368 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 9 



evidences many attempts to gain entrance. Growing plants in which 

 the pods mature rapidly are less susceptible to larval injury, while 

 plants that make vigorous vine growth but through some unknown 

 cause fail to mature the pods rapidly, usually prove on examination 

 to be vigorously attacked by the larvae. In plants which have died as 

 a result of disease, the pods are either free from larval injury, or 

 indicate that they are less subject to such attacks. This tends to con- 

 firm the statement that rapidly maturing pods are seldom injured by 

 the larvae. In some instances nearly the entire crop of pods borne 

 by a plant may be injured, while in others the proportion of injured 

 to uninjured pods is about equal. On plat 1, where peanuts are grown 

 each year, the pods indicate a greater percentage of larval infestation 

 than on plat 2, where peanuts are grown in rotation with other crops. 



The peanuts on both plats were harvested on October 18 and 19. 

 In order to ascertain the percentage of infestation, a certain definite 

 weight of peanut pods from both plats 1 and 2 was examined, and all 

 pods that indicated larval injury were separated from the uninjured 

 ones and their respective weights obtained. 



The total weight of peanut pods examined from plat 1, was 15y 

 pounds, this amount gave 8 pounds not injured to 7j pounds injured 

 pods. The percentage, therefore, was 53 uninjured and 47 injured 

 pods. 



The total weight of peanut pods examined from plat 2, was 10| 

 pounds, this amount gave 8 pounds uninjured, and 2^ pounds injured 

 pods. The percentage was, therefore, 76 uninjured and 24 injured 

 pods. 



Conclusion 



From the above observations it is shown that peanut pods, particu- 

 larly when still young and soft, are subject to serious injury by the 

 larvae of the twelve-spotted cucumber beetles {Diabrotica IS-punctata.) 



That plants in which the pods are matured or maturing rapidly are 

 either free from, or decidedly less injured by the larvae. 



That rotation, and a vigorous growing crop are decided factors in 

 controlling or keeping the crop free from the attack of the larvae. 



As alternates it is considered advisable to cease growing all cereal 

 crops, particularly corn, when rotating with peanuts. Cowpeas, 

 clover, potato, cabbage, spinach, kale, turnips, tobacco, and eggplants 

 are, so far as known, not subject to larval injury. 



