ENTOMOLOGY AND PLANT QUARANTINE 
53 
iiidicatod that such applications wore applied to best advantage economically 
during the period between the heading of the cabbage and harvest, or during 
the harvest period when harvest was prolonged and conditions were suitable 
for Insect development. 
In field studies to determine the economic status of the more common species 
of cabbageworms attacking cabbage in Louisiana and South Carolina it 
was found that, on an average, 41 perceiit of the cabbage plants failed to make 
marketable heads (U. S. Grade No. 1) owing to cabbageworm injury, that an 
aditional 23 percent failed to mature owing to causes other than worm 
injury, and that the remaining 3G percent produced marketable cabbage. In 
about half of the fields under observation the growers had applied derris 
dust mixtures, or paris green or lead arsenate, as well as poisoned bait for 
cutworms. In those fields where control measures had been practiced 30 
percent of the potentially marketable cabbage plants were rendered un- 
marketable by worms, as compared to 74 percent in the fields where no 
control measures were used, thus indicating the possibilities of improved 
yields by insecticide applications. In this same series of studies it was shown 
that, under the conditions existing wlien these observations were made, the 
cabbage looper and the imported cabbageworm caused approximately an equal 
degree of damage, per worm, and that either .species will cause about four 
times as much damage as an equal number of the larvae of the diamondback 
moth. If this relative importance of the three more important species of 
cabbageworms is found to persist from year to year, the importance of em- 
phasizing the control of the two first-named species is evident. 
When the physical characters of individual cabbage plants that may atfect 
the degree of cabbageworm infestation and injury were being studied, it was 
indicated that such characters as undulation, bloom, and color are appar- 
ently not important but that the type of plant within varieties may exert 
a decided effect in attracting the moths for deposition of eggs and in the 
subsequent growth and survival of the resulting larvae. 
Investigations of the cabbage webworm in North Carolina demonstrated 
that the most serious injury by this insect occurred during the seedling and 
transplanting stages of the host plant. Applications of undiluted calcium 
arsenate or of dust mixtures containing 0.5 percent of rotenone during tliis 
period of grov/th gav(^ jjminising indications of control. The cabbage web- 
worm failed to snivivc the winter of 1930-37 in North Carolina, even in the 
presence of unusually mild conditions. 
BERRY INSECTS 
Results of insecticide tests against the raspberry fruitworm in the Puyallup 
Valley, Wash., showed that dust mixtures containing 0.5 i)ercent of rotenone 
and sprays containing 0.01 percent of rotenone were effective as a control and 
did not leave a harmful r<>sidue on the marketed berries: that while pheno- 
thiazine gave the bpsr degree of fruitworm control, it injured the plants to 
such an extent that the yield was decreased greatly; that the use of arsenical 
f;prays or dusts after any of the blossoms have opened may leave a poisonous 
residue above the tolerance limit on harvested fruit; and that late applica- 
tions of in.secl i.-idcs ;r.ive tlie best conti-ol. 
Continued experiments in the conhol of the red berry mite (Erioplnjcs 
efisigi Hassan) in the Puyallup Valley demonstrated that the application of 
lime-sulphur .sprays dtu-iiig the dormant period of the plant, followed by 
sprays containing wettable sulphur or emulsions of refined petroleum or coal- 
tar oil during the growth of the plants and up to the time when the fruit 
begins to ripen, results in an adequate control of this mite. 
BEET LEAFHOPPER 
Investigations of the beet leaf hopper in the intermountain region of Colo- 
rado, Utah. Idaho, and Arizona resulted in the addition of important infor- 
mation respecting the critical breeding areas of this insect. Migration of this 
pest was traced delinitely from .'Southern Arizona bnuHling areas to the westtn-n 
Colorado beet fields. In field expt^riments. conducted in cooperation witli beet- 
seed producers, pyrethrum-oil .sprays directed against the beet leafhoppcu* on 
sugar beets grown for seed in Arizona indicated that beneficial results were 
obtained from this treatment as judged by an increased yield of seed per acre. 
Extensive field ol).servations indicated that the delayed planting of beans in 
southern Idaho decreased the severity of curly top dis(\Ms(\ which is trans- 
mitted by the beet leafhopper. In a study of factors governing curlv top in- 
