Comparative effects of five new synthetic juvenile hormone analogues against the red cotton bug Dysdercus koenigii F.

Five synthetic juvenile hormone analogues (nos, I-V: I, 1-(3,4-methylenedio xyphenyl)-4,8-dimethy nona-1,3,7-triene; II, 1-(3,4-methylenedioxyphenyl)-4 ,8-dimethyl nona-1,3-dieno-7-oxirane; III, 1-(3-methyl but-2-enyl)-3-(4-met hoxy phenyl)-2-propenoate; IV, 1-(3-methyl but-2-enyl)-3-(3,4-methylenediox yphenyl) -2-propenoate; V, 1-(3,4-methylenedioxyphenyl)-4,8-dimethylnona-1, 7-diene) have been evaluated (at 0.1% cone., 2 and 5 mu l topical) for thei r morphogenetic activity against the last instar nymphs of the Pyrrhocorid Dysdercus koenigii F, Compound no. V caused 100% 6th instar production at t he above-said dosages whereas with compound nos II and I, 35% and 10% 6th i nstars were formed respectively at 5 mu l. The percentage of adultoid produ ction was very high with compounds II and I whereas III and IV possessed no juvenomimetic activity. Compounds V, II, and I also induced a high mortali ty in the supernumerary instars or in the adultoids, With compounds I and I I, the egg hatch was totally inhibited at 5 mu l.