174 SHADE-TREES IN TOWNS AND CITIES 



pupate, great numbers of them collect at the bases of the 

 elm-trees. At that time they can be swept up and killed by 

 pouring hot water on them. This, of course, is not a very 

 effective measure; but still, it is helpful, and in order to 

 secure the best results the grubs and the pupae should 

 be destroyed every few days so long as they are seen 

 in numbers. 



The elm-leaf beetle is now a serious pest in many 

 Eastern States. The writer will therefore quote from his 

 records of observations of the work against this pest in 

 East Orange during 1909, as these will show approximately 

 up to what time spraying can be effective. Corrections, of 

 course, have to be made for variations in climate. 



"The spraying began on May 18. On June 2, it was no 

 ticed that the depositing of eggs on the under side of the 

 leaves had begun. The spraying, however, was continued 

 during the period of incubation with good results. On June 

 10, it was noticed that the hatching of caterpillars had 

 begun. On June 25, made an inspection of all the elms in 

 the city. The early spraying was extremely effective. Some 

 of the leaves were eaten by the adult beetles, but there were 

 few egg masses. Spraying done after June 14 was also 

 effective. Although the leaves showed many empty eggs, 

 there were practically no larvae, as these were poisoned as 

 soon as they began to feed after hatching. 



"On July 2, all spraying was stopped, as it was too late 

 for spraying to be effective. On July 7, the caterpillars of 

 the elm-leaf beetle were observed descending the trunks of 

 the elm-trees to pupate. The devastating effect of the pest 

 was then at its height. Not a single unsprayed tree within 

 the city limits was free from the attack. Only a partial 

 second brood of beetles was observed." 



