EFFICACY OF CLOVE OIL AGAINST TWO-SPOTTED SPIDER MITE, TETRANYCHUS URTICAE KOCH (ACARI: TETRANYCHIDAE)

Abstract

Clove oil (Syzygium aromaticum L.) exhibits promising potential as a bio-acaricide against the two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae). This destructive pest inflicts significant damage on various crops worldwide. Laboratory evaluations demonstrated acaricidal, ovicidal, repellent, and oviposition deterrent effects of clove oil against T. urticae. Increasing concentrations and exposure times resulted in progressively higher adult and nymph mortality rates. The 3% concentration achieved the highest mortality of 75% and 85% for adults and nymphs, respectively after 5 days of treatment application. Notably, nymphs exhibited higher susceptibility than adult females at all concentrations. The ovicidal activity revealed the lowest egg hatchability (45%) and the highest efficacy (52%) at the 3% concentration after 7 days. The LD50 values for adults were 2.478, 1.884, 1.010 and 0.569% and for nymphs were 1.788, 0.842, 0.428 and 0.235 % after 24, 48, 72 h and 5 days respectively, whereas for eggs were 2.473% after 7days. The clove oil also displayed significant repellency and oviposition deterrence against T. urticae. Repellency and deterrence rates escalated with dose and exposure time, showcasing the strongest effect at 3%. Convincingly, the deterrence effect proved more pronounced than repellency. These findings strongly suggest clove oil's potential development as a bio-acaricide for managing T. urticae.