chem. Co. 1933 5.22 7.47 0.06 0.08

Dearborn (37) in 1930 made a more detailed analysis of commercial
magnesium arsenates on th market. The methods of analysis used were
those described in the A. 0. A. C. book of methods (3). The results
obtained are tabulated below.

Magnesiumn arsenate

Sample 1 San:plo 2
Percent Percent Percent Percent
guaranteed found guaranteed found

Moisture -- 0.8 -- 0.7
Total arsenic (As205) 32.0 32.6 40.0 41.0
Water-sol, arsenic 0.35 0.04 0.35 0.10
(As2 0 5)
Water-soluble salts --- 2.5 -- 2.6
Arsenious oxide (As203) --- 0.1 --. 0.2
Acid insol.. 0.6 -- 0.7
Al03, F-O -- 0.3 -- 0.8
Calcium oxi -- 1.4 -- 1.5
Magnesium oxide -- 47.9 --- 44.2
Cubic inches per pound --- 145 -- 113
pH value of 2 susp. -- 9.8 ---9.8

Dearborn in 1934 collected s-'ples of magnesium arsenate insecticides
snd magnesium arsenate dusts for analyses. The results obtziMA. arc tabu-
lated below. ur., 6T


- 10--

..:-iiEr'-dium arsenate insecticides

*,!e i SIrm f Samiplo 3 ___
P %rc nt percent Percent Percent Fcrci-nt P rent
guaranteed found guaranteed found. guaranteed found
Moisture -. 1.09 -- 1.36 -- 1.47
Total arsenic (As 05) 32.0 39.09 32.0 38..17 32.0 38.12
Wator-soluble As2 1 0.35-. 0.29 0.50 0.33 0.50 0.35
Arsenious oxide -- none -- none -- none
Calciua oxidd 1.96 -- 1.96 -- 2.00
:dIgn.fsiuml oxide -- 45.64 -- 46.99 47.00
Carbon dio:idc -- 1.04 -- 0.83 0.76
Insoluble in acid -- 0.18 -- 0.10 0.10
Loss on ignition -- 16.39 17.01 16.93

______________ Mexican bean beetle destroyer

Percent .Percent
guaranteed found

Moisture C.13
Total arsenic (As205) 8.00 10.24
Arsenious oxide -- none
Water-soluble As20 0.50 0.15
Calcium oxide 55.44
Magnesium oxide -- 12.44
Carbon dioxide H.5
Loss on ignition 18.25
Insoluble in acid 0.26

3. Compatibility of Magnesiui-a Arsenate with
Fluosilicates and Cryolite

Carter (22) determined the compatibilitios of arsonicaJls
with the fluosilicates of sodium, potassium, calcium, and barium, and
cryolitc when mixed in w-,ter suspensions as judged by the "
soluble arsenic and acidclity. h-'.-:rsi-m arsenate ws only slightly
affected by barium fluosilicato, while cryolite inhibited the
formation of wator-soluble arsenic.

F. A'"h-.'ives a.nd Carriers for Insectioidal Dusts

Potts and 'Barnes (127) investigated thc. adherence of insectici-
dal durts to .r-wing :,nd nature foliage with and without the use of
adhesives, carriers, or diluents. They found that lead arscr.-te
LC,-hrc ipuch, better than c'id calcium or iag;-csium arscnatcs.
. L,;, I r.rscnate, hovocvcr, was superior to calcium ars.-nato.

- 11 -

G. Application of .--::.sium Arsena-te :.s an Insecticicc

1. I.Tcxican bear.n beetle (Epil.achna varivestis(L:uls.))

The L.':-- .ican bean beetle has been known to be present in the
western part of the Unit"c St-Ates since 1850.

List (100) describes a series of spraying experiments con-
ducted during 1917-20. Magnesium arsenate was used in 1920 only.
The arsenates of lead, zinc, and magnesium wore the most satisfactory.

Howard and Zr-ish (89) in 1921-22 tested a number of
sprays and dusts ag.-inct the beetle. Calcium, nagnesium, and load
arsenates were used. ".i.. sium arsenate was tu' least toxic to the
bean plant and yet toxic to the beetle.

Howard (78) in his annual re-oort for 1933 says that irrgncsium
arsenate was the best 7atcri'.l used duri-ic 1922 for controlling the
Mexican bean beetle.

Howard (83,'84) was the first to recommend the use of magnenosium
arsenate as a spr-" or dust in controlling the beetle. The rosllts
obtained during 1921-23 showed it to be safe to use on bean foliage.
The best results were obtained 7" spraying.

Howard (79) in 1924 reported that -...:rinents conducted in Ohio
with magnesium arsenate a.:-inst the beetle ; successful control.
This remedy is prob-,ably the best a-..ptcd for the use of growers, since
most of the other arsenicals, under certain conditions, injure the bean
plant. Marcovitch, however, (102) su>-,ests fluorine compounds as a
substitute for magnesium arsenate as an insecticide for the control of
the Mexican bean beetle.

Miller (115) in 1924 described the use of magnesium arsenate
dust in the control of the Iicxican bean beetle. The results in regard
to yield of beans and control of beetles were eaual to those ob-
tained with lead or calcium arsenate. Slight injury was reported,
but similar injury also resulted from the use of calcium and lead

Eddy (47) in 1925 r.corted that very satisfactory results
have been secured by applying calcium or magnesium arsenates mixed
with hydrated lime, in controlling the bean beetle. The magnesium
arscnato did no injury to the bean foliage.

Guyton and Knull (65), using the recommended materials for
controlling the *:-. foliage injury developed. The magnesium arsenate should not con-
tain more than one-half percent of water-soluble arsenic as

- 12 -

Howard (80) in 1925 rep32ted that lead arsenate, zinc
arsenite, -.nd lead arsenabe-lead oleate ii'xture were all injurious
to bean foliage under southeastern conditions, as well as a .nJole
of magnesium arsenate. The ordinary) commercial .-;:siun arsenate
is not inj1rious to bean foliage. Calcium arsenate and lime mix-
tures proved valuable, but they were more toxic to the bean plant
thIan ma,- nesiuru arsenate.

