^-,q6 - 
The South Oarolim Agricultural Exprrinent. Stp.tion (35l) in l'^3S 
roportod that la"boratorv tests wcro ^?.^.c- using lead arsenate, calcium 
arsenate, . ruaenesium arsenate, ?nd paris green as undiluted dust.p: for 
the control of the cowpep curculio. S^mthetic cryolite, natural cryolite, 
and derris vrere used p.^ spr'^ys in the same sopien of tests. Magnesium 
arsenate and calcium arsenate produced 20-pcrcent mortality, lead arsena-^e 
10-percent mortality, and the othrr materi-^ls no mortality. Under lahor^- 
tory conditions paris green caused severe burning of the foliage. Only one 
series of test-^ was made, and the results werCi not conclusi'""e, . Eeplic^trd 
field plots v;ere trca.ted vrith undiluted lead arsenate, calcium arsenate, 
and magnesium arsenate', and a 0,75 percent derris-talc mixture was used 
on one replicated plot. Because of unfa^'-orable weather conditions ■ only 
one iiisecticid'-: treatm.ent was .alven the plots* All the arsenicals caused 
foli-nge injury under' field conditions vrhile the derris dust 'treatment 
re-suited in no injury. None of the treatments vrero entirely satisfpctory. 
Conotrachelus nenup'-'.ar (Hhst*), the plu'i curcTilio 
Flint ( lUii) in 1929 reported very poor control of the curculio in ?■ 
soutbrrn Illinois apple orchard "by the applic-.tion of a vhit<c-oil emul- 
sion plus Derrlsol, 
Eotenono in oil va-:^ ineffective. —Turner {]J§) in 1932. 
Garma.n ( 1^6 ) in 193^ report f-'d thot, in- general, nicotine, pyrethrum, 
and rotenone preparations are ineffective against'-the adult plum curculio 
pnd that standard acid lead arsenate is the most effective of the ' arsenicels, 
G-arman (l_57, 1^8) reported tcstn made, in 19"^5 with substitutes for 
lead car-^enate. G-round derris root in combination with bentonlte r^xi^''. skim- 
railk powder gave poorer results than cither cryolite or lead arsenate, 
notwithstanding an additional applic?ition in Augn.st. Control of the cur- 
culio was particularly p'bor with this combination. Fo foliage burn w-^s 
noted in' the cryolite- sulfur plot and the trees in the derris-sprnved plot 
were in particularly good condition at the end of, the season. All tr-^es 
received a pink spray of load arsenate and flotation sulfur. The condition 
of the trees is shown in the following trble. 
With'^ut,' external Marked by ' Conspicuous 
^ ' T reatment insect in.i u ry* ■ ,, curculi o sp ray russet 
Percent Fere.eht " Per ce nt 
Lead arsenate plus flo- 
tation sulfur 91,5 ,0.U , 
i'atural cryolite plus 
flotation sulfur 65. '4 , 9.7 
Qryol.ite plus .Ccpoeil.>^' Us.3 18. S. 35. S- 
Derris spray ' ' '., . 32. 22. U 
Check (pink sr)r^y only) 2U .U __^ 23 . 8' 1.^' 
^ Fruit russet very severe^ Ts'.lc substituted for Coposil in July 
sprays. 
I 
