Impact of combine releases of the egg parasitoid, Trichogramma euproctidis (Girault) and the entomopathogenic nematode, Heterorhabditis bacteriophora to control Tuta absoluta (Meyrick) in tomato greenhouses in Egypt

Abstract In greenhouses, tomato plants are subject to attack by several pest species. The present study aimed to investigate the compatibility of releasing the egg parasitoid, Trichogramma euproctidis (Girault) (Hymenoptera: Trichogrammatidae), and the entomopathogenic nematode, Heterorhabditis bacteriophora, strain HP88 against the tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), in commercial tomato greenhouses (Cherry and Bushra varieties) at winter plantation of 2018–2019 in Egypt. Three commercial plastic greenhouses were used. The first plastic greenhouses were treated by the two tested biological control agents (BCG), the second sprayed by certain recommended pesticides (PG), and the third used for control. Pheromone traps were used for monitoring the appearance of T. absoluta moths. The combined use of T. euproctidis and H. bacteriophora resulted to reduce the population density of the T. absoluta gradually until the end of the season in BCG. In the 17th week of treatments by T. euproctidis and H. bacteriophora, the population density of T. absoluta was estimated as leaf mines/plant (0.8 and 1.26 mines/leaf, in Cherry and Bushra varieties, respectively) in BCG. Also, in the 17th week of treatments by recommended pesticides, the population density of T. absoluta reached 12.73 mines/leaf and 18.33 mines/leaf, in CG. Early use of pesticides, by the appearance of T. absoluta infestation, could not suppress its population density that continued to increase until the end of the season in PG. Results revealed that the combination of the tested biological control agents against T. absoluta is recommended to be a main part in pest management practices in tomato greenhouses.