New Guide Outlines Management Strategies to Battle Sorghum Insect Pests
By Olabimpe O. Okosun, Ph.D.
Sorghum is a highly valued crop cultivated worldwide, with the grain and the stover (roughage) being of equal importance in some developing countries. It is an ancient grain consumed as a staple diet in parts of Asia and Africa. The grain is used for food, alcoholic beverages, and biofuel, while the stalks are used for animal feed, fuel, building materials, and broom and fence construction in some rural areas.
The United States is the largest producer of sorghum worldwide. A large portion of the production is exported, but domestically, it is mainly used for ethanol production and livestock feeds. A bushel of sorghum can produce an amount of ethanol equivalent to a bushel of other feedstocks, but with the advantage of using one-third less water. Sorghum is a highly adaptable, high-yield crop that is drought tolerant, heat tolerant, and can withstand varying levels of soil fertilities.
The use of sorghum and its by-products has increased in high-income countries because of its high nutritional value and the anti-inflammatory and cholesterol-lowering properties of the grain. The greater public acceptance of sorghum in breakfast cereals, sorghum drinks, and other products suggests a high potential for future consumption of sorghum, especially as part of American plant-based, gluten-free, nutrient-rich diets. Sorghum production for bioethanol is energy efficient, which has the potential to be a source for renewable transportation fuel that could be used in passenger cars.
The increase in demand for sorghum has resulted in worldwide increase in cultivation and production, accompanied with diverse insect pests that find sorghum an acceptable host plant. There are about 150 insect species (in 29 families) that affect sorghum worldwide, attacking the plants at various stages of development. These insect attacks can reduce its productivity up to 50 percent, severely impacting the lives of low-income farmers in developing countries.
In our recent paper, “Biology, Ecology, and Management of Key Sorghum Insect Pests,” published this month in the open-access Journal of Integrated Pest Management, our team from the USDA-ARS Southern Insect Management Research Unit outlined the important insect pests of sorghum. We produced an extensive report complete with informative tables that include insect pests (soil dwellers, leaf-sucking species, leaf-feeding species, stalk or stem borers, pests of the panicle, and pests of the stored grain), noting the common name, species, description of damage, distribution, and pest status.
The tables function as a manual for those in the business of sorghum. We created these tables to be used as a decision-making tool for people managing sorghum crops. It’s like “Sorghum Google”—a quick and easy way to see what has been done for specific pests, and what has been shown to work in different regions. Because sorghum is grown in Africa, Asia, the United States, and worldwide, having quick access to information about host-plant resistance, selective insecticides, and natural enemies will prove very helpful.
Modern management strategies are explained and include cultural and biological control, botanical insecticides, synthetic insecticides, and host-plant resistance, with the goal of using an integrated approach to pest management. We summarize some of the most economic and effective ways to manage insect pests of sorghum, which starts with selecting resistant plant varieties that are well-adapted to local growing conditions of the area. Other tactics employed in sorghum IPM include crop rotation, field sanitation, optimal planting date, trap cropping, cultivation of non-host crops, and selective use of insecticides to protect pollinators and natural enemies.
“This review article is of general interest to the public and serves as reference material to the researcher working on sorghum entomology,” says research leader Gadi Reddy, Ph.D. “This unique review encompasses and highlights the importance of different management practices of insect pests of sorghum crop. This also points out several practical challenges and future aspects of managing sorghum insect pests with various cultivation systems.”
There is still much to be learned about potential management of insect pests of sorghum and many emerging ideas are on the horizon, including the use of semiochemical-based trapping, restrictions and regulatory policies to limit the invasion of new pests into sorghum-producing areas, and areawide land management approaches.
Journal of Integrated Pest Management
Olabimpe O. Okosun, Ph.D., is a postdoctoral researcher at the U.S. Department of Agriculture-Agricultural Research Service’s Southern Insect Management Research Unit in Stoneville, Mississippi. Email: email@example.com.