. Bulletin. Agriculture. 12 CONTROL OF PEACH BROWN-ROT AND SCAB. stools, about one-half inch in diameter, are produced from mummies which have remained on the ground through two winters partially or entirely covered with soil. (See fig. 1.) One mummy may produce ten to fifteen of these bodies, each of which produces myriads of ascospores. When disturbed by a puff of wind a little cloud of spores may be seen to rise into the air from one of the cups. These ascospores as well as the conidia, serve to infect the blossoms. A crop of sum- mer spores is in turn produced on the diseased blossoms and
. Bulletin. Agriculture. 12 CONTROL OF PEACH BROWN-ROT AND SCAB. stools, about one-half inch in diameter, are produced from mummies which have remained on the ground through two winters partially or entirely covered with soil. (See fig. 1.) One mummy may produce ten to fifteen of these bodies, each of which produces myriads of ascospores. When disturbed by a puff of wind a little cloud of spores may be seen to rise into the air from one of the cups. These ascospores as well as the conidia, serve to infect the blossoms. A crop of sum- mer spores is in turn produced on the diseased blossoms and some of the young, green fruits become infected by these, so that there is usually a great abundance of material ready for the infection of the mature crop of fruit, even if the old mummies have been removed from the trees. It has for years been recommended that the rotten fruit be picked from the trees and from the ground and destroy- ed in order to remove the source of infection for the following year's crop. This is a good practice, but it is usually disappointing, because the fungus is so prolific in spore production that the few mummies that inevitably escape the pickers are sufficient to furnish the initial infec- tion material for the en- tire crop of the following year. Protection of the fruit by spray- ing appears to be the only satisfactory means of combating this fungus, although the destruction of diseased fruits doubtless aids in checking it and should not be Fig. 1 .—An old brown-rot mummy with the cup-shaped bodies (apotheeia) of the fungus, in which myriads of ascospores are produced. INFLUENCE OF THE WEATHER. Most parasitic fungi are influenced by weather conditions. This is especially true of the brown-rot fungus. Moisture not only favors the growth of the fungus and the production and germination of the spores, but it also renders the fruit tender and watery and therefore more susceptible to rot. In a dry season, or one with only occasional ra
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