656 STATE BOARD OF AGRICULTURE. 



Comparing the manifestatious of the disease on various speeimeus 

 from different localities, it was observed that the American specimens 

 agreed closely with the description by Briosi and Cavara. Hence, it 

 would seem that the fungus in this country answers to the description 

 Sept. lycopersici var. Eitropaea. 



However, observation of the fungus under a variety of conditions 

 shows that there is not enough significance in the minor variations in 

 size of spot, emphasized by Passerini to warrant the establishment of 

 the variety. 



As has been shown (p. 15), the size of the spot formed depends upon 

 the number of spores with which the leaf is inoculated as well as upon 

 which surface the leaf is inoculated. With a i)ure culture'', in experi- 

 ments determining the pathogenicity of the organism, a spot involving 

 the entire leaf was frequently found. Spores from the same pure cul- 

 ture produced typical round spots when the spore suspension was fur- 

 ther diluted. Spots arising from inoculation on the upper side of the 

 leaf are much smaller and darker than those spots produced by inocula- 

 tion on the under side of the leaf. In the field, the spots were very vari- 

 able in size, depending upon the weather conditions. In cooler weather 

 larger spots were produced than in hot weather. It was observed 

 that spots formed in the secondary infection were much larger than in 

 the primary infection. Spots with hypophyllous pycnidia were very 

 common, both epiphyllous and hypophyllous pycnidia being usually 

 found in the same spot. However, as a rule, the pycnidia are on the up- 

 per side of the leaf. Microscopical examination of large numbers of 

 prepared slides showed all graduations from lenticular to globose pyc- 

 nidia. 



These observations are merely mentioned at this point to indicate 

 that the activities of the fungus, affected by environmental conditions, 

 cause manifestations sufficiently varied so that peculiarities of the les- 

 ion, which may be only functions of the intensity of attack, can hardly 

 be sufficient basis for the formation of a new species or variety. Such 

 a segregation to be valid would need to be based on carefully controlled 

 conditions of the host and fungus. 



The Exsiccati specimens accompanying the description by Briosi and 

 Cavara were examined and could not be distinguished from specimens 

 from American localities. 



The only part of Spegazzini's description, then, which does not coin- 

 cide with the manifestations as observed in this country is that the pyc- 

 nidia are "most frequently" hypophyllous. Whether this is evidence 

 that a different species or variety exists here is a question which is yet 

 to be settled. " 



If there is sufficient evidence that the fungus in Argentina is distinct, 

 then it follows that we must necessarily have a name for the form found 

 here. 



The important point that must be noted is that regardless of nomen- 

 clature, the form in Europe seems identical morphologically with that 



»In this paper all the work was done witl\ the progeny of a single spore isolated as described 

 on page 12. 



"Material has been sent to Spegazzini for comparison with his type material, and with the 

 organism as now found in Argentina. 



