Efeito letal de produtos alternativos sobre os ácarosTenuipalpus pacificus (Baker) e Brevipalpus californicus (Banks) (Prostigmata: Tenuipalpidae)

Abstract

The mite Tenuipalpus pacificus Baker, is one of the most important pests of orchids in the world. It feeds by sucking the contents of cells, causing cell death progressing to lesions on the leaves, making them exhibit silver spots, then strung up, with rusty look. The mite Brevipalpus californicus Banks, is an mite that attacks sweet potatoes, causing yellowing and necrosis in leaves and branches of infested plants. Control of the plane mites, T. pacificus and B. californicus consists of quarentenary, biological, plant resistance and chemical methods, the latter being the main cause of socioeconomic and environmental losses, since the lack of phytosanitary products registered for the respective crops in the control of the mites mentioned. Therefore, the objective of this study was to test alternative products in the control of T. pacificus and B. californicus. For this, we obtained plants of: Phalaenopsis sp., and sweet potato Ipomoeae potatoes L., these were obtained in floriculture and potato plantations respectively, In the municipality of Arapiraca, São Sebastião and Feira Grande-AL. Next, three experiments were carried out with alternative products, (two in orchid and one in sweet potato). It was used as treatments the Sulfocalcia syrup (3 mg/L); Hydrated lime (3 mg/L); Soybean oil (5 ml/L); Neutral Detergent (5 ml/L) and detergent + soybean oil (10 ml/L), as a control treatment, deionized water. Phalenopsis leaf discs and sweet potato measuring 1 cm in diameter, were immersed for five seconds in the Caldas, placed to dry the room temperature for 30 min.Twenty-five replications were used for each treatment, totaling 150 experimental plots in a completely randomized design. To study the residual effect, a total of 150 adult females of the two species mentioned in the reproductive period were transferred, 01 specimen per arena, which were then sealed with transparent plastic film. The arenas were kept in B.O.D. (25 ± 2 º C) with 12 hours of photophase and RH ± 70%. The evaluations were made with 24, 48, 72, 96, 120 and 144 hours. After the evaluation of the dead mites, the mortality averages were subjected to analysis of variance and compared with each other by the Tukey test at 5% of probability. For determination of LC50, LC90 and CL99 was selected the most efficient product. The data were submitted to Probit analysis using the SAS 9.1 statistical program. Products: sulfocalcide syrup, soybean oil, detergent + soybean oil, after 48h of the start of spraying, were the most efficient causing mortality of 64%, 68% and 80%, reducing the population of T. pacificus in an orchid. In sweet potato, the products: sulfocalcite syrup. In potato, the products: sulfocalcide syrup, hydrated lime, detergent + soybean oil were more efficient, causing mortality of 32%, 40% and 48% in the evaluation with 96 hours.