Pathogenicity of four native isolates of entomopathogenic nematodes against Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae)

The confused flour beetle, Tribolium confusum Jacquelin du Val, 1863 (Coleoptera: Tenebrionidae) is a major pest on stored grains. Chemical pesticides are usually used to control stored grain pests but insecticides residue and other negative effects on human and environmental health are the constrain ones in this concern. The biological control agents such as entomopathogenic nematodes (EPNs), which are used to control different harmful organisms, get attention in the alternative control methods. The aim of this study was carried out to determine biocontrol potential of local entomopathogenic nematode isolates, Steinernema carpocapsae (Tokat-Bakisli05), S. feltiae (Tokat-Emir), Heterorhabditis bacteriophora (TOK-20), and H. bacteriophora (11KG) against adult beetles of confused flour beetle under controlled conditions. EPNs isolates were applied at four different concentrations i.e., 0.0, 25, 50 and 100 IJs/beetle in 1 ml of distilled water at 15 and 25 +/- 1 degrees C temperatures. The highest mortality rates for H. bacteriophora (11KG) and H. bacteriophora (TOK-20) isolates at 25 +/- 1 oC were determined as 91.0 and 81.2%, respectively. H. bacteriophora (11KG) and H. bacteriophora (TOK-20) were found to be the most effective EPNs at a concentration of 100 IJs/beetle at 15 oC with a mortality of 57.7 and 55.6%, respectively. Mortality rates for the adult confused flour beetle were increased with an increasing the concentration of all EPNs species and also the degrees of temperature. Results showed that local EPNs isolates may use as an alternative biological control agent for T. confusum. Efforts should be made to develop new formulations that will allow nematodes to survive until they find their hosts, and they also need to be tested under field conditions.

Automated summary

The aim of this study was to determine the biocontrol potential of local entomopathogenic nematode isolates against the confused flour beetle. Results showed that the local isolates were effective biological control agents for the confused flour beetle, but further research is needed for field application.