CACTUS SOLUTION AS AX AD1IKSIVE. 19 



agitated. Its effectiveness as an insecticide was disappointing; in 

 fact, it is so low that it is doubtful that this arsenical can ever come 

 into general use as a spray. Much difficulty was experienced in ob- 

 taining uniform distribution over the surfaces sprayed, even when 

 used with cactus. The cactus increased its adherence and spraying 

 qualities, but not sufficiently to remedy matters completely. The 

 foregoing experiments show its effectiveness as compared with fer- 

 rous arsenate, zinc arsenite, lead arsenate, and Paris green. 



FINAL RESULTS FROM SPRAYING. 



The pot experiments carried on in the insectary for the belted 

 cucumber beetle and the other species concerned were undertaken 

 to assist in checking up results in the field. They served for more 

 than this, however, for in a short time it was possible to accumulate 

 much data as to the effectiveness of each spray that otherwise could 

 not have been secured in nearly so short a time, while the estimates 

 as to mortality in each of the experiments made would have been 

 much less conservative. 



It was found that the beetles could be best controlled by spraying 

 with zinc arsenite or with Paris green. The other arsenicals em- 

 ployed, while effecting a control in most cases, did not give as high 

 mortality as the two arsenicals mentioned. The number of appli- 

 cations rendered necessary varied with the location of the sugar 

 beets, i. e., their distance from crops where the beetles were breeding 

 in large numbers. One plat of sugar beets was sprayed only once, 

 while on the other hand several plats of beets, spinach, and cabbage 

 were sprayed from two to four times in order to prevent the crop 

 from being badly stunted in growth. The greatest damage is done 

 from the time the beets begin coming up until the leaves have reached 

 a height of 10 inches. Attention should be given the crop from the 

 time the seeds are planted, in order that no serious damage may be 

 clone before remedial measures can be put to practice. 



RECOMMENDATIONS FOR CONTROL. 



The control of such pests as the belted cucumber beetle does not 

 require the attention necessitated by some of the noxious caterpillars 

 and sucking insects. But to keep the injury clown to the minimum 

 frequent observation should be made while the plants are small, as 

 this is the time when the beetles are capable of doing the greatest 

 amount of damage. 



If the beetles are present in sufficient numbers partially to defoliate 

 a few plants, it is time to begin spraying. It may be necessary to 

 spray only once in order to effect control, but this will depend upon 

 the surrounding vegetation as well as upon the weather conditions. 



