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menace to the crop, yet, added to that of the remainder of the brood, 

 greatly increase the probabilities of serious damage. For these a long, 

 mild autumn, extending into December, would appear to be exceedingly 

 favorable, as it would enable their progeny to enter winter in a com- 

 paratively hardy state, and probably produce late appearing larvae 

 the following year simultaneously with or but little in advance of the 

 progeny of the earlier appearing adults of spring. In other words, the 

 one winters as advanced puparia or unemerged adults, the other as ad- 

 vanced larvse or newly formed puparia. It thus appears that while the 

 autumn usually has little effect on the major portion of the fall brood, 

 a mild October and November may emphasize the destructiveness of 

 the pest. So far as observed by me, a damp spring, even though a 

 cold one, is also favorable to the development of the insect, while dry, 

 hot summers are as unfavorable, and cause serious mortality to the 

 earlier stages of the fall brood of adults. 



PREVENTIVE MEASURES. 



These may be noticed as follows : Sowing at the proper time ; burn- 

 ing the stubble ; rotation of crops ; sowing long, narrow plats in late 

 summer as baits ; applying quick-acting fertilizers to seriously infested 

 fields in the fall in order to encourage attacked plants to throw up fresh 

 tillers, and to increase the vigor of these that they may make sufficient 

 growth to withstand the winter. 



None of the measures are original with me, and in fact the most of 

 them are as old as the history of the species itself. There is certainly 

 much to be gained by the farmer in timing his sowing so as to avoid 

 the larger part of the fall injury, and if all farmers of a neighborhood 

 would sow about the same time even a serious outbreak would be so 

 diffused as to lessen its injury. 



The burning of the stubble after harvest, when it is practical to do 

 so, is usually recommended by the majority of writers. The plan is 

 criticised by some authors on the plea that the parasites are also de- 

 stroyed, which, if allowed to continue, would themselves overcome the 

 fly. This idea has always appeared to me to be both theoretically and 

 practically wrong. If only the normal number of wheat plants allowed 

 by nature to spring up under a perfectly natural environment were pro- 

 duced, then the theory would be correct, because nature would then be 

 working out her plans from the beginning. As the facts exist hundreds 

 of thousands of plants are produced where nature intended but one. 

 Her domain is invaded and her law defied at the beginning. The Hes- 

 sian Fly is itself a parasite, the wheat plant being its host, and what we 

 term its parasites are practically only secondaries. In the Hessian Fly 

 nature has an efficient servant in controlling the wheat plant, and the 

 parasites of the former seem to be on guard to see that the duty is not 

 overdone. Now we outrage nature and expect that she will uphold us 

 by destroying these servants and permitting the indignity to go on. 