Ed-dy ,and. ic.Alister (48) in 1.326 found that m-,,gnesium
arsenate c-aused loss injury to b,-en pl,. nts wnen Custed with 4
parts of h'drated lime, and that it was as toxic to the beetle as
tany trial tried. The compounds tested were the arsenates of
calcium, m gnusium, lead, and zinc.

Cecil (24) in 1927 recomimended the use of :-s-nisum arsonate
as a dust or as a spray in the control of the ::-ican bean beetle.

Eddy and Clark (49) during 19e7-1i98 nade a study of the
control of the Mexican bear beetle. They considered magnesium
,arsenate the most effective arse-..icl that c,-n be used C against the
beetle in South Carolina.

GuyWton and a nUll. (36) state th-.t in Pennsylvania the Liexican
bean beetle wacs first discovered in 1324. Tostc wore conducted
with several during 1925 and 1926. The of
calcium and magnesium with hydrated lir-,e g-avo no burning when ac-
plied as dusts. Ma;lesimn arsenate, and crIcium arsenateo with
lime, wcre allo -secl as spray. LcD.c arscrnate caused slight urn-

Howard (81) in 1927 reported results of control studies on
the Mexican bean beetle. Of the stomach poisons under investi-
gation, calcium and magnesium arsenates are the most satisfactory
for use under average conditions.

Chapman and Gould (25) in 1928 preferred magnesium arsenate
either as a spray or as dust with lime for the control of the ilex-
ican been beetle. Calcium arsenate with hydrated lime has given
good results, but p'lait injury .iay result.

Cor! (28) in 1928 experimented, with arsenicals, both as
spra-ys and as dusts, in controlling the 7i.: ican b',.ri beetle, and
found both effective. II. -,-,;psium and ci-cium arsenates proved
superior to lead arsenate.

Howard (82) in 1928 sttedr tha:-t of the numerous m:-,terials
tested for controlling the Me::ican bean bcotle, the bust rcsull.s
were obtained with m'-n, slumn or calcium arsonates.

Howard (85) in 1928 concluded that m. -nosium or calcium
arsenates are superior to sodium fiuosilicato in comb- ting the
beetle. Analyses of sprayed beans indicated that there is no

- 13-

danger from the use of those poisons when applied as recommended.

In South Carolina (5) the poisons which gave the most en-
couraging res-alts in 1923 were magnesium anid. calcium arsenates,
both mixed with hydrated lime, and used as a dust. Lead arsenate
gave good control, but there was indication of foliage burning.
As sprays, only magnesium arsenate and calcium arsenrate mixed
with hydrated lime were suitable.

Britton (14) in 1929 described the discovery and control
treatment for the M1e::ican b--.n beetle in Connecticut. Magnesium
arsenate used as a spray or dust gives the most satisfactory control.
Calcium arsenAte and barium fluosilicate may also be used.

Burdette (17) in 1929 found, that magnesium arsenate caused
no injury to bean foliage when used as a spray or dust. Calcium
arsenate caused slight to severe injury. Lead arsenate caused
severe injury.

Cory (29) in 1929 ex.:.c-rimented "with arsenicals and found that
lead arsenate was the most injurious to the bean plant, calcium ar-
senate next in order, and. :Qa:iesium ara,-n.-te the least likely to
injure the bean fol. .e.

Cory (30) in 1929 cut the number of materials recommended
for the control of the beetle down to n'.-.n:esium arsenate as a
spray, before the pods had formed, and pyrethrum afterwards. For
dusting, magnesium arsenate with lime; or a mixture of 20 percent
copper sulphate, 20 percent calcium arsenate, and 60 percent hydrated
lime. The addition of copper sulphate, litharge, or zinc to the calcium
arsenate caused less burning. Copper sulThote in all tests reduced
the injury. Magnesium arsenate is the mot3t effective measure for
commercial control of beetles.

At the Georgia Exr-rinent Station in l1Z29 (149) tests
were conducted with calcium and magnesium arsenates, and zinc
arsenito for control of the .*:xican bean beetle. These materials
when mixed with lime and applied as a dust gave fair control of
the beetle, with little or no burning of the plant. When applied
as a spray, n.mgncsiun arsenato alone caused no injury and zinc
arsenite only slight burning.

HaMnilton (68) in 1929 reconmmendod magnesium arsenate or
calcium orsenate with lime as a spray for controlling the Mexican
bean beetle. For dusting he recomnncnded ncgnesium arsenate with
hydrated lime, or calcium arsenate' with hydrated lime, to which
nma-y be added sulphur, if desired.

Marlatt (104) in his report for 1929 stated that nagnesiun
arsenate as a spray proved the most effective control for the
beetle. Calcium arsenate applied as a dust was also effective,
but in Y.any instances, particularly in certain sections of the

- 14 -

Atlantic coastal pAain, plant burning followed treatment. Some
brands caused mc.rked crop injury.

Landers and L!.Mgford (1-32) in 19;J9 bejan a series of field
tests on snap beans to determine the relative effectiveness of
the vari,-us materials that were being used for controlling the
Mexican bean beetle. The materials experimented with as sprays
were the following: 1Ma:gnesium arsenate, alone and mixed with bordeaux;
calcium arsente alone and mixed with bordeauix and lead arsenate. The
materials used as dusts were the following: Calcium and magnesium
arsenates, and zinc arsenite, in various comoinations with monohydrated
copper sulphate and lime.

Calcium arsenate, which had given satisfaction elsewhere,
proved too injurious to the bean plant, even when used with lime,
either as spray or dust. Magnesium nrsenate ,'ave excellent control
of the beetle, was safe on foli'. e, and mi:ed well with bordeaux.
Zinc arsenite was unsafe. The copper-arsenic-lime dusts showed
commercial possibilities.

In 1929 the South Carolina Station (6) re-rorted an un-
expected case of bean fo] -I [e l"barnin.- from the use of rngnesium
arsenate. 1he insecticides experimented with were two tyjes of
magnesium arsenate.

E7fp.rimental r'or!: in South Carolina (7) on controlling
the Mexican bean beetle in 1929 showed that iiiagnesium arsenate was
the only satisfactory poison. Calcium arsenate, which had beeoon
fairly satisfactory during dry seasons, scorched the beans con-
siderably in 1929.

