Uso de geoestatística no monitoramento da doença atrofia letal da coroa do coqueiro e pulverização eletrostática no controle de Aceria guerreronis em plantio comercial de coqueiro.

Abstract

Pests and diseases are the main challenges for the agricultural production of coconut farming in Brazil. The ‘Lethal Atrophy of the Coconut Crown’ (ALCC) and the Aceria guerreronis mite have become threats to commercial coconut plantations in the country, causing large losses in production. The objective of this work was to characterize the spatial and temporal distribution pattern of the ALCC in a commercial area of green dwarf coconut plantations in Brazil, in the municipality of Santa Izabel do Pará. Evaluations were carried out from January 2014 to December 2018, checking plants with symptoms characteristic of ALCC. The geostatistical tool was used to generate semivariograms and make kriging maps. The model that best fit the spatial distribution of the disease was the spherical one as a function of R2. The Spatial Dependence Index (SDI) was moderate in the evaluations between 2014 and 2017, with the exception of 2018, which showed strong SDI. The use of an electrostatic sprayer proved to be efficient for coconut spraying. It was observed that the droplet density and size were satisfactory. Spray coverage and deposition were higher in the middle and lower thirds. As for the parameters, deposition and volumetric distribution uniformity, the best results occurred when the volume of 888 L ha-1 was used. The experiment showed that the electrostatic spray can be considered an efficient way to apply pesticides to adult coconut trees, reducing the volume of spray applied per plant. The average drop density values exceeded the need for 40 drops cm-1. The largest diameter of the volumetric median and the smallest did not compromise the quality of the sprays, as they generated medium and fine droplets.