Tratamento de sementes para manejo do percevejo-barriga-verde na cultura de soja e milho em sucessão

Abstract

Resumo -O objetivo deste trabalho foi avaliar o efeito do tratamento de sementes com inseticidas sobre o manejo de Dichelops melacanthus e a produtividade da soja e do milho, cultivados em sucessão. O estudo foi realizado em campo, nas safras 2012/2013 (I) e 2013/2014 (II). Avaliaram-se os inseticidas imidacloprido, tiametoxam, tiodicarbe, fipronil e abamectina. Determinaram-se: a densidade populacional do percevejo, a produtividade de soja e milho, e a intensidade da injúria em milho. A densidade do percevejo permaneceu abaixo de um inseto por metro quadrado, na maior parte do ciclo da soja. Os picos populacionais foram observados nas primeiras semanas, após a emergência do milho, e atingiram 2,2 (safra I) e 6,7 (safra II) percevejos por metro quadrado. Na cultura da soja, os inseticidas não reduziram a densidade populacional do percevejo. Na cultura do milho, o imidacloprido reduziu a densidade do percevejo em 23,2% (safra I) e 38,8% (safra II), e a injúria em 61,8% (safra I) e 26,4% (safra II). O tiametoxam reduziu a densidade dos insetos em 27,8% (safra II) e a injúria em 42,7% (safra I). O tratamento de sementes com inseticidas não proporciona aumento de produtividade à soja e ao milho, portanto, não se justifica sua utilização nas condições deste estudo.Termos para indexação: Dichelops melacanthus, controle químico, flutuação populacional, manejo integrado de pragas. Seed treatment for management of the green-belly stink bug in the crop succession of soybean and cornAbstract -The objective of this work was to evaluate the effect of seed treatment with insecticides on the management of Dichelops melacanthus on the yield of soybean and corn, grown in succession. The study was carried out in a field, in the 2012/2013 (I) and 2013/2014 (II) crop seasons. The evaluated insecticides were: imidacloprid, thiamethoxam, thiodicarb, fipronil, and abamectin. The following were determined: stink bug population density, soybean and corn yield, and corn injury. Population density remained below one stink bug per square meter, in most of the soybean cycle. Population peaks were observed in the first weeks, after corn emergence, and they reached 2.2 (crop season I) and 6.7 (crop season II) stink bugs per square meter. In the soybean crop, the insecticides did not reduce the stink bug population density. In the corn crop, imidacloprid reduced the stink bug density in 23.2% (crop season I) and 38.8% (crop season II), and injury in 61.8% (crop season I) and 26.4% (crop season II). Thiamethoxam reduced the insect population density in 27.8% (crop season II) and injury in 42.7% (crop season I). Seed treatment with insecticides does not provide increase for soybean and corn yields, therefore, their use is not justified in this study's conditions.

Prevalence, damage, management and insecticide resistance of stink bug populations (Hemiptera: Pentatomidae) in commodity crops

“…Although inconsistencies in seed treatment to control Dichelops spp. populations in corn and soybean have been reported (Chiesa et al, 2016), they appear to have occurred as a result of factors unrelated to changes in insect susceptibility.…”

“…In corn, another option to control species of Dichelops is seed treatment with neonicotinoids. Nevertheless, field tests suggest that control based on seed treatment can be variable depending on soil humidity and other factors (Harris, 1972), ranging from low (Chiesa et al, 2016) to high efficiency with reduced grain production losses (Chocorosqui & Panizzi, 2004). Moreover, seed protection does not last for more than 7-10 days (Bianco & Betiol Jr., 2017).…”

Telenomus podisi Parasitism on Dichelops melacanthus and Podisus nigrispinus Eggs at Different Temperatures

“…Palabras Claves: control biológico; parasitoide de huevo; efectos de la temperatura Dichelops melacanthus (Dallas) (Heteroptera: Pentatomidae), the most important stink bug species feeding on maize in South America, is controlled frequently with chemical pesticides (Bueno et al 2015). Pest outbreaks are favored by a "green bridge," i.e., by cultivating 2 crops per yr (soybean in summer, maize in fall and winter) (Bianco 2005) when an increase in the D. melachanthus population is observed during the soybean season (Chiesa et al 2016).…”

Susceptibility of corn to stink bug (Dichelops melacanthus) and its management through seed treatment

“…Dichelops melacanthus (Dallas) (Hemiptera: Pentatomidae), commonly known as green belly stink bug, currently occurs in Argentina, Bolivia, Brazil, Colombia, Paraguay, Peru, Uruguay and Venezuela (Dellapé et al, 2015). soybean, infestation is concentrated in the reproductive stages (Silva et al, 2013); while in some Poaceae, such as corn and wheat, infestation and damage occurs in the seedling stage as a result of migrating adults from surrounding crop debris or other plants within the field (Torres et al, 2013;Smaniotto and Panizzi, 2015;Chiesa et al, 2016). Damage to seedling corn causes brown spots, leaf discoloration and twisting, reduced yield (Crossariol Netto et al, 2015), or plant death (Roza-Gomes et al, 2011;Torres et al, 2013).…”

“…Damage to seedling corn causes brown spots, leaf discoloration and twisting, reduced yield (Crossariol Netto et al, 2015), or plant death (Roza-Gomes et al, 2011;Torres et al, 2013). In order to avoid yield loss in corn, neonicotinoid seed treatment is common (Martins et al, 2009;Brustolin et al, 2011;Crossariol-Neto et al, 2015;Chiesa et al, 2016). This insecticide group has been used alone or in combination with foliar insecticide treatment after crop emergence, or during crop desiccation and stalk destruction (Martins et al, 2009;Brustolin et al, 2011).…”