Management of Plant Viral Diseases Through Chemical Control of Insect Vectors

Abstract

In this article we consider the role of epidemiological factors and transmission processes of insect-vectored viruses on the effectiveness of insecticides in a disease management program. We also discuss the use of insecticides within the broader framework of the chemical environment surrounding vectors, and how chemical-induced alterations in the behavior of vectors can influence transmission. Our analysis confirms the belief of Heathcote, who stated in 1973, that "no one method of control is likely to keep crops entirely free from virus infection and as many preventative measures should be taken as are economically justified."

Insecticidal control of Bemisia tabaci (Hemiptera: Aleyrodidae) transmitting Carlavirus on soybeans and detection of the virus in alternate hosts

“…The efficacy of the insecticides tested in this study was variable in controlling the WFs. Similarly Perring et al (1999) mentioned that one of the problems in using insecticides is that their effectiveness against vectors of plant pathogens is variable. In Puerto Rico where a B. tabaci-borne Carlavirus is attacking soybean nurseries, our first task was to select insecticides that can best control the vector and identify host plants that serve as a source of inocula.…”

“…However, growers may become reluctant to incur personal expenses when the perceived benefits are broadly dispersed. It is very rare that a grower's best economic interest is to help reduce his neighbors' virus problems (Perring et al, 1999).…”

Inheritance of tolerance to Cowpea Mild Mottle Virus in soybean

“…Symptoms start appearing 2-3 weeks after infection, usually at blooming stage. Whiteflies can acquire and inoculate the virus during superficial try that take only a few seconds (Iwaki et al 1982, Muniyappaand Reddy 1983, Perring et al 1999, making the use of insecticides impractical. Moreover, vectors migration to soybean field from outside during the season is a continuous process.…”

Interação entre inseticidas e umidade do solo no controle do pulgão e da mosca-branca em algodoeiro

“…Esses fatores, aliados à freqüente irregularidade na precipitação, levam o algodoeiro à predisposição ao ataque de insetos sugadores, como moscas-brancas e pulgões (Basu, 1995;Van Emden & Harrington, 2007). O método mais recomendado de manejo contra pragas sugadoras e transmissoras de viroses é a aplicação preventiva de inseticidas com longo residual de controle (Perring et al, 1999). Inseticidas sistêmicos têm sido utilizados em algodoeiro, para o controle de moscas-brancas e pulgões, por meio do tratamento de sementes, aplicação em sulco de plantio e pulverizações foliares (Leclant & Deguine, 1994).…”

“…Inseticidas sistêmicos com alta solubilidade, aplicados ao solo, podem ser lixiviados se forem aplicados antes de um bom desenvolvimento do sistema radicular; quando possuem baixa solubilidade no solo, seu controle dependerá do local de aplicação e da umidade do solo (Woodford et al, 1988;Chapman et al, 1994;Perring et al, 1999). Assim, a reduzida efi ciência de inseticidas sistêmicos aplicados ao solo geralmente é conseqüência de entraves em sua absorção (Palumbo et al, 1996;Perring et al, 1999;Mowry, 2005). Uma alternativa para se maximizar a efi ciência de inseticidas sistêmicos é aplicá-los, dissolvidos em água, ao solo, sem contato com a planta, para se evitar perda de produto e impacto sobre inimigos naturais.…”