I30 INSECTS INJURIOUS TO VEGETABLES 



The Beet Root-aphis (Tyclica hrevicornis Hart, fig. 82) is 

 most destructive in Colorado. It has* a variety of alternate food 

 plants, and we can only learn by 

 experiment what are the best for 

 rotation. We should avoid corn, 

 sorghum, and other cereals, grasses, 

 and particularly should we avoid 

 weeds, including wild grasses. Oth- 

 erwise the remedies advised for the 

 beet-aphis are suggested. 



^ ' WHITE GRUBS AND 



Fig. 82.-.. Bean roo^aphis; b, WIREWORMS 



antenna;c,tarsus. Enlarged. (After ^ number of fotms of white- 

 Carman. ) 



grubs and of wireworms attack 

 beet roots, but none appear to favor this form of food. We 

 have yet to learn of severe and extensive damage by them. 



Remedies. — Among the best remedies are fall plowing, rota- 

 tion of crops, clean cultivation, in particular the suppression of 

 grasses, the use of potash fertilizers as stimulants to the plants 

 found affected, all of these remedies acting to a certain extent 

 on both forms of insects. 



In this chapter there have been considered quite briefly the 

 principal forms of insects which trouble the beet-grower or 

 which he may expect to meet in his fields. Several of the in- 

 sects mentioned in the last four pages require additional in- 

 vestigation before definite and detailed instructions can be 

 furnished for their suppression. For further information appli- 

 cation should be made to the Bureau of Entomology of the 

 Department of Agriculture. 



