6 ANNUAL BEPOBTS OF DEPABTMENT OF AGRICULTURE, 1936 
in which the Insect hibernates. Cage testa showed that if the plowing La done 
in winter, whm the Insect Is in the Larval stage, Little control La likely to result. 
Od the other hand, the burial of the shucks in the spring, when the larvae 
within them had transformed to pupae, prevented nearly all subsequent emer- 
gence Of the mot OS. 
The rearing technique for the production of the egg parasite TrichoQramma 
minutum was carried to a very high state of effectiveness, over 63,000,000 para- 
sites having been produced at the Albany, Ga., station in 1935. Unfortunately, 
the results of the held experiments were unsatisfactory on the whole, and it 
is believed that this method of < trolling pecan Insects cannot be employed 
profitably by the practical grower. The work with the utilization of Frieao- 
gramma has. therefore, been discontinued. As opportunity offers, however, 
attention will he given to other parasites of pecan Insects. 
Further experiments in 1835 with the ose of oil sprays on dormant | 
trees have confirmed earlier results Indicating that pecan trees are particularly 
susceptible to injury by oil sprays, especially if the trees are l-.w in vitality, 
and on the lower branches of closely planted, large tree-. The experiments 
iii 1936 included tests of oils of various specifications, Including the highly 
refined oils, emulsified with different materials and in different ways and 
applied at different times, to determine the influence of the various factors 
on The control of the scale, on injury by the oil. and on nut yield. 
With the pecan phylloxera {Phylloxera devastatrix Perg. and other species), 
control tests have confirmed previous results and have indicated that th< 
common species of phylloxera on pecans in the South may 1m> well controlled 
by spraying early in the spring with nicotine sulphate, combined with either 
soap or with liquid lime-sulphur. Biological studies are under way with a 
number of [ess well known species of phylloxera. 
DRIED-FRUIT INSECTS 
Further confirmation was obtained of former observations Indicating that 
effective protection against attack by certain dried-fruit insects may be ob- 
tained by use of tobacco shade cloth during the period when the fruits are 
drying in Stacked trays in the Held. Infestation in drying pears by the raisin 
moth \Ki>h> stm flgulttella Greg.) and the dried-fruit moth was reduced more 
than 90 percent by this means. Excellent protection for hexed raisins resulted 
from the same method, which also reduced fly-specking on drying apricots. 
Further extensive tests of a motor-driven shaker screen for sifting raisins to 
remove moth infestation gave a reduction in Infestation of seedless raisins 
averaging 78 percent, it is believed that this machine can be modified to do 
even'more effective work. A combination of the two control measures just 
mentioned should give a high degree Of freedom from infestation by the raisin 
moth. 
A comparison of two methods of drying raisins on wooden trays and en 
paper trays which are roiled into rather tight packages before drying is com- 
pleted showed that infestation by the raisin moth was nearly five tit . • 
great on wooden trays as on papers. 
Detailed records of seasonal emergence of the adult raisin moth showed 
that !>i percent of the spring generation appear while mulberries are the only 
which distributed food material available to them. Collected samples of mul- 
berries showed the presence in seme cases Of more than a million raisin moth 
larvae per ton during a period when most of the Insects would otherwise die 
of starvation. This serves to emphasize the importance of mulberries in the 
in'.- history of this Insect. 
Experiments in the fumigation of individual packs indicate that complete 
control of the raisin moth and Indian-meal moth can he obtained with mix- 
tures of three parts of ethylene dichloride and one part of ethylene oxide, the 
e being 7 cc for each 25-pound box of raisins, in certain testa 100-per- 
cent mortality was obtained with a 5-cc dose of the same mixture Methyl 
bromide killed all Insects at a dosage of i cc for each 25-pound hex. 
Studies of the dispersal habits of the dried-fruit l tie, carried on by the 
liberation of large numbers of marked insects and the;,- subsequent recovery 
in trap-. Bhowed that under certain conditions the beetles may migrate more 
than ■_■ mile- within a period of i days Unmarked beetles were taken at 
point- more than :; miles from anj known source of infestation. 
Further experiments have been carried on in cooperation with the Bureau 
of plant Industry to develop methods of disinfecting capriflgs containing 
