274 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 15 



The growing of beans diiring alternate years may prove worthy of 

 trial, but it would necessitate close community effort in areas at least 

 the size of a large county, because of the prolonged flights of which 

 the beetle is capable. 



The use of the Windsor or broad beans ( Victa faba) as a substitute 

 for garden beans for human consiimption will only partially alleviate 

 the situation, provided the- crop meets with public approval, because 

 in the South this crop can not be grown successfully during the summer. 

 It is an excellent early-spring crop, however, under southern conditions, 

 and the young, green seed, properly cooked, is relished by those who 

 know it. 



The use of substitute crops, since the soy bean and cowpea as forage 

 and cover crops are threatened, may prove promising. The mung 

 bean (Phaseolus aureus) has thus far proved absolutely resistant to 

 beetle attack, and a bush variety of the immune velvet bean might 

 fit into farm rotation in many cases. The adsuki bean, while slightly 

 susceptible, is not favored by the beetle, and this crop also may be 

 of value as a substitute. 



Necessity for Thorough Study 



A world-wide search for effective natural enemies, insect, bacterial, 

 and fungus, is im.perative before the bean beetle becomes more widely 

 distributed. Adaptation of one of the known stomach poisons so that 

 it may be applied with safety to the foliage of beans, involving determ- 

 ination of the causes of arsenical injury to foliage, is worthy of intensive 

 study. Search for new stomach poisons should be constantly made. 

 The perfection of m-achinery for the application of dusts to the under- 

 side of bean leaves is also important, and the solution of this last problem 

 is essential to the successful adaptation of dusting to the control of other 

 truck-crop insects. 



Mr. G. E. Sanders: Is copper in sm.all quantities, such as a mixture 

 of a small quantity of Bordeaux dust, used in combination with arsenic- 

 als as a preventing agent? 



Mr. N. F. Howard: We used a dust (our No. 23) comprising 10% 

 commercial Bordeaux powder of 22% metallic copper content; 10% 

 commercial arsenate of lead; and 80% hydrated lime. This dust did 

 not injure bean foliage in any of nine applications, but a ten per cent, 

 arsenate of lead-hydrated lime dust did not injure the foliage either. 

 Copper in Bordeaux as a wet spray seemed to increase injury. 



Mr. G. E. Sanders: You are sure it wasn't copper injury to the bean 

 plants direct, instead of arsenical injury? 



