Submitted to: Virus Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/6/2008
Publication Date: 1/17/2009
Citation: Castle, S.J., Palumbo, J.C., Prabhaker, N. 2009. Newer insecticides for plant virus disease management. Virus Research. 141:131-139.
Interpretive Summary: The highly polyphagous sweet potato whitefly Bemisia tabaci infests crops worldwide and is known to transmit over 110 plant viruses. It has a major impact on agriculture in the USA and also severely affects horticultural crops grown in protected environments. Outbreaks of B. tabaci occurred in the southwestern USA through the 1990s that resulted in crop loss and destruction due to direct feeding damage. In recent years, however, viral diseases have become prevalent in cucurbit crops such as cantaloupe and honeydew melons. Much lighter infestations than those that caused destruction in the 1990s are still sufficient to spread virus within a crop causing yield loss and quality decline due to virus disease. Newer insecticides having novel modes of action are being evaluated for their potential to reduce the spread of viruses in the crop. There are a number of promising candidates currently registered or in development, but their incorporation into a management program will require a cost/benefit analysis to determine how many applications must be made to prevent feeding and transmission of virus by B. tabaci. A further consideration is how to manage resistance to insecticides if more frequent applications are necessary.
Technical Abstract: Effective management of insect and mite vectors of plant pathogens is of crucial importance to minimizing vector-borne diseases in crops. Insecticides play an important role in managing vector populations by reducing the number of individuals that can acquire and transmit a virus, thereby potentially lowering disease incidence. Certain insecticides exhibit properties beyond lethal toxicity that affect feeding behaviors or otherwise interfere with virus transmission. To evaluate the potential of various treatments against the Bemisia tabaci transmitted Cucurbit Yellow Stunting Disorder Virus (CYSDV), insecticide field trials were conducted in Yuma, AZ, USA, during spring and autumn growing seasons. Differences in vector intensity each season produced mixed results, but at least five insecticide treatments showed promise in limiting virus spread during Spring 2008. Increasing concern among growers in this region regarding recent epidemics of CYSDV is leading to more intensive use of insecticides that threatens to erupt into unmanageable resistance. Sustainability of insecticides is an important goal of pest management and more specifically resistance management, especially for some of the most notorious vector species such as Bemisia tabaci and Myzus persiscae that are also highly prone to development of resistance.