Prospecção de plantas atrativas para inimigos naturais e o seu uso no manejo de insetos fitófagos

Abstract

Pest management in food production with no chemical residues and environmental impact is a challenge for agriculture. One of the appropriate tools to manage pests in an environmentally safe way is by offering and maximizing natural resources to natural enemies. Besides being a method that demands little energy when well implemented, conservative biological control modifies the layout of the agricultural landscape, increasing biodiversity as a whole, including that of natural enemies of pests. The greater supply of resources creates conditions for them to feed and reproduce in the refuge, with greater possibilities for controlling agricultural pests. However, there is a great lack of knowledge about which plants to use, how to use them, and in which situations or problems. The general objective was to evaluate the potential of plants for the attractiveness of natural enemies and their use in the biological control of phytophagous insects in organic crops. The experiments were conducted under field conditions in Seropédica-RJ, in two phases. In the first phase, from May to November 2017, the objective was to evaluate the vegetative and flowering performance of four plant species (Cosmos sulphureus - Asteraceae, Canavalia ensiformis - Fabaceae, Crotalaria spectabilis - Fabaceae and Foeniculum vulgare - Apiaceae), in two forms of cultivation (single and consortium in three planting densities 10.8; 14.3 and 21.5 plants. m-2, called mix 1, mix 2 and mix 3, respectively), and also evaluate the effects of these mixes on the community of predatory arthropods associated to them. In the second phase, from June to December 2018, the objective was to evaluate the effects of the combination of these plants that attracted greater diversity of entomophagous arthropods, planted in the lateral band, in organic cultivation of cabbage and common beans on the community of these arthropods, of phytophagous insects and the productivity in these crops when planted in succession, having as a comparison the spontaneous vegetation (positive control) and the bare soil with plastic mulch (negative control). Entomophagous arthropods and phytophagous insects were evaluated in the ranges and in three different distances of these [1, 3 and 6 meters]. The experiments were installed in plots of 3 x 4 meters and 3 x 8 meters in the first and second phases, respectively, spaced in 5 meters, using DBC with four blocks. The results are presented in four chapters, addressing: a) Performance of plants with potential for conservative biological control; b) Effect of floral compositions on the community of predatory arthropods; c) Use of floral resources in attracting natural enemies in organic cabbage cultivation; d) Use of floral resources in attracting natural enemies and pest control in bean cultivation, under organic system. Thus, it is concluded that the consortium tested with 21.5 plants.m-2 present adaptability from the phytotechnical point of view, in the soil and climate conditions of Seropédica-RJ, are attractive to predatory arthropods, can be used as a tool for insect management and diversification in agroecosystems such as cabbage and beans without reducing productivity