Pathogens responsible of brown rot Monilinia fructicola, Monilinia laxa, Monilinia fructigena and Monilinia polystroma detection test kit by using qPCR. Brown rot is one of the most destructive diseases of stone fruits, such as peach, nectarine, apricot, cherry, and plum. Monilia polystroma (formerly lumped into M. fructigena), cause brown rot on members of the Rosaceae. M. fructicola colonizes blossoms, twigs and fruit, primarily on Prunus spp., but also on pome fruit or other Rosaceae. M. laxa can colonize blossoms, twigs and fruit. M. fructigena is primarily a problem on the fruit of apple, pear, and other pome fruits.