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

Superplasticity in a nickel silicide alloy: Microstructural and mechanical correlations

The superplastic properties of a nickel silicide based intermetallic alloy have been investigated as a function of strain, strain-rate, and temperature. The evolution of the microstructure during superplasticity, including grain growth, grain refinement, and cavitation, is reviewed. The relationship of the flow stress to strain and to strain-rate and the activation energy of the deformation process have been established. Finally, deformation mechanisms for superplasticity in the alloy at intermediate and high strain-rates are proposed. 6 refs., 8 figs