Investigating the Side-Effects of Neem-Derived Pesticides on Commercial Entomopathogenic and Slug-Parasitic Nematode Products Under Laboratory Conditions

Abstract

Lethal effects of neem derived pesticides (neem leaf extract (NLE) and NeemAzal-T/S (NA)) were examined on different entomopathogenic (EPN) and slug-parasitic (SPN) nematodes. In our recent study, neem derived pesticides were tested against Phasmarhabditis hermaphrodita for the first time under in vitro conditions. Laboratory experiments were set up in 96-well microplates with different concentrations of NLE (0.1%, 0.3%, 0.6%, and 1%) and NA (0.001%, 0.003%, 0.006%, and 0.01%) and Milli-Q water as the control. After 24-h exposure time, mortality of individual nematodes was observed and recorded. Considering LC10 values, 0.1% of NLE could be used safely in combination with all the EPNs and SPNs tested in recent study. A concentration of NA three times higher than the recommended dosage did not harm either EPN or SPN species. In conclusion, NeemAzal-T/S might be applied with EPNs and the SPN Ph. hermaphrodita simultaneously, while the compatibility of neem leaf extract and beneficial nematode products needs further evaluation.

Keywords

• neem leaf extracts
• azadirachtin
• <i>Azadirachta indica</i>
• <i>Phasmarhabditis hermaphrodita</i>
• nematodes
• toxicity
• biological control agents
• botanical pesticides