Burdette (18) in 1930 experimented with materials for the
control of the ;:i;ican bean beetle. Calcium arsenate in combination
with monohydraed copper sulphate and lime (20-20-60) gave burning
in practically all tests, very severe in some cases. Lhavnosium
arsenate as spray or dust with hydrated lime caused no injury.
._L-gnosium arsen v'e is the only arsenical that can be: used safely
on bean foliage.

The Connecticut Agricultural Exreriment Station (15, 139)
reported good control of the beetle in 1930, using irLa.-nesium

Cory, Sanders, and Henerey (351) give a generall account of
the campaign carried oit in 'Maryland in 1929 "j-iinst the Mexican
bean beetle. Tests of materials to determine whether they would
render aCrsenicals less likely to injure the foliage showed an
advantaic from the use of copper sulph'tte, load monoxide, and
zinc with calcium arsenate. Copper sulphate reduced injury both
in dusts and sr-:0s. I-:gncsium arsenate as a spray proved the most
Effective mcAtcri7l for securing commercial control of the beetle.

- 15 -

-,dy and Clarke (50) in their circular consider that mag-
nesium arsenate is the only arsenical that is effective in control-
ling the Mexican bean beetle and yet harmless to the plant.

Howard (86) in 1930 considered :.g:C-esium arsenate, as a spray,
the best known remedy for the protection of beans g-ainst the
Mexican bean beetle.

Howard and Brannon (87) both consider that from the large
number of remedies that have been tried, magnesium arsenate has
given the best control against the beetle.

Knull (95) in 1930 recommended the use of magnesium arsenate
for the control of the ie:::cic bean beetle. If magnesium arsenate
is not r.v-.ilable, !.d ars--_i te as spray or dust co!n be used. 71,cn
used as a spray or dust, hydrated lime is added. Greater injury
to the bean plant w-. caused by calcium arscnato than by lead arsenate.

List (101) in 1930 sta-Ited that in Colorado magnesium arsenate
and zinc arsenite m.-,y be used safely on bean foliage, with good con-
trol of the beetle. Magnesium arsenate is more generally used in
the eastern sections of the United States.

Marlatt (105) in his yearly report stated that during 1930
experiments were conducted on attract'-nts and repellents, using
the bean beetle in tests. 3Bcan foliac sprayed with arsenicals
was repellent, but not sufficiently so to prevent feeding. Lead
arsenate was the most repellent, mancosium arsenate was less so,
and calcium arsenate the least.

Marlatt (105) in 1930 reported that tha results of further
experiments with control ueasures agree closely with those obtained
in previous year's, and that ,.i-gnesium arsenate is the best material
to use for controllinr- the Me- ican bean beetle. It did niot injure
bean foliage to an;: appreciable extent in any of the sections where
tested. Calcium arce.nate resulted in injury"n many instances.
Lead arsenate c.-used heivw plant injury.

Peairs (124) in 1930 mentioned the use of lead, calcium, and
magnesium arsenates with lime as sprays or as dusts in controlling
the Mexican bean beetle.

Burdette (19) in 1931 tested several materials for the control
of the Mexican bean beetle. Calcium arsenate in a large number of
cases caused considerable injury to bean foliage. :iagZnesium arsenate
caused no injury as a spray or dust and is recommended for control

In 1931 the entomologist of the Connecticut station (140)
drew conclusions from a study made in 1930 on the control of the
beetle. He found that bean damage could be prevented by spraying
or dusting combined with certain cultural practices. Spraying was

- 16-

most effective when using magnesium arsenate with caseinr-lime.

Friend and Tur-ner (56) in 1931 stated. that the first maaterial
recommended for the beetle control was paris green, but tlis injured
the bean severely. Lead. arsenate used in Colorado in 1921 and in
New Mexico in 1907 was fairly satisfactory, although some
resulted. Later investigations have shown that lead arsenate reduces
the yield of beans, in some cases up to 59 percent, even though no
visible injury develops. Calcium arsenate was not quite so injurious;
visible injury occurred in most cases, however. ',:-;-esium arsenate
caused no visible injury, but a reduction in yield occurred in three
cases, one when the niaterial was used alone, and the other two when
diluted with hydrated lime.

Hedrick (74) in 1931 stated that the 'Mexican bean beetle had
been known on Long Island since 1928. E,-periments were cor'menced
in 1930 to determine the relative value of recommended spray and
dust mixtures, as indicated by the tolerance of bean plants to such
sprays or dusts. It was found that both spray and dust mixtures
containing lead or calcium arsenates were decidedly toxic to the
plant. The burning effect was slightly reduced when the arsenicals
were used with bordeaux mixture or copper-lime dusts. Magnesium
arsenate and. barium fluosilicate appear to be noninjurious to the

Huckett (90) in 1931 made field tests with commercial brands
of arsenicals, both as sprays and as dusts. Ls nesium arsenate
was the safest to use on bean foliage at the commonly recommended
strengths. Lead and calcium arsenates caused considerable reduction
in yield and serious injury to the foliage.

Huckett -(91) during 1931 conducted field tests with five ar-
senicals to determine the amount of injury caused to bean foliage.
They were applied as spray and as dust. Acid and basic lead ar-
senate, calcium and magnesium arsenates, and zinc arseiite were used.
Magnesium arsenate, both as sp-oray and. as dust, was the satisfa-ctory

Langford (97) in 1931 recommended the use of magnesium
arsenate as a svr-,y for the control of the Mexican bean beetle.

Harlatt (106) in 1931 reported extensive tests conducted
with barium fluosilicate, cryolite, and potassium fluoaluminate
against the beetle. No conclusive results were obtained. The
indications were that when used as dusts, these materials will not
give such satisfactory control -.s does ra.ngnesium arsenate or
calcium arsenate, as they do not adhere to foliageo as e7ll as
the arsonicals.

Sherman (136) tested calcium and magnesium arsenatcs
a'.:r.inst the beetle. I-Minesium arsenatte gave the bect results.

