# Pests and diseases

By [kryst168](https://paragraph.com/@kryst168) · 2021-10-29

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Apple trees are susceptible to a number of [fungal](https://en.wikipedia.org/wiki/Fungus) and [bacterial](https://en.wikipedia.org/wiki/Bacterium) diseases and insect pests. Many commercial orchards pursue a program of chemical sprays to maintain high fruit quality, tree health, and high yields. These prohibit the use of synthetic pesticides, though some older pesticides are allowed. [Organic](https://en.wikipedia.org/wiki/Organic_farming) methods include, for instance, introducing its natural predator to reduce the population of a particular pest.

A wide range of pests and diseases can affect the plant. Three of the more common diseases or pests are mildew, aphids, and apple scab.

*   [Mildew](https://en.wikipedia.org/wiki/Mildew) is characterized by light grey powdery patches appearing on the leaves, shoots and flowers, normally in spring. The flowers turn a creamy yellow color and do not develop correctly. This can be treated similarly to [Botrytis](https://en.wikipedia.org/wiki/Botryotinia)—eliminating the conditions that caused the disease and burning the infected plants are among recommended actions.[\[65\]](https://en.wikipedia.org/wiki/Apple#cite_note-pest4-65)
    
*   [Aphids](https://en.wikipedia.org/wiki/Aphids) are a small insect. Five species of aphids commonly attack apples: apple grain aphid, rosy apple aphid, apple aphid, spirea aphid, and the woolly apple aphid. The aphid species can be identified by color, time of year, and by differences in the cornicles (small paired projections from their rear).[\[65\]](https://en.wikipedia.org/wiki/Apple#cite_note-pest4-65) Aphids feed on foliage using needle-like mouth parts to suck out plant juices. When present in high numbers, certain species reduce tree growth and vigor.[\[66\]](https://en.wikipedia.org/wiki/Apple#cite_note-pest5-66)
    
*   [Apple scab](https://en.wikipedia.org/wiki/Apple_scab): Apple scab causes leaves to develop olive-brown spots with a velvety texture that later turn brown and become cork-like in texture. The disease also affects the fruit, which also develops similar brown spots with velvety or cork-like textures. Apple scab is spread through fungus growing in old apple leaves on the ground and spreads during warm spring weather to infect the new year's growth.[\[67\]](https://en.wikipedia.org/wiki/Apple#cite_note-Bradley-67)
    

Among the most serious disease problems are a bacterial disease called [fireblight](https://en.wikipedia.org/wiki/Fireblight), and two fungal diseases: [_Gymnosporangium_](https://en.wikipedia.org/wiki/Gymnosporangium) rust and [black spot](https://en.wikipedia.org/wiki/Black_Spot_\(disease\)).[\[66\]](https://en.wikipedia.org/wiki/Apple#cite_note-pest5-66) Other pests that affect apple trees include [Codling moths](https://en.wikipedia.org/wiki/Codling_moth) and [apple maggots](https://en.wikipedia.org/wiki/Apple_maggot). Young apple trees are also prone to mammal pests like mice and deer, which feed on the soft bark of the trees, especially in winter.[\[67\]](https://en.wikipedia.org/wiki/Apple#cite_note-Bradley-67) The larvae of the [apple clearwing moth (red-belted clearwing)](https://en.wikipedia.org/wiki/Synanthedon_myopaeformis) burrow through the bark and into the phloem of apple trees, potentially causing significant damage.

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*Originally published on [kryst168](https://paragraph.com/@kryst168/pests-and-diseases)*