Population density of aphids in chrysanthemums grown under photoselective screens

Abstract

The chrysanthemum is one of the main ornamental species in the world. It has great relevance in the market. Aphids are the main pests that affect the chrysanthemum crop and cause various types of damage to this plant. The objective of this study was to evaluate the influence of different cropping systems using photoselective screens on the population density of aphids in cut chrysanthemum. The study was carried out in an experimental area of the Federal Institute of Espírito Santo – Campus Itapina (Brazil) in a randomized complete block design, according to the split-plot scheme over time. The experiment was established in 3 blocks of 12 m in length with plots of 3 m containing different photoselective screens (red, silver, and black) and the control treatment (open field). Repeated evaluations at different times were done at 0, 15, 30, 45, and 60 d. Data were checked for normality and homoscedasticity and submitted to the Tukey’s test (P<0.05) and a non-parametric method of smoothing a dispersion graph with local weight (LOESS regression). Regardless of the color of the photoselective screen, there was a lower incidence of aphids compared to the open field treatment in the chrysanthemum culture with an average reduction of 84%. For the different sampling times, the Tukey test did not show significant differences between the means of aphid incidence in the evaluated period. Black, red, and silver photoselective screens promoted significant reductions in aphid populations in chrysanthemums of the variety Zembla in the environmental conditions of southeastern Brazil.