ISHS Acta Horticulturae 585: VIII International Rubus and Ribes Symposium
MANAGING ROOT WEEVILS IN WASHINGTON STATE RED RASPBERRIES |
| Authors: | L.K. Tanigoshi, J.R. Bergen |
| Keywords: | Black vine weevil, Otiorhynchus sulcatus, clay-colored weevil, O. singularis, oviposition, timing, control. |
| Abstract:
The black vine weevil, Otiorhynchus sulcatus (F.) is the most common root weevil found on small fruit crops in Washington. Overwintering black vine weevils began laying eggs in the lab immediately after they were collected in late April. Productivity declined somewhat in mid-summer and then increased in late summer. Summer emerging adults collected in early June laid eggs about one month later at the onset of harvest. Daily oviposition was similar with both generations during the egg laying periods, but the average cumulative oviposition per weevil was greater with the overwintering adults due to a longer ovipositional period. Average fecundity of overwintering weevils was over 300 eggs per weevil and 170 eggs per summer emerging weevils. Laboratory trials support empirical observations that overwintering black vine weevils contribute a significant proportion to summer oviposition and in-field population increases over a prolonged period. Clay-colored weevil, O. singularis L., is a serious early season pest on red raspberry in Whatcom and Skagit counties in northwest Washington. The critical period for control is within a week or so of the first adult emergence from the soil, as weevils migrate into the canopy to begin feeding on buds and early fruiting lateral growth. Application of registered organophosphorus and pyrethroid insecticides, targeted to the lower third of the canes, is the preferred control tactic. | |
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