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An IPM Checklist for Vermont
As previously indicated, each issue of the Vermont
Apple Newsletter will contain parts of the IPM list that Dr. Elena
Garcia and I developed through a USDA project entitled: "Linking Food Safety
to Farm*A*Sys and IPM to Reduce Microbial and Pesticide Risks in Apples. The
checklist is intended to be a quick reminder; details can be found in other parts of
this newsletter or in other available resources.
Petal
fall through June
- Scout your orchard at least once a week to be aware
of what is going on so that if problems are developing, corrective or preventative
measures can be taken.
- Be aware of any restrictions on pesticides used
during this period and their 'Pre-Harvest Intervals'.
- Check to see if European Apple Sawfly captures have
reached threshold levels.
- Inspect fruit for evidence of first signs of Plum
Curculio damage; begin to accumulate degree days for use in model to determine when
insect activity is over.
- Examine middle-age fruit cluster leaves to determine if
threshold has been reached for European Red Mites.
- Check Codling Moth traps daily and begin to
calculate degree days (base 50F) from first adult catch. Most effective time
for management of first generation is at 250-360 DD in orchard blocks where the insect is
a problem.
- Check for first generation sap-feeding larval mines in
leaves to determine if Leafminer threshold has been reached.
- Examine leaves for presence of first generation Leafhopper
nymphs and adults to determine if threshold has been reached.
- Assess level of infestation by Aphids and presence
of Natural Predators to determine if biological control is likely.
- Hang Apple Maggot Fly traps in orchard during the
last week of June.
- If a Fire Blight infection period occurred during
Bloom, monitor degree day accumulation and observe blossoms and developing shoots
for first signs of blight. The first symptoms of blossom blight is predicted to occur when
an additional 103 degree days have accumulated (base 55F). Depending on how
extensive the number of "strikes" are, cut out strikes to reduce inoculum for
further disease spread on sunny days when rain is not predicted. Follow
recommended procedure for the "ugly stub" method for removing strikes.
- Use the Apple Scab ascospore maturity model
to determine the projected end of the primary infection season. As a conservative
estimate, the final Scab ascospore release in commercially managed orchards can be assumed
to have occurred when 900 DD have accumulated before a daytime rain of at least 0.1 inch
and temperatures of at least 50F during the wetting period.
- Before disease management intervals are extended,
assess the foliage and fruit for Apple Scab incidence approximately two weeks after
the last primary infection period.
- Keep track of the hours of leaf wetness starting at ten
days past Petal Fall in order to determine the period of greater risk of Fly Speck.
- Assess fruit set by monitoring fruitlet growth and
weather conditions.
- Thin the fruit. Following your Extension
recommendations and weather conditions, determine your fruit thinning strategies.
Thinning breaks up fruit clusters which allows for better drying conditions and better
spray coverage.
- Mow row middles (if possible, delay mowing until 10
-14 days after petal fall) and keep an 18-inch weed free area next to trees.
- Begin calcium sprays to decrease incidence of Ca
deficiencies disorders.
- Monitor soil moisture conditions and irrigate when
necessary to avoid dry conditions that can stress trees making them more vulnerable to
disease.
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