Bioefficacy of certain plant extracts against the red spider mite, Oligonychus coffeae (Nietner) (Acarina: Tetranychidae) infesting tea in Tamil Nadu, India

Bioefficacy, ovicidal action and ovipositional deterrence of a few selected bio-pesticides such as neem kernel aqueous extract (NKAE), pongam kernel aqueous extract (PKAE) and garlic aqueous extract (GAE) were evaluated in the laboratory against the tea red spider mite (RSM). Data were collected on the mortality of eggs and adults and also on the reduction in the fecundity of female mites. The acaricidal property of the biopesticides was compared with that of Derrimax, a commercial bioformulation. Ovipositional deterrence as well as ovicidal and adulticidal properties were evaluated using laboratory reared mites, by directly spraying the test material onto the leaf discs. The results revealed that, Derrimax and NKAE could inflict more than 90% mortality on RSM compared to PKAE and GAE. However, all the adult mites were killed within 96 hrs after treatment by all the tested botanicals, except NKAE @ 5.0%. Ovipositional deterrence ranged between 80 and 100%.