R. Gols et al., Jasmonic acid induces the production of gerbera volatiles that attract thebiological control agent Phytoseiulus persimilis, ENT EXP APP, 93(1), 1999, pp. 77-86
Jasmonic acid (JA) is a plant hormone that is involved in the induction of
plant defence in response to herbivore attack. We studied the effect of exp
osure of gerbera leaves to JA on indirect plant defence, i.e. attraction of
natural enemies of herbivores. Treatment of gerbera leaves with JA or feed
ing damage by the herbivorous spider mite Tetranychus urticae, both induced
the production of a complex odour blend that attracts the predatory mite P
hytoseiulus persimilis. This phytoseiid predator is a very effective biolog
ical control agent of the spider mite T. urticae. Comparison of headspace c
omposition of gerbera leaves exposed to either JA or T. urticae revealed a
large degree of resemblance, but some quantitative and qualitative differen
ces were recorded. The major chemical group in both treatments is formed by
the terpenoids which quantitatively comprised up to 80% of the total odour
blend. These terpenoids included (E)-4,8-dimethyl-1,3,7-nonatriene, (E)-be
ta-ocimene and linalool that are known to attract P. persimilis. Aldehydes,
alcohols, esters and ketones, together with nitrogenous compounds formed t
he remaining constituents of the odour blend. The induction of predator att
ractants in plants by JA may be applied in biological control programs, whi
ch is discussed in this paper.