Tackling fall armyworm lays groundwork for other pest control

DES MOINES, Iowa – An army is marching across Africa, decimating croplands and causing substantial financial losses, yet its soldiers are only 1.5 inches tall.

Fall armyworm arrived in Africa in January of 2016 and, so far, the pest has swept across sub-Saharan Africa to the tune of a potential loss of 8.3-20.6 million tons of maize lost per year. In Ghana, for example, an estimated $160 million in losses are expected in 2017.

“Fall armyworm has the potential to roll back years of yield improvements [in Africa],” said Martin Fregene, advisor to the vice president of Agriculture, Human and Social Development at the African Development Bank.

This pest is particularly difficult to combat, compared to other invasive species, due to its voracity, adaptability and rapid spread. Two strains of the pest exist: those that target maize and those that target rice. Both strains can also interbreed and produce hybrids.

Though the most worrisome strain prefers maize as a food source, fall armyworm caterpillars feed on more than 80 plants total, according to The Center for Agriculture and Bioscience International. Adults can travel up to 100 kilometers each day, with females laying batches of 50 eggs that hatch in two to three days.

Pedro Sanchez, research professor of tropical soils at the University of Florida, outlined what is currently being done to combat the fall armyworm and what is necessary for success.

“We need to have cooperation among countries and employ integrated pest management systems,” said Nteranya Sanginga, director general of the International Institute of Tropical Agriculture.

Much of the current collaboration occurs among scientists in different countries as they work to create crops resistant to fall armyworm.

Mark Edge, director of collaborations for developing countries at Monsanto, said that gene editing is widely accepted as the most effective tool for breeding resistant crops, but it cannot be the only tool used.

Other aspects for farmers to consider include storing insecticides properly so compounds remain viable, avoiding monoculture planting, controlling grass and broadleaf fall armyworm host plants, and more, Greg Nuessly, director of the University of Florida Institute of Food and Agricultural Sciences Everglades Research and Education Center, said.

Combatting the fall armyworm through chemical compounds such as insecticides and parasitoids requires attacking the worm at every stage in its lifecycle.  Segemet Kelemu, director general of the International Center of Insect Physiology and Ecology in Nairobi said that a larval parasitoid in development currently has 50-70 percent effectiveness, adding overcoming fall armyworm is possible if all available technologies and research are put to use.

Part of using all available resources involves addressing weaknesses that caused the current crisis.

“If there was a capacity on the ground for an early detection system, I’m pretty sure this problem would have been contained at an earlier stage,” Kelemu said. The eggs, larvae and adults can be difficult to spot on plants, so frequent field checks are necessary.  Those frequent checks require a great deal of manpower to complete fully.

The plans developed for control of fall armyworm and prevention of future outbreaks could possibly be translated into other invasive pest control in the future.

“We are not trying to work on one pest at a time, but instead in a more comprehensive way,” Kelemu said.