Oviposition behavior and thermal constants for egg development of the filbertworm Cydia latiferreana (Lepidoptera: Tortricidae)

Graduation date: 1987Cydia latiferreana Wlshm. is recognized as the key\ud insect pest of cultivated filbert (hazelnut) in Oregon.\ud The purpose of this study was to obtain information on\ud mating and oviposition behavior of the adult insect, to\ud calculate the lower temperature threshold and degree-days\ud required for egg development, and to develop an\ud ovipositional model based on the information derived in\ud this study.\ud Field studies showed significant differences between\ud the number of eggs deposited on the foliage of filbert\ud varieties Daviana and Barcelona. Data showed that Daviana\ud trees were preferred for oviposition over Barcelona. On\ud both varieties, significantly greater numbers of eggs were\ud deposited on leaves located within 15 cm. of a nut or nut\ud cluster than on those located farther than 15 cm. No\ud significant differences were found between numbers of eggs\ud collected from two canopy heights.\ud Oviposition was observed in the field at dusk, and\ud mating was observed at night. The role of climatic\ud conditions, particularly temperature, and time of day as\ud major influences on initiation and frequency of oviposition\ud was discussed.\ud Laboratory studies using field-collected eggs\ud indicated that ca. 77.8 degree-days are required for egg\ud hatch above a threshold of 10.3° C