EXPERIMENT STATION BULLETINS. 295 



weakened that they may not develop fruit buds for the next year's crop, 

 while those that are formed will be so weak that they are likely to be killed, 

 even in a mild winter. Particularly upon young trees, the disease may 

 also attack the tender shoots and they will be killed back by it. 



The " curl " is most troublesome in seasons when the weather, during 

 the two or three weeks following the putting out of the leaves, is cold and 

 wet. After the disease has run its course, and new leaves have come out, 

 there is seldom any further attack, provided the weather comes off warm. 

 The diseased leaves become considerably swollen and blistered and, as it is 

 generally more or less irregular, they are often considerably curled and 

 twisted. The swelling is caused by the working of the mycelium of a! 

 fungus within the tissues, and in a few days the upper Surface will take on 

 a mealy appearance, owing to the development of the innumerable crop 

 of spores. 



The spores remain in the branches and fallen leaves during the remainder 

 of the year and, as soon as the new foliage appears in the spring, are 

 at hand to spread the disease. While the tissues are still soft, they can 

 readily penetrate the epidermis, but it would seem that after they become 

 firm there is no further danger, although any new leaves that appear will 

 be subject to contagion. 



To secure good results from aay treatment, it is well to head back the 

 branches in the spring, carefully removing any that were injured by the 

 " curl " the previous year, lest the mycelium of the f ungas might remain 

 in the tissues and spread to the new leaves when they appear. 



Our experience for two years goes to show that, when the trees have 

 been properly pruned and are in good condition, the disease can be held in 

 check if they are sprayed with Bordeaux mixture, making the first appli- 

 cation just before the buds open and repeating it as soon as the trees are 

 out of bloom and again at the end of ten days or two weeks. 



With each application, Paris green should be used for the curculio. 

 Our own experiments in several places in the state, seem to indicate the 

 value of the above treatment, and the fruitgrowers who have made use of 

 the remedy are well pleased with it, in nearly all cases. It is likely that 

 where failures occurred some of the conditions noted for success were not 

 furnished. 



If the disease is in the tissues from the previous year, or if the new 

 leaves were left for a number of days uncovered with the copper compound, 

 the germs could readily enter the tissues of the leaves and no later spray- 

 ings would save the leaves attacked, although they would prevent the 

 spread to others. 



BROWN ROT {Oidium fructigena, Kze. and Schm.). 



The peach is also seriously injured by this disease, of which a description 

 will be found under the diseases of the cherry. From the fact that the 

 conditions for the development of the disease are particularly favorable at 

 about the time their fruit begins to ripen, the early varieties seem to be par- 

 ticularly susceptible to the attack of this disease. The germination and 

 work of this fungus are so rapid that frequent applications of fungicides are 

 necessary to hold it in check, especially as the June showers, in which the 

 disease seems to revel, are unfavorable to the highest success, through the 

 washing off of the fungicide. 



