FORTY-FIRST ANNUAL REPORT. 85 



penetrates the twigs killing them back from the tips. Later attacks 

 show on the joung fruit as a small brown rotten spot which grows 

 rapidh' in favorable weather. Soon pnstules of grayish matter appear 

 in concentric circles in the rotten spot and often are so numerous as 

 to give a moldy appearance to the fruit. These are bunches of summer 

 spores which correspond to the seeds of higher plants. These spores 

 are rapidly spread by wind, rain, or insects. The curculio is very active 

 in some localities in spreading these spores, and in some cases as high 

 as 90 per cent of the fruits affected have been traced back to curculio 

 injury. Another source of loss is in the handling of the fruits. The 

 pickers handle some of the diseased fruit while harvesting the crop, 

 and thus some of the spores get on the sound fruit. At the packing 

 house these are further spread so that during long shipments in hot 

 moist weather as high as 50 per cent of fruit, sound at packing time, 

 is spotted with rot on arriving at market. 



To control this disease, we must know how it lives from one year to 

 another. The mycelium in the twigs may live through the winter and 

 grow the following season ; spores may winter on the mummied fruits 

 on the trees; and in the fruits that fall to the ground, the mycelium 

 lies dormant for two winters and in the second spring sends out toad- 

 stool-like growths which bear ascospores (winter spores) which appear 

 about blossoming time. These will also cause the same form of disease 

 as the summer spores. These mummied fruits lie partially buried in 

 leaves or soil and their development is due to moisture. 



In pruning remove and burn all old mummies and dead twigs from 

 trees. Plow under the mummies on the ground. This will reduce the 

 sources of infection and the rest must be controlled by spraying. Spray- 

 ing must include treatment for the spores and the curculio. For the 

 spores, self-boiled lime-sulphur is used because peach leaves are very 

 sensitive to Bordeaux or commercial lime-sulphur of the strength used 

 for apple summer spraying. The self-boiled spray is made of eight 

 pounds lime, eight pounds of sulphur, to fifty gallons of water. Slake 

 the lime in a barrel by nearly covering with Avater, add the sulphur 

 by sifting it on the boiling mass. As soon as boiling ceases, cool the 

 mixture with water to prevent lime-sulphur compounds being formed. 

 A mechanical mixture of the lime and sulphur is all that is desired and 

 this is formed by the boiling action in slaking. Spray should be applied 

 about three times : first, about ten days after petals fall, two pounds 

 arsenate of lead to fifty gallons of water, — for the curculio; second, 

 about two weeks later, two pounds arsenate of lead with the lime- 

 sulphur, — for the curculio and brown rot; third, about four weeks be- 

 fore fruit ripens, with lime-sulphur for broAvn rot. 



Experiments have shown that about 90 per cent of fruit that rot on 

 unsprayed trees can be saved by spraying. In one large fruit farm this 

 was found to average one-half bushel per tree, or about fifty cents worth 

 of fruit could be saved at a cost of about five cents for spraying. 



