88 Annals of Horticultiu'e . 



prevents over-bearing, and he suggests planting plum trees in 

 apple orchards to prevent injury to the apples. Webster has 

 reported * the results of his experiments in breeding curcu- 

 lios on different varieties of apples and plums, and concludes 

 positivel}^ that plums planted among apple trees do not protect 

 the latter. As with many other species, it is probably a ques- 

 tion of the number of insects; when numerous enough they 

 will take every fruit suitable to their purpose. When compara- 

 tively scarce, they may exercise a choice. Gillette reports^ as 

 the results of his studies, that the curculio prefers the import- 

 ed to the native varieties of plums, 48.8 per cent, of the former 

 and only 6.6 per cent, of the latter being infested. He also 

 reports that he found spraying an excellent remedy, although 

 not applied under the best conditions. He has since repeated 

 his spraying experiments under the best possible conditions 

 and reports absolute failure. The sprayed trees were more 

 infested than the unsprayed checks. Green, who tried spray- 

 ing with arsenites in Minnesota J again reports the most grati- 

 fying success. It is evident from these contradictory experi- 

 ences that spraying is far from being a satisfactory and reliable 

 remedy for the injuries of the plum curculio. The special cir- 

 cumstances that produce success in the one case and failure in 

 the other, are still beyond our ken. 



"J. B. Smith has made some experiments in a different 

 line. § He finds that the insects will not develop in growing 

 apples, Avhile in dropped fruit, almost every egg-puncture was 

 represented by a full-grown larva later on, provided the ap- 

 ples were allowed to decay. When decay was prevented by 

 keeping the fruit absolutely dry, none of the larvae developed. 

 As a consequence, he strongly urges the systematic gathering 

 and destruction of all fallen fruit as the best way of prevent- 

 ing the maturing of the species. Nine full-grown larvae were 

 found in a single apple, and the destruction of all such fruit 

 must do much to lessen the numbers for the following reason. 



''All of the publications confirm the statement that there 

 is only a single annual brood of the curcuHo, although &gg 

 laying extends to the end of July, or even later. 



" Gillette has also studied the plum-gouger {Coccotof^Jis pni- 



* Insect Life ii. 305. t Bull. 9, Iowa Exp. Sta. 



X Bull. 10, Minn. Exp. Sta. gGarden and Forest. Nov. 19, \%o. 



