Corn Borer, 1950

a corn borer he needs no introduction to some farmers and he'll introduce himself to many others he is in our cornfields and he's probably there to stay year after year he's going to go on causing lower yields making picking harder perhaps even causing accidents he was first discovered in our country in the vicinity of Boston for the first commercial damage in 1917 although he probably came from Europe as early as 1910 after that he spread rapidly by 1932 he was well on his way into the Midwest corn belt by 1942 he had crossed the mississippi river by 1945 there was some infestation as far west as Nebraska he probably won't stop until every major and minor corn producing area in the United States has been infested what's more we can't count on our severe winters to help us very much in snow-covered corn fields one of our most serious crop pests is hidden let's see if we can dig him out of the snow almost any corn stock will show corn borer damage a hole in the stalk is a sign of corn borer activity but we can't be sure finding a boar until we cut open his hiding place he's there all right having a deep sleep in a deep freeze but after a few warm days and spring he's all set to go about his business some folks try to get rid of him by burning stock field this practice cannot be recommended because it is wasteful soil erosion and it doesn't do the job some other methods of reducing overwintering borer populations include disking the use of various types of stock cutters such as the horizontal the vertical and the multiple hammer typed and of course the familiar plow birds and other predators normally kill some boars and parasites destroy their share to these all reduce the number of lawyers somewhat but did not prevent the possibility of damage to the next crop of corn but let's go back in spite of these natural hazards and control measures many boars escaped injury these go into a cocoon during the latter part of May in this pupil case the worm changes into the adult mall the male is usually smaller and darker than the female if one were to light on your coat it would be just a little larger than the buttons these laws are strong fliers they may emerge from one stock field and still lay eggs on your corn perhaps several miles away the mods are choosy they actually seek out the tallest most vigorously growing corn most of the worms hatching on corn less than 35 inches tall die off from natural causes it's the eggs laid on corn over 35 inches extended heighth that worry us for more of them survive now it is important to make accurate daily counts so that we know when to treat for best results there are a number of ways to apply insecticide effectively high volume high pressure grounds phrase seem to give best results however low pressure low volumes phrase are almost as good airplane sprays rank third thus our next ineffectiveness under the same conditions however getting the insecticide on at the right time is more important than the method you here's why egg masses themselves are not affected by insecticides as they go through their development the eggs are glistening quite when newly laid and as the eggs develop they change color until three to seven days after laying the blackhead stage appears when the blackheads of the worms are visible through the eggshell they will hatch in less than 24 hours it is important that insecticides be on the leaves and in the world so they will be killed as they crawl through or feed upon the poison even though you've done a good job of treatment some lawyers will escape to damage leaves and the developing tassel broken tassels are typical signs of corn borer presence when you can see Fras the droppings of bores feeding in the plant the borer damage in the stalk is already underway it means that the borer has interfered with the normal flow of food to the ear and has opened the way for plant diseases which add tube or damage while strong stocked strong shank varieties will help to reduce the loss from broken stalks and drop tears their use will prevent borer attack and boar attack lowers yield unless prevented by insecticides about the first of August all borers are full-grown some go through the rest of the season as worms others go into cocoons to spend 12 to 14 days before emerging as second brood laws which are as active as the first rude these laws emerge from early planted corn and fly to the late planted corn they prefer the greener later planted and lay their eggs in the vicinity of the ear these eggs develop as did those of the first brood that is just as important to make accurate daily examinations to time treatment for best results again it is necessary to have poison on the plants so that the worms are killed before entering the plant for second brood borer control specialized equipment is necessary ground equipment which puts the spray in the vicinity of the ear is better than the airplane but again getting the insecticide on at the right time is more important than the method used treatment does make a difference here is untreated corn note the height and the open appearance of the cornrow due to the leaf breakage and the dryness compare this to the treated corn only a few rows away note again the height and the density of the vigorous undamaged leaves and the greenness of the corn an air view of the same field showing strips of treated and untreated corn tells the same story treatment does pay at harvest time sprayed corn stands up well and picks clean unsprayed corn is broken over maybe you can't see it when you look at the corn from the road but look at the individual he'll properly treated corn has big good quality years bore infested corn is largely nubbins and Chaffee ears which make poor quality feed for livestock a nest of all treatment pays for itself in more bushels of high-quality corn per acre if you want more corn in the crib remember that the use of insecticides will do the most toward controlling the border after all the picking is done the borer is safe in the stock hold up for the winter he's there ready and waiting for your next crowd we've got to be ready for camping you