O uso de modelos matemáticos como ferramenta para avaliar a distribuição espacial de insetos-praga da cultura da soja no estado do Paraná

Abstract

Glycine max (L.) Merrill is one of the main agricultural crops of the country and it integrates a set of agricultural activities with more evidence in the world market. This work aims to determine through models in which regions of the State Chrysodeixis includens Walker, 1858 (Lepidoptera: Erebidae), Anticarsia gemmatalis Hübner, 1818 (Lepidoptera: Erebidae), Euschistus heros Fabricius, 1794 (Hemiptera: Pentatomidae) and Nezara viridula Lineaus, 1758 (Hemiptera: Pentatomidae) has a higher occurrence, as well as to analyze possible influences on a change in the population distribution. Official data were obtained regarding the number of agronomic recipes issued for each municipality regarding the main biological targets, classification of the main products used and active ingredients most used, through the Agência de Defesa Agropecuária do Paraná (ADAPAR), regarding the crop of soybeans 2014/2015 and 2015/2016. Using the Google Earth ™ application, the geographic coordinates (latitude and longitude) in the UTM format of each municipality were collected. The percentages of revenues generated (RE) of each municipality were calculated, after the organization of the data the manipulation of these data was initiated in the program Quantum Gis® 2.16. Subsequently, the percentage of RE numbers was calculated by classification of the products used and the active ingredients, both for the 2014/15 and 2015/16 crops. Based on the information received through the Sistema de Controle do Comércio e Uso de Agrotóxicos no Estado do Paraná (SIAGRO), it was possible to calculate the volume in tons of commercialized insecticide and the volume for the active ingredients with the highest number of RE 2014/15 and 2015/16 crops. Information on RE numbers per municipality was cross-referenced and the area planted in hectares, described as a percentage, was used to support a possible justification for the distribution of the pest insects studied. The analysis of the distribution of the main pests of the soybean, through the emission of the agronomic prescriptions, proves to be a tool capable of estimating the amplitude of this distribution. It was observed that the western region of Paraná had the highest rates of emission of agronomic prescriptions issued for the control of A. gemmatalis, C. includens, E. heros and N. viridula in the two harvests (2014/15 and 2015/16) . However, it was not possible to affirm that there were changes in the population distribution of these insect pests due to the use of applied insecticides, because the data obtained do not support this assertion. Therefore, more centralized studies and more detailed data are needed to ascertain the possible causes in the distribution differences of the pest insects. The modeling technique and the use of geostatistical programs constitute a potential alternative for the implementation of control protocols, consequently reducing the environmental impacts generated by excessive application and inadequate periods of pesticides.