Pest Management – United States
Smart strategies for insect and weed management
In the United States, more than 100 types of pests attack cotton, and left unmanaged, these pests can devastate cotton crops. Efficiently and effectively reducing the amount of cotton lost to pests is critical for sustainability, grower profitability — and for producing consistent yields of the high-quality fiber that people around the world love.
When pests damage cotton crops, they also affect cotton’s sustainability by decreasing the crop’s overall resource efficiency. Less cotton can be produced per acre, and more fertilizer, tillage, or irrigation may be required to make up for decreased efficiency and plant health. Inversely, some pest control methods, like using herbicide-tolerant transgenic cotton varieties, also enable sustainable practices like reduced tillage and cover crops. Additionally, grower profitability is highly dependent on growing a productive crop and reducing the amount of cotton lost to pest... leaving more fiber for the clothes we love.
For all of these reasons, effective pest management is a historic priority for cotton growers. Pesticides – including insecticides, herbicides and fungicides – are a necessary tool in some circumstances. But to steward the environment well and preserve an abundant, high-quality cotton supply over the long term, producers and researchers are approaching cotton pest control from multiple angles, including integrated pest management (IPM) and biotechnology.
The result is that the total amount of cotton crop pesticides applied today is significantly lower than just a few decades ago: for example, producers today use approximately 50% fewer insecticide applications compared to the late 1980s. The total amount of pesticide used also continues to drop1 (though more slowly in the last decade), and in 2019, 44% of planted cotton acres received no foliar insecticide applications at all.2
Cotton farm pest populations, however, often adapt to new pesticides and management practices. In addition, rising temperatures, changing weather patterns and higher atmospheric CO2 levels have the potential to exacerbate pest challenges.4,5 Continuous, sustainable improvement in insect and weed management is imperative, and U.S. growers and researchers are on it.
Understanding Integrated Pest Management (IPM)
IPM is an environmentally sensitive strategy that “focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation, modification of cultural practices, and use of resistant varieties.”6
The IPM process enables growers to manage pests in the most economical way while reducing unnecessary pesticide use — thus decreasing potential hazards to people and the environment and mitigating the risk of pesticide-tolerant insects and weeds.
In IPM, pesticides are never a first resort. Instead, cotton growers integrate multiple practices targeted at their specific needs, which they identify based on ongoing data collection. IPM principles show growers when pesticides are or are not needed.
IPM includes methods to:
- Prevent: keep a pest population from infesting cotton fields
- Avoid: use cultural measures to mitigate or eliminate damage from pests
- Monitor: detect and identify pests by systematically scouting fields
- Suppress: control or reduce existing pest populations to decrease crop damage
Cultural practices include farm management practices such as conservation tillage or crop rotation. Precision agriculture, computer-aided monitoring and management systems, biological control and transgenic technologies are also common elements in IPM.
|Top Pest Management Practices by IPM Category, 2019 (% of cotton planted acres)|
|Prevention||Cleaned equipment and implements after field work||61%|
|Avoidance||Chose crop variety for specific pest resistance||61%||Monitoring||Scouted for weeds||91%|
|Suppression||Used pesticides with different mechanisms of action to prevent pests from developing resistance||45%7|
Researching to improve: insect management
Researchers across the cotton industry, land grant universities and the USDA regularly undertake projects to better understand and develop new IPM methods — methods that will help growers balance economic, social and environmental outcomes.
During the 2022 growing season, for instance, approximately 55 entomology research projects across 16 states were underway, and almost all aimed at enhancing IPM practices. Many of these projects also support outreach efforts through newsletters, field days and popular press.
One joint project between Arkansas State University, University of Arkansas and USDA is championing a series of interdisciplinary studies to document how cotton production systems that integrate soil and water conservation plus IPM improve efficiency, sustain profitability and improve environmental outcomes. The project includes practical field-testing of the Agronomic Trial Data Collection Tool to support the Cotton Incorporated research effort with Partnership for Data Innovation (PDI) and the USDA Agricultural Research Outcomes System (AgCROS) network. The results will help refine management recommendations for IPM tactics used in conservation production systems.
At the University of Arizona, another project is aimed at better understanding the positive effects of selective pesticides over time. It’s essential that pesticides used in IPM do not harm the natural enemies of pest species or other beneficial insects. And, as with all pesticides, it is paramount that they are safely used by agricultural workers. This project aims to demonstrate and verify that the gains made in insect IPM are linked with significant reductions in risks to both human health and the environment. The insights generated by the project’s data will help guide the cotton industry in further reducing risks to humans and to the natural enemies of pest insects.
Researching to improve: weed management
Historically effective herbicide options are shrinking as widespread weeds like Palmer amaranth (also called pigweed) develop herbicide resistance. Weeds of any kind compete with cotton plants for nutrients, but herbicide-resistant weeds are also a barrier to adopting no-tillage soil conservation practices. Growers typically increase tillage to kill those weeds, thus increasing soil erosion and depletion of organic matter.
The cotton industry has an opportunity to benefit growers and the environment by driving deeper understanding and higher adoption of integrated weed management methods that reduce the likelihood of herbicide resistance.
As of the 2022 growing season, approximately 15 weed management projects were in motion across 13 states. Through research and outreach, these projects focused on cultural, chemical and biological options for controlling weeds — with Palmer amaranth being the primary target.
Multiple projects are exploring viable cultural management options for reducing weed competition and reproduction. These options include precision mechanical approaches to combat herbicide resistance management in real-time, with benefits in the short and long terms. For example, some projects are evaluating see and spray technologies that increase herbicide efficiency by targeting the herbicides only where the weeds are present. So far, the research suggests that this has the potential to reduce herbicide use by over 50%8.
