Effects of Temperature, Free Moisture, and Relative Humidity on the Occurrence of Walnut Anthracnose

Publisher Website
Google Scholar
Abstract
Black walnut [Juglans nigra] seedlings grown in a greenhouse were artifically inoculated by brushing an aqueous suspension of Marssonina juglandis conidia (perfect stage: Gnomonia leptostyla) onto the foliage. Little infection occurred at 27.degree. C, none at 32.degree. C, and symptom appearance was delayed at 15 and 10.degree. C. At the optimum temperature (approximately 21.degree. C) more than 6 h with free moisture on the leaflets were required for the development of significant amounts of infection. Longer wetting periods were required at lower temperatures. No infection occurred at relative humidity levels below 98% (.+-. 2%). Conidia survived for 2 wk on the leaflet surface, infecting the seedlings when moisture became available.

This publication has 0 references indexed in Scilit: