Influence of Application Method and Pest Population Size on the Field Efficacy of Entomopathogenic Nematodes


  • J. Curran


Application method had an appreciable effect on the efficacy of Heterorhabditis sp. (isolate T390) in reducing the numbers of Otiorhynchus sulcatus infesting field-grown strawberries. Results were related to nematode placement. In Trial 1, the mean weevil mortality was 36% for trickle-irrigated Steinernema sp. (isolate NC513) at a dose of 100,000 nematodes per plant, whereas the same dose of Heterorhabditis sp. (isolate T390) resulted in mortality of 65% and 86% for trickle-irrigated and surface-sprayed nematodes, respectively. Mortality rate (y) was inversely related to initial weevil population size (x) by y = 4.96x^[-0.957] and y = 4.71x^[-0.558] for trickle-irrigated Steinernema sp. (isolate NC513) and Heterorhabditis sp. (isolate T390), respectively. In Trial 2, using 100,000 Heterorhabditis sp. (isolate T390) per plant, mean weevil mortalities were 61%, 63%, and 79% for single-injection, irrigation, and multiple-injection techniques, respectively. Key words: application method, biological control, Fragaria, Heterorhabditis, nematode, Otiorhynchus sulcatus, pest density, Steinernema, strawberry.