Population dynamics of thrips (Insecta: Thysanoptera) in cut chrysanthemum cultivated under photoselective screens

Abstract

The chrysanthemum is one of the main ornamental species in the world, having high relevance in the market of cut flowers and potted plants. Thrips are among the main pests of the chrysanthemum crop, causing direct and indirect damage to plants. The objective of this work was to evaluate the influence of photoselective screens and climatic factors on the population density of different species of thrips chrysanthemum. The study was carried out in the experimental area of the Instituto Federal do Espírito Santo – Campus Itapina, in a randomized complete block design, with split plots in time. The experiment was established in 3 blocks of 12 m in length, with plots of 3 m in length containing the different photoselective screens (red, silver, and black) and the control treatment (open field), which consisted of the primary factor. Repeated evaluations in time (0, 15, 30, 45, and 60 d) consisted of the secondary factor. Data were submitted to Tukey's test (p < 0.05) and the multivariate technique of principal component analysis (PCA). The mean of the thrips population at 60 days was statistically higher. The climatic variables rain and average humidity showed a highly significant negative correlation with the population fluctuation of the pest. Black, red, and silver photoselective screens promote significant reductions in thrips populations in chrysanthemums of the Zembla variety in the environmental conditions of southeastern Brazil.