Reproduction of entomopathogenic nematodes (Steinernema feltiae) on different insect hosts under laboratory conditions

Abstract

Goal. To identify the effectiveness of entomopathogenic nematodes (Steinernema feltiae isolate with a biological product «Entonem» ™ Copert) on the larvae and adults of different insect pests at various ways of their infection, and to explore the possibility of generating a significant amount of the invasive larvae of entomopathogenic nematodes (EPN).

Research methods. The material for our study is the 7 types of test insects: larvae of the large and the small wax moth, castaneum flour, gyroscope, common cabbage butterfly, Kovalik pilosula, as well as the may beetle, which was used stage larvae, as well as individuals of adult beetles (imago). All the studied insects infected with EPN (pathogen — Steinernema feltiae with biopreparation «Entonem» (™Koppert)) in the laboratory on filter paper or in sterile soil. Recorded date of infection and death of insects and counted the number of allocated of each type of insect infective larvae of nematodes. Estimated duration of migration and reproductive potential of different test insects.

Results. The use of different methods of infection (dry contact parasite and insect hosts on filter paper or by making a dose in sterile soil, which was placed insect-host) at a dose of 50 larvae per one insect, showed that in half of the cases a significant difference between them is not detected. However, castaneum flour, Kovalik pilosula and ordinary spinning top, the best was the method of contamination in the Petri dishes, and adults of the may beetle — in groundwater samples. The duration of the process of migration of larvae of the entomopathogenic nematodes from the cadavers of insect hosts ranged from 27—51 day and were more dependent on the insect host than from its method of infection. A short period of migration of the larvae of large and small wax moth (27—36 days), long (35—45) from larvae of a top common and castaneum flour, the longest period of time (48—51 hours) — larvae of cabbage butterflies and a beetle may. Performance in relation to the amount of the newly formed infective larvae determines the insect host. Among the investigated 7-insects-the home of highest performance was observed in the may beetle (115980—120060 larvae) and the cabbage (93440—97880 larvae). Less productive was the great wax moth, the flour castaneum and the grasshopper pelousy (respectively 26880 ± 420; 34500 ± 430; 32400 ± 673).Less productive are the common top, the May beetle (imago) and the small wax moth, in which from 15640 to 26880 invasive larvae were formed.

Findings. In laboratory conditions, without significant material costs, you can get a sufficient number of entomopathogenic nematodes. The method of directly introducing entomopathogenic nematodes onto test insects in Petri dishes proved to be the best compared to soil invasion. The duration and volume of migration of larvae of entomopathogenic nematodes is determined mainly by the species of host insects. The shortest migration period was recorded in wax moth larvae (small and large), significantly longer (almost 1.5 times) in the larvae of May beetle and cabbage. The most productive in relation to juvenile larvae of EPN were the cabbage and the larvae of the May beetle, and the least productive ones were the common top, May beetle (imago) and small wax moth.