Compatibility of bio-nematicide and plant stimulant of microbial origin with Heterorhabditis bacteriophora

Abstract: Entomopathogenic nematodes (EPN) are often combined with plant stimulants, inorganic and organic plant fertilizers in the integrated pest management. Previous studies mostly evaluated a compatibility of chemical pesticides and fertilizers with EPN. We evaluated the compatibility of bio-nematicide and plant stimulant of microbial origin on viability of Heterorhabditis bacteriophora infective juveniles (IJs) under controlled conditions. The viability of the IJs of H. bacteriophora was determined 1, 3, 24 and 72 hours after direct exposure to bio-nematicide and plant stimulant used in their commercial formulations. To assess infectivity, IJs were tested for their virulence against Achroia grisella larvae for 96 h. We found that bio-nematicide was highly toxic to H. bacteriophora. Three hours after direct exposure to bio-nematicide IJs were paralyzed, and level of mortality was 100% after 24 h, respectively. The plant stimulant did not affect nematode viability or infectivity. Our results demonstrate that H. bacteriophora is highly susceptible, intolerant to bio-nematicide, and compatible with the plant stimulant with no loss in viability and infectivity up to 72 h of exposure.