A new application method of hybrid entomopathogenic nematode strain Heterorhabditis bacteriophora HBH in control of some insect pests

Chemical insecticides, which are harmful to human health and cause insects to gain resistance, are generally used against agricultural pests. Entomopathogenic nematodes (EPNs) of the families Heterorhabditidae and Steinernematidae are being used as biocontrol agents against many soil-borne insects pests in agriculture. EPNs are a good alternative to chemicals used to control soil-dwelling pests. However, above-ground applications against the insects are usually unsuccessful due to the lack of humidity. Therefore, EPNs rapidly lose their effectiveness. In this study, a new application method was developed for the use of Heterorhabditis bacteriophora (Poinar, 1976) (Rhabditida: Heterorhabditidae) HBH hybrid strain against the migratory locusts (Locusta migratoria (Linnaeus, 1758) (Orthoptera: Acrididae)) and Turkestan cockroaches, Blatta lateralis (Walker) (Dictyoptera: Blattidae). The hydrophilic fabric traps were set to provide the moist environment needed by the EPNs on aboveground. Three different application rates of H. bacteriophora (50 IJ/cm2, 250 IJ/cm2 ve 500 IJ/cm2) were applied to the trap system. The fabric was inoculated with the EPNs and combined with a reservoir containing 200 ml of ringer solution. The dead and live EPNs were recorded periodically to determine their persistence on the fabric. The mortality of L. migratoria and B. lateralis were also recorded to determine the infectivity of H. bacteriophora. As a result of this study, the above-ground persistence and infectivity of HBH could be achieved more than 4 weeks by using hydrophilic fabric. In addition, the mortality rates of the Turkestan cockroaches were found to increase depending on exposure time and the nematode dosage.