328 FUNGOUS DISEASES OF PLANTS 



that penetration of the fruit is probably gained through some in- 

 jury or abrasion. A dark spot is invariably produced, but ordina- 

 rily no rot results. The spot on the fruit, however, may not manifest 

 itself before shipment to market, and therefore the quality of a 

 large shipment may be materially affected. 



On the lime. Upon the lime practically all forms of the disease 

 are to be seen, and it is the host which is most seriously affected. 

 It occurs as wither-tip, and the infection is through the terminal 

 bud. It may also occur as a fruit canker, and more particularly as 

 an " anthracnose " on the young growing shoots. 



The fungus. According to Rolfs, the acervuli are produced in 

 many of the diseased areas, whether of leaf, twig, or fruit. The 

 spores are produced on short conidiophores, among which are inter- 

 spersed, especially at the margin of the acervuli, certain fuliginous 

 setae, from 60 to 160 fi long, and once or twice septate. There 

 are, however, smaller setae throughout ; yet on tender twigs few 

 setae may appear. The conidia develop from short conidiophores 

 3 to 1 8 \x, arising from a more or less definite stroma. 



Control. It has been found that the disease may be held in 

 check by proper spraying, especially with Bordeaux mixture. The 

 time of spraying, however, depends upon the form of the disease, 

 wither-tip and leaf spot being preferably pruned out and the trees 

 subsequently sprayed. The fruit of the lemon will not, however, 

 permit of the use of Bordeaux, and the lemon spot may, there- 

 fore, be best controlled by sprinkling the fruit with ammoniacal 

 solution of copper carbonate before picking. 



XXIX. ANTHRACNOSE OF CLOVER AND ALFALFA 

 Colletotrichum Trifolii Bain 



Bain, S. M., and Essary, S. H. Selection for Disease-Resistant Clover. 



Tenn. Agl. Exp. Sta. Built. 75 (Vol. 19, No. 1): 1-10. figs. 1-5. 1906. 

 Bain, S. M., and Essary, S. H. A New Anthracnose of Alfalfa and Red 



Clover. Journ. Mycology 12 : 192, 193. 1908. 



An investigation of the causes of failure in red clover growing 

 in Tennessee has resulted in the discovery of an anthracnose as the 

 chief agent. This fungus attacks also alfalfa, but alsike clover is 

 practically immune. The fungus has been reported also from 

 West Virginia and Arkansas. 



