Ys. Xie et al., BIOLOGICAL-ACTIVITY OF EXTRACTS OF TRICHILIA SPECIES AND THE LIMONOIDHIRTIN AGAINST LEPIDOPTERAN LARVAE, Biochemical systematics and ecology, 22(2), 1994, pp. 129-136
Crude extracts of several Trichilia species (Meliaceae) were evaluated
for their behavioral and physiological effects on the polyphagous lep
idopterans Peridroma saucia and Spodoptera litura. A majority of extra
cts of nine Trichilia species, collected primarily from Costa Rica, si
gnificantly deter larval growth of P. saucia. Extracts of wood and bar
k are generally more active than those of foliage. Effects of various
tissue extracts from T. connaroides on P. saucia and S. litura were co
mparatively studied. Extracts of bark, the most active tissue compared
to those of wood, seed, exocarp and leaf, reduced larval growth of P.
saucia and S. litura by 50% at dietary concentrations of 29.1 and 185
.1 ppm, respectively. The limonoid hirtin, a constituent of Trichilia
hirta, significantly inhibited larval growth of P. saucia in a dose-de
pendent manner, with a dietary EC50 (effective concentration to inhibi
t growth by 50% relative to controls) of 13.0 ppm. Hirtin and various
extracts from T connaroides significantly reduced larval growth and co
nsumption rates, as well as dietary utilization, indicating that these
substances possess both behavioral effects and post-ingestive toxicit
y.