Controle Biológico do pulgão Aphis gossypii Glover (Hemiptera: Aphidae) em cultivo protegido de pepino com cravo-de-defunto (Tageres erecta L.)

Abstract

Protected crop is a used practice in Brazil and abroad. Some characteristics like stable climate, high temperature and availability of food, favor the occurrence of pests on these systems, among them the Aphis gossypii. These insects are usually controlled chemically, which when applied in closed systems have little dispersion, thereby increasing its concentration and favoring the insects´ resistance. The use of attractive flowering plants, keep and increase the natural enemies population on these systems, can be an efficient alternative, practical and low cost. The objective of this work was to evaluate the potential of the marigold plant (Tagetes erecta) in the conservation control of A. gossypii on cucumber crop in greenhouse. Firstly was evaluated if the marigold, if grown with the cucumber, would not favor the aphids, increasing its host plants range. In another experiment, it was evaluated if the location of host plants (cucumber) related to the marigold, would influence on the aphid population growth, as well as their parasitism rate and the survey of natural enemies occurring in the system was made. On the first experiment, we observed that the T. erecta is not a good aphid host. On the second one, it was noted that the proximity of the marigold influenced negatively the aphid population growth and positively on the parasitism rate. The most abundant natural enemies in marigold were not the same for the cucumber, with emphasis on Orius insidiosus and parasitoids of the Scelionidae and Aphelinidae families in the first, and predatory larvae of the Syrphidae and Coccinellidae families and adults of Hippodamia convergens in the second plant. In conclusion, the marigold has potential to be used on conservation biological control of A. gossypii crop systems.