22 



distance by the trap crop. Its value, in fact, depends to a considerable 

 extent on this migratory habit of the moths. 



The experiments in question, as finally arranged, provided for belts 

 of corn around and through the cotton fields, planted so as to be in 

 prime silking condition about August 1. By this means, the large 

 generation of moths appearing in late Jul}^ and August, from larvae 

 infesting roasting ears in the surrounding cornfields, was largely 

 detracted from the cotton, and egg-laying was concentrated on the 

 trap rows of corn. The number of eggs found on a single corn plant 

 was often surprisingly great. Thus, in the trap rows at Willspoint 

 during early August, when the moths were out in large numbers, 804 

 boUworm eggs were counted on a single corn plant, and the average 

 of eight typical plants at this time was 495 per plant, distributed as 

 follows: 175 on the leaves, 45 on the leaf sheaths, 120 on the tassels, 

 and 155 on the silks. Furthermore, the trap rows of corn were attract- 

 ive to the moths all through the season, from the time the plants were 

 from 12 to 18 inches high until ripening began. The total number of 

 eggs deposited on a plant during its entire period of growth must be 

 very great, and a simple calculation will indicate the enormous number 

 of bollworm eggs that are kept from cotton b}^ a series of belts of corn 

 planted through the cotton field. 



i It might be supposed that, by thus furnishing the insect with its 

 favorite food, its increase and consequent greater destructiveness 

 would be the result. This, however, is not the case. From the sev- 

 eral hundred eggs that may be found on a single corn plant but two or 

 three larvse will eventually succeed in attaining their growth, owing to 

 the cannibalistic habits of the larvae themselves, and for other reasons 

 already pointed out. 



SPECIFIC RECOMMENDATIONS. 



The earlier investigations of the Division of Entomology and its 

 work the past season warrant the recommendation of the following 

 methods of lessening bollworm injury: 



I. Plant an early maturing variety of cotton as earlj'- as possible in 

 the spring and give the plants good cultivation. By good cultivation 

 is meant five or six plowings, with three or four choppings. By plowing 

 and cultivating in this way a good crop ma}" usually be insured before 

 the bollworms become destructive in August. In the territory infested 

 with the cotton boll weevil this course becomes doubl}^ necessar}^, as it 

 is only by such methods that ordinarily a crop of cotton ma}^ be made. 

 The possibility of the plants developing a crop after the bollworms may 

 leave is removed on account of the presence of the weevil. Earh^ plant- 

 ing of early maturing varieties will also allow of the crop being gathered 

 much earlier in the fall than is possible with plantings of ordinary gin 

 seed at the usual time. It will thus become possible to a considerable 



