RELATION OF WEATHER TO FUNGOUS INFECTIONS. 57 



leaves than the usual drying process followed by the authors. In 

 summer and fall, fungus left remaining on leaves, as well as when 

 scraped off and kept in bottles, has produced infections as long as 

 two months after picking. 



RELATION OF WEATHER CONDITIONS TO FUNGOUS INFECTIONS. 



Wliile it is an estabHshed fact that good infections of tlio red and 

 yellow AscluM-sonias arc occasionally secuied as early as April and 

 May, and as late as early October, experiments have shown that 

 weather conditions during these months are too subject to variation 

 for even reasonably reliable results. Unless due regard be given to 

 existuig conditions, more failures than successes follow uitroduction 

 at this season. Considering the difficulty with which fungus can be 

 secured so early in the season, the tendenc}' toward imfavorable 

 weather conditions, and the better infections secured later m the sea- 

 son in return for the same expenditure of time and money, the au- 

 thor's do not reconnnend the introduction of fungi befoi-e June or, at 

 least, until the summer rains begin. All experiments have sho^vn 

 that it is useless to force nature; that fungi can not be successfully 

 introduced unless the weather conditions are such that the fungi are 

 spreading naturally m infected groves. At Orlando this did not 

 occur till June in 1907 and 1908, but in 1909 occurred by the middle 

 of May. Wliile infections of red and yellow Aschersonias haA'e been 

 secured as late as early October during the past three years, it is 

 recommended that introductions of these fungi be completed dui-ing 

 the summer rainj^ season. Our records show that numerous attempts 

 by various means to introduce the brown fungus earlier than the 1st 

 of September have frequently been failures, while previous to that 

 time the slight infections secured have spread veiy slowly. 



During the rainy season itself, all experiments to determine just 

 what combination of humidity and temperature would give the best 

 infections have, as a whole, been thoroughly negative. No difference 

 in resulting infections has been observed whether the spore solutions 

 were appUed on bright, sunny days or on cloudy, muggy days; on 

 ordinary days, days with, frequent showers, or directly after such 

 showers; at various times in the day from 5 a. m. to 6 p. m., with the 

 temperature high and the humidity low, or vice versa. 



It would appear that apj)lications have been made under every 

 conceivable combination of weather conditions, and from the entire 

 mass of experiments nothing can be learned aside from the fact that 

 it apparently makes no practical difl'erence at what time of the day 

 or under what conditions of humidity, temperature, prevalence of 

 showers, etc., the spores are applied, so long as typical Florida sum- 

 mer weather prevails. 