Other multi-state projects are investigating ways to decrease weed seed development. This approach is outside the traditional timeframe of weed management, but it can lead to a long-term reduction in weed populations. Reducing weed seed would also slow the development and distribution of herbicide resistance.
The effect of cover crops on weed suppression is also being explored alongside their use for soil health improvements. Most research is focused on annual cover crop systems, but the cotton industry is also supporting research from the University of Georgia on “living mulch.”
Typically, cover crops are grown from harvest till planting; the dead stalks and leaves are then left on the soil surface like a mulch after planting to protect the soil, decrease evaporation and decrease weed emergence. Living mulch, on the other hand, grows alongside the crop. This project is designed to quantify the benefits to cotton production from cover crop and living mulch systems compared to conventional management with no cover crop. Researchers are collecting data on:
- Cotton productivity
- Weed suppression and field renovation
- Soil carbon sequestration, health, nutrient content and hydrology
Within the two years of the study, the data showed benefits of cover crops and living mulch: significantly fewer Palmer amaranth weeds emerged, and the living mulch drastically reduced the amount of herbicide needed.9
Going forward, U.S. cotton industry organizations will continue to promote integrated weed management and work with companies to identify non-tillage weed management options and bring them to the market.
The role of cotton varieties
Cotton is available in different varieties that provide different benefits related to pest management.
Transgenic cotton varieties, for example, produce their own resistance to particular insects or tolerance to herbicides. They have proven particularly effective in helping growers reduce cotton insecticide applications. Researchers and growers across cotton-growing states regularly partner with agribusinesses to evaluate the effectiveness of new transgenic cotton varieties and provide applied data to help improve the varieties before they become commercially available.
A project at the University of Arkansas is surveying commercially available cultivars (not all of which are transgenic) and advanced breeding lines to establish differences in Tarnished Plant Bug (TPB) host plant resistance. Insights gained through this work will help producers determine which cultivars are best for their fields. If they suffer from TPB damage, changing their cultivar to a more resistant variety can help and decrease the need for insecticides. This project will also pave the way for breeding new TPB-resistant cotton varieties.
Transgenic herbicide tolerance technology has played an important role in helping producers move away from conventional tillage to conservation tillage systems. Cotton varieties that are safe from the effects of herbicide enable growers to spray rather than till the plant cover between rows. Reduced tillage facilitates soil carbon sequestration and reduces tractor fuel use, which in turn helps reduce greenhouse gas emissions. It also helps reduce soil loss and increase biodiversity in the soil.
Cotton pesticide regulations and oversight
Growers comply with multiple federal and state regulations to protect the safety of farm workers, consumers and the environment.
In the U.S., cotton is regulated as a food crop since cottonseed oil, meal and other by-products are used in human and animal foodstuffs. This involves strict Food and Drug Administration (FDA) and Environmental Protection Agency (EPA) regulations for approval, labeling and application of all chemicals and the use of genetically modified varieties.
EPA conducts in-depth worst-case studies, vetted by numerous third-party scientific expert review panels, to determine when, how and if a pesticide can be safely used. The studies take into account interaction with humans, plants, pollinators, water, animals and protected species.10
Federal laws that dictate how pesticides are used in U.S. cotton production include the following:
- Federal Insecticide, Fungicide and Rodenticide Act (FIFRA)
- Food Quality Protection Act (FQPA)
- Toxic Substance Control Act (TSCA)
- Occupational Safety and Health Act (OSHA)
- Clean Air Act (CAA)
- Safe Drinking Water Act (SDWA)
- Endangered Species Act (ESA)
- Federal Food, Drug and Cosmetic Act (FFDCA)
Committed to leading the way
U.S. cotton growers are actively participating in enhanced pest management strategies that enable them to use the right pesticides, at the right times, in the right ways to effectively limit their overall usage. U.S. pest management research is available to cotton-growing countries around the world.
Effective pest management benefits grower profitability and our world’s supply of quality fiber. It directly and indirectly influences cotton’s environmental sustainability. Similar to clothing brands’ initiatives to support farm-level water conservation and soil quality, the entire cotton supply chain has good reasons to support growers as they implement sustainable pest management practices.
1 Field to Market: The Alliance for Sustainable Agriculture. (2020). Trends in pest management in U.S. agriculture: Identifying barriers to progress through collective action. Accessed May 12, 2022.
2 National Agricultural Statistics Service. (2020). 2019 Agricultural Chemical Use Survey.
3 Table created from Mississippi State University Beltwide Cotton Crop Loss data. Accessed May 12, 2022
4 Skendžić, S., Zovko, M., Živković, I. P., Lešić, V., & Lemić, D. (2021). The Impact of Climate Change on Agricultural Insect Pests. Insects, 12(5), 440.
5 Ziska, L., Blumenthal, D., & Franks, S. (2019). Understanding the nexus of rising CO2, climate change, and evolution in weed biology. Invasive Plant Science and Management, 12(2), 79-88. doi:10.1017/inp.2019.12
6 University of California Agriculture and Natural Resources. Statewide Integrated Pest Management Program. Accessed May 12, 2022
7 National Agricultural Statistics Service. (2020). 2019 Agricultural Chemical Use Survey.
8 Ongoing research with University of Arizona, funded by Cotton Incorporated.
9 Lameiras, Maria M. (Jan. 6, 2022). UGA researchers evaluate the benefits of cover crops, living mulches in Georgia cotton. CAES Newswire. Accessed May 13, 2022.
10 Learn more about EPA’s pesticide registration process by starting with “Understanding the Science Behind EPA’s Pesticide Decisions”