4 ANM AL KIII'OK'I S OK I H :i'A K'l .M KNT OF A( JRK TLTrKK. ll«o7 
the thrills in the prctdiictioii of the nissct or scab t.vi)o of injury to prnnos did 
not j,MV(' conclusivt' results. It is apparent that both the th rips and mechanical 
injuries are in part resiM)nsible for this condition, but tlieir rehitive inip'Ttance 
has not yet been fully determined. 
PEACH INSECTS 
During,' the summer of lit.'if) a study was undertaken of the insc<is that in- 
fest peach orchards where the jthony peach disease is found under conditions 
of natural spread, in an elTort to obtain circumstantial evidence pointing to 
an insect or insects which may be resiM)nsible for the si)read of this disease. 
In order to carry on this work a mobile research laboratory has Un-n installed 
in a trailer of tlie usual tourist type. This is drawn by a motortruck which 
carries a ix)wer unit to furnish electri(,' current for lijihtinj; and for the oi)- 
eration of eciuipment. In less than 8 months iluring 1030 this lal)<»ratory 
traveled more than 10,()()() nnles and collected H.Kn) lots of insect material 
from peach orchards at GO locations in 11 States. To have conducted the 
same amount of work by the use of the usual type of laboratory (piarters 
T^V'ould have recjuired several times the i>ersounel, and the maiulenanc-e of a 
Jiumber of seasonal or temporary laboratories. In the spring; of VS^l a se<'(»nd 
nmt was purchased and ecjuipped for use in a similar survi'y of inach orchards 
in areas affected by the peach mosaic disease in the Southwestern States. 
As in previous years, special attention has been given to the introduction 
p.nd coloniziition of foreign and domestic parasites of the oriental fruit moth, 
in cooju'ration with numerous State agencies. During the calendar year IfWG 
•eight shipments of parasite material were received from Japan. imi>orte<l by 
tlK^ Division of Foreign Parasite introduction. Out (»f this material ;^.4(>6 
living adults of 15 different si)ecies of primary i)arasites were reared. Many 
of these were further propagated in the laboratory. During lU'.^i), isj; release- 
meuls of 42.138 parasites were made in 14 different States. Two hundred and 
fifty-eight recovery collections were made by the P>ureau and c(>o]»erating State 
woikers in IG different States. This work is being continued during tin- cal- 
endar year 11J87, with greater emphasis on recovery col^ections in the vi<-inity 
of previous releases, in order to obtain more complete informatir>n on the 
status of the introduced parasites. 
In field experiments with substitutes for lead arsenate for the <«intr(il f>f 
the plum curculio, both barium fluosilicate and cryolite caused considerable 
damage to peaches, similar to the injury that occurred during the season of 
1935, in spite of the fact that the materials were used in fewer applications 
than' in lfM5. The foliage was uninjured. 
Of a nundier of water-soluble compounds tested against the peach borer, 
dichlorethyl ether has given a very high degree of control when applied 
during February and March. At higher tempera turt\-; in both fall and spring 
th\< material has given variable results, and has caused a certain amount of 
injury. Dichlorethyl ether has also given promise for use as a soil funngant 
against the plum curculio. 
GRAPE INSECTS 
During the 1036 season i)heiiothiazine gave very satisfactory control of the 
grap<' berry moth, with no seriously objectionable staining of the fruit at 
harvest time, but it increased somewhat a tiMidency toward rusM'ting of the 
beirics. As was the case in the experiments with codling moth control, pheno- 
Ihiazine had a very unfavorable efft'ct on certain of the operators Mho were 
<'ngaged in applying it. Several forms of nicotine-bentoiute gave a considerable 
<legree of control but caused some objtM-tionabh* staining, which was partiru- 
larly serious in the case of a taidv-mixt'd nicotine-bentonite. 
Further experiments with burning, carried on in the spring of 193G. <-on- 
firiued the previous year's c(Uiclusions that an important reduction in the i>opula- 
tion of grape leafhoppers { Enjthrovrura comes (Say)) can b(> cbtaiuiMl by burn- 
ing over the areas surroiuiding the vineyards in which the leafhopp(M*s are pass- 
ing the winter. In the vineyard in northern Ohio, around which the work was 
<-on(lticted. the leafliopper infestation was tln^ lightt^st in many years, in marked 
contrast to (»lher vineyards in the same locality, wlu re the le.aflioiiper infesta- 
tions were altnormally severe. 
In cage experiments plienothia /ine gav«> practically coni|<lete kill of ibo 
grape roolworm and was apparently more (ffective than the arseiucals. Nico- 
line-bentorute, as in the preceding year, was not very toxic to the ro<.tworm 
julults. 
