From July on needles at first pale green, then yellowish and finally brown, remaining on the twigs for while; on the brown needles colourless fruiting structures (identification requires high quality stereo-microscopes)
Affected tree species
Similar to Mycosphaerella-needle cast of larch, Meria-needle cast is very common on larches of all ages in the Alps. Epidemics are favoured by high precipitation in spring. The disease can become a serious problem for young plants. Dying of older trees has not been observed so far. It is not yet known, if Meria-needle cast is able to stress trees to become susceptible to secondary agents.
Curative measures With old larches no control necessary; avoidance of afforestations on sites with high humidity; in seedling beds annual change of the tree species; curative application of fungicides (see Official Register of Plant Protection)
Meria-needle cast of larch: spore head on a wilting needle
Meria-needle cast of larch: spore head
Meria-needle cast of larch: spore bearing structure (transmission microscope)