52 ANM AL i:i:r»»K i s oi' i \ im :^ii:n'i of A(;iii< t ltukk. 1'j37 
Laltoi iilory tnxi<iiy studies on ilic vcKelabU' wt-evil (Icinonst rated that pyre- 
thniiii diluted with eciual parts of china clay compared lavorahly in toxicity 
with undiluted cah iuni arsenate, hut that both of these were distinctly suix.*rior 
to derris conihinat ions containing 0.;>, 1.0, and 2.0 iM'rcent of rolenone. resixH.*- 
tively, and to suli)liur. In field experiments directed against the turnip apliid 
on turnips and mustard, however, it was shown incidentally that dust mixtures 
containinji 1 iM'rcent of rotcnone, with cfjual parts ( hy w( i;rht ) of finely Kiound 
dust in;; sulphur and toliacco dust as the diluent, and derris sprays containing 
approximately 0.<i2 i)ercent of rotenone. with or witli<»ut an alkylphenylhenzene- 
sulphonic acid spreader and wetting agent, were elTectivc in protecting the 
turnips and nuistard from damage hy larvae of the vegetable weevil. These 
in.sect icidal applications were begun when the plants and the infesting weevil 
larvae were snnill. They were repeated at intervals of 14 days, from four to 
six tiealments being applied. Judging from the.se experiments it appears that 
rotenone compounds may be effective when applied to plants infested with small 
vegetable weevil larvae. 
Ob.servations in California upon the effect of eradicating nightshade, the 
overwintering host of the pepper weevil, as a control measure for this in.sect 
demonstrated that under favorable conditions this meth(»d leads to a marked 
reduction in infestation. Tests with several insecticides not tried previou.sly 
against the pepper weevil demonstrated that phenothiazine. diben/.(»thiai)hene, 
and commercially prepared combinations of pyrethrum were not as elTective 
as calcium arsenate against the insect. Observations of commercial operations 
indicated that treatments of calcium arsenate applied at the proper time 
and in the proper manner gave commercial control of the weevil and that 
the latest developed washers were effective in removing the excess ar.senical 
residues from i)eppers before they were dried or directly after harvest. 
Investigations on mole crickets i Sea }jt( risen -s spp.) under Florida condi- 
tions have disclosed that their principal food consists of organic matter present 
in the .soil, instead of living plant tissue as formerly suposed. that fre.sh baits 
are preferred to deconiposcMl baits, that paris green in baits is di'finitely repel- 
lent, and that sodium lluosilicate in baits is not definitely repelk'nt. (.'ontrol 
experiments have also demonstrated the ineffectiveness of magnesium sulphate 
(Epsom salt) in baits. 
A study of the seasonal occurrence in the Salt River Valley. Ariz., of 
several species of loopers (Antof/rapha spp.), the beet armyworm, and cut- 
worms injuring lettuce disclosed that tlie.se depredating worms do not undergo 
any distinct hibernating period in this territory and that all stages of these 
in.sects may be found during the year. The cool winter weather, however, 
retards the activities of these worms to such an extent that it usually has a 
distinct bearing on control measures. Fall-grown lettuce develops very rapidly, 
and the results of experiments with this crop indicated that one application 
of insecticides containing arsenicals. when the i)lants were small, protected 
such plants luitil they had established them.selves suliiciently to overcome 
the attacks of the worms. Experiments in small field i)lots demonstrated that 
the organic insecticides derris and pyrethrum. appliecl after the lettuce had 
been thinned, would control the loopers but would not control the beet army- 
worm or cutworms. 
An improvement in hand nuMhods of p.-irasit i/at i(tn of the European earwig 
rendered it ])ossible to ])arasiti/.e earwigs lO times faster than heretofore, thus 
making available a large number of i)arasites { nif/nnicln fx .^( tiponiis Fall.) 
for reinforcing (existing colonies and starting new ones. Uecov(>ry oper.-itions 
indicated that the i)arasites had spread to a distance of at least four blocks 
in the case of colonies liberated in th(» city, and fo a distance of three-fourths 
of a mile in the case of parasites lilx^rated in the country. In field exi>eri- 
menfs with i)oisoned baits for the earwig it was determined that bait con- 
taining s:ilt in place of fish oil was ii«it s<» efl'ectivc^ as tlie st.iudard bait, that 
bait crmtaining sodium fluoride was almost ;is efTective :is tlu^ sodium silico- 
fluoride us(>d in the standard bait, and that bait containing one h.-ilf the 
customary dosage of s(tdiuin silicolluoride was unsatisfactory. 
rOU: ( HOP INSF( TS 
Investigations on cabhagew«»nns attacking cabbage in E»»uisiana and Sotith 
< arolina yiehled definite pr<»gress in the fcuinulat i«>n of a control program. 
It was f(tund. in tln' iiisianc«' of the spring crop of cablmg*'. that timely apitli<'a- 
tions of a derris dust mixture <'ontaining (».."> percent of rot<Mione protiM-ted the 
i-roj) adequately ag.iinsi the <'onnnon sjiecies of cabbag»'worins ( Auioqrapha 
hrtissietir Riley, \sria rdjxic F.. and l*l\ihU<i ))inriilii>riniis Curt.). UesnltS 
