The following is a re-print of a past column by former Advertiser columnist Stephen Thorning, who passed away on Feb. 23, 2015.
Some text has been updated to reflect changes since the original publication and any images used may not be the same as those that accompanied the original publication.
Wellington’s centennial year of 1954 did not consist only of celebrations and new projects.
In mid-July, concurrent with the big celebrations in Fergus, an epidemic of army worms frustrated the efforts of farmers and gardeners, particularly in the northern and central parts of the county.
The term “army worm” is applied, in general usage, to several species in addition to the true army worm. All are the larval stage of a small moth, and all have similar appearances and habits.
The worms are hairless, with striped bodies, and between one and two inches long at maturity. Colour ranges from green to brown shades.
They look very much like tent caterpillars, which are sometimes included in the broad category of army worms when an outbreak is particularly severe, and they completely denude trees and shrubs. A farmer with an infestation is seldom interested in a lesson in entomology – the worms of all species can devastate a crop in a day or two.
The “army worm” name derives from the fact that, given the right conditions, they multiply prolifically (a female can lay up to 2,000 eggs), producing hordes of worms that can exceed 100 per square foot. Seeking fresh sources of food, they move across the ground in an army-like formation that sometimes is so dense that it looks like a moving carpet.
Those who have studied these insects note that they seem to appear in cycles of 10 to 12 years. The worms do best in gaining a foothold during a wet and cool spring. There are usually three or four generations, and in Wellington, the last would strike in the second half of July. They feed and move mainly at night, hiding during the hot daytime hours in leaf crevices or in the ground.
The 1954 outbreak was the second in Wellington in five years, proving that the 10-year cycle theory did not always apply.
In 1949 reports of the worms came from across southern Ontario in the third week of July, mostly in grain crops, and particularly in oats.
Don Black, who was then the Wellington County Agricultural Representative, noted the worms in Minto and Arthur during the last week of July 1949. He said the worms had a particular fondness for the oat heads, rather than the leaves. Worst cases that year were on Richard McLellan’s farm, Concession 11 of Arthur, where he saw four acres of oats totally destroyed. Almost as bad was an infestation on John Patterson’s farm in Minto.
Black did not expect the 1949 outbreak would cause major damage. The plague arrived late in the season: farmers were about to begin their harvest of oat crops. The weather in late July 1949, hot and dry, further retarded the worms.
The 1954 outbreak seemed to be a repeat of that of 1949. In late July Don Black received reports of the worms in the Palmerston, Harriston, Teviotdale, Rothsay and Goldstone areas. Infestations appeared in surrounding counties as well: Simcoe, Grey, Bruce, Huron, Perth and Waterloo. As in 1949, these worms preferred oats, but would also attack barley and hay fields.
There were fears that they might move on to corn, which was making inroads locally as a major forage crop. At first, Black believed that the outbreak was less serious than in 1949, but events soon proved him wrong. Soon, the worms were devouring roadside grass, lawns and vegetable gardens.
Pesticide control of the worms can be difficult even with today’s improved chemicals, and in 1954 there were far fewer practical controls. The most effective method then was to plough a single furrow around a field to be protected and to place bait in the bottom, where it would be discovered and eaten by the invading army of worms.
The suggested formula for the bait was 25 pounds of bran, two quarts of molasses, and a pound of Paris green (a very poisonous compound of arsenic and copper acetate), all mixed with three gallons of water.
Alternately, the bait could be sprinkled in an infected field late in the day, before the worms emerged from the ground. They would discover the bait before climbing up the grain stalks.
The 1954 outbreak peaked at the end of July. In places, the worms were so thick that highways became slick with worms crushed by passing motor cars. At least one railway train stalled when crushed worms on the rails lubricated the locomotive driving wheels, making them spin ineffectually.
Battalions of the worms left farm fields and headed into the towns and villages of Wellington. Home gardeners patrolled their plots at night, flicking any advance scouts into a tin can, and watching for the clusters of eggs laid on the undersides of leaves.
Hot dry weather in early August helped to end the outbreak. As well, grain harvests quickly removed the favourite food source for the worms. Nature also provided remedies. The army worm attracts several parasites, including a fly that lays eggs on young larvae. When they hatch, the fly larvae eat the worms from the inside. Army worms are also a delicacy for fire ants.
Sometimes the outbreaks can be local in nature, depending on how the pests survive the winter. Wellington County has not suffered a major plague since 1954, but the worms do appear from time to time. In 1914 they caused major damage in this county, and there were reports in several other years between then and 1954.
More recently, Nova Scotia suffered a major infestation in 2000. There were more reports in 2001, in the Eastern Townships of Quebec and in the Maritimes. Later that year, at the end of August, army worms devoured crops in the Hamilton area.
This year (2004), army worms have been reported in southwestern Ontario, and in the eastern part of the province. Generally, though, they are much more of a pest in the great republic to our south, with frequent reports in Ohio, Kentucky, and through the midwestern states.
The farmers and horticulturists of Wellington County will be happy to have no repeat of the 1954 army worm infestation.
*This column was originally published in the Wellington Advertiser on Aug. 13, 2004.
