New application method for entomopathogenic nematode Heterorhabditis bacteriophora (Poinar, 1976) (Rhabditida: Heterorhabditidae) HBH strain against Locusta migratoria (Linnaeus, 1758) (Orthoptera: Acrididae)

Abstract

Entomopathogenic nematodes (EPNs) of the families Heterorhabditidae and Steinernematidae are being used as biocontrol agents against many soil borne insect pests in agriculture. Above-ground applications against the insects are usually unsuccessful due to the lack of humidity. Therefore, EPNs rapidly lose their effectiveness. In this study, conducted in 2018 under laboratory conditions in Bursa-Turkey, a new application method was developed for the use of Heterorhabditis bacteriophora (Poinar, 1976) (Rhabditida: Heterorhabditidae) HBH hybrid strain against the migratory locust, Locusta migratoria (Linnaeus, 1758) (Orthoptera: Acrididae). A new trap system is coated with hydrophilic cotton fabric to provide the necessary humidity to allow the use of EPNs above-ground. Three different application rates of H. bacteriophora (5000, 25000 and 50000 IJs) were applied to the trap system. The fabric was inoculated with the nematodes and combined with a reservoir containing 200 ml of ringer solution. The dead and live nematodes were recorded periodically to determine their persistence on the fabric. The mortality of L. migratoria were also recorded to determine the infectivity of H. bacteriophora. The infectivity and persistence of the nematodes was sustained for more than 4 weeks by this method.