Distribution of the Infection Time of Ascospores of Venturia inaequalis .

Autor: Philion V; Institut de Recherche et de Développement en Agroenvironnement, IRDA, 335 rang des Vingt-Cinq Est, Saint-Bruno-de-Montarville, Quebec, Canada J3V 0G7., Joubert V; Institut de Recherche et de Développement en Agroenvironnement, IRDA, 335 rang des Vingt-Cinq Est, Saint-Bruno-de-Montarville, Quebec, Canada J3V 0G7., Trapman M; Bio Fruit Advies, Dorpsstrat 32a, 4111 KT Zoelmond, The Netherlands., Hjelkrem AR; Division of Food Production and Society, Norwegian Institute of Bioeconomy Research, 1431 Ås, Norway., Stensvand A; Division of Biotechnology and Plant Health, Norwegian Institute of Bioeconomy Research, 1431 Ås, Norway.; Department of Plant Science, Norwegian University of Life Sciences, 1433 Ås, Norway.
Jazyk: angličtina
Zdroj: Plant disease [Plant Dis] 2020 Feb; Vol. 104 (2), pp. 465-473. Date of Electronic Publication: 2019 Dec 10.
DOI: 10.1094/PDIS-11-18-2046-RE
Abstrakt: In many areas where spring is wet, fungicides are applied in relation to rain events that trigger ejection of ascospores of Venturia inaequalis , which cause primary infections of apple scab. Past studies established the rate of ejection during rain in relation to light and temperature, and determined the wetting time required for infection. Simulation software uses this information to calculate risk and help time sprays accordingly. However, the distribution of the infection time required by a population of spores landed on leaves was never studied, and assumptions were used. To estimate this, we inoculated ascospores of V. inaequalis on potted trees at different temperatures for specific wetting times. Lesions were enumerated after incubation. Lesions increased with wetness time and leveled off once the slowest spores infected the host, closely matching the monomolecular model. Wetness hours were best adjusted for temperature using the Yin equation. The minimum infection time on the youngest leaves was about 5 h, matching results from previous studies, whereas half the lesions appeared after 7 h of infection. Infection times for leaves with ontogenic resistance were longer. Our results improve current software estimates and may improve spraying decisions.
Databáze: MEDLINE