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There are many types of drippers with different flow path length, flow path shape and filtration surface. EPN delivery performance of the most commonly used four different types of drippers (in-line short path, in-line long path, in-line cylindrical and on-line button) was examined with a drip irrigation system in laboratory conditions. Under four different pressures (0.5, 1, 1.5, 2 bar), EPNs were applied to 1-liter beakers with irrigation system and discharged nematodes were counted under a stereomicroscope. The effect of pressure on application and EPN mortality were also determined. The results showed that there were significant differences between the discharge ratio of EPNs from drippers. Among the four drippers, on-line button dripper sustained the highest and fastest discharge ratio. Pressure alone had no significant effect on delivering EPNs. However, it should be considered that long pressure exposure may harm EPNs. Regarding our results, different irrigation drippers have significantly different effects on EPN discharge ratio. Therefore, optimizing drip irrigation systems for EPN applications may increase their performance.

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.

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SummaryEntomopathogenic nematodes (EPNs) are environmentally safe alternative control agents. Nematodes in the Heterorhabditidae and Steinernematidae families are widely used in biological control frameworks, especially for soil-inhabiting insect pests. In this experiment, Heterorhabditis bacteriophora (Poinar, 1976), Steinernema feltiae (Filipjev, 1934) and S. carpocapsae (Weiser, 1955) adapted at high temperature were assessed in order to detect differences in virulence between adapted and non-adapted populations. All species were exposed to 38 °C for 2 h. After this treatment, live infective juveniles (IJs) were used to infect to last instar Galleria mellonella (Linnaeus, 1758). larvae at the following doses: 1, 2, 3, 4 and 5 IJs/larva. The LD 50 and LD 90 were obtained for these species. Non-adapted populations of the nematode species were used as controls for this experiment. The results indicated that differences in S. feltiae and S. carpocapsae virulence between the adapted and non-adapted populations were signifi cant; no signifi cant difference was observed between the adapted and non-adapted H. bacteriophora populations.