THE POTENTIAL OF HETERORHABDITID NEMATODES AS CONTROL AGENTS OF ROOT WEEVILS

Publisher Website
Google Scholar
Abstract
Greenhouse and field trials were done to determine the potential ofHeterorhabditis heliothidis(Khan, Brooks and Hirschmann) Poinar (NC19 strain), an undescribedHeterorhabditissp. (NC447 strain), andSteinernema feltiaeFilipjev (A32−6 strain) to control British Columbia populations of black vine weevil (Otiorhyncus sulcatusFab.) and strawberry root weevil (O.ovatusL.). An outdoor application ofH.heliothidisapplied at rates of 500 and 5000 nematodes per litre of soil gave significantly better control of black vine weevil larvae on potted, lodgepole pine trees (Pinus contortaDougl.) than did a diazinon drench. Under greenhouse conditionsHeterorhabditissp. NC447 was the most effective nematode of the three tested againstO.ovatuson potted, Douglas-fir seedlings (Pseudotsuga menziesii(Mirb.) Franco) andS.feltiaethe least effective, at all dose rates tested. A field trial usingH.heliothidisagainstO.ovatusin a forest nursery did not provide a significant degree of weevil control. This lack of control is attributed to the average outdoor temperature (11 °C) during the treatment period, which was below the nematode’s optimum temperature range, and the higher-than-average rainfall.