Plano de maneio integrado de pragas e doenças dos citrinos: caso da Empresa Agrofarm

Abstract

The present work had as objective to elaborate an integrated management plan of pests and diseases of citrus fruits existing in the Agrofarm company. The work was carried out between the months of December 2003 and April 2004 in selected orchards with ages ranging from 4 to 15 years old, approximately. Ten orchards were selected for this purpose, 2 of which were orange with Umbigo and Valencia cultivars and 8 grapefruit with Marsh Seedless and Star Ruby cultivars. To carry out this work, informal interviews were carried out and samples of soil, leaves and pests were collected for later observation and analysis in the laboratory. The observations were made in a systematic way, using the zig-zag method, taking 25 plants where the symptoms and signs of pests and diseases were analyzed. The parameters considered for the assessment of the situation of the orchards were the percentage of incidence and the severity. The identification of methods and the proposal for the management plan were based on informal interviews and on existing plans for citrus production. The economic analysis of costs and benefits was based on the balance between charges and expected revenues, using the partial budget method. The main pests found in Agrofarm's orchards were the ferruginous mite, fruit fly, ants, scale insects and thrips. The results indicated the existence of an average incidence in the 10 orchards of 85.7% of trees infested with ants, 90.8% with thrips, 74.4% with ferruginous mite, 37.8% with red scale, 44% with fruit fly, 31.2% with miner caterpillar and 72% with sooty mold. The average density of the caterpillar was 2.56 larvae per plant. Cochineal density was an average of 142 mealybugs in every 100 fruits observed. The methods proposed for the integrated management of pests and diseases were chemical, biological and cultural methods. As an integrated management strategy, monitoring of pests is recommended in order to minimize the effects of pests and diseases on yield and the use of treatment thresholds as a decision criterion on chemical applications. The costs for the management of pests and diseases in the orchards were estimated at around 18,004,476 meticais and the benefits (net returns) at 156,924,071 meticais (TRADUÇÃO NOSSA)