ppm (0.25 lb) when used alone and when drying
conditions are poor. The addition of Regulaid (1 pt) to
streptomycin has increased the level of control. If
streptomycin is added to any of the other fungicides,
increase the rate of streptomycin to 75 to 100 ppm (0.38
to 0.5 lb).
Applications during poor drying conditions are
much more effective. Late evening or night spraying is the
preferred method. Do not apply during a rain or when rain
is forecast as the material must be taken up systemically
to be effective.
Control has been more effective when sprays are
applied at 3x to 6x. Control is slightly less effective when
applied dilute and much less effective when applied above
6x.

[!]Post-bloom Sprays. Apply streptomycin sulfate at 10- to 14-day intervals from petal fall until conditions become unfavorable for spread. When hail occurs, apply a spray immediately following the storm, regardless of when last application was applied. Do not use within 50 days before harvest. Moldy Core. This disease can become troublesome

in some years when the petal-fall spray is delayed too
long. For control use captan 50WP (2 lb) before the calyx
closes.

Powdery Mildew. The powdery mildew fungus,
Podosphaera leucotricha, overwinters as mycelia in the
terminal buds. Although the disease is present every year,
it is more prevalent during years when weather is dry and
morning dews are heavy.
The mycelium becomes active early in the season.
Therefore, control should begin at the pre-pink stage.
Additional sprays are required through the third cover
spray.
Sulfur, Bayleton, Nova, Procure, Rubigan, and
Funginex are effective against mildew, but sulfur produces
russeting with some varieties. Varieties not sensitive to
sulfur russet are Rome Beauty, McIntosh, Cortland, and
Golden Delicious. Varieties sensitive to sulfur russet
include Starr, Twenty Ounce, Rhode Island Greening,
Stayman, and Delicious.
As soon as first noticed (about pink stage), branches
or twigs showing systemic or over-wintering mildew
should be pruned out to reduce secondary mildew. This is
particularly beneficial in young blocks.

Summer Diseases

The summer diseases consist of X-Disease, Black
Pox, Brook's Spot and Fly Speck. Infections can occur
any time from FIRST COVER through harvest, but
infections are most common and numerous from early
August through September. A section on Brook's Spot
and one on Sooty Blotch and Fly Speck appear below.

Sooty Blotch and Fly Speck. These diseases
almost always occur together and the control measures are
the same for both diseases. The fruit infections are
superficial on the skin and can be brushed off with
vigorous rubbing.
The fungi causing these diseases over-winter on dead
twigs and brush within and around the orchard site.
Rainfall is needed for spore release, dispersal, and
infection. Infections occur most readily when the Relative
Humidity (RH) is 95% or higher and temperatures are
between 60 and 70F. Temperatures between 50-60F and
70-80F are quite favorable for fruit infections.
Conditions which increase disease incidence include:
[!]Frequent showers and high RH with moderate
temperature.
[!]Inadequate pruning which restricts drying.
[!]High inoculum levels in dead twigs within the tree,
in adjacent hedgerows or on the ground within the
orchard.
[!]Use of ineffective fungicides or fungicides with short
residual activity. Once infection occurs, at least 30-
45 days incubation are required before fruit infections
become visible to the naked eye. Heavy levels of
fruit infections may occur when the last fungicide
application is made more than 30 days before harvest.
Captan 50WP (6 lb/A) and Captan combined with
Benlate/Topsin M are effective in control.
[!]

1998 New Jersey Commercial Tree Fruit Production Guide

115