Exploring trait mediated interaction units in the pest complex of rice (Oryza sativa)
Monday, November 16, 2015
Exhibit Hall BC (Convention Center)
Emily Kraus
,
Department of Entomology, Louisiana State University, Baton Rouge, LA
Michael Stout
,
Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA
Lissorhoptrus oryzophilus, the rice water weevil, is the most economically important pest of rice in the U.S. This insect has spread from its native region in North America and has become a global pest. The adults feed on foliage of plants, causing little damage. The larvae however feed on roots reducing tillering and shoot growth. This feeding activity reduces overall panicle densities and grain harvest weights.
Spodoptera frugiperda,Fall armyworm is also a pest of rice. Control for fall army worm includes managing nearby grasses, flooding, and chemical insecticides. Generally fall armyworm is an early season pest with rice water weevil coming onto the scene mid-season.
These two insects with rice form a Trait Mediated Interaction Unit (TMIU). We hypothesized that the fall armyworm feeding would induce plant traits decreasing plant suitability for weevils. In order to investigate we artificially infested small plots with fall armyworm larvae. Larvae were allowed to feed on plants for 7-10 days and damage was then rated. At this time plots were flooded, and weevils were allowed to naturally infest the field. Core samples taken after two weeks indicate that early season defoliation by fall armyworm decreases oviposition and overall larval infestation by rice water weevil. The information may be incorporated into management programs to reduce the associated costs of pest control, as it may call for reconsideration of fall armyworm thresholds.
