Agriculture Reference
In-Depth Information
Test your soil before planting to determine if nematodes that serve as
virus vectors are present. Control aphid, leafhopper, and mite infestations.
Root Diseases
Root diseases can be serious in orchards and, once established, are virtually
impossible to remove. Conventional fruit growers have several fungicides
available that suppress root rots, but none eradicate the pathogens. The soil-
borne pathogens can survive for many years in the soil, either in resting
stages in the soil or on the roots of alternate host plants. The keys to avoid-
ing them are to carefully select the site, prepare and maintain it well (ensur-
ing good water drainage), and use healthy planting stock.
Phytophthora
A serious disease, Phytophthora attacks the roots and collars of many tree
fruit crops. Several closely related water molds (
Phytophthora
species) can
cause root rots in fruit trees. Infections can take place on fine feeder roots or
through wounds on larger roots.
Symptoms.
Infected roots die, and the pathogen moves upward in the tree to
the collar where the trunk meets the root system. Most trees show gradual
or rapid decline, with scorching and possibly wilting leaves, and thinning fo-
liage on the upper branches.
Prevention.
One of the most important factors in preventing Phytophthora
root rot is well-drained soil. The pathogens require free water to move in and
are seldom a problem in orchards grown on sandy or otherwise well-drained
soil. Try to correct drainage problems before planting.
Start with healthy nursery stock from a reputable nursery. Avoid excess-
ive irrigation. Do not mulch naturally cool, wet soils. Keep your soil well-
drained and biologically diverse.
