How do soil parameters affect Heterorhabditis bacteriophora viability for the biological control of the grape root borer (Vitacea polistiformis) in Muscadine vineyards (Vitis rotundifolia)?

The movement of the entomopathogenic nematode Heterorhabditis bacteriophora was studied in a muscadine vineyard in Tallahassee, Florida to evaluate the effects of soil parameters and the application via drip irrigation on its viability as a biological control agent against Vitacea polistiformis (Harris) the grape root borer. Parameters studied included moisture, temperature and pH. In addition, the movement and survival from the drippers was studied around the vine. The efficacy of H. bacteriophora and H. megidis was evaluated. The mean of GRB pupal cases observed in the grapes treated with H. bacteriophora, H. megidis, and two applications of H. bacteriophora were not significantly different from each other, but the three nematode and Lorsban treatments were significantly different from the control. Pupal counts for H. bacteriophora were significantly lower than the Lorsban 4E while pupal counts for H. megidis were not. The vines with the double treatments of H. bacteriophora had mathematically fewer pupal cases than the single treatment of H. bacteriophora and H. megidis but were not significantly lower. Nematodes were successfully recovered from the nematode treatment plots but not the Lorsban 4E treatment or control.