194 FUNGOUS DISEASES OF PLANTS 



Control. Preventive treatment should be begun in late winter 

 or very early spring and must consider two possible sources 

 of infection : (i) conidia adherent to bark or bud scales, and 

 (2) the mummied, diseased fruits or blighted twigs. A thorough 

 spraying, equivalent to disinfection with strong Bordeaux (6-6-50), 

 would be effectual against the free conidia. In addition to such 

 spraying, however (and it may be well to do this in late autumn), 

 it is essential to destroy the old, diseased fruits. Prune them or 

 knock them from their attachment to the twigs, rake them from 

 beneath the trees, and destroy or turn under deeply. Spores may 

 be blown long distances, however, so that an appearance of the 

 disease may be expected at any time during the growing season, 

 aside from the fact that it is hardly possible to kill all adherent 

 conidia. In some sections of the country a 3-4-50 Bordeaux 

 made with good lime has been used advantageously after foliage 

 and fruit are well developed, with no injury resulting either to 

 peaches or Japanese plums ; but this is not uniformly the case, 

 and seasonal conditions unquestionably have a considerable in- 

 fluence on the amount of injury caused by the spray. It might, 

 where practicable, be employed until the fruits are more than 

 half grown, after which time some other liquid spray or Bordeaux 

 dust should be substituted. It is sometimes advisable to use a 

 copper acetate solution (6 ounces to 50 gallons) when color be- 

 gins to appear in the fruit. During a season of infrequent rains 

 the writer has used a lime spray with some success. 



Some experiments have recently been made 1 with the lime- 

 sulfur spray, and it is sufficiently promising to warrant trial. 

 Apparently, the safest and most effective preparation is made 

 by mixing 10 pounds of sulfur and 15 pounds of good lime. 

 Upon slaking the lime the sulfur is " self -cooked " from the 

 heat generated, and the mixture is finally diluted to 50 gallons. 

 During a single fairly dry season (a most favorable one for this 

 mixture) the loss has been considerably reduced, — 73 per cent 

 in the unsprayed plot as compared with from 10 to 30 per cent 

 in the sprayed. 



1 Faurot, F. W. Brown Rot of Peach. Mo. State Hort. Soc. Rept. (1907) : 

 285-289. (Scott, who cooperated in this work, has also published the results of 

 these experiments in detail. Compare Bureau Plant Ind., U. S. Dept. Agl. Circular 

 1 : 12-16. 1908.) 



