Journal of Economic Entomology (1995) 88, 859-863

Peter C. Schroeder, Carol S. Ferguson and Elson J. Shields (1995)
Spring activity of adult alfalfa snout beetles (Coleoptera: Curculionidae): Upward movement from overwintering sites, dispersal, and oviposition
Journal of Economic Entomology 88 (4), 859-863
Abstract: The upward movement of adult alfalfa snout beetles, Otiorhynchus ligustici L., from overwintering sites in the soil was monitored and described in 2 alfalfa fields in upstate New York in 1991 and 1992. Oviposition and dispersal of emerged adult O. ligustici was also described and related to cumulative degree-days (CDD) estimated from soil and air temperatures at each field. Cumulative degree-days estimated from soil temperatures (30 cm deep) and a 7°C base threshold temperature significantly correlated with the upward movement of adult O. ligustici from overwintering sites in the soil. Ninety-five percent of the beetles reached the uppermost 2.5 cm of soil 30 CDD after complete soil thaw. Beetles began to lay eggs 166 CDD (3.3°C base threshold) after complete soil thaw. Peak oviposition occurred at 200 CDD (3.3°C base threshold) after complete soil thaw. After reaching the soil surface, adult O. ligustici began to disperse in search of acceptable food plants. Dispersal mostly occurred between 1st oviposition and peak oviposition.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)

Research topic(s) for pests/diseases/weeds:
population dynamics/ epidemiology
environment - cropping system/rotation

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Otiorhynchus ligustici	Alfalfa/lucerne (Medicago sativa)	U.S.A. (NE)