452 Journal of Agricultural Research voi. xxii. No. 9 



five different temperatures.^ After 10 days' storage notes were taken 

 and results obtained as shown in figure i. 



All of the cherries at 15° and 20° C. were partially or entirely rotten 

 and nearly all of those at 10°. At 5° sixty-six per cent were affected, and 

 at 0° thirty-four per cent. The results show the great inhibiting effect of 

 low temperatures but perhaps give greater emphasis to the extreme diffi- 

 culty of controlling Monilia rot at any temperature when the fruit has 

 already received bad treatment and an opportunity has been given for 

 the rot to pass through its initial stages while the fruit was warm. 



PRUNES 



But one temperature test has been made on prunes. The fruit was 

 from Wenatchee, Wash., and was shipped from that point in a pony 

 refrigerator August 31, 1920, arriving in Washington, D. C, in good 

 condition 13 days later. Inoculations were made with Monilia and 

 Rhizopus, and the fruit was distributed at once to the various tempera- 

 tures. Figure 2 shows the development of the rots 5 days after inocula- 

 tion. 



PEACHES 



A large number of temperature experiments have been made with 

 Monilia and Rhizopus on peaches. The Carman, Belle, and Elberta 

 peaches used in the 191 8 experiments were purchased in the Washington 

 market. The Belle and Elberta used in 19 19 were from Rockville, Md., 

 and the experiment was started the day after they w^ere picked. The 

 Carman and Belle peaches used in 1920 were from Vienna, Va., and were 

 inoculated the day after they were picked. These peaches were slightly 

 greener than those of the other experiments. 



The curves of the various figures show very great uniformity. The 

 Rhizopus cultures from peaches gave results similar to the cultures from 

 cherries and strawberries, both in temperature response and in rapidity 

 of rotting. 



An interesting contrast is seen between the behavior of the fungi on 

 peaches and on dextrose potato agar. A comparison of figiu-es 3, 4, 5, 

 and 6 with figure 7 shows that Monilia has grown just as freely at the 

 higher temperatures and much earlier and more rapidly at the lower 

 temperatures when grown on peaches than when on agar. At 10° C. rots 

 usually became evident on the fruit within 3 days, while on the agar there 

 was practically no growth at the end of 7 days. At 5° the rots were well 

 started in 6 days, while the agar colony had scarcely made an equivalent 

 growth at the end of 14 days. At 2>^° the rots made a start in 8 to 12 

 days, but there was no evidence of growth on the agar at the end of 20 

 days. A comparison of figures 8, 10, 12, 14, 15, 16, and 17 with figures 9, 

 1 1 , and 1 3 show^s that the reverse condition holds with Rhizopus. This 

 fungus made a more rapid growth and developed at lower temperatures 

 on the culture media than it did on the fruit. On both food materials it 

 had its most rapid growth at 30°. With the culture media tlie growth at 

 20° and 25° was but little slower than at 30°, but on the peaches the 

 growth at 20° fell far behind that at 30°. At 15° and also at 10° the 



1 Temperature equivalents: 



°C. °F. 'C. "F. 



20 68 5 41 



IS 59 o 33 



10 50 



