FARMERS' REGISTER— MOTH- WEEVIL. 



829 



establish the fact that the weevil egg had been laid 

 and hatched, and that the insect had passed through 

 every change of form, to the perfect winged state, 

 ^vithin the time between the2ndof September and 

 6th of October. On all the grains, except three, 

 the cells were now visible, externally ; and these 

 three, when cut open, were found to be equally 

 well supplied with weevil. Some were in the 

 chrysalis state, but generally in the larva or mag- 

 got state, and nearly all well grown. Of the 19 

 grains, 2 contained 3 weevil each, 8 contained 2 

 each, and the remaining 9 had one in each. 



The results of these experiments seemed clearly 

 to disprove all the prevailing opinions of the origin 

 and propagation of weevil, and to establish that a 

 few (and generally but very few) of their eggs arc 

 deposited on corn in the field, which usually do not 

 hatch before the next summer, when they send 

 forth the progenitors of several successive broods, 

 produced in short periods of time, and rapidly ma- 

 turing to propagate others. In this manner, their 

 propagation, if not prevented by some means of de- 

 struction, would be, in geometrical j)rogression, 

 increasing by a very large ratio — and their num- 

 bers, at the end of a few generations might rise to 

 an amount that Avould at first seem incredible and 

 in possible. For example — suppose the number 

 of eggs laid by each female weevil to be 200, 

 (which is not an extravagant supposition, if we 

 may judge by comparison with many other insects,) 

 and that three successive broods are deposited in, 

 and issue from corn during the warm season of any 

 year. According to this supposition, a single fe- 

 male, laying her 200 eggs in October, will pro- 

 duce 200 millions of winged and perfect weevil in 

 the last brood of the next autumn. The prodigious 

 magnitude of this number, will be better compre- 

 hended, when I state that 600 barrels (or 3000 bu- 

 shels) of corn, do not contain so many as 200 mil- 

 lions of grains. I will exhibit the rate of increase 

 upon the foregoing supposition, and also at half of 

 that ratio. 



One pair of weevil, supposed to produce 200 

 eggs in October, which hatch early in July, making 

 100 females in the first generation, 

 10,000 in the second, in August, 

 1,000,000 in the third, in September, 

 100,000,000 in the fourth, in October, or 

 200,000,000, counting the males as equal in number. 



But if the rate of increase is only half as great, 

 or 50 pairs are produced from each female, the 

 fourth generation so multiplied would amount to 

 12,500,()00 — which would be nearly as many as 

 there are grains of corn in 40 barrels. 



These examples are by no means intended to re- 

 present any possible actual increase, but to show 

 that there is no want of procreative power to pro- 

 duce inconceivable numbers, from the smallest ori- 

 ginal stock, if all circumstances are favorable for 

 the propagation and preservation of the race. This 

 prodigious procreative power, though not repressed 

 (as in most other animals) by any want of food, is 

 greatly limited by unfavorable temperature, short 

 summers, and all the enemies that prey on those fee- 

 ble and helpless insects. It is only when these cir- 

 cumstances are guarded against, (as in my first 

 experiment,) that some a{)proach to the real rate 

 of increase can be seen. The manner and rate of 

 increase will serve to explain why more weevil 

 may appear in the last week of a long warm sea- 

 son, than in all the previous time. 



Vol. 1—12 



There are so many circumstances which, without 

 being suspected to operate, may completely change 

 the results of experiments, that we ought not to 

 trust to the most decisive in appearance, without 

 additional trials, and under varied circumstances. 

 I therefore ask of others to repeat these experi- 

 ments, and aid in establishing or overthrowing the 

 conclusion which is irresistible, if there is no delu- 

 sion in them, viz : That eggs of the weevil are 

 laid on corn in the field, but in very small num- 

 bers : but that these few are sufficient to fill the 

 whole crop with their progeny during the follow- 

 ing summer. If these are truths, the most im- 

 portant inferences grow out of them, which will 

 teach us how to restrain almost entirely the ravages 

 of the Moth-Weevil. 



If either of the three existing opinions of the 

 origin of this insect is admitted as true, it serves to 

 repress, as useless, every attempt to prevent the 

 propagation of the weevil, or to destroy the insects 

 after they assume the winged form, and have 

 ceased to injure the grain. But it will not be so 

 when we know that the first laying of eggs serves 

 merely as the seed for the abundant and destructive 

 broods which follow in the second and third gene- 

 rations. If we could prevent the few first eggs 

 being laid — or could prevent their hatching — or 

 could kill the first small brood as it hatches — either 

 would remedy the evil. And, though altogether 

 mistaken as to the propagation and habits of the 

 insect, chance and observation have long ago taught 

 us how to prevent the worst effects, both on wheat 

 and corn. If we will attend to the truths now as- 

 certained, and use carefully the proper means of 

 prevention, there can be no more considerable 

 danger from this cause. I will state some of the 

 probable, as well as the already known means of 

 prevention. 



1. Some few eggs of the weevil are laid on the 

 upper exposed grains, while in the field. — This is 

 proved by grains of very forward corn being found 

 weevil-eaten when gathered. But these are so few, 

 that even if they live and hatch, their direct dam- 

 age would be not worth consideration. If all corn 

 intended to be kept later than the 1st of July, was 

 put up without shucking, that protection to the ear 

 would prevent the second brood being laid in the 

 corn — and perhaps the closeness of the bulk would 

 prevent nearly all of the first small brood from 

 hatching. This course would be directed by the 

 supposed origin of weevil — and it is also supported 

 by experience. Corn put up in the shuck, dry 

 and clean, will be far better preserved from weevil 

 than in any other way ; and all corn intended for 

 bread in summer and autumn, ought to be kept in 

 that manner. I have kept large quantities in the 

 shuck (when the price was so low as to make sel- 

 ling inexpedient,) to the second, and sometimes the 

 third summer after gathering, and found very lit- 

 tle damage from weevil, compared to any shucked 

 corn the next summer after gathering. To save 

 room, and trouble in handling, the outer shucks of 

 my corn had been broken from the ears in gather- 

 ing, which lessened the protection against the wee- 

 vil. If all the shucks had been left, the number 

 of damaged grains would probably have been much 

 fewer. 



2. We have been told how to destroy the weevil 

 in its winged state effectually by the fumes of burn- 

 ing sulphur, and even by the smell of the leaves of 

 Pride of China. The last method has been pub- 



