360 BOARD OF AGRICULTURE. [Pub. Doc. 



from the truth, however. Japanese plums are much less severely 

 attacked by black-knot than the ordinary varieties, but they are not 

 immune. Plum trees, even of the most susceptible varieties, which 

 receive good care will rarely suffer from black-knot. Spraying will do 

 something to check the disease, but the pruning knife will do more. 

 Every black-knot should be cut out and burned as soon as it is seen. If 

 a general pruning is given the trees in June, most of the black-knot 

 will be discovered in its earliest stages; then is the best time for its 

 removal. The fruit grower should go through the plantation again 

 during the period when the leaves are off, when any fully developed 

 knots are more plainly visible; these should then be removed and 

 burned. If this practice is kept up year after year, there will be no 

 difficulty whatever. 



Another disease which is very embarrassing to the plum grower at 

 times is the brown rot or ripe rot, most conspicuously seen on the fruit 

 just at ripening time. This often ruins a large proportion of the 

 crop. It is caused by a fungus which grows in the twigs and fruit 

 throughout the summer season, but which manifests itself most con- 

 spicuously on the fruit at ripening time. Considerable check will be 

 given to this disease also by properly spraying with Bordeaux mixture. 

 Careful hand-thinning of the fruit will do more toward checking the 

 disease. Many varieties of plums, especially the Japanese, may be 

 picked some days before they are dead ripe, and this offers another 

 means of getting ahead of the brown rot. 



Insects. 



As the black-knot is considered to be a universal and fatal disease, 

 so the curculio is commonly considered to be an insect ruinous to the 

 plum grower's interest. It is true, of course, that in many cases a 

 large part of the crop is injured by this insect, and sometimes prac- 

 tically the entire crop is damaged. This seldom or never occurs, 

 however, in large blocks of plum trees, or on trees which are cultivated 

 or grown in poultry yards. In fact, in our experience the curculio is 

 a distinct blessing. The fruits are usually punctured early in the 

 season, when they are about the size of peas. Punctured fruits com- 

 monly fall off early in the season, and the curculio thus becomes an 

 efficient assistant in thinning the fruit. This practice of thinning out 

 the fruit on plum trees is very important, and should be attended to 

 every year about the last of June. After the curculio has taken off 

 from 10 to SO per cent of the crop, it is usually necessary to pick 

 another large amount by hand; the curculio thus saves much ex- 

 pensive hand labor. It is not the purpose of this article to praise the 

 curculio, nor to recommend its adoption as a universal field assistant 

 in plum growing, but simply to point out that it is not a serious 

 menace to the business. 



The San Jose - scale is by all means the most important insect which 



