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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #107520
Title: INFLUENCE OF TEMPERATURE AND PHOTOPERIOD ON THE PREOVIPOSITION DURATION ANDOVIPOSITION OF THE STRAWBERRY ROOT WEEVIL, OTIORHYNCHUS OVATUS (L.) (COLEOPTERA: CURCULIONIDAE)

Author
item Fisher, James
item UMBLE, JON - OSU, CORVALLIS, OREGON

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2000
Publication Date: 11/1/2003
Citation: Fisher, J.R., Umble, J.J. Influence of temperature and photoperiod on the preoviposition duration andoviposition of the strawberry root weevil, otiorhynchus ovatus (l.)(coleoptera: curculionidae). Environmental Entomology.

Interpretive Summary: The strawberry root weevil is a noxious pest of strawberries, caneberries, and nursery crops grown in the Pacific Northwest. It is difficult to control because the most damaging stage (grub) is soil dwelling and the above ground stage (adult weevil) is nocturnal in its activity. There has been almost nothing known about its biology. Future efforts to manage the affected crops and this pest will depend upon the ability of growers to predict the seasonal occurrence of vulnerable (to chemical or biological treatments to suppress populations) life stages. In order to develop models that predict when certain stages occur we need to know how the abiotic environment affects development of all stages. In this paper we explore the effects of temperature and photoperiod on the sexual maturation and egg laying potential of this pest. Increasing photoperiod significantly increased the number of eggs laid; the most were laid at a photoperiod of 18 hours and very few were laid at a photoperiod of 12 hours. Through this study we found that the most eggs were laid at temperatures that are usually experienced on a warm summer night (21 -27 degrees C) and at a day length normally found in the temperate areas of North America, north of the 40th parallel. This allows us to speculate that this insect is not really adapted to more southern climates and thus, this may be one reason they are not a significant problem in areas such as southern California, Arizona and Florida.

Technical Abstract: The influence of temperature and photoperiod on the preoviposition duration and oviposition of the strawberry root weevil, Otiorhynchus ovatus (L.) (Coleoptera: Curculionidae) was studied in strawberries (Fragaria X ananassa Duch. Var. 'Totem'). The effect of temperature and photoperiod on preoviposition and oviposition was examined by subjecting adults to constant temperatures from 3-33 degrees C at 30 degrees C intervals and by subjecting adults to 4 photoperiods at 21 degrees C. Oviposition was monitored for all treatments. Adults fed at all temperatures from 3-33 degrees C and oviposited at temperatures between 18 and 30 degrees C. The longest preoviposition period (32.8 d) and the fewest total number of eggs (2.2) were laid at 18 degrees C. The shortest preoviposition period (15.1 d) and the largest total number of eggs (282.5) were observed at 27 degrees C. A temperature range of 21 to 27 degrees C appeared to be optimum for oviposition. Relative to other temperatures, preoviposition time was the shortest, mortality was the lowest, and the greatest total number of eggs were laid. Weevils oviposited at all photoperiods. Length of preoviposition did not vary significantly among treatments (P was less than or equal to 0.05). Adults laid an average of 15.1 eggs at 12:12 (L:D) and an average of 148 eggs at 18:6 (L:D). The cumulative number of eggs for each photoperiod increased significantly (P was less than or equal to 0.05) with each increase in day length.