ORIGINALLY PUBLISHED | OCTOBER 5, 1940 | CANADIAN COUNTRYMAN
This year the corn borer has increased in numbers to such an extent that it has attracted the attention of almost every grower and consumer of table corn as well as growers of field corn. The Provincial Entomologist, Professor R. W. Thompson, has sent us the following statement regarding the borer situation this year in Ontario:
"This year the corn borer is more abundant in Ontario than it has been since 1927 and 1928 when the corn industry of Essex and Kent counties was seriously threatened. In the present outbreak not only are large numbers of borers present in these two counties, but also in most of the counties in Old Ontario from Windsor to the Quebec boundary. The annual fall inspection of corn fields has just been completed in the counties west of Toronto. In this area the average stalk infestation, as compared with 1939, has been almost doubled and in some counties almost trebled.
On several occasions Professor L. Caesar (Professor Thompson’s predecessor) has warned that if we had three consecutive seasons in which weather conditions were favorable to the borer in the critical months of June and July, this insect would increase to the point where it would cause commercial damage in spite of strictly enforced cleaning up of all corn refuse. During 1938, as a result of slightly favorable weather conditions, the borer infestation increased in some counties from what it had been in 1937. In 1939 there was a more marked increase in borer populations in some parts of the territory where clean-up is enforced and also in some areas outside this territory where previously the borer had not been serious. This year, the third successive year and the one most markedly favorable to the borer, has given proof of the importance of Professor Caesar’s warning. The weather this season has provided conditions which are close to ideal for the borer. There was an abundance of moisture throughout the whole critical period of the corn borer’s life cycle, coupled with adequate temperature during a large part of July and early August, thus permitting the moths to live longer and to lay more eggs than in previous years. In addition, the prolonged wet weather of the early season delayed the planting and the development of corn, thus making entry into the more succulent plants far easier for larger numbers of young borers than would be the case in a season of normal rainfall.
In areas where regulations for control were not in effect, severe borer damage has been noticed by many for the first time this year. In this connection it must be borne in mind that if control measures for this insect had not been enforced in counties where regulations are in effect, the damage there would have been much more severe than is the case.
In 1927 and 1928, in Essex and Kent counties particularly, the corn crop was largely broken down and hard to harvest as a result of borer injury. This season in this area, in spite of the large numbers of borers, the total amount of stalk breakage, by comparison, is much reduced and it is hoped that it will continue to be so. Many fields in both of these counties are planted with one or other of the more promising hybrid corn strains. Many such fields were examined during the past week and in spite of large borer populations, in almost every case, they were found to be standing erect and with every indication of continuing to do so.
Only a few fields of corn have yet been cut. Every man who will be cutting corn this season, by taking special care, can save himself labor and also can help to prevent the borer from again increasing next season. Corn should be cut as close to the soil level as possible. The use of a hoe is suggested as preferable to a sickle for this purpose, if corn is cut by hand, since the hoe permits cutting at the soil level, thus obviating any necessity for further work with stubble. Where binders are used it is urged that these be set to cut the shortest possible stubble of which they are capable, since short stubble is much more easily plowed under permanently. To avoid unpleasant, hard labor next spring, it is suggested that care be taken to remove all uneaten corn stalks from mangers and similar feeding devices before they are tramped into manure. Long stalks in manure are difficult to handle and are, moreover, difficult to destroy by means other than burning. Wherever possible, the work of clean-up should be advanced as far as can be done this fall, so that only a short time is required for this work next spring. In plowing under corn stubble this fall, or for that matter at any time, see to it that all is completely buried so that subsequent cultivation will not drag the stubbles or other refuse to the surface.
The attention of all corn growers in counties where regulations are in effect is drawn to the fact that, in these areas, it is contrary to the law to sow wheat on corn stubble unless the latter has been plowed under satisfactory and not dragged up in subsequent cultivation. Any individual who plants wheat on corn stubble which has been only disced or cultivated is faced with the alternative of picking up all such stubble and destroying it by burning, or of plowing down his wheat. This regulation is too frequently ignored until the following spring. Any such fields left until the next spring must be attended to before May 1. The earliness of this date sometimes causes hardship in the removal of stubble and therefore this warning is issued to help growers to avoid such hardship.
Care in the harvesting of corn and the disposal of corn refuse, both this fall and next spring, is of paramount importance if we are to continue growing corn profitably in Ontario."