- 17 -

Sweetman (150) in 1931 recommended the use of m:,-gn-:sium
arsenate as a dust or spray for the control of the :...::ican bean

Bourne (11) in 1972 nade preliminary tests with various in-
secticides for control of the Mexican bean beetle in Masoachusetts.
:.aTnesium arsenate either as spray or dust was found the safest and
most dependable material on the market. Both lead and calcium
arsena.tes caused severe burninga, in most cases killing the plant.

Brannon's (13) observations on the control of the Mexican
bean beetle on snap beans, when heavily infested with the onion
thrips, showed that magnesium arsenate caused plant injury, which
was probably due to laceration of the oidcrmis of t'.e leaf by the
thrips with subsequent entrance of the arsenicnl. If nicotine
sulphate is added to the spray no arsenical injury results.

Huckett (92) rocorycmndod in 1932 the following materials
for the control of the M',:-.ican bean beetle:


Magnesium arsenate, with }:yso or flour paste, or with
skim milk and hydra ted lime.
Calcium arsrrate pith bordcau:r mixture, or with h:':-ted


Mc,.gnusium arscn=te with hydrated lime.

Calcium arsenate with d.h-'.'.rated copper sulphate and lime.

Marlatt (107) in 1932 reported th-t mAgnesium arsenate as a sprpy
remained, for most areas and conditions, the best means of controlling the
beetle. Fluorine compounCs do not give protection to the bean plant for
so long a period as does c'!.:n-,-esium arsenate.

Sherman (137) conducted further tests with r.,.:;nesium arsenate
for the control of the beetle. He showed that the arsencial is highly
toxic to the beetle and at the same time has little or no injurious
effects on the bean plant. Dusts were preferable.

Sherman (138) in 1932 experimented with substitutes for magnesium
arsenate in controlling the Mexican bean beetle. Conclusions Vere not
dra'.wn, but the cost of the substitutes was greater than that of miagnesium

Turner (152) in 1932 found that magnesium arsenate was the most
satisfactory material to use for the control of the beetle.

- 18 -

Bourne (12) in 1'9. experimented with materials for controlling the
beetle. 'an,;anar (nanja:icse arsenate) with lime caused severe burning
of bean foliage. Iatox (barium fluosilicate) com -oound compared favorably
with -nn-rsium arsenate, the standard material for controlling the Mexican
bean beetle. (42) in 19;33 carried out cx-roriments fo.r controlling the
Mexican bean beetle in w Mexico. Ho used lead, calcium, and ma.,i-sium
arscnates. In 1929 lead arsenate caused the greatest amount of injury,
magnesium arsenate causing the least.

In 1933, Howard, Brannon, and. Mason (88) reported results
of field tests on the control of the Mexican bean beetle, cover-
ing a period of 3 years. They reported that-there appears to
be no advantage in changing the current recommendations for the
use of magnesium arsenate.

Marlatt (108) in 1933 reported the continuation of field
and laboratory tests in Ohio and Virginia ,',-inst the beetle.
Fluorine compounds have not given satisfactory control when used
as dust. The use of magnesium arsenate, however, is still recom-
mended. -

Turner and Friend (155) in 1933 recommended a spray con-
sisting of 3 pounds of magnesium arseonate and 2 pounds of casein-lime in
100 gallons water for controlling the U.exican bean beetle. This
mixture ,roved very satisfactory in 1933. Monohydrated copper
sulphate 19 percent, calcium arsenate 17 porc'-. t, and hydrated
lime 64 percent was the most satisfactory dus t.

Turner and Friend (153) in 1933 reported further tests with
materials for use naninrst the Mexican bean beetle. A dust composed
of monohydrated copper sulphate 19 percent, calcium arsenate 17
percent, and hydrated lime 64 percent, proved highly satisfactory.
It was superior in control to magnesium arsen'te, but was more
expensive. For spraying-,: ri.-'-nesiu n arsenato !with casecin-lime is
rocormendod. For dusting, the above mentioned copper-arscnic-limo
mixture, magnesium arsenate with line, or barium fluosilicate with
hydrated lime arc recor.incded.

Turner and Friend (154) in 1933 roco i:cnded the use of a
spray consist'g; of magnesium arsou:-te and calcium caseinate for
the control of the beetle.

Huckett (93) in 1934 successfully used dorris dusts as a
substitute for magnesium arsenate in the control of the Mexican
bean beetle on c-n,-p and lima beans during the period -f pod forma-

" 19 1

2. 3ean leaf beetle (Cerotoma trifurcata (Forst.))

Eddy and Nettles (51) report work done on the control of the
bean leaf beetle. Calcium arsenate and magnesium arsenate were
used in experiments conducted at Clemson College. In these tests
calcium and magnesium arsenates were about equally effective in
controlling the adult insect. TEagnesium arsenate is recommended
as a spray or dust in control measures.

3. -Codling moth (Caroocapsa pomonella (L.))

Sanders (131) in 1919 stated that russeting of apple fruit
due to bordeaux mixture may be avoided by the addition of lime.
In Nova Scotia, russeting is prevented by using calcium or
magnesium arsenate in place of bordeaux mixture as a spray.

Dutton (46) in 1920 made a comparison of various sulphur-
arsenate dust mixtures I'leadarsenate, calcium arsenate, and
magnesiCrn arsenate. These materials were used on apple, cherry,
plum, peach, currant, and potato foli-e. Lead arsenate was
recommended for general use on all kinds of fruits, as it had
given uniformly better results than any other arsenate. Calcium
arsenate gave excellent results when used on potatoes and other
similar crops, but was not always satisfactory on fruit trees.
Magnesium arsenate caused severe foli-ge injury on peach and apple
and failed to give satisfactory control of the codling moth.

Halligan (67) conducted tests in 1920 to determine the com-
parative value of numerous arsenical compounds for controllin,- the
codling moth. Lead arsenate proved to be the standard material. for
fruit spraying, Calcium arsenate, even with the addition of lime,
caused severe foliage injury to apple and peach. I-r-nesium arsenate
also proved unsatisfactory.

,.-.landor's (109) investigations into the best treatment for
controlling the codling moth showed that calcium arsenate is inferior
to lead! arsenate, and magnesium arsenate still inferior to calcium

Fernald and Bourne (53) in 1922 found that calcium metarsenite,
magnesium arsenate, end zinc arsenite were unsafe to use on fruit
tree folinteo.

