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A study of the apple aphid, Aphis pomi Dc Geer, was conducted in 1959 on young Cortland and Red Delicious apple trees under a treated (artificial) and check (seminatural) environment. The population was highest in the check and was twice as high on Cortland as on Red Delicious. The highest number of aphids on Cortland occurred in the check. On Red Delicious they were more numerous in the treated section. Alates were most numerous the first of July and were primarily responsible for the buildup of aphids following the second aphicide application in the treated section. The aphid population reached a peak on the check trees July 14, one week before maximum populations occurred on treated trees, then decreased slowly, and disappeared by late August. Parasitism was less than 0.1%. Predators included syrphid fly and aphid lion larvae, anthocorid nymphs, and coccinellid larvae and adults of which Cocciuella novemnotata Herbst was the most abundant. Aphid abundance (intraspecific competition) was the primary biotic factor limiting the aphid population. The increase in terminal growth on treated trees was significantly greater (1% level) than that on the check.

The bionomics of the eye-spotted bud moth, Spilonota ocellana (Denis & Schiffermuller), on sour cherry in Wisconsin from 1960 through 1961 showed that the eggs had hatched by the last week in August and larvae had left the leaves by October 4 to construct overwintering hibernacula, entering hibernation as third instar larvae and moulting once inside the hibernacula before spring. Seventy per cent of the larvae overwintered on fruiting spurs. Natural mortality of the overwintering larvae averaged 15% in 1960 and 17% in 1961. The larvae became active when the buds started swelling in late April, left their hibernacula approximately 1 week later when the terminal leaf buds showed ⅛ to ¼ inch green extended growth, and attacked the fruit buds primarily, eating into the base of the bud and feeding therein on the developing flower parts. The larvae gradually left the fruit buds to feed on the expanding leaves, and later constructed “leaf nests” in the fully developed terminals. Larval activity was correlated closely with temperature as shown by an increase in fruit bud injury from 4% to 53% and from 5% to 33% in the 7-day interval between green tip and popcorn stage of tree growth in 1960 and 1961, respectively. By the petal-fall stage 92% and 65% of the fruit buds were injured, 86% and 51% of the pistils destroyed and 100% and 85% of the leaf clusters infested by larvae in 1960 and 1961, respectively. An average of 4% of the cherries was injured between petal fall and harvest in 1961. Larvae started pupating by June 15 and pupation was nearly completed by July 20, primarily in “twig nests” on the wood. Adults were present from the first week in July until the last week in August, reaching their peak abundance the first week in August. Eggs were deposited primarily on the underside of the leaves.

A study was made on the control of the European earwig, Forficula auricularia . L., using aldrin, chlordane, heptachlor, and dieldrin, under both field and greenhouse conditions. Dieldrin showed the longest residual effects. Through contact action only, a 50% kill was achieved after 524hours from a concentration of 1 pound per 100 gallons. Aldrin at a 2-pound rate and chlordane at a 4-pound rate gave a fair kill after 207hours. Heptachlor had little residual value but gave the quickest kill, showing a high rate with I-second exposure to the insecticide, and a substantial reduction in field populations within 12 hours of the applications. Dieldrin was second in the rate with which field populations were reduced. After 25 days, field populations of earwigs were reduced by 95% or more through the application, as granules, of 4 pounds of the active ingredient per acre of each of these four insecticides.

Populations of foliage-feeding Lepidoptera were studied under an aphicide-treated and a check environment in a young, nonbearing Red Delicious and Cortland apple orchard in Door County, Wisconsin, in 1959 and 1960. Seventeen species in nine families were collected from the orchard in 1959 and 83 species in 19 families in 1960. The greatest number or species were represented in the Noctuidae. The three most abundant species were Spilonota ocellana (Denis & Schiffermuller), Argyrotaenia velutinana (Walker), and Lithocolletis crataegella Clemens in that order. Four species occurred in two generations; all others had a single generation. The number of individuals and species present were influenced by tree variety, plot environment, and year, the highest counts occurring on Red Delicious and under the check environment.

Thuricide® (a microbial insecticide having 30 × 109 spores of Bacillus thuringiesis Berliner per gram) applied on apple for control of the eye-spotted bud moth, Spilonota ocellana (Denis and Schiffermuller), apparently retarded spring larval development and produced noticeably smaller larvae. Mortality of the spring larvae in the Thuricide-treated section was 16.5% on Red Delicious and 18.7% on Cortland. In the check only 1.5% and 9.5% mortality occurred on Red Delicious and Cortland respectively. Significantly greater numbers of summer larvae were collected in the check than in the treated sections Reared adult moths from the Thuricide block were significantly smaller than those from the check. This size difference was greater with later adult formation periods. The length and width of both males and females in the Thuricide-treated section decreased significantly with later formation periods but increased significantly in size in the check with later formation periods. The immediate effects of Thuricide on the eye-spotted bud moth population were not considered economic control; however, the long-range effects might be promising.