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Gymnosporangium is a genus of heteroecious plant-pathogenic fungi which alternately infect members of the family Cupressaceae, primarily species in the genus Juniperus (), and members of the family Rosaceae in the subfamily Amygdaloideae (apples, pears, quinces, shadbush, hawthorns, rowans and their relatives).
These applications are to protect the apples from spores being released from the cedar host in mid-spring. If cedar apple rust disease is diagnosed on apple fruits and leaves it is far too late to spray. Although curative fungicides also exist for cedar apple rust, they must still be applied before trees begin to develop symptoms. [13]
Rust fungi can produce up to five spore types from corresponding fruiting body types during their life cycle, depending on the species. Roman numerals have traditionally been used to refer to these morphological types. 0-Pycniospores from Pycnidia. These serve mainly as haploid gametes in heterothallic rusts. I-Aeciospores from Aecia.
Leaf spots can vary in size, shape, and color depending on the age and type of the cause or pathogen. Plants, shrubs and trees are weakened by the spots on the leaves as they reduce available foliar space for photosynthesis. Other forms of leaf spot diseases include leaf rust, downy mildew and blights. [4]
Gymnosporangium sabinae is a species of rust fungus in the subdivision Pucciniomycotina. Known as pear rust , European pear rust , or pear trellis rust , it is a heteroecious plant pathogen with Juniperus sabina (savin juniper) as the main primary ( telial ) host and Pyrus communis (common pear) as the main secondary ( aecial ) host.
Many rust fungi induce gall formation, including western gall rust, which infects a variety of pine trees and cedar-apple rust. Galls are often seen in Millettia pinnata leaves and fruits. Leaf galls appear like tiny clubs; however, flower galls are globose. Exobasidium often induces spectacular galls on its hosts.
Gambeya africana is a medium-sized species of tree in the family Sapotaceae. Along with the closely related species Gambeya albida , it is sometimes known as African star apple . [ 3 ] Both species have similar leaf indumentum and are widespread in the Lower and Upper Guinea forest mosaic.
Phyllocoptes malinus, also known as the apple leaf mite, is a species of mite belonging to the genus Phyllocoptes. It causes a gall, which is a swelling on the external tissues, on the leaves of apples (Malus species). The mite is found in Europe and was first described by the Austrian zoologist Alfred Nalepa in 1892.