190«j.] PUBLIC DOCUMENT — No. 33. 117 



usually makes its appearance in the spring on greenhouse 

 plants, and the mildew about the 15th of August on either 

 outdoor or greenhouse crops. Both of these blights can be 

 readily controlled in the greenhouse by judicious attention 

 to cultural methods. Neither of them will survive if atten- 

 tion is given to light, ventilation and especially moisture. 

 When the foliage is kept dry these fungi are unable to get a 

 start. In case syringing is necessary to keep the red spider 

 down, it should be done in the morning in bright sunlight, 

 at which time the plants will dry out readily. In case these 

 blights have attained some headway, the pipes should be 

 painted with sulphur and oil. Beneficial results have been 

 reported by difterent growers who have tried this method. 



Sun Scald. 



The general interest manifested in shade trees in this State 

 is quite apparent from the large number of specimens sent 

 us each year, and the amount of correspondence touching 

 upon various matters concerning them. The number of 

 cases of sun scald to shade trees the past summer was un- 

 precedented. This was particularly noticeal^le in rock maples 

 and white pines, although this same trouble occurred with 

 many trees and shrubs to some extent. The sun scald on 

 rock maples was unusually abundant, and more severe than 

 usual. Some trees which were under our observation had 

 as much as ninety per cent, of their foliage as dry and crisp 

 as casted leaves. Some maple trees possess the peculiarity 

 of having their leaves badly scorched each year, where other 

 trees of the same species located near them are entirely free 

 from this trouble. 



As a result of the prolonged drought and the excessive 

 heat during mid-summer, many rock maples developed foli- 

 age of a peculiar bronze color. There was also much pre- 

 mature fidl coloring and defoliation on many trees. The 

 cause of so much sun scald during the past summer was 

 drought and dry winds. 



Where fine specimens of lawn or roadside trees exist, 

 every efibrt should be made to maintain them in the best 



