The compatibility of the fungicide azoxystrobin with Pochonia chlamydosporia, a biological control agent for potato cyst nematodes (Globodera spp.)

摘要

The biological control potential of Pochonia chlamydosporia against root-knot (Meloidogyne spp.) and cyst-forming (Heterodera and Globodera spp.) nematodes is widely appreciated. In spite of this, little has been undertaken to determine the compatibility of this fungus with modern fungicides. A series of experiments were undertaken to investigate the effect of azoxystrobin on P. chlamydosporia. Initial Petri dish experiments found a significant reduction in the growth of P. chlamydosporia. EC values were calculated at 7 and 14 mg Lp#, respectively, for hyphal growth and chlamydospore germination. A microcosm experiment based on counts of the colony-forming units of the re-isolated fungus showed a reduction in EC values for azoxystrobin in soil after 12, 20 and 40 days incubation (1.25, 1.00 and 3.00 mg kgp# soil, respectively). There was evidence the fungus recovered over time in response to azoxystrobin application. This was also demonstrated in a glasshouse experiment where EC values of 1.32 and 4.4 mg kgp# soil were obtained for 35 and 49 days after planting (DAP), respectively.