Melander (110) in 1923 reported results of spraying experi-
ments against the codling moth. Calcium and magnesium arsenates wore
inferior to lead arsenate. Slightly better results were obtained
when calcium caseinate was added.

- 20 -

Newcomer, Yothers, and. Whitcomb (119) in 1924 stated that
magnesium arsenate,' calcium .ar.en'I.te, and paris .reo.-n have been
used as codling'moth sprays, but are not so desirable or so safe
on the foli.o4&- as i&lad arsenate.

Howard. (.81) in 1927- reported the use of substitutes for lead
arsenato din or,'h.r .,spraying, which included ma_-enosium arsLnatoe.

Spuler (144) in .1927 conducted experiments a,'t the
codling moth with lubricating and drying oils to determine the
value of the. latter as an. adhesive for arsenical s-prays, the
value of lubricatii-. oil as a combined odhesive and ovicide, .rand
the possibility of substituting lubricating oil for lcadl arsc--Atc.
Fish oil was coribined ,with calcium .oLd magnesium arsenates. The
result obtained by combining; fish oil was better than when.-calcium
or ma.gnesium arsenntes was used alone., but thoi-r toxicity was not
so good as obtained with lead arsenate.

Alden and Ycomans (2) in 1928 -vyerimonted with non-lead
arsenical sprays for controlling the codling moth. All gave poor
results when to lead arsenate, and mos-t of them injured
the foilage severely. Magnesium arscnate gave the best results of
the new sprays.

In the report of the committee of econc. e entomologists
(126) to formulate plans for investigating the codling moth (published
in 1928) a summary of 4 laboratory and 1- field" tests showed
theft M- -su rc
tht magesium arsenate was about one-half as effective as lead
oarsenate in controlling the pest. Severe injury to the foliage
recorded in several cases.

Howard (82) in 1928 reported that the compounds tested
against the codling moth were considerably loss effective than load
arsenate, and that some caused important foliage.' injury. I:dIgnesiun
arsenate was one of the arsenicals used.

E:.perimental ..ork was conducted in 1928 at the Washi.,nton
Station (145) On codling moth control in which the arsen:ates of
manganese, calcium, and magnesium were used. None proved as' efficient
as lead arsenate.

'TOwcomor and Yothers (118) conducted a series of laboratory
and orchard experiments in controlling the codling moth over the
period 1919-29, The arsenates of lead, calcium, and magnesiUm
were tested.. ",orm of the arsenicals tried in these tests in the
laboratory equaled lead arsenate.

- 21 -

Spuler (146) in 1929 tested a series of arsenicals against
the codling moth. The arsenates of calcium, :-.:-nesium, manganese,
and aluminum were used. Calcium and. magnesium arsenates j-.v& such
poor results that tests were discontinued. at the end of the first
brood of the codling moth.

Talbert, Hooker, and Startwout (151) tested in 1929 various
sprays for the control of the codling moth. They -4ound. that
magnesium arsenate defoliated peacih trees, but only slightly in-
jured ar-ules in general and controlled the codling moth and plum curculio
as well as did lead arsenate. Jonathan and Ingrar. a- iles suffered
considerable burr.: from :-i",.gne.sium- 'Er.te.

Peairs (124) tested promising insecticides in 1931 to find a
substitute for lead arsenate. The insecticides tested included
calcium and rm-rnesium arsenates. The best results were obtained with
maCnesium arsenate.

'r1st (57) in 1i.32 reported the results obt:Ained from spraying
and dc:ating e.:_ eriments carried o'rt in Pennsylvania over a period
of 8 ye trs on a-vpl ''s. He r -ported th'.t slightly less injury oc-,
curred in sp-raying than in dusting experiments. Calcium and mag-
nesium arsenates were found to be as effective as lead arsenate.
Magnesium arse:iate combined with lime-sulphur caused no injury to
fol i age.

Garman (59) carried out some experiments in 1933 on apple
and peach trees. The arsen.ites of calcium, manganese(n,_: r),
magnesium, and zinc were used. M, ---nesium arsenate caused severe
foli-ge injury to apple trees. T1--h. data were not extensive enough
to warrant conclusions. On peach, m gr...sium arsenate caused severe
dofoli,.tion, fruit drop, and bark canker.

Hanrman (70) conducted experiments in 19.:'. in w-st,-rn 'J-2v.
York with five cover sprays of various materials against the codling
moth. The materials tested included lcad, calcium, :,nd magnesium
arsenates. The most effective mat ..ial was lead 'sen--te which
S've 80 percent uninjured fruit. Calcium arsenate with bordeaux
mixture caused considerable yellowing ond drop ing of foliage.
All of the arsenicals left a residue in excess of permitted
tolerance. Washing for 25-30 seconds in 1 percent h;- drochloric
acid solution at 59 C., within 2 weeks after picking, effcctivoly
reduced arsenical residue, except on .--.]e.s sprayed with manganese,
mn'"ncsi-um, and lead arsenates.

Cutright (35) in 19.3". tested five arsenicals '-i.,..inst the
coiling moth on apples. Lead and magnesium arsenates were the least
toxic to the foliage, b'ut the latter av'c poor control of the insect.

Flint (55) in 1934 reported that Hutson in Michir-:.n experimented
with calcium, zinc, and magnesium arsenates for controlling the codling

- 22 -

r oth. Tnhey gave lower control than lead arsenate, and were not in-
jurious to vigorous trees. In Ohio they i,.:de field tests and reported
their efficiency in the following order: **Load, zinc, calcium, and
rafnosium arsenates. .. '

Parrott (121) in 1934 conducted experiments with the most
promniising insecticides for controlling the codling moth in ITcw York.
Lead, calcium, and magnesium arsenhtes -wcre used. lead ?r cn.nte, alone
or with oil, proved, to be the most effective. Whon tested in the
orcha-'c, none gave as good results as lead arsenate. The ,oor control
of the nonlead arsenicals and the relatively high d.:c-rc of injury
resultin; from their use practically- eliminated. all of them from
further consideratio-n.

