Chinch bug nymphs on sorghum (Kansas State University Extension Entomology)
Chinch bugs plowed through Sangamon County cornfields in 1934. Combined with a miserable springtime drought, the infestation drove corn yields statewide to their lowest figure – 20.5 bushels per acre – since 1866.
Chinch bugs, tiny bugs that propagate in massive numbers, feed on grasses and smaller grains, including wheat, sorghum and corn. Periodic chinch bug outbreaks – the bugs love hot, dry weather but die off in wet conditions – were a major problem for central Illinois farmers in the 19th and early 20th centuries.
“About noon to-day,” the Illinois State Register reported July 1, 1871, “this city was invaded by an army of chinch bugs, which were flying through the air with the greatest of ease. The air was literally filled with them for some hours. They directed their flight toward the east.”
(Those flying chinch bugs were adults. Both old and young chinch bugs feed on crops, but the most damage usually is done by immature, non-flying nymphs.)
In 1896, Sangamon County farmers thought their wheat and corn fields were headed for bumper crops … until a hot, dry spell brought on a ravenous brood of chinch bugs. The Illinois State Journal reported on farmers’ despair that May.
The worst feature of the appearance of chinch bugs is the helplessness of the farmer in attempting to deal with them. Many schemes for ridding the field of the bugs are proposed every year, but the farmers have never found anything practical by which they can kill them
Oft before they have ruined the crops in seasons when the weather has been favorable for their propagation. A good rain is the only thing that will injure them, and the farmers will join in blessing the weather bureau, and will forgive it all the late frosts of which it has been guilty in the past, if it will only send a few soaking showers to confound their little enemies.
The long-term solution turned out to be an alternative crop: soybeans, which don’t attract chinch bugs. Soybean acreage exploded in central Illinois beginning in the 1920s, thanks largely to the discovery of new uses for soybeans and to intensive promotion by the A.E. Staley Co. of Decatur. But beans’ immunity to chinch bugs was no small factor in the change.
Farmers line up in Aledo (northwestern Illinois) for their quotas of creosote in June 1934 (Courtesy State Journal-Register)
Bean acreage, however, was still relatively low in 1934, when a dry spring, following a dry summer in 1933, sent millions of hungry chinch bugs into Sangamon County farm fields.
Edwin Bay, Sangamon County’s longtime farm adviser, was already suggesting in May that local farmers substitute soybeans for grain crops. Otherwise, however, combating chinch bugs was an impromptu process.
“Numerous farmers are doing this (planting fields of soybeans),” the Journal reported. “Some others are planting two beans to a hill of corn – a method recommended by the state university – on the theory that the soy beans will give shade to the new corn, and chinch bugs do not like shade.”
Other farmers built creosote barriers between bug-plagued acreage and their cornfields. A farmer would plow a single furrow where the two fields met and dribble a thin line – perhaps only a half-inch wide – of creosote or tar along the top of the furrow. Postholes were then dug every 15-50 feet on the bugs’ side of the line.
Chinch bug nymphs would travel along the barrier looking for a creosote-free opening and in the process fall into one of the postholes. There, they could be killed by poison or tamping.
Barriers were a labor-intensive remedy, because the creosote had to be reapplied every morning. The good news was that the bugs have a short life cycle, and a barrier needed to last only two or three weeks. The bad news was that the bugs also reproduce quickly, so a farmer might have to battle two or more broods in a single season.
Stll, “saving an acre of corn in most cases will pay for the cost of maintaining the barriers as long as it is needed,” the Journal said.
The federal government paid for about 30,000 gallons of creosote for Sangamon County in 1934, which the Farm Bureau then distributed at a rate of one barrel per farmer. Bay estimated in June that the work done in a single week had saved 100,000 bushels of Sangamon County corn from being destroyed by chinch bugs.
Overall in Illinois, however, damage from the dry weather and the bugs culminated in that dismal November crop report: “The northwestern and southeastern counties … had the best yields; elsewhere, the ears vary from undersized to nubbins.”
But the report also included a sign of the future: Soybean production doubled in Illinois in 1934, to more than 8 million bushels. (By comparison, in 2023, Illinois produced almost 650 million bushels of soybeans, more than any other state in the country.)
Thanks to farmers’ adoption of crop rotation and some chemical preventivess, chinch bugs today mainly damage homeowners’ lawns.
Edwin Bay
Edwin Bay, 1963 (SJ-R)
Ed Bay (1898-1975) was Sangamon County Farm Adviser for more than 36 years, from 1926 until 1963. During that period, he was elected president of both the Illinois and National Association of Agricultural Extension Advisors and received multiple awards in his profession.
When Bay retired as county adviser in 1963, programs he had developed in 4-H, livestock, soils and crops and community development, along with the overall Sangamon County extension service, were said to be among the best in Illinois.
After stepping down from the local post, Bay spent four years in India, where he also provided technical assistance in agriculture.
Hat tip: To “Soil & Soul: Farming in the Sangamon River Valley” (2024), a documentary video and exhibit focusing on 10 Sangamon Valley farm families. “Soil & Soul” drew SangamonLink’s attention to the chinch bug phenomenon.
“Soil & Soul” was produced by Rich Saal and Noah Sabich; Anne Moseley of the Sangamon Experience at the University of Illinois Springfield helped produce UIS’s “Soil & Soul” exhibit, which will continue at least through April 2025 at the UIS Public Affairs Center.
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