Peach:
Brown Rot: Blossom infections from the brown rot fungus can occur whenever pistils are exposed and a favorable climate exists. Infections can occur during any wetting period when temperatures are between 41 and 86 °F. However, optimum conditions for infection occur with wetting and temperatures in the mid 70’s. During long wetting periods (several days or more) blossoms can be infected regardless of temperature. Generally infections that occur when conditions are sub optimal are less severe. Blossoms and fruitlets will remain susceptible until the pistil dessicates (sometime between petal fall and shuck split).
Oriental Fruit Moth: A biofix point for OFM was set on April 8 in Gloucester County. Insecticides for first generation Oriental Fruit Moth control should be applied at 170-200 degree days after biofix. This timing generally coincides with petal fall in peaches. Once all petals are off insecticides targeting OFM may be applied. This timing should be about next week in southern counties and the week after in northern counties.
Plum Curculio: Plum curculio adults are active and can be found in orchards. Adults are feeding now on young fruitlets but have not yet started ovipositional activity. Any feeding now will result in aborted fruit. Economic damage will not occur until the weather warms and fruit is out of the shuck. No treatment is needed for PC at this time.
Green Peach Aphid: GPA colonies begin forming sometime during bloom. Examine trees for the presence of colonies from pink to shuck split. Count the number of colonies on ten trees and use a treatment threshold of 2 colonies/tree at petal fall for peach, and 1 colony/tree for nectarine. The best way to scout for aphids during bloom is with a beating tray. Blossoms may also be collected, opened, and examined for the presence of aphids using a hand lens. Where needed treatments may be made for aphids starting at petal fall. See the NJ Commercial Tree Fruit Production Guide for recommended materials and rates.
Tarnished Plant Bugs and Other Catfacing Insects: Catfacing insects are starting activity but cause little damage at this time of the year. Catfacing insects will become more of an issue as temperatures warm and mowing and other ground cover activities become more common. Insecticides for catfacing insects are not recommended until after bloom.
Apple:
Diseases: Apple Scab, rust diseases, and fire blight are the main targets at this stage. The NEWA scab models are estimating about 25% ascospore maturity during this period in southern NJ. Northern counties will have less ascospore maturity. The first significant spore discharge is forecast for the end of this week in southern counties. Primary apple scab spores are released during any substantial infection period. Begin antibiotic applications for fire blight control on apples and pears when the first blossoms open. Materials available include formulations containing streptomycin, oxytetracyclene and kasugamycin. Rotate these chemistries for resistance management.
