Herbivore-induced plant volatiles from red spider mite, Oligonychus coffeae infested tea plants as attractant cues for the predatory mite, Neoseiulus longispinosus

Gas chromatographic studies revealed qualitative and quantitative variations in the volatile profiles of red spider mite (Oligonychus coffeae) infested and uninfested tea leaves. So further studies were conducted in laboratory using ‘Y’-tube olfactometer to determine whether the odours of O. coffeae induced plant volatiles from tea leaves are detectable cues for the attraction of the predatory mite, Neoseiulus longispinosus preying on red spider mite. Alpha farnesene, Beta ocimene and Linalool were found only in the volatiles from infested tea leaves. When predatory mites starved for 0 to 10 h were introduced into the experimental set up with four leaves each with 100 prey mites against uninfested tea leaves, the predatory mites which starved for 6 and 10 h showed significant preference to volatiles from infested tea leaves. Four leaves each with 12 prey mites did not show significant attraction of predatory mites over uninfested leaves. But predatory mites were significantly attracted to infested leaves when more numbers of prey mites were presented. There was no significant variation in attraction when mechanically damaged or previously infested tea leaves were presented against normal leaves. Preference was most significant to four leaves each with 100 prey mites when supplied against clean air. Results of this study deserve importance as data base for further determination of the feasibility of manipulating volatile info-chemicals as attractants for N. longispinosus in tea plantation.