Levantamento e flutuação populacional de insetos-praga em lavouras comerciais de soja no município de Dois Vizinhos - Paraná na safra 2015/2016

Abstract

Soybean cultivation plays an important economic role in the Brazilian agricultural scenario, and suffer the action of several pathogens, including diseases of difficult control, weeds and pest complex, which have changed over the years, by monoculture and the use of too much synthetic chemicals. Knowing the population fluctuation of the main species of pest insects in commercial soybean plantations contributes to the development of management strategies in a rational and sustainable way. The objective of this work was to conduct a survey and population fluctuation of pest insects in commercial soybean crops in the municipality of Dois Vizinhos, Paraná, in the 2015/2016 harvest, observing the stages of development of the soybean crop and the influence of abiotic factors such as pluviometric precipitation, temperature and relative humidity. Fortnightly assessments of pest insects were carried, in eight different soybean commercial crops. Data of temperature, relative air humidity and rainfall were obtained through the Group of Studies and Biometeorology – GEBIOMET, of the Federal Technological University of Paraná - UTFPR Campus Dois Vizinhos. In the early stages of development of soybean visual observations were made and, from the V6 stage was used the wide cloth of beat. The insects were identified using the dichotomous key and and Digilab Basf® electronic collection. There was a higher occurrence of pest insects of the orders Coleoptera (61%), Hemiptera (24%) and Lepidoptera (15%). It was observed a population increase of the orders Hemiptera and Lepidoptera as the rainfall intensified, unlike that observed for the order Coleoptera. The study demonstrates the population growth of the species Diabrotica speciosa (Coleoptera: Crisomelidae) during the stages of vegetative development of soybean, and Euschistus heros (Hemiptera: Pentatomidae) during stages of reproductive development of soybean. Chrysodeixis includens (Lepidoptera: Noctuidae) was the most frequent species of lepidopteran, D. speciose the species of coleoptero of greater occurrence, and E. heros the species of hemiptero of greater occurrence. The abiotic factors evaluated contributed to the occurrence of Lepidoptera, interfered in the occurrence of Coleoptera and did not influence the occurrence of Hemiptera. Species D. speciosa, E. heros and C. includens occurred more frequently in the evaluations, independent of climatic conditions.