Codling Moth Oviposition and Fate of Eggs

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Abstract
During the season of 1938, 520 marked bearing fruit spurs on apple trees were examined twice weekly. Of 3,581 codling moth (Carpocopsa pomonella) eggs observed, only 6% were deposited on fruit. About 50% more eggs per bearing spur were deposited in the upper part of unbaited trees than in the lower part; the distribution on baited trees was equal. On unsprayed trees parasitization by Tri-chogramma minutum averaged 32% in May and June and 43% from July to Sept., inclusive. Only 37% of first-brood eggs and 25% deposited from July to Sept. hatched. Predators (probably Chrysopa spp.) destroyed 19% of lst-brood eggs and 23% of 2d-brood eggs. Approx. 10% of the eggs died or were lost. This loss was greatest where the visible spray deposit was heaviest. Bait traps appeared to reduce parasitization slightly but did not reduce the work of predators. Mineral oil with Pb arsenate or nicotine bento-nite also reduced parasitization but the work of predators increased. Parasitization was greatest and destruction by predators least in a plot sprayed with phenothiazine. Heavy spray deposits of Pb arsenate and tank-mix nicotine bentonite with soybean oil appeared to reduce oviposition apparently by making leaf and fruit surfaces unattractive to gravid [female][female].

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