754 EXPERIMENT STATION RECOBD. 



In the study of the germination of the spores of tlie fungus it was found that 

 tlie coiiidiospores germinate much slower than the ascospores. This is believed 

 to explain the fact that a smaller percentage of successful infections is secured 

 in artificial inoculations with conidiospores than with ascospores. 



In connection with the work of the inspection of chestnut tree nursery stock, 

 investigations were carried on to determine the possibility of carrying the chest- 

 nut bark disease by other nursery stock and the value of fumigation for prevent- 

 ing the spread of the disease. It was found that the usual fumigation of the 

 nursery stock subject to this disease had no effect whatever upon the spores of 

 the blight fungus. 



In accounts of the field investigations in pathology, attention is called to the 

 nonparasitic form of the fungus known as the Connellsville form (E. S. R., 28, 

 p. 551). A brief account is given of studies on the dissemination of the fungus, 

 and it is stated that ascospores of the perithecial stage of the fungus are more 

 easily and rapidly dispersed than was previously believed. Agar plates placed 

 upon the ground at a distance of 50 ft. from moistened pustules caught spores 

 from them. It seems probable that spores would also be caught in wounds on 

 trees, and this has proved to be the case in a number of instances where arti- 

 ficial wounds were made. Notes are given regarding the growth of the fungus 

 during the winter, but while growth continued into October there was no in- 

 crease observed in the cankers during November or December. Inoculations 

 made during October, November, and December also showed no signs of infection. 



A series of experiments to determine the longevity of spores was undertaken, 

 in which the ascospores were found to retain their vitality for as much as 34 

 weeks. Couidia in the laboratory kept their vitality for 28 weeks, and the limit 

 of vitality of none of these spores had been reached at the time the report was 

 written. 



Beport of the physiologist, Caroline Rumbold (Rpt. Penn. Chestnut Tree 

 Blight Com., 1912, July-Dec, pp. 4^-47, pis. 8). — The work of the physiologist 

 in connection with the control of chestnut bark disease has been to ascertain 

 whether the growth of the chestnut blight fungus can be checked by the intro- 

 duction of chemicals into growing chestnut trees, to determine whether the 

 fungus can be killed by such processes, and whether the tree can be rendered 

 immune to disease. 



Various alkaline compounds were tested, of which lithium carbonate was the 

 most toxic when applied to the spores. When injected into the trees none of 

 the substances seemed to have any effect in retarding the disease, and many of 

 them were destructive to the vitality of the tree. 



The author in conclusion states that no general method for either killing or 

 checking the growth of the chestnut blight fungus has been found. A successful 

 method for injecting fluids into the trees has been devised, which, with modifi- 

 cations, can be used for injecting gases also. The present indications are that 

 the heavy metals will not be of value in tree medication. 



Preliminary note on birds as carriers of chestnut blig'ht fungus, F. D. 

 Heald and R. A. Studh alter (Science, n. ser., 38 (1913), No. 973, pp. 278- 

 280). — This is an account of investigations conducted in cooperation with the 

 Pennsylvania Tree Blight Commission. 



It is stated that " during the past spring the writers have devoted considerable 

 time to the testing of birds as carriers of the blight fungus. , , . 



" To summarize, our results show that the spores of the blight fungus carried 

 by birds are pycnospores and not ascospores and that the maximum numbers 

 are being carried during the few days following rain periods. We are also led 

 to the conclusion that the pycnospores carried are brushed off from either the 

 normal or diseased bark or both in the movements of the birds over these sur- 



