REPORT OF THE STATE ENTOMOLOGIST I913 35 



June to September, there being during these months from an inch 

 to nearly an inch and a half less than the normal precipitation. 

 The next year, 1907, although there was a slight increase in the 

 annual precipitation, there was a considerable shortage for the 

 months of July and August, this amounting respectively to 3.36 and 

 2.05 inches. In 1908 there was a shortage of 1.56, 1.99 and 1.79 

 inches for the months of June, September and October respectively. 

 The following year, 1909, there was a scarcity of rain during May, 

 June and July, amounting respectively to 1.46, .09 and 2.56 inches, 

 there being an excess of 3.41 in August, and a shortage in September 

 of 0.93. In 1910 there was a shortage in May of 1.52 inches, an 

 excess in June of 1.84 and a shortage in July, August and Septem- 

 ber amounting respectively to 4.31, 2.40 and 2.16 inches. The slight 

 excess in June could hardly offset the large deficit of July and the 

 continued scarcity in August and September. Again, in 191 1 there 

 was a deficient precipitation in May, July and September, amounting 

 respectively to 2.27, 2.99 and 2.08 inches, while in 1912 there was 

 a deficiency from June to September, amounting to 2.09, 1.28, 1.76 

 and 0.21 inches, for the four months in the order named. 



It will be noted from the above facts, although the deficiency 

 during this period was not as a whole very excessive, it was pro- 

 gressive and the shrinkage in rainfall almost invariably came during 

 the growing months and at times most likely to affect vegetation 

 adversely. The general result in this region was abundantly 

 evidenced by the unfavorable condition of the trees throughout the 

 section, it being particularly marked in 1910 and 191 1 and was 

 accompanied by an abnormal scarcity of water. Many cities and 

 villages in this general region suffered about this time from a severe 

 shortage of water. A number of trees, particularly soft maples and 

 others standing in naturally moderately moist, low localities, died, 

 the major cause probably being scarcity of moisture. 



With the above facts in mind, it seems very reasonable to believe 

 that these unfavorable climatic conditions may have reacted upon 

 our hickories, reducing their normal resistance considerably and 

 resulting in conditions which were extremely favorable to the multi- 

 plication of bark borers and the subsequent destruction of many 

 trees which would otherwise have survived. 



There are doubtless other factors which may be primary in bark 

 borer attacks, especially in extended forest areas. Fires, wind 

 storms and injudicious cutting may precipitate an outbreak by pro- 

 ducing conditions favorable for the development of hosts of these in- 



