Economic Thresholds in Soybean-Integrated Pest Management: Old Concepts, Current Adoption, and Adequacy

Abstract

Increasing global demands for food underline the need for higher crop yields. The relatively low costs of the most commonly used insecticides in combination with increasing soybean market prices led growers and technical advisors to debate the adequacy of recommended economic thresholds (ETs). The adoption of ETs and pest sampling has diminished in Brazil, leading to excessive pesticide use on soybean. The reduced efficacy of natural biological control, faster pest resurgence, and environment contamination are among the side-effects of pesticide abuse. To address these problems and maximize agricultural production, pest control programs must be guided by a proper integrated pest management (IPM) approach, including the ET concept. Therefore, the most appropriate time to initiate insecticide spraying in soybean is indicated by the available ETs which are supported by experiments over the last 40 years in different edapho-climatic conditions and regions with distinct soybean cultivars. Published scientific data indicate that preventive insecticide use is an expensive and harmful use of chemicals that increases the negative impact of pesticides in agroecosystems. However, the established ETs are for a limited number of species (key pests), and they only address the use of chemicals. There is a lack of information regarding secondary pests and other control strategies in addition to insecticides. It is clear then that much progress is still needed to improve ETs for pest management decisions. Nevertheless, using the current ETs provides a basis for reducing the use of chemicals in agriculture without reducing yields and overall production, thereby improving sustainability.

Identification of Soybean Resistance to Pod Sucking Bug (Riptortus linearis) by No-Choice Test

“…The economic threshold (ET) different between countries. The current recommended ET for controlling sucking bugs in Brazil is 2 insects per meter for seed production and only 1 per meter for crop seeds (Bueno et al, 2013). In Mississippi, 14.13 CV= coefficient of variation; * = significant at 1 % probability level (p < 0.01), ** = significant at 5 % probability level (p < 0.05), ns = not significant 50.030 a Susceptible Numbers followed by the same letter in the same column are not significantly different at DMRT 5%.…”

Monitoramento do percevejo marrom Euschistus heros (Hemiptera: Pentatomidae) por feromônio sexual em lavoura de soja

“…Para comparar a eficiência dos monitoramentos pelas armadilhas com feromônio e pelo pano de batida no manejo de populações de E. heros, os dados de captura semanal nas armadilhas e no pano de batida (nas parcelas sem armadilhas) foram utilizados como parâmetro para a tomada da decisão de controle populacional, tendo-se estabelecido os seguintes níveis de controle: parcelas monitoradas por meio de armadilhas com feromônio de 1,7 percevejo por armadilhas por semana ; e parcelas monitoradas pelo pano de batida, com dois percevejos adultos por metro linear (Bueno et al, 2013).…”

“…Predominante nas lavouras de soja no Estado de Mato Grosso, esse inseto pode ocasionar danos irreversíveis à cultura, pois, para se alimentar, suga diretamente os grãos de soja, o que acarreta redução na produção e na qualidade das sementes (Depieri & Panizzi, 2011;Silva et al, 2012 O controle das populações do inseto, muitas vezes, é realizado por meio de aplicações preventivas de inseticidas sintéticos (Bueno et al, 2013). O uso excessivo desses produtos promove a seleção de populações de percevejos resistentes, a redução dos inimigos naturais, a contaminação ambiental e riscos à saúde humana (Sosa-Gómez & Silva, 2010;Bueno et al, 2011;Belo et al, 2012).…”

“…Para o monitoramento de percevejos na soja, recomenda-se o método do pano de batida, no qual se considera como nível de controle a presença de dois percevejos adultos por metro linear, para a produção de grãos, e de um percevejo, para a produção de sementes (Bueno et al, 2013).…”

Competition between the phytophagous stink bugs Euschistus heros and Piezodorus guildinii in soybeans

“…The number of recorded host plants used by E. heros in neotropical regions is lower than the number recorded for P. guildinii or N. viridula , which mainly restricts the populations of the former to soybean fields. Other factors such as the widespread adoption of no‐tillage cultivation systems, the introduction of multiple cropping and higher insecticide tolerance have certainly contributed to the expansion of E. heros in Brazilian territory and into adjacent countries such as Argentina . In the present study, we investigated the role of competition as a contributing factor for the increased incidence and importance of E. heros in neotropical soybean fields over time.…”