Fly Pollution Sickness

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Fly pollution disease on the peel of an apple

The Fliegenschmutz- or sooty blotch is a plant disease of apples . It is caused by the fungus Schizothyrium pomi and possibly other related fungus species and occurs worldwide in all regions with a humid climate during the growing season . It is one of the most common fungal diseases in temperate and humid regions. It develops its harmful effect by lowering the marketing value of the fruit.

description

Follow-up of the shell changes

The name of the disease is based on the appearance of the infected fruits: At an early stage, which in Central Europe usually becomes visible from the end of May, gray coatings and large-scale spots appear on the skin. Black spots around 0.3 millimeters in size later form in these areas, which resemble the excrement of the house fly . The extent of the fungal attack and the darkness of its color increase as a result.

The damage pattern is similar to soot stain disease , but it is caused by a different group of fungi. In addition, both diseases often occur together on the same fruit. In English-speaking countries, they are usually addressed and treated together as sooty blotch and flyspeck (SBFS) or apple summer desease. Even in the German-language research literature, the name "Regenfleckenlkrankheit" is used both as a middle name for both clinical pictures and as a self-term for their combined occurrence. Also feeding openings of aphids that of Rußtaupilzen be populated, have a similar visual appearance.

It is unclear whether similar diseases in pears, bananas , papaya , persimmons and various other types of fruit are also caused by Schizothyrium pomi.

Pathogen

The fungus Schizothyrium pomi from the order of the soot-dew-like (taxonomically not classified) is considered to be the cause . However, there are research results that point to a larger number of possible causers from the class Dothideomycetes within the hose fungi .

Course of infection

Fly pollution, like many other fungal diseases, is favored by a damp spring. A number of other plants are believed to be vectors. Both the primary infection and the secondary infection between the fruits of an already infected plant occur via conidia and parts of the mycelium that are spread by wind and rain. Older apple trees and varieties with only slightly colored skin (such as Golden Delicious ) appear to be particularly susceptible.

The disease only affects the wax layer on the apple peel. There the fungus lives saprovor , i.e. exclusively on dead organic material, possibly on small amounts of fruit juice that escape through the skin. The gray spots appear around 20 to 25 days after infection, under weather conditions that are particularly favorable for the fungus with persistently high humidity and temperatures of around 20 degrees Celsius after around ten days.

Economical meaning

The fly pollution disease has no impact on the health of the plant, nor on the development and food quality of the fruit. However, the topping, which can only be partially removed mechanically, and an increased tendency for the fruit to shrink during storage, mean that they are no longer for sale in retail outlets.

However, the evaluation of a series of tests by the Competence Center Fruit Growing - Lake Constance in 2010 comes to the conclusion that the economic damage caused by fly pollution in Central Europe is negligible compared to soot stain.

Combat

As a preventive measure, choosing a sunny location away from typical foggy locations and an airy cut of the tree can reduce the moisture inside the tree canopy. A sufficiently large distance between the fruit trees and other trees and keeping the undergrowth short make primary infection more difficult. Infested apples should be quickly removed from the crop by removing windfalls and fruit mummies and quickly transporting the harvest away.

Fungicides that work against apple scab also fight fly pollution disease. The marketability can be improved by brushing and washing fruits with visually less infestation. In countries where this is permitted, agents containing chlorine are added to the washing water.

Web links

Commons : Fly Pollution Sickness  - Collection of Images, Videos and Audio Files

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