Lorraine P. Berkett1 , M. Elena Garcia2 and Morgan L. Cromwell1 1University of Vermont and 1University of Arkansas
Safety and quality have always been top priorities for Vermont apple growers. IPM is an important component in producing high quality fruit and in reducing pesticide risks in apple production.
We are in the process of examining Organic IPM using organically approved materials, reviewed and approved by the Organic Materials Review Institute (OMRI) and the state's certifying agency. Thresholds used in standard IPM orchards should be viewed as provisionary in organic apple orchards until more experience is gained.
The Organic IPM checklist was developed to serve as a quick reminder of IPM considerations during different times of the year. As such, it does not go into details. It is a "work-in-progress" and will be modified as the authors gain more experience in organic apple production. Details can be found in other publications.
It is the grower's responsibility to ensure that any crop production practice or material used in the orchard is acceptable in their particular state's organic certification program.
Some materials deemed organically acceptable on the National List may not be acceptable in some states. Contact your certifier to know what is acceptable and to ensure compliance with regulations in your state.
December to March
Evaluate
completeness of your organic IPM records from the previous growing season.
In addition to legal requirements, do they reflect scouting information
and application of findings in decision-making, do they include tree
health information, foliar and/or soil analyses? Does your organic certification
record-keeping system need improvement?
Use
records to review pest management strategy and results from the previous
growing season and make necessary adjustments.
Read
fact sheets, articles and other resources on the biology and life cycles
of different orchard pests and beneficial organisms; attend fruit workshops
and meetings to obtain updates on thresholds and improvements to organic
IPM strategies and options; get on the mailing and email lists for newsletters
and alerts.
Review
materials approved by the Organic
Materials Review Institute (OMRI) and accepted by the state's certifying
organization for any changes or new organic options.
Review
information on any potential non-target effects of organic options on
biological control agents and determine what materials will be effective
yet conserve beneficial organisms if intervention is needed.
Investigate
sources of local
weather information; determine what equipment will be used to monitor
environmental conditions (i.e., rain, temperature, leaf wetness) in
the orchard for pest models and for assessing spray conditions.
Network for Environment and Weather Applications (NEWA)
provides New England growers with useful local weather data and pest
and disease predictions, from which to make more informed management
decisions.
How To Use NEWA
Start
any major repairs to orchard spray equipment so that it will be ready
to calibrate and function properly when the season begins.
Order
organic IPM monitoring supplies.
Clean
and sharpen pruning tools.
Prune
trees to provide good tree structure but also to open canopy for
light and air penetration, which will have both horticultural benefits
(i.e., better fruit coloring with more light) and pest management benefits
(i.e., make conditions less favorable for disease development; allows
better pesticide penetration). Remove cankers, dead or weak wood. Remove
mummified fruit.
While
pruning, note any sections of orchard that have high numbers of overwintering
European Red Mite eggs.
European Red Mite eggs
Check
for winter damage. Look for peeling or cracked bark.
Contact
beekeeper and write a pollination contract
Review
foliar and soil analysis recommendations. Weak or overly vigorous trees
will be more susceptible to certain arthropod pests and/or diseases.
March to Silver Tip Bud Stage
Conduct
final pre-season maintenance check of sprayer(s). Replace worn nozzles,
weak hoses, and inaccurate pressure gauges.
Review
tree-row-volume calculations for each orchard block.
Set
up map and record-keeping system for monitoring of orchard blocks
Check
for bud winter damage.
Remove
prunings and brush piles from within and around orchard and burn or
chip if possible since they can harbor inoculum for wood and fruit rot
diseases and provide habitat for voles.
Meadow vole (top), Pine vole (bottom)
http://www.hort.uconn.edu/ipm/imgcatlg/homectlg.htm
Vole trunk girdling damage after snow melt
in early spring
Note
vole activity during snow melt; a lot of activity in the snow could
mean high overwintering populations
As
soon as snow cover is gone and the rows are drivable, flail-mow as a
sanitation practice for management of apple scab (reduces overwintering
inoculum).
