Resistência de genótipos de morangueiro ao ácaro-rajado

Abstract

In strawberry cultivation, several pests can compromise production. Among the strategies that can be adopted in an integrated pest management program is the introduction of resistant plants, reducing the use of chemicals in crops and, at the same time, not allowing the pest to settle at population levels capable of harming the crop. One of the most important pests of the strawberry plant is the spider-mite - Tetranychus urticae Koch. The spider mite causes injuries by feeding on the cellular content of the leaves. Severely infested plants can be recognized by staining and browning of the leaves and the presence of webs. The pest, when not controlled, can compromise production and lead to plant death. With these premises, the objective of the research was the evaluation of biological and behavioral parameters of the spider mite, T. urticae, when subjected to the presence of different national and imported strawberry genotypes, in order to verify if there are any resistance characteristics present among these genotypes. Experiments were carried out, one of antixenosis, also evaluating the presence of trichomes, and the other of antibiosis, evaluating the biology of the spider mite, under laboratory conditions. It was possible to verify that there is resistance among the studied genotypes. Genotypes 35-22; 35-25; 35-06 are promising for the manifestation of antixenosis-type resistance, due to the finding of low feeding and oviposition rates, however, they are not linked to the density of nonglandular trichomes in the leaves. The cultivar Camarosa and the genotypes 32-05 and 04-03 showed antibiosis-type resistance to T. urticae, as they negatively affected 9 the reproductive parameters of the spider mite. These findings warrant further investigations aimed at detecting and quantifying other factors associated with spider mite resistance of the most promising strawberry genotypes.