Differential isolation of Pythium species from soil by means of selective media, temperature, and pH

Abstract

Pythium aphanidermatum, with an optimum temperature for growth at 35C, grew welland was readily isolated from soil on pimaricin-vancomycin medium (MPVM) when incubated for 24h at 38-40C. The pH of the medium affected recovery; maximum numbers developed above pH 6.0. Other Pythium spp. were recovered on MPVM at 20-25C, but were excluded by incubation at 38-40C. These Pythium spp. included P. ultimun, P. paroecandrum, P. irregular, P. mamillatum, and an unidentified Pythium sp. These species grew well and were readily siolated from soil on gallic acid medium (GAM) when incubated for 24-8h at 20 C.P. aphanidermatum and P. myriotylum grew from mycelium on GAM, but their oospores did not germinate nor could they be isolated from soilon this medium. P. myriotylum grew well on MPVM, but was only rarely isolated, evenfrom soils with known high potential for disease caused by P. myriotylum. Propagules of Pythium were enumerated by a plate-dilution frequency method or by a smearplateethod is valuable for studies on the ecology, survival, and inoculum potential in soils with mixed populations of P. aphanidermatum and other Pythium spp.

Detection and Quantification of Pythium tracheiphilum in Soil by Multiplex Real-Time qPCR

“…The identification of Pythium from soil samples traditionally requires the use of dilution plating on selective media combined with morphological observations of isolated structures (Conway 1985;Jeffers and Martin 1986;Lumsden et al 1975). However, there are significant similarities between morphological traits of the asexual structure of some Pythium spp.…”

Effects of temperature and pH on growth and oospore production of three water‐borne Pythium

“…The fungi as a large group of these organisms play an important role in the formation and destruction of numerous natural products in soil and water. Meagre information is available regarding theeffect of certain environmental factors such as temperature, pH, oxygen, moisture, and carbon source on the growth and reproduction of soil-borne Pythium (COCHRANE 1958, DEVERALL 1965, HASKINS 1965, CANT 1971, ADAMS 1971, PLOWERS and LITTRELL 1972, LUMSDEN et al 1975, HANCOCK 1977, and EL-SHAROUNY 1980, and by many others).However, little information is available concerning the effect of environments on growth and reproduction of water-borne Pythium. Because of this fact, this investigation was undertaken to determine the influence of temperature and pH on growth and oospore formation of three water-borne Pythium, namely Pythium torulosum COKER and PATTERSON, P. catenulatum MATHEWS, and P. butleri SUBRAMANIAN.…”

“…The fungi as a large group of these organisms play an important role in the formation and destruction of numerous natural products in soil and water. Meagre information is available regarding theeffect of certain environmental factors such as temperature, pH, oxygen, moisture, and carbon source on the growth and reproduction of soil-borne Pythium (COCHRANE 1958, DEVERALL 1965, HASKINS 1965, CANT 1971, ADAMS 1971, PLOWERS and LITTRELL 1972, LUMSDEN et al 1975, HANCOCK 1977, and EL-SHAROUNY 1980, and by many others).…”

Characterization of species associated with Pythium soft rot of ginger and evaluation of Pythium Oligandrum as a biocontrol

“…from soil has been shown in the literature to be dependent on the target species and for P. myriotylum in particular, others have also reported difficulty (Lumsden et al 1975;Wang and Chang 2003).…”

“…However, for other species such as P. myriotylum, a dilution plating method was more difficult, so that estimation of the population of P. myriotylum using this method before the growing season was not possible (Lumsden et al, 1975;Wang and Chang, 2003).…”