OVERWINTERING PHENOLOGY AND ECO-FRIENDLY MANAGEMENT OF TWO SPOTTED SPIDER MITE TETRANYCHUS URTICAE KOCH (ACARI: TETRANYCHIDAE) ON COUNTRY BEAN

Abstract

Two spotted spider mite, Tetranychus urticae Koch is a major mite pest of vegetables in Bangladesh. The harsh condition of winter has important effect on the tiny and soft bodied pest mite. Diapause in arthropod is a physiological state of dormancy which promotes survival during adverse conditions especially in winter. In the present study, we tested the diapause propensity of pest mite under the combined conditions of prevailing temperature ranges of three winter months in December (13-20.2oC), January (10.6-23.8oC) and March (18oC - 30.8oC) and four photoperiods (8:16, 9:15, 10:14 and 11:13 L: D) with one generation exposure in laboratory using 20 replications. Variation in temperatures and photo periods significantly affected the females for diapauses induction. Result showed that the 100% diapause was induced in the month of December in two photoperiodic regimes 8:16 and 9:15 (L: D) and one photoperiodic regime (8:16 L: D) in the month of January. All the adult females of each treatment oviposited eggs in indicating no diapauses induced in these periods. Egg to adult period was longer at 8:16 photoperiodic regime in December and January. The highest egg laid per day in the month of March at 8:16 photoperiodic regime where due to diapauses induction no egg laid per day in December and January on same photoperiodic regime. The present findings might be used in devising integrated pest management of TSSM on various vegetables in Bangladesh.