Efectividad de la azadirachtina en la inhibición de la embriogénesis de Aegorhinus superciliosus (Guérin) (Coleoptera: Curculionidae)

Abstract

Raspberry is cultivated in the southern part of Chile mainly for export. Its fruit is severely affected by the raspberry weevil (RW) Aegorhinus superciliosus (Guérin), a Curculionidae native of Chile. Little is known about the biology RW and control measures. Conventional insecticides have been tried against the adult, however, their use has been hindered in the practice by the coincidence of the presence of the mature insect with flowering and fructification periods. Entomopathogenic fungi are being incorporated lately, but still not massively used. This work aimed to evaluate azadirachtin, using the commercial product Neem as a growth regulator. Six doses of Neem, 0.5, 1, 2, 3, 4, and 5 ml/L of water, were applied under laboratory conditions, maintaining a check with no insecticide. RW adults stayed confined on the foliage of raspberry bushes treated with Neem during five days and in thirty days during egglaying. Number of eggs, number of emerged larva, percentage of born larva, effectiveness; effective half dose (DE50) and ninety effective dose (DE90) were determined. Neem treatments had significantly lower egg-laying amount, lower emergence of larvae and greater effectiveness, compared to the untreated check. The lowest egg-laying number was obtained with 2 ml of Neem, however, 5 ml of Neem resulted in the smallest number and percent of emerged larvae. DE50 and DE90 were found to be 0.0290 and 8.923 ml of Neem for liter of water, respectively. It was concluded that Neem can significantly alter egg-laying and embryogenesis of the RW.