Spuler (147) in 1934 found that the addition of a semi-
drying oil, such as fish oil, increases the efficiency of calcium
aid mjnesium arsenates, whi-'ch when used"alond have not been satis-
factory for controlling the codling moth.

4. Plum curculio (Conotrachelus nenuphar `(Herbst))

Snapp (143) in 1928 made a study of the tocic value of
ar."senicals and fluosilicates on the plum curculio. Lead, calcium, and
narnesium arsenates were used. Lead arsenate -7sa more toxic than
the other arsenates, the toxicity Lbeing in the following order: Lead,
calcium, and magnesium arsenates.

Talbert, Hooker, and Startwout (151) in 1929, in testing various
sprays, found that magnesium arsenate defoliated.peach trees, but
that it was only slightly injurious to apples in general and controlled
the codling moth and the plum curculio as well as did lead arsenaate.
Jonathan and Ingram apple trees suffered considerable burning from the use
of :n.gnesium arsenate.

Studies in Connecticut (141) on substitutes for lead arsenate
in 1933 revealed the fact that m)jnosium arsenate caused s-vere
burning of peach foliage. The best control of the curculio.was
obtained with lead arsenate with zinc sulphate corrective.

Howard (81) in 1927 reported that extensive tests were mado
in Georgia to determine the relative toxicity of a number of a.rscnicals
to the nlum curculio on peach. The i.rccn--tes of tri-calcium, barium,
and zinc, in the order named, were found, rather toxic to "the insect.
The arsenates of magnesium, manng"irnesc, and aluminum were less toxic.

Howard (82) in 1928 reported that in Georgia. tests were made
to determine the toxicity of a number of arsenicals again'.;t the
plum curculio. Laboratory studies were' completed on the effects of
hydrogen-ion concentration upon the arsenateos of acid lend, tri-
calcium, and nernosium. Considerable correlation had been found to

exist between the burning produced upon peach foliage and the
speed with which iese arsenates decompose in a solution having
a T)H equal to that of rain water or dew.

5. Japanese beetle (Popillia japonica(Newm. ))

Leach (99) in 1926 discovered that the larvae of the Japanese.
beetle died when they fed in soil containing a sufficient amount of
certain arsenates. He experimented with the basic and acid arsenates
of lead, magnesium, and calcium. The basic arsenates of lead and
magnesium were found to be nontoxic to the larvae as well as to the

Van Lecuwen (158) in 1932 tested a number of materials in the
field for repelling the Japanmese beetle. The materials tested were
acid lead arsenate, acid lead arsenate mixed with other materials,
basic lead arsenate, magnesium arsenate, and calcium arsenate.
Foliage sprayed with water was used as a check. A larger number of
beetles left the trees sprayed with magnesium arsenate than from the
unsprayed trees.

Marlatt (106) in his report for 1931 -ys that experiments
were conducted to determine whether stomach poisons would be effective
insecticides against the Japanese beetle larvae, when introduced into
the soil. Certain fluosilicates are effective when freshly applied,
although much slower in action than acid lead arsenate. Magnesium
arsenate was found to be almost equally effective. Basic lead arsenate
proved to be of little value. The insecticidal action of the arsenates
was only slightly lessened after being in soil for 1 year.

6. 'Rusty tussock moth (Notolophus antiqua (L.))

Crowley (32) conducted experiments on controlling cran-
berry insects in 1927-28. He discovered that magnesium arsenate
was much superior to lead arsenate as an insecticide against the
tussock moth.

Crowley (33) in 1929 carried on further experiments with
ijaCgnesium arsenate. He found that the tussock moth was controlled
by magnesium arsenate, which proved to be a very efficient spray.

Fulmek (58) in 1929 made a "study of the differences in
toxicity of various arsenical insecticides, in Sumatra, on a number
of caterpillars. Toxicity did not correspond with the percentage of
arsenic oxide in the samples. In practice the following sequence
was observed: Paris green, load, calcium, zinc, and iron arsenates.
Feeding experiments in Austria in 1927 with the caterpillars of
Pieris brassicae L. revealed similar discrepancies. In 1928 tests
were made with six arsenites and six arsenates on caterpillars of
Notolophus antiqua (L.), Gastrorpacha quercitolia (L.), and Pieris
brassicae (7.) In seqtlence of killing power the arsenites were
magnesium; then lead, calcium, and copper of the same toxicity; iron,

- 24 -

and zinc. The arsenates were lead, copper, calcium, magnesium,
zinc, and iron. The toxicity of the arsenites was superior to that of
the Prsenates.

7. Cranberry fireworm (Bhopobota vacciniana (rTck.))

Crowley (33) in 1927-28 experimented with magnesium arsenpte
spray in controlling the cranberry insect. It was found superior to
lepd Prsenate, but doubt was expressed whether it could be used
alone as a fireworm spray.

8. Potato flea-beetles (Epitrix cucumeris
Harris and E. subcrinita Leconte)

Hanson (69) conducted experiments with numerous arsenicnls
and nonarsenical materials in controlling the potato flea-beetle.
The nrsenicals used were calcium and magnesium arsenates and
both acid anmd basic lead arsenate. The best control was obtained with
calcium and acid lead arsenates, used .s a dust -nd mixed with lime.
Calcium arsenate was the most effective arsenical when used either
as a dust, a spray, or in combination ,'ith bordcrux.

Daniels (36) in experiments with the flea-beetle used
calcium and magnesium arsenates. Both spray and dust experiments
were made. The results with m-gnesium arsenpte vere discouraging,
with no tubers entirely free from worm tracks.

9. Oriental peach moth (Grapholitha molesta (Busck))

Peterson (125) in 1920 tested a number of arsenicals on
peach foliage and twigs in experiments on controlling the peach
moth. The arsen;tes of lead, calcium, and magnesium were used
as sprays and dusts. None of the arsenical sprays stopped the
larvae from entering the twigs. When the f.rscnicals were applied
as dusts, the cp.lcium and magnesium arsenates, alone or in com-
bination with lime, killed approximately the same percentage of the
larvae as did lead arsenate.

