1891.] PUBLIC DOCUMENT — No. 33. 223 



have appeared, and on which it is intended to plant turnips, 

 cabbages, radishes, or any cruciferous crop, tlie next year, 

 should be carefully cleaned of all refuse, leaves, etc., as 

 soon as the crop is harvested ; since these fungi winter 

 over by means of resting spores developed in the leaves 

 and stems, and set free by their decay. 



Late potatoes have been an almost total loss throughout 

 the State, on account of the attacks of the Potato-rot 

 fungus (^Phytofhtkora infest ans (Mont.) de By.). As the 

 weather early in the season was not especially favorable to 

 the development of the fungus, early potatoes were, as a 

 rule, harvested in excellent condition ; but a period of 

 warm, moist weather in September was fatal to the late 

 crop. A few complaints of rotting were received earl}' in 

 the season, but whenever specimens were sent they showed 

 no fungus, but merely a browning and shrivelling, due 

 probably to the rather severe drought prevailing at the 

 time. In accordance with a request, the following brief 

 account of the characteristic appearance of leaves attacked 

 by the rot fungus is here given. The spots, at first yellow, 

 soon become of a dark-brown or blackish, muddy color, 

 quite different from the clearer and lighter brown of merely 

 dried leaves. Another peculiarity of these spots is their 

 soft, rotten condition, very different from that produced by 

 drying up, or by most other fungi. Around the edges of the 

 dark spots may usually be observed, on close examination, 

 especially with a hand magnifier, and chiefly on the lower 

 side of the leaf, a delicate white "fuzz," composed of the 

 spore-bearing threads of the fungus. The disease usually 

 appears first at some part of a field, and thence spreads, 

 frequently in a definite direction, with the prevailing wind. 



Only the promptest action can save a field where the 

 fungus has begun to spread ; but it has been repeatedly 

 shown that the sufficiently prompt and frequent application 

 to the plants of the Bordeaux mixture, the materials for 

 which must be kept on hand, will avert a very large part of 

 the threatened loss. 



The Elder Rust {yScidiu7u Sambuci Schw.) has been 

 very abundant during the past season on our common elder 



