Occurrence of pests in weeds with different crop managements

Marco Aurélio Castro,Vitória Fátima Bernardo,Sebastião Ferreira De Lima,Rita De Cássia Félix Alvarez,Lucymara Merquides Contardi,Germison Vital Tomquelski

doi:10.33448/rsd-v9i7.4120

Abstract

Weeds can be important hosts for potential crop pests. Thus, the objective was to evaluate the occurrence of pests in weeds in three crop management strategies. The experiment was conducted in the 2016/17 harvest. Each management had an area of 0.5 ha, used to assess pests: (1) cotton / soybean / Urochloa decumbens; (2) millet / soybean / millet and (3) millet / soybean / Crotalaria. Pest surveys were carried out monthly on weeds during the management of soybean crops and on coverages in succession. Shannow-Weaner diversity, abundance, dominance, frequency and constancy indices and population fluctuation were determined. Fourteen species of pests were identified in association with weeds in the three rotation systems. The order Hemiptera had the largest number of individuals collected, followed by the order Lepidoptera. The millet / soybean / Crotalaria rotation provided the highest number of pests and the cotton / soybean / U. decumbens rotation had the lowest number of pests. The pests Bemisia tabaci, Aphys gossypii and Daubulus maidis presented the largest number of individuals in the evaluations in the three managements.

Highlights

Soybean (Glycine max (L.) Merril) has become the most important legume cultivated in the world (Bornhofen et al, 2015) and its management is among the activities that showed high production growth rates (Hirakuri & Lazzarotto, 2014)
Some authors argue that non-weed control affects the population dynamics of arthropod pests, which persist throughout the year in economic crop environments in the absence of major crops (Sá et al, 2009)
Crop rotation can define the evolutionary behavior of fauna and flora ecophysiology, which takes into account plant ecology and integration with the living environment (Erasmo, Pinheiro & Costa, 2004), In general, the effects of weed control and pest control are studied separately

Summary

Introduction

Soybean (Glycine max (L.) Merril) has become the most important legume cultivated in the world (Bornhofen et al, 2015) and its management is among the activities that showed high production growth rates (Hirakuri & Lazzarotto, 2014).In Brazil, soybean is the main grain produced and should reach a production of 120.3 million tons in the 2019/20 harvest, in a cultivated area of 36.8 million hectares, with an average productivity of 3.3 thousand kg ha-1 (CONAB, 2020). Competition with planted weeds aggressively intervenes in the crop, due to reduced resources such as water, light and nutrients, resulting in a fall in grain productivity (Braz et al, 2010; Silva et al, 2009). These weeds occupy space and aggressively consume primordial elements for establishing crops, such as water, space, light, nutrients and minerals, etc. Some authors argue that non-weed control affects the population dynamics of arthropod pests, which persist throughout the year in economic crop environments in the absence of major crops (Sá et al, 2009). This research aimed to evaluate the occurrence of pests in weeds with different crop managements

Objectives

Methods

Results