18 INSECTS AFFECTING VEGETABLE AND TRUCK CROPS. 



Phldippus coloradensis Thorell, a spider, was found rareh', feed- 

 ing- on the smaller larvae. 



RECOMMENDATIONS FOR CONTROL. 



Diirino- 1911 the writer conducted several spraying experiments 

 against the larva^ with Paris green, arsenate of lead, and arsenite of 

 zinc. It was found that the larva? of all sizes were readily killed 

 with arsenicals. In fact this is one of the most easily controlled 

 pests which occur on sugar beets in the Arkansas Valley. 



Paris green proved more quickly effective than other poisons tested, 

 and the following formula is recommended : 



Paris green pounds 3 



Whale-oil soap do G 



Water gallons.- 100 



This mixture should be applied to sugar beets with a field sprayer 

 (Plate V) at the rate of from 75 to 100 gallons to the acre. It is 

 necessary to wet onh' the surface of the leaves with spray. 



CONCLUSION. 



In the Arkansas Valley the striped beet caterpillar is a minor 

 enemy of sugar beets. Ordinarily it is held in check by cultural 

 methods and natural enemies. Occasionally, hoAvever, it develops in 

 injurious numbers, and when this occurs the larva^ can be easily con- 

 trolled by spraying with Paris green. 



ADDITIONAL COPIES of this pnWication 

 -l\- may be procurod from the Superintend- 

 ent OF Documents, Governnu'iit I'linting 

 Cilice, Washinpton, D. C. , at 5 cents per copy 