10. Boll weevil (Anthonomus grpndis (Boh.))

Walker and -iills (159) in 1927 tested over 100 poisons and
poisonous mixtures against the cotton boll weevil in the laboratory.
Magnesium and zinc arsenates showed weevil toxicity about equal to
or greater than calcium arsenate, and caused little or no plant

11. Cabbage insects

Fulmek (58) in 1929 determined the toxicity of a number of
arsenates and arsenites, using the caterpillars of the cabbage moth
and the leaf weevil. The order of the toxicity of the arsenates
was found to be lead, copper, calcium, mpgnetium, zinc, -nd iron.
The arsenites were in the following order: Magnesium, lead, clcium

- 25 -

topper, iron; and zinc,

Reid (123) in 1934 tested numerous materials. against, the
cabbi'e looper (Autographa braf'sicae (Riley)), the diamond-/bck :oth
(Plutella maculipennis (Curtis)), and the imported cabbage worm
(Ascia rapae (L.)). Calciuma and -nosium arsonitcs werc not so
toxic as derris and pyrethrum powders.

12. Strawberry root weevils (Brachyri-inus ovtaus (L.)
and B. rugiirons (-yll.))

I-elander and Spuler (iii) in 1926 tested various poison baits.
Calciiun, T.:agnPsium, and lead ar:.enates, i)aris green, white arsenic,
sodium fluoride, and paradichlorobenzone were used. Of these materials,
magnesium are.-7.te -.roved most satisfactory.

Melander, Webster, and Spulor (112) in 1926 investigated
soil treatment for controlling the strawberry root weevils. The
materials used were the arsenr.tos of magnesium, calcium, and zinc;
and sodium fluoride. -.nesium arsen.*.te proved to be the most
toxic to the weevils.

Downes (45) in 1927 ex' erimentod with a poisoned apple-waste
bait a;._,iIst the strawberry root e.Cevils. He used sodium fluo-
silicatc and calcium and r'.-nesium arscnates. All gave good results.

Mto anrA. Wilcox (117) in 1927 experimented with poison bait
in controlling the rootweevils. 3:1 tcnsive field and
l-.".raUory tests were conducted in order to dceterr-iine which poison
would give the best results under var-in,7 conditions. The arsernatos
of c-'lcium, lead, and m-tio.esium were used. Calcium arsonate was
found to be the most effective in the tests.

TJrc-'hns (157) considers :o,nesium .arsenatc unsafe for spray-
ing upon folifc, but states that it is cc.iin into more general use
in connection with I:oison b-it for the control of strawberry root
wcovils, and possibly other forms, such as h vegetable weevils.

13. Beet webworm (Loxostege sticticalis (L.))

Gi31ette (60) in 1919 reported experiments with paris green, and
calcium, lead, and magnesium arsenrtes on controlling the webworm
of the s-,ar beet. All these materials were satisfactory when
.ap.,lied in double the ordinary strength used for controlling
ordinary leaf-eating cato-rpillars.

Gillette and List (61) in 1920 successfully controlled the
webworm on sugar beetz by spraying with calcium, i-r.i.r-sium, and
load arsenates.

- 26 -

14. lurnip webworm

Robi.nson (130) in 1931 repo:cted the use of 13
materials in tests to detern.-ine the best control of the turnip
webiworT.. Five materials, including 1.ead a-id calcium arsenate,
when applied as a dust gave 100 percent 1kill of the larvae. The
mortality from the other ma+-irials dusted, which included- magnesn ium
arsenate, were so lo i that no furt'-er tests were made with them.
Thoy were tested as sprays and proved va.lueless.

15. Spotted blister beetle (EiAca-hta maculata (Say))

Pairs (124) in 191 found that rjagnoesium -rs-nate applied
as a dust or spray yve good control of tnhe blister beetle
Epicauta macuclata on the fruit trees.

16. Black vine weevil (Bra.chyrhinus sulcatus (F.))

Smith (142) in 1 :27 mde a study of the con'-.ol of the black
.vine weevil in grec:.'i-.use' and nurseries. Lead a'senate'as 'a
soil insecticide offered sone rorise. Poisoned dri.d-aple waste
baits containing 5 percent :unesium arsenate or lead arsenate
were tested without -uch success.

17. Euroi,, an corn borer (Pyra-asta nubilalis (Hbn.))

Caffrey and. Vorthley (20) in 1922 concluded that the appli-
cation of arsenical -oisons had not been found to protect growing
corn plants from the Eauroeanai corn borer. Lead,
calcium, and magnesium arserrtes Tere tested.

Caffrey and Huber-(21) in 1928 reported experimental work
covering 5 years. The materials tested alone or in various
combinations as spi.'a.-s or lusts were lead, calcium, and magnesium
arsenates. No materials were recommended by them for practical use.

18. Blueberry maa:ot (Fhy letiL pomonella (Walsh))

Lathrop and Nickels (98) in 1932 rc-orted dusting experi-
ments with lead, calcium, and magnesium arsenates against the blue-
b. 'rry- r ifot in Maine..

19. Squash beetle (E ilalchna boroalis (F.))

Underhill (156) in 1923 experimented with calcium, magnesium,
ande lead arsenates in the control of this beetle, feeding on watermelons.
Calcium arsenate _:avu the best control. All the compounds had a more
or less repellent action. The lar-n.e are more susceptible than the
beetle to the ocisons.

27 -

20. Plum web-sawfly (7.:: urotoma inconspici-i (Norton))

Severin (135) in 1920 conducted spraying cxpcriments with
stomach and contact poisons on the control of the plum web-sawfly.
The stomach poisons were much more effective. Calcium and magnesium
ars. .nates caused considera.blc scorching to the trees. Lead arsenate
gave satisfactory control; it was also effective as a dust.

21. Grapeberry moth (Polychrosis viteLana (Clem.))

Howard (76) in 1921 reported the use of arsenical sprays
against the berry moth feeding on grapevines. Calcium arscnatc
can be used on Concord grapes but burns the leaves of most other
varieties. sium arsenate is more injurious than lead arscnato,
and can not be used on grape foli i.,-.

