''Neonectria ditissima'' (syn. ''Neonectria galligena'') is a fungal

plant pathogen Plant diseases are diseases in plants caused by pathogens (infectious organisms) and environmental conditions (physiological factors). Organisms that cause infectious disease include fungi, oomycetes, bacteria, viruses, viroids, virus-like orga ...

. It causes

canker A plant canker is a small area of dead tissue, which grows slowly, often over years. Some cankers are of only minor consequence, but others are ultimately lethal and therefore can have major economic implications for agriculture and horticultur ...

s that can kill branches of trees by choking them off.

Apple An apple is a round, edible fruit produced by an apple tree (''Malus'' spp.). Fruit trees of the orchard or domestic apple (''Malus domestica''), the most widely grown in the genus, are agriculture, cultivated worldwide. The tree originated ...

and

beech Beech (genus ''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to subtropical (accessory forest element) and temperate (as dominant element of Mesophyte, mesophytic forests) Eurasia and North America. There are 14 accepted ...

trees are two susceptible species.

Host range

''Neonectria ditissima'' host range encompass a variety of hardwood tree species such as, ''Fagus'', ''Populus'', ''Salix'', ''Betula'' and ''Acer'' species. These tree species population are present in both America and Europe. Phylogenetic studies have revealed genetic divergence among both populations, at specific loci (ß-tubulin, RPB2). However, due to high levels of within-population diversity of the American populations, it has been hypothesized that America is ''N. ditissima'' place of origin.

Disease management

''Neonectria ditissima'' is a difficult pathogen to eradicate—but there are many ways to limit its spread and infection rate. Effective control requires a combination of cultural and chemical treatments.

Cultural control

Multiple cultural techniques can manage the spread of ''N. ditissima''. To minimize the number of wounds the pathogen can enter through, select trees that are well adapted to the local climate. In certain areas, trees must be able to resist damage due to environmental stresses such as cold temperatures. If cankers are present, it is important to prune out the damaged tissue in dry conditions. Dry conditions are unfavorable to the pathogen because it prohibits the development of fruiting structures and spore dispersal. It is essential to disinfect the equipment before and after

pruning Pruning is the selective removal of certain parts of a plant, such as branches, buds, or roots. It is practiced in horticulture (especially fruit tree pruning), arboriculture, and silviculture. The practice entails the targeted removal of di ...

to prevent the spread of the pathogen to uninfected trees. Cankered prunings must be removed from the area and burned to eliminate the risk of continuing spore production. It is crucial to limit the use of high nitrogen, especially in manure, because it encourages and facilitates ''N. ditissima''.

Chemical control

Fungicides that control ''N. ditissima'' are limited. Infection by ''N. ditissima'' often occurs through wounds in the autumn and spring-summer period, therefore, it's best to apply fungicides at those times. Fungicides prevent or decrease sporulation of existing cankers, which in turn decreases inoculum available to spread the pathogen. Fungicides may also protect trees from ''N. ditissima'' through a fungitoxic deposit over favorable infection sites. A mixture of

carbendazim Carbendazim is a fungicide, a member benzimidazole fungicides. It is a metabolite of benomyl. The fungicide is used to control plant diseases in cereals and fruits, including citrus, bananas, strawberries, macadamia nuts, pineapples, and pomes. ...

and a scab fungicide, such as dithianon, is the suggested treatment in areas with a severe canker problem. In areas with a reduced risk of canker, it is recommended that a scab fungicide be applied in the spring-summer and copper oxychloride applied at leaf-fall to avoid infection. Although scab fungicides are commonly used for managing

apple scab Apple scab is a common disease of plants in the rose family (Rosaceae) that is caused by the ascomycete fungus ''Venturia inaequalis''. While this disease affects several plant genera, including '' Sorbus, Cotoneaster,'' and '' Pyrus'', it is ...

, cankers are also controlled when applied at the correct time. Thiophanate-methyl is another fungicide that is highly effective because it protects trees against the pathogen and suppresses sporulation of already infected plants. However, the application of thiophanate-methyl is limited due to its harm on organisms such as mites.

References

{{Taxonbar, from=Q10597558 Fungal tree pathogens and diseases Apple tree diseases Nectriaceae Fungi described in 1865 Taxa named by Edmond Tulasne Fungus species