ENTOMOLOGY 353 



owing to destruction and exposure of the winter resting stage in the 

 late fall. The corn stalk borer, one of the best known and most 

 injurious insects to that crop as well as corn billbugs will also 

 be handicapped in passing the winter owing to the fall destruction of 

 corn stubble. This same practice is also advantageous against cow- 

 pea pod weevils which cannot live on rye or oats. While this rota- 

 tion is intended to be typical, it may be modified to suit the circum- 

 stances. 



In a rotation the handling of the various crops must be gov- 

 erned by the soil fertility. Whether the given crop should be re- 

 moved or plowed under for the purpose of incorporating humus 

 must be determined by the circumstances. On account of the com- 

 parative scarcity of live stock and absence of a systematic rotation the 

 upland soils in many sections are deficient in humus, a most impor- 

 tant factor in insect control. Some of the field crop insects of first 

 importance do their principal, if not the entire damage, to the young 

 plants and such damage is generally more pronounced on the less 

 fertile upland soils. The incorporation and maintenance of humus 

 in such soil is essential for it enables the farmer by the addition of 

 necessary fertilizer to hasten the 'crops over such danger periods. 

 This is especially true of corn in this state ; while easily damaged by 

 insects under adverse conditions, it responds very readily when these 

 conditions are corrected. 



Other schemes of rotation may be devised to suit special cases. 

 In the above recommendations are involved the basic principles of 

 good farming. They embody the idea of diversification and clean 

 farming. In planning the farm operations from year to year it is 

 important to consider what effect a given procedure will have upon 

 the increase or decrease of certain insect pests that were destructive 

 to one more of the crops during the past season. (Bui. 150 S. Car. 

 Agr. Exp. Sta.) 



CONTROL OP INSECTS BY CULTURAL METHODS. 



It is much easier to ward off an attack of insects or to make 

 conditions unfavorable for their multiplication: than to destroy 

 them after they are once in possession; and in controlling them, 

 methods and systems of farm and orchard culture have long been 

 recognized as of the greatest value, more so even than the employ- 

 ment of insecticides, which, in most cases, can only stop an injury 

 already begun. Insects thrive on neglect, multiply best in land 

 seldom or never cultivated, and winter over in rubbish, prunings, 

 or the undisturbed soil about their food plants, and become, under 

 these conditions, more numerous every year. It is a fact of common 

 observation that it is the neglected farm, vineyard, or orchard filled 

 with weeds or wild growth which is certain to be stocked with all the 

 principal insect enemies; and, on the other hand, thorough and 

 constant culture, with the removal and burning of prunings, stubble, 

 and other waste, the collection and destruction of fallen and dis- 

 eased fruit, and the practice, where possible, of fall plowing in dis- 

 turb the hibernating quarters of field insects, will almost certainly be 

 accompanied by comparative immunity from insect pests, 



