Dinâmica de Aleurocanthus woglumi Ashby (Hemiptera: Aleyrodidae) em lima-ácida Tahiti em diferentes adubações: respostas ecofisiológicas e bioquímicas

Abstract

Aleurocanthus woglumi Asbhy is an insect pest responsible for causing changes in the physiological and biochemical performance of the plant due to the symptoms and damage caused in the nymph and adult phases. This work aimed to study the population dynamics of A. woglumi in Citrus latifolia submitted to different fertilizations and the ecophysiological and biochemical responses of plants under field conditions. The experiment was installed in a citrus groves in the city of Paço do Lumiar - MA. Sixty randomly selected Tahiti acid lime plants were used, naturally infested by A. woglumi. The treatments consisted of: T1- Control (Soil without fertilization); T2- Organic fertilization (bovine manure); T3- Organic fertilization (bovine manure) + Potassium silicate (K2O3Si); T4- NPK and T5- NPK + K2O3Si. First, the population dynamics of A. woglumi (incidence and distribution of A. woglumi eggs and nymphs in the basal, median and apical strata, at 30, 60 and 90 days after the last fertilization plot) was evaluated. Then, the ecophysiological parameters (chlorophyll content and gas exchange) and biochemical parameters (total protein content, peroxidase and polyphenoloxidase activity) were analyzed in leaves of C. latifolia infested by A. woglumi in both the dry and rainy periods. In determining the population density of A. woglumi, reductions in the number of eggs and nymphs were observed in treatments with organic fertilization + K2O3Si and NPK + K2O3Si and greater incidence in NPK treatment in the basal, median and apical strata. Plants of C. latifolia fertilized with NPK + K2O3Si and organic fertilization + K2O3Si are less susceptible to A. woglumi, which hinders the oviposition of the postures and the development of the biological cycle of the pest at 30, 60 and 90 days of evaluation, while the plants fertilized with NPK are more susceptible to A. woglumi. There is a higher incidence of laying, eggs and 1st instar nymphs in the apical stratum and incidence of 2nd, 3rd and 4th instar nymphs are favored in the basal and median strata in C. latifolia. The results obtained for the ecophysiological parameters showed that the treatments with the presence of K2O3Si favored the increase of the production of photoassimilates by the plants, due to the increase of the photosynthetic assimilation of CO2 and the SPAD Index and were less susceptible to the attack of A. woglumi. C. latifolia fertilized with NPK and organic fertilization are more susceptible to A. woglumi and cause physiological changes regarding the SPAD index, photosynthetic CO2 assimilation, stomatal conductance, instant sweating and VPDleaf-air during the dry and rainy season. For biochemical parameters, the highest total protein content was found in citrus plants with organic fertilizer + K2O3Si, NPK and NPK + K2O3Si and higher peroxidase and polyphenoloxidase activity in C. latifolia infested by A. woglumi. Plants of C. latifolia fertilized with NPK + K2O3Si and Organic fertilization + K2O3Si are less susceptible to the development stages of A. woglumi and plants fertilized with NPK present greater susceptibility in dry and rainy periods. Higher content of total proteins is expressed during the dry period in plants with organic fertilization + K2O3Si, NPK and NPK + K2O3Si. The addition of mineral and organic fertilizer decreases the activity of peroxidase and increases the activity of polyphenoloxidase promoting changes in C. latifolia infested by A. woglumi.