Efficacy of "ABG-9008" against burrowing nematode (Radopholus similis) on bananas

DiTera(R) is a biological nematicide of microbial origin with potential for managing several plant-parasitic nematodes in different crops. Efficacy of ABG-9008, an earlier formulation related to DiTera(R), to control the burr owing nematode of bananas was evaluated using direct-contact and root-penet ration assays, and in a greenhouse test. Nematodes were incubated for 48 hr at 25 degrees C in 112 and 224 mu g/ml suspensions of ABG-9008, correspond ing to 112 and 224 kg/ha on a broadcast basis. Suspensions at 15 000 and 75 000 mu g/ml also were included. Efficacy of ABG-9008 was assessed at die s ame rates on Radopholus similis-infected banana root segments in microtiter plates. Efficacy of the product was evaluated under greenhouse conditions by applications at day 0 and 5 after inoculation. Water and fenamiphos at 4 .65 mu g/ml (4.5 kg/ha) were included as standard controls in all experimen ts. Percentages of mortality in suspensions, which ranged from 16.8 to 24.6 %, were not significantly different between those for 112 and 224 mu g/ml a nd 15 000 mu g/ml of ABG-9008. Percentages of mortality for fenamiphos (76. 4) and 15 000 mu g/ml ABG-9008 (69.8) did not differ (P = 0.05). Nematode r ecovery was greatly suppressed after 48 hr of incubation of infected banana roots exposed to 15 000 mu g/ml ABG-9008 or fenamiphos, and mortality was significantly greater than the other ABG-9008 rates used. Numbers of R. sim ilis from plants treated with 56 and 224 mu g/ml of ABG-9008 were similar t o those on untreated plants under greenhouse conditions with only fenamipho s giving effective control. Time of application of the products (0 and 5 da ys after inoculation) did not affect their efficacy on this nematode. ABG-9 008 at 10 000 mu g/ml was phytotoxic under greenhouse conditions.