Field Tests of Formulated Products Containing EitherVerticillium chlamydosporiumorArthrobotrys dactyloidesfor Biological Control of Root-knot Nematodes

Granular formulations containing eitherVerticillium chlamydosporiumorArthrobotrys dactyloideswere applied at 55–880 kg/ha in seven field trials on a range of soils in Queensland, Australia. Granules were incorporated into soil prior to planting tomatoes and the effectiveness of the formulated fungi in reducing damage caused by root-knot nematodes was compared to an untreated control and a granular formulation of fenamiphos. Formulations ofV. chlamydosporiumwere used in three experiments but the fungus did not increase egg parasitism or reduce galling or nematode numbers at harvest. Formulations containingA. dactyloideswere more effective, as galling was reduced 4–8 weeks after planting in four of five experiments. However, these effects generally disappeared later in the season, as significant reductions in galling were only observed in one of seven experiments at harvest. Fenamiphos generally reduced galling both at 4–8 weeks and at harvest. Yield increases due to fenamiphos or any of the biological treatments were not obtained in any experiment. The results suggested that formulations ofA. dactyloidesapplied at 220–440 kg/ha substantially reduced the number of nematodes present in roots 4–8 weeks after planting. Since tomato is relatively tolerant of nematode damage under the crop management systems used in northeastern Australia, such formulations could provide useful nematode control, particularly if used in conjunction with other control measures. However, formulations with greater biological activity will be needed if the level of nematode control obtained with chemical nematicides is to be achieved withA. dactyloides.