Identification of Phytophthora Species : by L.H. Leonian.

Effects of temperature onPhytophthora porri in vitro, in planta, and in soil

“…Leonian (1934), using Foister's isolate, published a more precise maximum of 27 o, which was confirmed by several authors (Table 1) and in the present work, but not by Waterhouse (1963) and Waterhouse et al (1983) after examining 'authentic material', and Ribeiro (1978), relying on Waterhouse's data. Kouyeas (1977) and Ho (1983) pointed out that Waterhouse's isolate is an extreme variant.…”

Lack of specificity in accumulation of sterols byPhytophthora cactorum

“…The Pythiaceous fungi, which include Phytophthora cactorum, lack sterol synthetic capability (1)(2)(3)(4). Nevertheless, they exhibit vegetative growth in the total absence of sterol (5,6), a phenomenon that is unique among eucaryotes. When supplied in the growth medium, however, sterols are readily accumulated by these fungi (5).…”

Characteristics of Two Phytophthora Species

“…Such strains indicate that there is no distinct separation between P. cryptogea and P. drechsleri. Leonian (1934) observed that his isolate of P. cryptogea did not grow in the presence of malachite green when the dye was added to nutrient solution prior to autoclaving at a concentration of about 0.083 ppm. In these tests all isolates grew in the presence of the dye at a concentration of 0 .…”

“…When tested at 37.5" neither ecotype grew, although Tucker (1931) stated that growth of this fungus occurs between 10 and 37.5". Leonian (1934) observed that P. cryptogea did not grow in the presence of malachite green at a concentration as low as about 0.083 ppm while P. drechsleri grew slightly in a nutrient solution containing this dye at a concentration of 0.125 ppm; but he also had only one isolate of each species at his disposal. Waterhouse (1963) described an authentic culture of P. drechsleri (but not the type culture) and stated that it did not form oogonia in dual cultures with P. cinnamomi Rands.…”