Tomato stem trichomes and dispersal success ofPhytoseiulus persimilis relative to its preyTetranychus urticae

Tomato varieties used at present for commercial production in Dutch glasshouses have a high density of glandular trichomes on the stem, but a very low density on the leaves. The two-spotted spider mite, Tetranychus urticae Koch, and the predatory mite, Phytoseiulus persimilis Athias-Henriot, usually disperse from leaf to leaf via the stem, thereby incurring high risks of entrapment (and death) in the exudate of the glandular trichomes. These risks have been quantified on the tomato cv. 'Turbo' and an accession of Lycopersicon peruvianum almost free of glandular trichomes. The possible consequences for biological control are discussed and new perspectives for predator release strategies and for plant breeding are considered. © 1987 Elsevier Science Publishers B.V

Aspectos alimentares e de criação de Bradysia hygida Sauaia & Alves (Diptera, Sciaridae) em laboratório Aspects on alimentation and rearing of Bradysia hygida Sauaia & Alves (Diptera, Sciaridae) in laboratory

<abstract language="eng">In nature, the Sciaridae live in moist and shady places, where exists vegetable material in decomposition. It is very dificult to determine the proper Sciaridae's alimentary habit and then, it is dificult, also, to rear Sciaridae species in laboratory. To improvement the Bradysia hygida rearing, the objectives of this research were to analyse the nutritive value of mucuna bean foliage for the larves, to verify the role of the ground (as larvae substrate and in diet composition) and also to verify the possibility of ground substituition by another kind of substrate. Two kinds of sand were employed in the place of the ground and three diets, free of ground, were prepared. The parameters analysed were: duration of the life cicle, porcentage of emergence, egg production by female and adult size. The results showed that the mucuna bean foliage have a good nutritive value for B. hygida rearing; the ground, as substrate, can be substituted by any of the sands and the ground, in the diet, is also dispensable. The alimentary habits of Sciaridae is discussed