Cotton insect pest management program

Investigators: Malone, Sean

Abstract: Cotton acreage has increased dramatically in Virginia in the last few years. It is a viable alternative to other less profitable row crops and fits well into crop rotation programs in the areas it is grown. In Virginia, cotton is in its northernmost location in the US and therefore experiences a unique combination of insect pest problems. Each year, numerous field experiments are conducted at the Tidewater AREC to evaluate common pests (primarily tobacco thrips and cotton bollworm) and to develop management programs. Among the many objectives are evaluating compensation ability and yield impact after pest damage, determining the most efficient timings and application systems for standard pesticides, evaluating GMO insect-resistant varieties and new alternative pesticides, and developing and improving control decision guidelines.

Description:

There are currently between 85,000 and 100,000 acres of cotton grown in Virginia with a cash receipt value of almost $39 million. Growers are challenged by a variety of insect pests that threaten lint yield and quality. Tobacco thrips, a complex of hemipterans such as green stink bug and tarnished plant bug, and a bollworm complex including cotton bollworm and tobacco budworm are the major pests. Insect pests caused an estimated 1.9% yield loss in 2004, or 1,761 bales, with a value of $507,276. This program addresses development and implementation of pest management programs to minimize losses to these pests using the most economic and environment/user friendly practices available. Each year, many field research experiments are conducted to evaluate new insecticides and GMO insect-resistant varieties for managing these pests. Research is also underway to develop new scouting practices and economic thresholds. Because of its northern latitude, Virginia has fewer available heat units relative to other cotton-producing states and there may be limited opportunity for compensation from loss of developing bolls to insect feeding. A 3-year study evaluating the impact of removing different numbers of insect-susceptible bolls showed that cotton could compensate from boll loss as high as 20% which allowed the threshold to be increased. These studies, as well as county on-farm replicated strip trials with cooperating growers, are used for in-season educational programs where agents, growers and Ag-industry view plots and receive training in sampling and determining treatment thresholds. A regional (VA, NC, SC, GA, AL) project is underway to develop new thresholds and sampling procedures for hemipterous pests of cotton. Data summaries are used to develop weekly email advisories and placed on a website (www.sripmc.org/virginia), are used to develop educational aids including production guides (www.ext.vt.edu/pubs/cotthton/424-300/424-300.html), and are presented at multi-county winter production meetings. View the 2005 presentation: (http://arecs.vaes.vt.edu/arec.cfm?webname=tidewater&section=about_us&pid=herbert).

Program outcomes:

In 2005, an estimated 369 cotton producers representing 130 farms took part in the Cotton Insect Pest Management program either by participating in educational training events or by hosting field plots on their farms. In recent years, many have adopted recommended management practices that include use of field scouting and use of economic thresholds. For example, currently only an estimated 56% of the total cotton acreage is treated for mid-season pests, compared with almost 90% in North Carolina, our closest comparison point. Growers make an average of 2.8 insecticide applications per acre, at a total cost of $45.40 per acre (product + application cost) which is one of the lowest cost insect control programs of all southeastern states. This is in part due to differences in pest species and abundance, but is also due to the success of this program in instilling an IPM, spray-conservative mentality in Virginia cotton growers.

Commodities: Cotton

Resources: Agricultural Experiment Station Facilities, Cotton Production Guide, Graduate Assistantship Opportunities, State-Owned Vehicles

Disciplines: Integrated Pest Management

Audiences: Agribusiness, Commodity Groups, Extension Agents, Government Agencies, Producers, Researchers