Ocorrência e flutuação populacional de tripes, pulgões e inimigos naturais em crisãntemo de corte em casa de vegetação

Abstract

Aphids and thrips play an important role on chrysanthemum crops in greenhouses. The objective of this work was to evaluate the occurrence and population densities of thrips, aphids and natural enemies in cut chrysanthemum cultivars ('White Reagan', 'Yellow Snowdon' and 'Sunny Reagan') in commercial greenhouse. Thrips sampling was made by the tapping method, while aphids were sampled by direct counting on the plants. Frankliniella occidentalis (Pergande) (>90%), F. gemina, Frankliniella sp., Caliothrips phaseoli (Hood) and Haplothrips gowdeyi (Franklin) were the thrips species found. A higher number of thrips/ plant was found in 'White Reagan' compared with 'Yellow Snowdon' cultivar. The aphid species Aphis gossypii (Glover) (>80%), Myzus persicae (Sulzer) and Dysaphis sp. were found. A higher number of aphids were found in 'White Reagan' than in 'Sunny Reagan' cultivar. The predatory bug Orius insidiosus (Say) was the only species found associated with thrips in all chrysanthemum cultivars. A positive correlation between thrips and O. insidiosus populations was found. Among the natural enemies associated with aphids the parasitoids Aphidius colemani Viereck and Lysiphlebus testaceipes (Cresson), and the predators Chrysoperla sp., Cycloneda sanguinea (L.) and Scymnus sp were collected. A positive correlation between aphids and their natural enemies' populations in 'White Reagan' and 'Sunny Reagan' cultivars was found. Natural enemies can naturally occur on chrysanthemum in greenhouse and they can affect the pest population.