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ARS Home » Midwest Area » Wooster, Ohio » Application Technology Research » Research » Publications at this Location » Publication #80408
Title: SYNERGISM OF IMIDACLOPRID AND ENTOMOPATHOGENIC NEMATODES: A NOVEL APPROACH TO WHITE GRUB CONTROL IN TURF GRASS

Author
item KOPPENHOSER, A - UNIV CALIF/DAVIS
item KAYA, H - UNIV CALIF/DAVIS
item Klein, Michael

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/30/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Control of grubs in turfgrass by nematodes (EN) has been effective at times, but often not. EN performance may be improved when used with other control agents. The insecticide, Imidacloprid (IMI), has low vertebrate toxicity (LD50 greater than 1858) and is applied at low rates. IMI, however, is ineffective against third instar scarabs, the stage that causes the most visible damage and is usually detected and treated. Our hypothesis was that IMI would act as a stressor on third instar grubs and increase their susceptibility to EN. In the first experiment, against 3rd instar Cyclocephala hirta, Heterorhabditis bacteriophora (Hb)(4x108 infective juveniles (IJs)/ha) was applied 14 days after IMI (25, 50, 100, or 200 g AI/ha) (recommended field rate is 400 g AI/ha). Grub mortality was significantly higher in combinations (63-90%) than for IMI (1-20%) or Hb (30%) alone. Using C. hirta, the combination of Hb (4x108 IJs/ha) and IMI (200 g AI/ha) caused higher mortality (85%) than IMI (5%) or Hb (54%) alone. Against third instar C. pasadenae, combinations of Hb (109 IJs/ha) and IMI (200, 100, or 50 g AI/ha) caused higher mortality (50-72%) than IMI (0-4%) or Hb (23%) alone. In all experiments, the interactions between IMI and nematodes were synergistic. We evaluated IMI and EN compatibility in tank mixes. Hb (500 IJs/ml) was shaken in solutions of IMI (0, 10, 40, or 160 mg AI/Liter) at room temperature for 24 hr. IJ survival and infectivity against wax moth larvae were not affected. Combinations of IMI and EN have a very high control potential. The use of multi-functional agents (i.e., IMI, EN and its mutualistic bacterium) reduces the likelihood of selection for resistance.