The black cutworm, Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae), is almost a cosmopolitan pest in distribution. It is a polyphagous insect attacking nearly all vegetables and many economic field crops in the world. The present study was conducted to investigate the disturbing effects of entomopathogenic nematodes (EPNs), Steinernema carpocapsae and Heterorhabditis bacteriophora on the activities of phosphatases and transaminases in the haemolymph of A. ipsilon larvae. The newly moulted penultimate (5 th ) instar larvae had been infected with LC50 values of S. carpocapsae and H. bacteriophora (21 IJs/ml and 62 IJs/ml, respectively) and the influenced enzymatic activities were determined in the haemolymph of last (6 th ) instar larvae, at three-time intervals, 6, 24 & 48 hr, respectively. The most important results could be summarized as follows. The acid phosphatase (ACP) activity significantly increased in haemolymph of 6 hrold last instar larvae of A. ipsilon. In contrast, ACP activity was remarkably decreased in 24 and 48 hr-old larvae. The alkaline phosphatase (ALP) activity increased in the haemolymph of 6 hr-old larvae. On the contrary, ALP activity was considerably reduced in haemolymph of 24 and 48-old larvae. Glutamic oxaloacetic transaminase (GOT) activity significantly increased in the haemolymph of 6 hr-old last instar larvae. In haemolymph of 24 hr-old larvae, GOT activity considerably increased by H. bacteriophora but was slightly decreased by S. carpocapsae. At the last time interval, GOT activity greatly decreased, regardless the EPN species. Glutamic pyruvic transaminase (GPT) activity was predominantly declined in larvae infected with S. carpocapsae or H. bacteriophora, at all-time intervals, with an exception of a slightly increased activity in 6 hr-old larvae after infection with S. carpocapsae. Moreover, GPT activity was increasingly reduced with the time intervals. Also, H. bacteriophora exhibited stronger reducing potency on the GPT activity than S. carpocapsae. In conclusion, the disturbances of activities of phosphatases and Transaminases, as a result of the interactions between these nematodes and their symbiotic bacteria versus the immune responses of the host insect, end in the host death. Therefore, the tested EPNs can be used as a part of the Integrated control program against A. ipsilon.

The black cutworm Agrotis ipsilon (Hufnagel) (Lepidoptera: Noctuidae), is globally distributed. It is a polyphagous insect attacking nearly all vegetables and many economic field crops in the world. The objective of the current study was to investigate the efficacy of two Entomopathogenic nematodes, Steinernema carpocapsae and Heterorhabditis bacteriophora on the main body metabolites in haemolymph of the infected larvae. The newly moulted penultimate (5th) instar larvae of A. ipsilon had been infected with LC50 values of S. carpocapsae and H. bacteriophora (21 IJs/ml and 62 IJs/ml, respectively) and the influenced contents of the metabolites in haemolymph of last (6 th ) instar larvae were determined at three-time intervals of the instar, 6, 24 & 48 hr, respectively. The most important results could be summarized as follows. The protein content in the infected larvae was predominantly reduced by both nematode species. Moreover, it was tremendously reduced at the last time interval of exposure (21.94 & 26.45% protein reductions, by S. carpocapsae and H. bacteriophora, respectively). Thus, H. bacteriophora exhibited stronger reducing potency than S. carpocapsae. Also, the lipid content in haemolymph of EPN-infected larvae was gradually reduced with the time intervals. The greatest reduction of lipids was determined at 48 hr post-infection (26.55 & 21.73% lipid reduction, by S. carpocapsae and H. bacteriophora, respectively). Thus, S. carpocapsae exerted greater reducing action than H. bacteriophora. The carbohydrate content was predominantly reduced in haemolymph of infected larvae. S. carpocapsae exhibited a higher reducing effect on carbohydrate content than H. bacteriophora, at 48 hr of the last instar. Almost, S. carpocapsae had greater reducing potency against the main body metabolites in haemolymph of the last instar larvae of A. ipsilon, leading to drastically disrupted intermediary metabolism. Therefore, S. carpocapsae can be applied as an effective part of the Integrated Pest Management program against this serious pest.