i8o 
Journal of Agricultural Research 
Vol. XXI, No. 3 
culture of Macrosporium solani was obtained from L. O. Kunkel and that 
of Rhizoctonia solani from M. Shapovalov. Three strains of R. solani 
were used in the inoculation of 400 plants, but as all three showed about 
the same degree of infectiousness only one was used in later experiments. 
Most of the tomato plants used were 2 to 3 inches high, but some were 
5 to 6 inches, and a few 10 to 12 inches in height. All were in good 
growing condition. 
The inoculations were made by placing mycelium from a fresh culture 
against the stem, at or slightly below the surface of the soil. From cul¬ 
tures of Verticillium both mycelium and spores were used. Usually 
the epidermis was not injured before applying the inoculum, but in a few 
experiments it was lightly scratched. To keep the fungus moist until it 
had time to infect the stems, the soil was thoroughly watered before the 
plants were inoculated. By placing the fungus between the stem and 
this moist soil it was kept wet. Usually the plants were left standing in 
the greenhouse after inoculation, but in a few experiments they were 
kept in a moist chamber 48 hours. 
Repeated inoculation experiments were made with Verticillium, sev¬ 
eral hundred plants being inoculated and as many more used as controls. 
RESULTS OR INOCULATION WITH VERTICILLIUM 
Young tender seedlings, such as grow in a seed bed, were very easily 
infected by this fungus (PI. 42, A). Plants that had grown slowly and 
were somewhat woody were less susceptible and not infrequently re¬ 
covered from the disease. Larger plants 10 to 12 inches high were 
scarcely susceptible. Infection was obtained on more than 80 per cent 
of the inoculated plants 1 to 6 inches high, while only an occasional 
infection; 1 or 2 per cent, occurred on the control plants. The latter 
was due to the presence of a small amount of the fungus in the green¬ 
house soil. 
Nearly all these infections were obtained without previously injuring 
the epidermis. In fact, puncturing the epidermis seemed to make little 
difference, as the fungus was able to penetrate the tissues very easily 
in either case. 
DESCRIPTION OR RUNGUS 
Verticillium lycopersici, n. sp. 
Dense colonies (PI. 41, B), at first white and later bluish green, are formed by this 
fungus on most culture media. The conidiophores are distinctly septate at the base 
(PI. 43, D), 70 to 350 fx (occasionally 700 n or more) in length, verticillately branched. 
The primary whorls average 5 to 7 in number; the secondary whorls of each branch 
average 1 to 3. The sterigmata are hyaline, somewhat bottle-shaped (PI. 43, B, C), 
and 7.5 to 11.5 fi by 3.5 to 4 /x in size. The conidia (Pi. 43, C, E, F), are globoid to 
ellipsoid, the globoid being 3.8 to 4.7 /x in diameter, the ellipsoid 3.8 to 4.7 n by 4 to 5.8 
M in transverse and longitudinal dimensions. They are bluish green on most culture 
media but yellowish on potato agar. From tips of the sterigmata they are cut off 
singly but frequently adhere in heads of the so-called Acrostalagmus type. 
