Laboratory Valuation of The Efficacy of Entomopathogenic Nematodes Against Some Insect Pests of the Potato crop (Solanum tuberosum L.)

The potato crop (Solanum tuberosum L.) is one of Egypt's most fundamental food crops and global. It is an onslaught by many insect pests that as the potato tuber moth, Phthorimaea operculella (Zeller), the hard black beetle, Pentodon bispinosus (Kuster), and the Egyptian cotton leafworm, Spodoptera littoralis (Boisduval). The current research aims to study the efficacy of entomopathogenic nematodes (EPNs); Heterorhabditis bacteriophora, Steinernema glaseri, and Steinernema carpocapsae, against some major pest species that infest the potato crop.The experiment of P. operculella4^thlarval instars and pupae treated with H. bacteriophora and S. carpocapsae gave the highest mortality compared with S. glaseri. The LC₅₀ values of H. bacteriophora and S. carpocapsae were calculated in the 4^thinstar larvae of P. operculella as 127.1496 and 148.5994 IJs/larva, respectively. While the LC₅₀ value of S. glaseri recorded, was 247.2687 IJs/larva. Treatment of P. bispinosus larvae S. glaseri showed the highest efficacy against the 2^ndand 3^rdinstars larvae of P. bispinosus compared with H. bacteriophora and S. carpocapsae. The LC₅₀ values of S. glaseri were 1073.640 and 1330.312IJs/larva to combat the 2^ndand 3^rdinstars larvae of P. bispinosus. In the experiment of S. littoralis on 3^rdand 5^thinstar larvae, the H. bacteriophora and S. carpocapsae showed higher mortality than S. glaseri. LC₅₀ values of H. bacteriophora and S. carpocapsae were (38.489 and 40.791) and (42.149 and 51.932) IJs/larva in the 3^rdand 5^thinstar larvae of S.littoralis, respectively. While in the case of S. glaseri, correspondent LC₅₀ values recorded were70.106 and 95.295 IJs/larva. H. bacteriophora recorded the most elevated mortality in (the 4^thlarval instars and pupae of P. operculella) and (3^rdand 5^thinstar larvae of S. littoralis), followed by S. carpocapsae. S. glaseri recorded the highest mortality (100%) of2^ndand 3^rdinstars larvae of P. bispinosus compared with H. bacteriophora and S. carpocapsae. The results also concluded that S. littoraliswas the most sensitive to the use of EPNs, followed by P. operculella and then P. bispinosus. EPNs can be relied on as successful biocontrol agents against soil-dwelling pests and add nematodes to pest control programs.