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Insect and mite pests cause serious damage to the hazelnut crop worldwide. The control strategies used against these pests include application of insecticides, classical and augmentative biological control, utilization of resistant varieties, and use of Bacillus thuringiensis-based preparations. In the United States, extensive research has been directed toward elucidating ecological interactions among different pests and natural enemies and understanding the role of abiotic factors in pest population dynamics. Differences exist worldwide regarding the understanding of pests and natural enemy biologies and, to a limited extent, control practices. An integrated pest management approach based on utilizing effective sampling and monitoring techniques and a near complete reliance on biological control and "soft" pesticides, including insect growth regulators, is currently under development both in North America and Europe/Turkey. Hazelnuts are on the verge of becoming one of the first crops in the United States that could possibly be produced commercially without the use of any broad-spectrum organic insecticides.

The developmental rates of various life stages of Rhagoletis completa Cresson (Diptera: Tephritidae) were determined in the laboratory at seven different constant temperatures: 8, 12, 16, 20, 24, 28, and 32 ± 1°C, RH 80 ± 10%, photoperiod L16:D8. Preoviposition developmental rate was fastest at 28°C (10 ± 1 days, mean ± SD) and slowest at 12°C (26 ± 1 days). About 83% of the females deposited eggs at 20 and 24°C and only 25% oviposited at 32°C. Females laid the highest number of eggs at 24°C and the lowest at 8°C. Egg development increased with increasing temperatures up to 28°C, then declined. The fastest egg development was noticed at 28°C (55 ± 1 h) and slowest at 8°C (389 ± 2 h). Over 90% egg hatch was observed at temperatures between 12 and 32°C, but decreased to 73% at 8°C. Larval development was fastest also at 28°C (20 ± 0.2 days). Over 65% pupation was recorded at 20 and 24°C, but decreased to 15% at 32°C and 12% at 8°C. Pupal development was most rapid at 24°C (53 ± 1 days) and slowest at 8°C (162 ± 2 days). More than 70% of adult emergence was noticed in treatments between 16 and 24°C but decreased to 20% at 8°C. Based on a linear regression model of temperature‐development rate relationship, the lower developmental thresholds were determined to be 6.6, 5.3, 2.9, and 5°C for preoviposition, egg, larval, and pupal stages, respectively. Based on a non‐linear developmental rate model, the upper developmental thresholds were 34°C for preoviposition, egg, and larval stages and 30°C for pupal stage.

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