The fungus phytophthora will cause the common root rot disease in fruit trees. This infection can become a dangerous ailment to some trees, while posing no negative consequences for others. Preventing root rot before infection is the main way of protecting trees.
Phytophthora fungus is a common fungus that attacks and potentially kills plants in all their stages by spreading the root rot contagion. The name is derived from Greek to mean "plant destroyer". The fungi spores are spread through rain and water and are favorable in soil that has been moistened for over 12 days due to excessive rainfall or improper irrigation.
Root rot will effect a tree's root system, inhibiting the absorption of necessary water and nutrients needed for proper growth. Root rot can be diagnosed by checking the inner bark of the tree. A dark reddish-brown color is the main indication of root rot. As the disease spreads and begins to damage the roots, the tree will experience other symptoms. The tree's growth will become greatly inhibited, fruit production will be unable to continue and the leaves will yellow. When left untreated, death is the common outcome for many trees.
The soil-borne fungi will cause root rot in a wet soil that favors infection. During the spring and autumn, while the fungi begin to spore, fruit trees are the most susceptible to infection.
The most common form of prevention for fruit trees is to plant tree varieties that are less susceptible to root rot. Some trees are bred as hybrids to offer such protection to cultivars. Plum and pear trees are the least susceptible to root rot, along with Ottowa-3 apple trees and Morello cherry trees. Another form of prevention is to ensure that trees have proper drainage within their soils to prevent the growth of fungi.
Root rot is susceptible to fungicides. It will kill the fungi within the soil before it has a chance to infect the tree. Once a tree is infected, fungicides become ineffective. Growers should consult a tree specialist for possible alternatives.