Table11.1 classifies peach and nectarine varieties
according to their relative susceptibility to infection.
Many of the newer varieties listed are the result of
evaluations performed in New Jersey orchards.
The amount of disease that occurs in any given
season is dependent on the weather, spray efficacy and
timing, inoculum availability, and varietal resistance. All
varieties have some susceptibility to the disease, but
those less susceptible will have lower levels of fruit
infection in years favorable for infection. Thus, the best
control measure is to plant only varieties with the least
amount of susceptibility.

Brown Rot. The plant-pathogenic fungus Monilinia
fructicola causes brown rot. Infection can occur at bloom
or during the preharvest period. Bloom infection results in
blossom blight a necrosis of flowers. Once a flower is
infected, the fungus can also proceed into the stem and
cause a canker. A spore produced on these flowers and
cankers then becomes the inoculum for subsequent
infection during the preharvest fruit rot phase.
Normally, two sprays are applied during the bloom
period, the first at 5-10% bloom and the second at full
bloom. If the weather is very dry, then only one spray
may be needed. Conversely, if much rainy weather is
encountered, then a third spray at petal fall may be
desirable.
During bloom, the most susceptible part of the flower
is the pistil. With varieties that possess short petals, the
pistils may be exposed for a considerable period before the
flower opens, whereas in varieties with large petals, the
pistil is protected until the flower is open. Consequently,
the first bloom spray should be timed to coincide with
that period when most of the anthers have just become
exposed.
As the fruit softens during the ripening process, it
becomes more susceptible to brown rot. Maintain
protection by applying fungicides at regular intervals.
Apply the first spray at 14-21 days preharvest, or at first
color. Usually, only two sprays at 7-14 days apart are
needed, but a third spray may be necessary in the event of
very wet weather. A final application of a systemic
material just before harvest is also a good practice to
protect fruit during shipping and packing operations.
Fungicides differ in spray and preharvest intervals, so
follow labels carefully.
Insect feeding injury increases brown rot infection;
therefore, maintain adequate insecticide protection. Also,
experiments indicate that brown rot is most difficult to
control where peach trees make excessive growth. In such
orchards, use nitrogen-containing fertilizers sparingly.
Special attention to brown rot control is required
where trees are planted closely or where the orchard is
surrounded by woods. Such conditions reduce air
drainage, and dew or rain evaporates more slowly from
blossoms and fruit than where air drainage is better.
A large variety of fungicides are available for control
petals, the pistils may be exposed fora considerable
period before the flower opens, whereas in varieties with
during both the blossom blight and fruit rot stages of
disease development. Refer to the stone fruit spray

schedule and fungicide sections for details on materials
and resistance management.

Cytospora cankeris one of the principal causes of
limb loss and tree death. Control of the disease can be
achieved using the guidelines listed below.
In all cases where a wound occurs or pruning is
performed, paint larger cuts with a water-based asphalt
emulsion containing 1 tablespoon of Benlate per quart of
asphalt emulsion. An interior white latex paint can be
substituted for the asphalt paint during periods when the
sap is not "running" profusely.

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Delay pruning until growth begins in spring,
preferably after bloom and before shuck-split.
Spray new pruning wounds before a rain occurs with
Benlate 50WP (0.5 lb) or paint as indicated above.
Remove cankers from critical areas as soon as
possible after they begin to gum.
Control brown rot, scab, borers, and Oriental fruit
moth to reduce the number of infection sites. In
blocks with a high level of disease, peach tree borer
control is often difficult.
Do not cultivate so close that bark is injured. Where
"hilling" is employed, it is extremely important to
cut out any infected area of the lower trunk that will
be covered with soil.
Paint the trunks with white latex paint before January
(see section on winter injury). Do not use acrylic
latex paint, for many of these are phytotoxic.
Burn all prunings from cankered trees, and burn all
trees that are removed from orchards infected with
canker. A permit is required for burning.

Fusicoccum cankerresults in the death or necrosis of
both vegetative and fruiting shoots. The fungus that
causes this disease is suspected of entering the shoot
through leaf scars in the fall or through bud scale scars
during early spring. Once inside the shoot, the fungus
proceeds to form a canker which eventually girdles the
twig. Dying shoots with yellow leaves are usually found
during early to mid-summer.
A leaf spot phase has also recently been identified.
This phase may be a means of canker spread from block to
block. However, the extent of any sporulation and its
significance is not known.
Management of fusicoccum canker requires sprays
during the fall leaf drop period and during the spring when
bud scales are detaching. Research is underway to
determine material efficacy, timing, and importance of fall
vs spring spraying. In the meantime, growers are advised
to (1) prune out all canker during mid-summer when dead
shoots are most visible and (2) apply a fixed copper spray
(see fungicide section) at delayed-dormant and during the
leaf fall period. These sprays will also be helpful for
control of leaf curl and for reducing bacterial spot
inoculum (spring spray).
Peach and nectarine varieties differ in susceptibility to
this disease. In a recent survey in NJ, the varieties
Autumnglo, Jerseyglo, Encore, Cresthaven, Biscoe,
Sunqueen, Harbrite, Jerseyland, Redhaven, and Harcrest

106

1998 New Jersey Commercial Tree Fruit Production Guide