Cereal residue and planting date-related factors affecting colonization and consumption of pea, Pisum sativum L., by the pea leaf weevil, Sitona lineatus (L.) (Coleoptera: Curculionidae)
Ryan P. Hanavan, firstname.lastname@example.org, Nilsa A. Bosque-Pérez, email@example.com, Sanford D. Eigenbrode, firstname.lastname@example.org, and Dennis J. Schotzko, email@example.com. University of Idaho, Department of Plant, Soil and Entomological Sciences, PO Box 442339, Moscow, ID
The pea leaf weevil (PLW), Sitona lineatus (L.), is a pest of pea, Pisum sativum L., in northern Idaho and eastern Washington. In field surveys, PLW abundance and injury to the crop are lower in peas grown using no-tillage (NT) methods, in which the seed is planted directly through the prior year’s cereal stubble, than in peas grown using conventional tillage (CT). This study tested two potential mechanisms to explain this pattern: 1) PLW colonization rates are greater into CT fields than into NT fields due to weevil responses to differences in albedo between the two tillage treatments, 2) PLW colonization rates, damage to the crop, or both, are greater in CT because of tillage-related effects on plant quality. To test the first mechanism, pre-ovipositional colonization by PLW was measured in plots of CT pea augmented with cereal residue to mimic the albedo of NT, or left untreated. These residue treatments were tested over peas planted on two dates and a no-pea control. In 2005 and 2006, significantly higher PLW colonization occurred into plots without cereal residue and into plots planted earlier. To test the second mechanism, preferences of PLW adults for pea tissue from NT- and CT-grown peas and peas planted on two different dates were measured in choice tests in the laboratory. Significantly more feeding occurred on CT-grown and earlier-planted plants in these bioassays. The data support both of the potential mechanisms for the greater PLW abundance and injury in CT vs NT peas.
Species 1: Coleoptera Curculionidae Sitonalineatus (pea leaf weevil) Species 2: Fabales Leguminosae Pisumsativum