Mapeamento do controle biológico e químico de pulgão em trigo no sudoeste do Paraná

Abstract

Brazil produces only half the wheat it consumes, the southern region being the main producer of wheat. Wheat is attacked by numerous species of aphids that cause direct and indirect damage to the plant. The aphids caused great damage in the 60's because they arrived in Brazil free of natural enemies. In the 1970s, Embrapa inserted 14 parasitic vespines and 2 ladybugs predatory to aphids, where the microhomoptera, the families Aphidiidae and Aphilinidae, will stand out. Therefore, the objective of this work is to evaluate the efficiency of biological control and to correlate with areas of higher prescribing emissions for pest control. For this, four crops were evaluated in Pato Branco and micro-region every 15 days. For each crop, 10 random points were chosen, at each point the number of parasitized and nonparasitized aphids was quantified in 2 plants, totaling 20 plants per crop. To perform the interpolation of data provided by ADAPAR that contained the number of prescriptions issued for aphid control, the free software QGIS was used. Satisfactory percentages of parasitism were found in the crops evaluated from the fourth evaluation, with approximate means of 73% in the fourth and fifth evaluations and 100% of parasitism in the last evaluation, in the first evaluations the percentage of parasitism was low as well as the percentage of aphids found. The most common aphid found in the evaluated areas was that of the species Sitobion avenae. It was not possible to identify the parasitoid, as it did not succeed in hatching the parasitoid from the mummies of aphids. In the chemical control, despite the fact that the Southwest did not have the largest wheat area in Paraná, it had a high rate of prescription, even with the high percentage of parasitism.