Deteriorated acid and alkaline phosphatase activities in certain tissues of Spodoptera littoralis (Lepidoptera: Noctuidae) by some novel chitin synthesis inhibitors.

Objective of the present study was to investigate the effects of novel chitin synthesis inhibitors (CSIs), viz., Novaluron, Cyromazine, and Diofenolan, on the activities of acid (ACP) and alkaline (ALP) phosphatases in two larval tissues of S. littoralis. Each of LC50 values of these CSIs (2.71, 74.44 and 7.65 ppm, respectively) was applied on the penultimate instar larvae and the enzyme activities were determined in the successfully moulted last instar larvae of different ages. All CSIs enhanced larvae to gain increasing ACP activity in haemolymph, with few exceptions. In fat bodies, each of Novaluron and Cyromazine enhanced larvae to gain remarkably increasing enzyme activity, regardless the age. In contrast, Diofenolan exhibited an inhibitory effect on the enzyme activity, with an exception of 6-day old larvae. All CSIs promoted larvae to achieve elevated level of ALP in haemolymph, with few exceptions. On the contrary, they exhibited inhibitory effects on the enzyme activity in fat bodies of larvae, regardless the age.