Side-effects of three neem (Azadirachta indica A. Juss) products on the predator Macrolophus caliginosus Wagner (Het., Miridae)

The side-effects of three neem formulations (Neem-Amin EC, Stardoor and B.P . 20/S) were tested on the mirid predator Macrolophus caliginosus Wagner in the laboratory. Direct toxicity tests on 1 st instar nymphs exposed to fre sh dry residues on glass plates at different doses demonstrated that all th e products are harmful to the insects with LD50 values much lower than the maximum recommended rate (1.217, 0.264, 1.083 mg a.i./l instead of 15, 31.5 and 80 mg a.i./l for Neem-Amin EC, Stardoor and B.P. 20/S, respectively). Moreover a reduction of fecundity of the surviving females was assessed wit h Neem-Amin EC and B.P. 20/S. Persistence tests were carried out on sharp p epper plants treated at the maximum recommended rate. High mortality was re corded when the insects were introduced onto the plants just after the trea tment, but no significant differences compared with the controls were obser ved 5 days after the treatment and any consequence on the fecundity of surv iving females was detected. Our experiments showed how azadirachtin can be noxious to M. caliginosus, but the short persistence makes this active ingr edient a promising solution in integrated pest management programmes, when a lapse of time is guaranteed between the treatment and the introduction of the predator.