Influence of rainfall on mite distribution in organic and conventional coffee systems

Abstract

Climate changes, such as temperature rise, prolonged drought and heavy rainfall, impairs man’s life and food production. Rainfall is one of the most important natural, life-sustaining factors on the planet and it is essential in agriculture, not only in the watering of plants, but also in regulating pest organisms in crops, through mechanical control. The mites Brevipalpus phoenicis (Geijskes, 1939) and Oligonychus ilicis (McGregor, 1917) (Acari: Tenuipalpidae, Tetranychidae) are important coffee pests which are also influenced by the rainfall regime. The aim of this work was to study the distribution of coffee predatory (Phytoseiidae family) and phytophagous (B. phoenicis and O. ilicis) mites in function of rainfall, between June/2006 and June/2008, in organic and conventional coffee cultivation systems. The experiments were conducted at the Cachoeira (organic coffee production) and Taquaril (conventional system) farms, located in the municipality of Santo Antonio do Amparo, Minas Gerais state, in Brazil. Leaves were removed monthly from the middle part of the coffee plants from both the organic and conventional systems. It was concluded that rainfall influences the populations of pest and predatory mites in the different coffee production systems, but this effect was less intense on the organically cultivated coffee.