Population development and reproduction of fungus- and bacterium feeding nematodes in the presence of insect growth regulators.

The insect growth regulators (IGRs), diflubenzuron and BAY SIR 8514, at 300 and 1,000 ppm a.i. in potato dextrose agar (PDA) inhibited the radial growth of the fungus Rhizoctonia solani host of Aphelenchus avenae. The IGRs had no effect on the growth of the bacterium Pseudomonas pseudoalcaligenes host of Acrobeloides nanus and Diplogaster iheritieri. At 59 ppm a.i., neither IGR inhibited the population development of A. nanus and D. iheritieri on P. pseudoalcaligenes; however, diflubenzuron stimulated the population development of D. iheritieri. At 300 ppm, both IGRs inhibited the population development of A. nanus and D. iheritieri; however, BAY SIR 8514 was more effective than diflubenzuron except on A. nanus L's. At 300 ppm, only BAY SIR 8514 affected the population development of A. avenae, except the L's. At 1,000 ppm, both IGRs inhibited development, except diflubenzuron for L and L's. Again, BAY SIR 8514 was more effective than diflubenzuron. With single females of A. nanus and D. iheritieri, both IGRs at 300 ppm reduced egg laying, inhibited embryonation, and slowed larval development.