Teagasc (Agriculture and Food Development Authority)
Abstract
Outdoor trials with potted primroses (1997 and 1998) and field-grown strawberries (1998) artificially infected with vine weevil (Otiorhynchus sulcatus) were conducted in Ireland to assess the best time of nematode (Heterorhabditis megidis, isolate UK211) application in autumn. Approximately 75 to 85% control was obtained in primrose in both years when nematodes were applied at the end of September to mid-October. The 1997 primrose trial showed that an early September nematode application helped to avoid plant damage (important when protecting young and vulnerable plants), but that October and November nematode applications gave a higher (95%), but delayed, control level when left until spring. Control in strawberry was similar to that in primrose, with maximum 76% control. Maximum control levels obtained with nema todes were similar to those obtained with chlorpyrifos (Dursban) in strawberry and gamma HCH (Lindane) in primrose. These results clearly show that nematodes can be applied successfully outdoors, under Irish weather conditions, until mid-October
