Resistance of strawberry cultivars to the Tetranychus urticae Koch (Acari: Tetranychidae)

The two-spotted spider mite, Tetranychus urticae Koch is considered a major pest of strawberries. His control is hampered by the low efficiency of the products used, populations resistant to acaricides and the high reproductive potential of this pest. This difficulty has led to the indiscriminate use of pesticides, leading to a sequential increase of pesticide residues in fruit. Thus the use of resistant plants is one regarded as optimal control method. Allows maintenance of the pest below the levels of economic damage, minimizing the environmental impact of the use of pesticides without causing damage to the environment and without additional burden to the farmer, also served as an auxiliary tool in integrated pest management, and may be associated with other practices of pest management. In this sense, the study aimed to evaluate the resistance of strawberry cultivars to two-spotted spider mite, through the study of the development of the mite in biology experiment, test non-preference for feeding and oviposition and no-choice laboratory and evaluation of the reaction field two-spotted spider mite in different strawberry cultivars. The experiments showed that strawberry cultivars influenced the preference for feeding, development and oviposition, indicating the existence of resistance among cultivars to two-spotted spider mite.O ácaro-rajado, Tetranychus urticae Koch é considerado a principal praga da cultura do morangueiro. Seu controle é dificultado pela baixa eficiência dos produtos empregados, populações resistentes a acaricidas e ao alto potencial reprodutivo dessa praga. Isso tem levado ao uso indiscriminado de agrotóxicos, ocasionado um aumento seqüencial de resíduos de agroquímicos na fruta. Assim, o emprego de plantas resistentes é um método considerado ideal de controle, pois permite a manutenção da praga em níveis inferiores aos de dano econômico, minimizando o impacto ambiental do uso dos defensivos, sem causar prejuízos ao meio ambiente e sem ônus adicional ao agricultor, servindo também como ferramenta auxiliar no manejo integrado, podendo ser associado com outras práticas de manejo da praga. Nesse sentido, o trabalho teve como objetivo avaliar a resistência de cultivares de morangueiro ao ácaro-rajado, através do estudo do desenvolvimento do ácaro em experimento de biologia, teste de não-preferência à alimentação e à oviposição com e sem chance de escolha em laboratório e avaliação da reação a campo de cultivares de morangueiro ao ácaro-rajado. Os experimentos realizados mostraram que as cultivares de morangueiro influenciaram na preferência à alimentação, desenvolvimento e oviposição, indicando a existência de resistência diferenciada entre cultivares estudadas para o ácaro-rajado

DEVELOPMENT OF Tetranychus urticae KOCH (ACARI: TETRANYCHIDAE) IN DIFFERENT STRAWBERRY CULTIVARS

ABSTRACT Two-spotted spider mite, Tetranychus urticae Koch, is considered the main pest in strawberry crop. The control of this species is hampered by the low efficiency of products currently used, occurrence of populations resistant to acaricides and high reproductive potential of this pest. This leads to the use of pesticides and increased agrochemical residues in fruits. The use of resistant cultivars is considered the ideal control method because they maintain mite populations below levels of economic damage, minimize the environmental impact of pesticides at no extra cost to the farmer, and serve as an auxiliary tool in integrated pest management. In this sense, this study evaluated the resistance of strawberry cultivars to T. urticae by studying the development of its biological aspects. Comparative biology experiments and non-preference tests for feeding and oviposition for spider mite were carried out in 16 strawberry cultivars under laboratory conditions. Based on results, it was found that Camarosa, Florida Festival, IAC Campinas and Sabrosa strawberry cultivars indicated the possibility of antibiosis type resistance to spider mite, influencing the preference to food, development and oviposition, indicating the existence of differentiated reaction in population development among cultivars