Howard (77) in 1922 reported the use of calcium and magnesium
arsonatcs on grape folJ.-.g for controlling fK'-.Je insects. They arc
not so safe to use as lead arsenate on the foliage.

iHoward (82) in his rciijrt for 1928 .-iy- that sprays of
calcium and mugncsium arsenates have been tested "Inst grapevine
insects. The results of experiments in 1927 ,'O;w that the arsenates
of calcium and magnosium give the same control of the berry moth as
does lead arsenate.

22. Green clover worm (Pl-thyuena scabra (F.))

Stirrett (148) gives the history and blonomics of this
noctuid in North America. The first outbreak in Canada was in 19.31.
Control measures consisted in dusting or spraying with calcium or
magnesium arsenate. Beneficial results were obtained in most cases,
with no re orts of foliage injury.

23. The pyralid Maruca testulalis (Geyer)

Bruner (16) in 1931 described ,he larva, pupa, and adult of
this pyralid, wnhi-ch burrows into pf0 of lima beans in Cuba. Spray-
ing with a mixtiire of lead arsenate and bordeaux mixture is far
from satisfactory, Magnesium arsenate mr.ay prove more suitable.

24. Colorado potato be.:tle (Leptinotarsa decomlincata (Say))

Couturier (54) in 1933 experimented with spr:y-s against the
potato beetle. It was found that, based on an equal content of
arsenic pentoxide, copper and aluminum arsenates were nearly as
toxic as lead arsenate, and rm:.grnesium arsenate was more so.

Fernald and Bourne (52) ih 1919 made experimental spraying
tests with lead, calcium, and magnesium arsenates, in combination
with bordeaux mixture, on potatoes to control insects. The three

arsenicals appeared to be equaally good.

25. Red-logged graf hopper (Mcl._no,:-lus fcmur-rubr.=m (Lcg.))

MArcovitch and StandlIy (103) in 1929 e:cperimentcd with bran
baits containing 0.5 percent by weight of various poisons -.inct
the rcd-logged grasshopper. The percentage of mortality obt:'Uncd in
30 hours with the materials was: barium fluiosilic!te, 95 percent;
sodium fluosilicate, 100 percent; nr:.iniesium arsenate, 0 percent.

26. LLia bean pod borer caterpillars (Mairuca testulalis

(Geyer), Fundclla cistipennis (Dyar), and Etella zinck-
'__- e nellga (oreit.)) -

Wolcott (161) in 1933 gave notes on the bionomics of the lima
bean pod borers in Puerto Rico. E.:pcriments with sprays of bordeaux
mixture, with or without magnesium arsenate, failed to reveal any
promising method of control.

27. G-'rsy moth (Porthetria dispar (L.))

Marlatt (106) in 1931 reported that various insecticides wcre
used to ascertain to what extent they were toxic- to the gypsy moth
caterpillars. Laboratory tests were conducted, using sprigs- of
foliage treated with the different poisons. With the lethal dose as
a standard, the toxicities of the materials wor-; as follows: lead
arsenate, 100-percent; calcium arsonate, 100 p'-cent; magnesium
arsenate, 50 percent.

28. Miscellaneous.

Austin (4) in 1927 reported the results of experiments with
insecticides under Ceylon conditions. Lead and ra ngncsium arsenates
were used.


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88. Howard, N. F., Branncn, L. W., and Mason, E. 0.
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89. Howard, N. F., and English, L. L.
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90. Huckott, H. C.
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91. Huckett, H. C.
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92. Huckett, H. C.
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93. Huckett, H. C.
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95. Knull, J. N.
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96. Kotschoubey, P.
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97i Langford, G. L.
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98. Lathrop, F. H., and. nickels, C. B.
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99. Le. ch, 3. R.
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100. Liu;t, G. .
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101. List, G. M.
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102. iMarcovitch, S.

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103. M1rcovitch, S. end Stanley, W.
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104. Marlatt, C. L.
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105. 4Iarlatt, C. L.
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106. Marlpott, C. L.
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107. Marlatt, C. L.
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108. Marlatt, C. L.
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109. Melander, A.L. .. .. ....
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110. :.Lelander, A. L.
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111. Melinder, A. L., and Spuler, A.
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112. MIeland-er, A. L., Webster, R. L., and Spuler, A.
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114. :c-llor, J. W.
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115. I m1, A. :E... .
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116o 3.Iolinari, 'E',
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117. l.Ioto, D. C., and Wilcox, J.
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118. :T0coorr, E. J., and Yothers, :.I. A.
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119. T-.',cormcr, E. J., Yothers, I. A., and. 'Jitcomb, 'J. D.
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120. Olsen, J. C.
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121. Parrott, P. J.
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122. Patten, A. J.
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123. Patten, A. J., and 0tieara, P.
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124. Peairs, L. M.
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125. Peterson, A.
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126. Porter, B. A., et al.
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127. Potts, S. F., and Barnes, D. F.
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128. Reid, 17. J.
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129. Reischauer, C. G.
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130. Robinson, J. I.
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132. Sanders, P. D.,.and Langford, G. S.
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133. Schiefer, Fr. C. B.
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134. Saaton, M., Y.
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135. Soverin, H. C.
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136. ShPrm F.
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137. Shermoan, ,
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138. Shermn, F -.
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139. Slto, W. L.
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140. Slate, W. L.
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141. Slate, W. L.
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.144. Spuler, A.6
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^,145^ Spulor, A. .*
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146. Spuler, A,
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147. Spuler, A.
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148. Stirrett, G. M.
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149. Stuckoy, H. P.
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150. Sweetman, H. L.
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151. T7lb-.rt, T. J., Hocker, H. D., and Startr.out., H. G.
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152. Turner, N.
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153. Turner, H., and Friend, R. B.
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154. Turner, :I., and Friend, R. B.
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155. Turner, N., and Friend, R. B.
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156. UJnderhill, G. W.
The squash lady-bird beetle. Va. Agr. Ept. Sta. Bull. 232.

157. Urbohns, T. D.
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158. Van Leeuvie i, E. R.
Reaction of the Japanrse beetle to spray deposits on foliage.
U. S. Dept. Circ. 227. 1932.

159. Taelkor, H. .. eand Mills, J. E.
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160. -.-ill, H., Bohn, C. and Engelbach, Th.
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161. Vblcott, G. N.
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