40 MAINE AGRICULTURAL EXPERIMENT STATION. 



destructive disease of the plum in Maine. In some years, as 

 in 1912, it does much more damage than in others. Cherries are 

 also affected with a similar malady. In this disease the fruit 

 early in the season becomes enlarged to several times the natural 

 size. No stone is formed and the entire fruit is converted into 

 a large, thin-walled, bladder-like stmcture, at first yellowish 

 but later becoming gray as a coat of spores forms on the surface. 

 The disease does not seem to spread with great ease but the 

 fungus may live over winter in the twigs so that a tree once 

 infected may continue to produce a crop of plum pockets each 

 year instead of normal fruit. 



The treatment consists of pruning back severely all affected 

 twigs as fast as the diseased fruits appear on them and spraying 

 the trees heavily with a 5-5-50 bordeaux mixture just before 

 the leaf buds open in the spring. 



DISEASES OE FIELD AND GARDEN CROPS. 



While many plant disease specimens of this nature have been 

 received and examined during the past season, bean anthrac- 

 nose, onion mildew and the various potato diseases are by far of 

 the greatest importance. 



Bean anthracnose or "pod spot," more commonly known as 

 "rust" by Maine farmers was very destructive last season, some 

 fields being entirely ruined by its attacks. The term "rust" as 

 applied to this disease is a misnomer. Moreover there exists 

 in Maine a true rust of beans, but this produces small brown or 

 black pustules on the leaves, particularly on some varieties of 

 pole beans. These are most conspicuous in late summer. The 

 bean anthracnose is much more destructive, and attacks both the 

 leaf petioles and the pods. On the former it produces brown 

 streaks, finally girdling the leaf stems and causing defoliation. 

 On the latter the appearance is well known to every bean 

 grower. The attacked pods are covered with what are first 

 small brownish or discolored areas, which later enlarge forming 

 rusty-colored pits or ulcers. The fungus frequently grows 

 through the pods into the seed beans beneath, and beans so 

 infected carry the fungus over winter. 



To avoid bean anthracnose, rotation of crops is advised, and 

 perfectly clean seed obtained from fields where the disease has 



