Fruits Affected

Apple, Peach, Plum, Pear, Nectarine, Cherry, Apricot

Also See

Replant disease is a sickness caused by a complex of soil-born pathogens that consists of fungi, oomycetes or "water molds," and nematodes. This disease overlaps with phytophthora, as the phytophthora oomycetes are part of the complex of replant disease.

Symptoms

Sickly, stunted trees with shortened internodes; necrotic, discolored and stunted roots.

Organic Treatments

Replant disease can be avoided by alternating pome (apple or pear) and stone trees through the same site. But what if you only want apple trees? Understandable. In this case, you should choose rootstocks that are resistant to replant disease: any of the Geneva series with the exception of G.222. The highest tolerance is found in G.41. Additionally, choose well-drained sites whenever possible and add organic matter to your soil to maintain its health and minimize compaction. Finally, the spread of harmful nematodes is largely caused by root disturbance when removing old or dead trees. Cutting the tree to a stump and leaving roots undisturbed will significantly reduce replant disease risk.

Conventional Treatments

Same as organic treatments.

Disease Cycle

Replant disease is a sickness caused by a complex of soil-born pathogens that consists of fungi, oomycetes or "water molds," and nematodes. This disease overlaps with phytophthora, as the phytophthora oomycetes are part of the complex of replant disease. Replant disease, also known as sick soil syndrome, soil exhaustion, and replant disorder can affect the root systems of both pome fruits and stone fruits. While names like "soil exhaustion" suggest depletion, the cause of the problem is actually a witches brew of pathogens present in the soil. It is typically encountered when a site is replanted "like after like" (a pear or apple replacing a pear or apple, or any stone fruit replacing a stone fruit).

Symptoms will be visible shortly after a new tree is planted. A sickened tree will appear stunted, often with shortened internodes (the spaces between buds), and it may die within the first year. Trees that survive will remain stunted and suffer from low productivity. When dug up, afflicted trees show discolored, necrotic, or stunted roots.

For more information, see A Growers Guide to Organic Apples from the Cornell Cooperative Extension.