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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #105033
Title: TEMPERATURE-DEPENDENT DEVELOPMENT OF OTIORHYNCHUS OVATUS PUPAE.

Author
item UMBLE, JON - OSU
item Fisher, James

Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/5/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: The strawberry root weevil is a major pest of strawberries in the Pacific Northwest. Little is know of the basic biology of this pest. Present management strategies are pesticide based and have not changed in over 45 years. In order to develop new 'green' technologies the basic biology of the pest must be studied. This study describes the development of pupae of the SRW in relation to temperature and describes the development of 5 simplistic degree-day models for predicting emergence of adults in the spring. The first two weeks of adulthood are the best times to institute control strategies. Rate of pupal development was optimal at 30 degrees C. The threshold of development of pupae was found to be 4.3 degrees C. All prediction models that were discussed predicted emergence within 7 days of actual weevil emergence from the soil.

Technical Abstract: Temperature-dependent development of strawberry root weevil (SRW), Otiorhynchus ovatus (L.), pupae was studied in strawberry (Fragaria x ananassa Duch. var. Totem). The development of pupae was investigated at constant temperatures from 3 ¿ 33 degrees C at 3 degrees C intervals. The upper thermal lethal limit for SRW pupae was between 30 and 33 degrees C. Pupae did not eclose below 6 degrees C. Pupal duration was 127 d at 6 degrees C and 7 d at 30 degrees C. Rate of development (1/days) was greatest at 30 degrees C. We used the development of SRW as a model system to suggest a modification on the traditional method creating linear degree-day models. This method used weighted regression and was based on the assumption that the purpose of creating prediction models is to model the development of insects based on the temperatures to which they are exposed in the field. The predictive ability of this weighted model was compared to a traditional non-weighted linear degree-day model by relating predictions to the observed occurrence of SRW lifestages determined by field sampling. The weighted linear pupal prediction model produced a developmental threshold of 4.3 degress C and a degree-day requirement of 227.3. The non-weighted linear pupal prediction model produced a developmental threshold of 6.2 degrees C and a degree-day requirement of 163.9. Using a weighting method maintains the utility of a linear model while allowing for more accurate estimate of the lower developmental threshold.