Effects of temperature on the latent period of the rose powdery mildew pathogen, Sphaerotheca pannosa

Abstract

The effects of temperature on the length of the latent period of rose powdery mildew, caused by Sphaerotheca pannosa var. rosae, were studied. At constant temperatures over the range of 10-28ЊC, the length of the latent period ranged from 4 to 10 days. The relationship between temperature and the rate of fungal development during the latent period (expressed as the reciprocal of the latent period) was described by a nonlinear (thermodynamic) model. The resulting curve was asymmetrically bell-shaped with an optimum temperature of about 22ЊC. The latent period was further subdivided into two periods: incubation period (from inoculation to visible colonies) and postincubation period (from visible colonies to the first sign of conidiophores). The relationship between temperature and the rate of fungal development during the incubation period (expressed as the reciprocal of the incubation period) was also well described by a thermodynamic model. In contrast, the relationship between temperature and the rate of fungal development during the postincubation period (expressed as the reciprocal of the postincubation period) was approximately linear. The latent period under fluctuating temperatures was predicted using a two-stage integration scheme at a step of 24 min by first integrating the incubation rate and then the postincubation rate. The predicted length of the latent period agreed well with the observed values.

Assessment of Partial Resistance to Powdery Mildew (Podosphaera pannosa) in a Tetraploid Rose Population Using a Spore-suspension Inoculation Method

“…This time point is preceded by a 5-6 day latent period, which is in line with 5 days for other genotypes at optimal conditions (Frinking and Verweij, 1989;Xu, 1999) and a 6 day period with mild symptom development. The symptoms increased dramatically after 11 dpi when a second infection cycle became evident.…”

Effect of Temperature on Growth and Sporulation of Botrytis fabae, and Resistance Reactions of Faba Bean against the Pathogen

“…In strawberry leaves inoculated with Colletotrichum acutatum conidia and incubated at different temperatures with continuous wetness, the number of germinated conidia tended to decrease with increasing temperature due to cell lysis [55]. Xu [46] also found that low rate of disease development in rose powdery mildew at supraoptimal temperatures is likely due to higher mortality of spores.…”

“…Disease severity in round-leaved mallow inoculated with Colletotrichum gloeosporioides [44] and in soybean infected with Colletotrichum truncatum [45] increased with increase in temperatures between 10 and 25°C and sharply decreased at 30°C. With regard to incubation period, Xu [46] and Xu and Robinson [47] noted that the median incubation period was longer at lower and higher temperatures than at intermediate temperature ranges in rose and hawthorn powdery mildew.…”

Labor-saving Preservation of Powdery Mildew of Strawberry by Sterilized Seedling Culture

“…This indicates that naturally intact leaves are insufficient for stock cultures of mildew because contamination with other mildew strains often occurs. For Rosaceae belonging to strawberry, the latent infection by Sphaerotheca pannosa 16 and Podosphaera clandestina 17 have been reported on rose and hawthorn, respectively. It is important to use seedlings from sterilized seeds as described in this paper to prevent contamination with other powdery mildew strains.…”