13 



Fulton (11) reports that a detailed study of a spot infection 

 at Orbisonia, Pa., by Mr. R. C. Walton showed beetle larvae 

 in or near fully nine-tenths of the old lesions, and about two- 

 fifths of the youngest lesions. He concludes, therefore, that 

 the larvae usually follow rather than precede the infection. 

 Various other writers have noted this evident relation between 

 chestnut blight cankers and the holes and tunnels of wood 

 borers, and this is no doubt one of the reasons that insects have 

 been so frequently suggested as carriers of spores. Anderson 

 and Babcock (2) call attention to the fact that probably all of 

 the larvae living in chestnut trees emerge either as adults^ 

 leaving the pupal case behind them, or else go into the ground 

 to pupate immediately after emerging; in either case they 

 would have very little opportunity of carrying spores from 

 one tree to another. 



Ants have also frequently been found in old blight lesions 

 (11, 39), and have therefore been rather extensively accused of 

 spreading the blight spores and causing infections. Anderson 

 and Babcock (2) have carried out a number of experiments 

 with ants taken from blight cankers. In one of these the ants 

 were permitted to run over potato agar plates, but no colonies 

 of Endothia parasitica developed. The experiment was re- 

 peated by Mr. R. D. Spencer, under Mr. Anderson's supervision, 

 with the same negative results. We agree with Mr. Spencer (2) 

 that the method is very likely at fault, for the comparatively 

 slow-growing colonies of the blight fungus would soon be 

 crowded out and overrun by other more rapid-growing fungi 

 or bacteria. A more satisfactory method was employed in the 

 next experiment reported by Anderson and Babcock, in which 

 five vials of ants were placed into melted agar, which was just 

 warm enough so that is would not solidify. The tubes were 

 well shaken and the agar poured into Petri dishes. "Ants from 

 three of the vials proved to have spores on them. The spores 

 had been artificially placed on the ants in one of the vials, 

 however. The ants in the other two had been taken from the 

 bark of the diseased chestnut trees after a rain. This indicates 

 that the ants can carry the spores." It would be interesting 

 to know the actual number of spores carried in these instances. 



