Ascospore discharge in Drepanopeziza punctiformis in relation to infection of some poplar clones

Abstract

Ten years study of the discharge of ascospores is described. As the discharge started each year before the first flushing leaves reached the susceptible stage, growers can determine the best date of the first spraying simply from the flushing stage of the host. Radio warnings based on the first date of ascospore discharge are superfluous. AbstractLiterature on pathogens observed on lodgepole pine {Pinus contorta var. latijolia S. Wats.) grown in Einland is briefly reviewed. Heterobasidion annosum (Er.) Bref and Scleroderris lagerbergii Gremmen appear to cause the most serious damage. Lachnellula subtilissima (Cke.) Dennis Crumenulopsis sororia (Karst.) Groves and Sclerophoma pityophila (Gorda) v. Hohn. cause damage less frequently. The majority of over 300 stands have reached an age of 40-60 years and their health is described as satisfactory to good.

Biology of Septoria musiva and Marssonina brunnea in hybrid Populus plantations and control of Septoria canker in nurseries

“…Ascospores from perithecia of Mycosphaerella and apothecia of Drepanopeziza were released from leaf debris beginning in April with numbers peaking usually at the end of May. Drepanopeziza ascospores often were discharged just before, or at leaf flush, as has been reported (DE KAM 1975).…”

Studies of microconidia of Marssonina brunnea and apothecia of Drepanopeziza tremulae

“…Their dissemmation would occur by water-splash and wind-blown rain. By contrast, in view of their windborne dissemination, ascospores should be more effective at establishing new infection foci at a distance (DE KAM 1975).…”

“…In Southern Italy, the winters are milder and ascospore discharge coincides with flushing (CASTELLANI and FRECCERO 1968). In Holland (DE KAM 1975) and France (PINON and POISSONNIER 1975) the liberation of ascospores usually coincides with the flushing of poplars so that ascospores can initiate primary infection foci. Laborator)ŝ tudies confirm the influence of temperature on apothecial development and indicate that optimum development occurs at basal temperatures between 5 and 8°C.…”