Mar. 3s. 191S Dissemination of Chestnut-Blight Fungus 



505 



In the night of September 18 a rain of 0.6S inch was recorded, the 

 time of cessation being the next morning before 3. 45. Fog again pre- 

 vailed all day September 19 and a noticeable spray fell until 5.38 a. m. 

 and began again after 2.41 p. m. Ascospore-trap tests (Tables XII and 

 XVII) showed that in 10 out of the 17 traps examined there was spore 

 expulsion after 7.35 a. m. Of the eight plates exposed prior to this 

 time but two yielded colonies of this Endothia. The first three plates 

 were exposed in an open field at considerable distances from the trees 

 (fig. 2, stations 41, 42, and 43) in the same direction toward which the 

 wind was blowing, but no spores of E. parasitica were caught. These 

 negative results may be accounted for by the action of the falling mist. 

 Later in the day four exposures at various inter\'als yielded one colony 

 each of the chestnut-blight fungus. 



Table V. —Record of exposure plates made on September 20, igi3, at West Chester, Pafl 



Plate 



No. 



Time. 



5041 

 5042 



5043 

 5044 

 SO45 

 5046 



SO47 

 5048 



SO49 

 5050 

 S051 

 5052 



5°53 

 5054 

 5°5S 

 5056 

 5057 

 5058 

 S°59 

 5060 

 5061 

 5062 



S063 

 5064 



5065 

 5066 

 5067 

 5068 



Length of 

 exposure. 



5.503. m.... 



5.55 a. m.... 



5.56 a. m 



6.03 a. m. . . . 

 6.14 a. m. . . . 

 5.18 a. m. . . . 

 6.20 a. m. . . . 

 6.40 a. m. . . . 



7.07 a. tn. . . . 

 7.32 a. ra.... 



7.40 a. m. . . . 



8.24 a. m. . . . 

 g.09 a. m. . . . 



9.37 a. m 



10.01 a. m. . . 

 10.32 a. m. . . 

 II. og a. m. . . 

 11.44 a. m. . . 

 12.08 p. m. .. 



1.05 p. m. . . . 



1.35 p. m.... 



2.08 p. m. . . . 



2.36 p. m. . . . 



3.09 p. m. . . . 

 3.42 p. m.... 



4.06 p. m. . . . 



4.41 p. m. . . , 



5.25 p. m.... 



Minutes. 

 16 



13 

 14 

 I2j< 



I2X 



% 

 II>^ 



^3 , 



16K 



10 



I3K 



I4K 



I4K 



10 



II>< 



10 



WA 



13K 



14K 



15K 



^5% 



14 



18 



12X 



12 



Station 

 No. 



44 

 43 

 46 



SI 

 47 

 48 



49 



II 



I 



9 



5° 



6 



8 



27 



6 



10 



29 



26 



10 



30 



II 



10 



8 



9 

 29 



23 

 12 



12 



Wind. 



Direction. 



Miles per 

 hour. 



" Rainfall, night previous. 0.09 inch. Time of cessation, 3.25 to 3-55 a- ni. 



While there was but 0.09 inch of rain in the night of September 19, 

 very important results were obtained on September 20. Tables II and 

 V give the results secured. Fog prevailed during the entire day, and the 

 bark on the trees dried very slowly. Examination of the ascospore traps 

 to determine the duration of spore expulsion (Tables XIII and X\'II) 

 showed that in 8 out of 19 the perithecia were active after 9.18 a. m. 



