11 ANNUAL REPORTS 01 DEPARTMENT OF AGRICULTURE, 1951 
pests are now available. The lack of a practical means of controlling 
the hickory shuckworm is Btill a major obstacle to the satisfactory 
development of a complete spray program. 
Plum Curculio Yields to Various Materials 
Several of the newer organic insecticides gave good control of the 
plum curculio without injuring the trees or fruit in tests on apples 
and stone fruits from New Fori south to and including Georgia and 
west to eastern Illinois. Included .• 1 1 1 1 « » 1 1 lt the materials were para- 
thion, ethyl p-nitrophenyl thiobenzene phosphonate (EPN), cnlor- 
dane, a 1 to 2 mixt ure of L,l-bis(/>-chlorophenyl)-2-nitropropane and 
L,l-bis(/Mmlorophenyl)-2-nitrobutane (Dilan), aldrin, dieldrin, and 
methoxychlor. They were generally more effective against the plum 
curculio, especially on stone fruits, than lead arsenate, the material 
depended on for many years. No one material was markedly sup 
t<> all <>t hers in all respects. 
In a large-plot experiment in a Georgia peach orchard, either four 
applications of parathion or chlordane or t wo applications of benzene 
hexachloride followed by two applications of lead arsenate were 
highly and about equally effective against the plum curculio. The 
treatments were markedly more effective than the regular three-ap- 
plication schedule of lead arsenate. A five-application schedule of 
parathion, the last one 2 weeks before harvest, gave almost complete 
control and was superior to other t reat ments. Both the total number 
of peaches that dropped and the percentage of dropped fruit that was 
wormy were much greater when lead arsenate was used alone than 
when parathion, chlordane. or a combination of benzene hexachloride 
with lead arsenate was used. In a single-tree plot experiment <>n 
peaches in Georgia, parathion. aldrin. dieldrin. and a split program 
of parathion and EPN gave outstanding control. Dilan and 2.2- 
p-fluorophenyl)l,l,l-trichloroethane (DFDT) did not give satis- 
, factory cont rol. 
In heavily infested peach field plots in West Virginia, parathion. 
aldrin. and dieldrin were superior to lead arsenate, lindane, benzene 
hexachloride. and low-strength EPN in preventing curculio injury. 
In Indiana, under conditions of light infestation, parathion. EPN, 
Dilan, dieldrin. methoxychlor, lindane, chlordane, aldrin. and ben- 
zene hexachloride were about equally effective in holding down cur- 
culio injury. In a large test in Illinois parathion -pray held curculio 
injury to l percent, while benzene hexachloride dust applied by the 
grower allowed injury by the curculio to 11 percent of t he fruit in one 
nea rby block and 12 percent in anot her. 
< )f the insecticides tested on pea die- in Indiana, only benzene hexa- 
chloride and. to a lesser degree, lindane gave the fruit, either fresh 
or processed, an off-flavor. In Georgia only benzene hexachloride 
usee in a full schedule, the last application a month before harvest, 
caused off-flavor in fresh peaches. When the peaches were canned. 
however, «>tl flavor was noted in those that had received either benzene 
• Idonde or lindane in a full schedule and in those that had re- 
ceived benzene hexachloride 7 I days he lore harvest. 
The -pi-.i\ residue on harvested peaches was comparatively low in 
all the experiments, except where methoxychlor or DDT was used 