Flail
mowing to reduce apple scab overwintering inoculum
At
Silver Tip phenological bud stage, place visual sticky traps for tarnished
plant bug and leafminers in the orchard.
Putting Out Early Season Leafminer Traps
Putting Out Tarnished
Plant Bug Traps
In
very young, or dwarf high density, orchards, maintain an 18 inch reduced-weed
area next to tree to increase air circulation around tree, to eliminate
competition for water and nutrients, and to remove habitat for voles.
An option to maintain a reduced-weed area is bark mulch spread over
entire area, but make sure the mulch is pulled away from tree trunks.
Bark
mulch is spread to maintian a reduced-weed area along organic orchard
rows
Green Tip through Pink Bud Stages
Check
for bud winter damage.
Remove
solid plastic vole guards and replace with mesh guards that allow air,
light and pesticide penetration. [Impacts borer management]
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.
Monitor
weather/environmental conditions for degree-day calculations, disease
models, etc., and if intervention is necessary, to determine optimal
time to spray to minimize drift.
At
Tight Cluster bud stage and again at the late Pink bud stage, determine
the necessity to manage tarnished plant bug and leafminers.
Tarnished plant bug adult
Spotted tentiform leafminer
adult
Apply
oil application(s) for management of European red mites and San Jose
scale. [Oil acts to coat and suffocate the overwintering stages.]
At
early Pink bud stage, place visual traps in the orchard to monitor for
European apple sawfly. Check at late Pink to see if traps have already
reached threshold.
European apple sawfly sticky trap
Manage
apple scab infections in the primary stage to reduce the need for fungicides
during the latter part of the growing season.
Determine
when environmental conditions are favorable for apple scab infection
periods.
Begin
checking for primary apple scab lesions about 9 days after first infection
period to determine the effectiveness of your scab program.
Primary apple scab lesions on underside of leaf
Bloom
Monitor
environmental conditions to determine the risk of fire blight infection.
Continue
management of apple scab.
Hang
codling moth pheromone traps in orchard to monitor this insect.
Assembling Pheremone Wing Traps
Codling moth baited pheromone sticky trap
During
late Bloom, begin to inspect fruit on early-blooming cultivars in perimeter
rows for fresh plum curculio egg-laying scars.
Fresh plum curculio egg-laying scars with ooze
Crescent-shaped plum curculio egg-laying scar
Bring
bees colonies at 10% to 15% bloom
Monitor
pollination conditions.
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.
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.
Fire blight damage to young fruit
Fire blight damage to tree
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. An 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.
Sap-feeding leafminer larval mines on underside of leaf
Remove
fruit drops, if feasible, to potentially reduce plum curculio populations
Examine
leaves for presence of first generation leafhopper nymphs and adults
to determine if threshold has been reached.
Leafhopper adult
Leafhopper nymph
Assess
level of infestation by aphids and presence of natural predators to
determine if biological control is likely.
Predatory Cecidomyid larvae (orange larvae) and aphids on underside
of leaf
Predatory lacewing eggs on underside of leaf
Predatory Syrphid larva
Hang
apple maggot fly traps in orchard during the last week of June to monitor
activity and to determine if and when threshold levels are reached.
Apple maggot fly sticky red ball trap
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.
Scab lesions on fruit
Severe scab symptoms on leaf ('sheet' scab)
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.
Mow
row middles (if possible, delay mowing until 10-14 days after petal
fall).
Begin
organically approved 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.
July
Check
sprayer calibration and adjust for summer applications.
In
blocks were codling moths are a problem, determine if 1260-1460 DD (base
50F) have accumulated from first trap capture in pheromone traps since
this is the most effective time for management of second generation.
Codling moth adults on sticky trap
Internal damage caused by codling moth larvae
Check
for second generation sap-feeding larval mines in leaves to determine
if leafminer threshold has been reached.
Examine
middle-age terminal leaves to determine if threshold has been reached
for European red mites.
Check
apple maggot fly traps on a regular basis to determine if threshold
has been reached. Clean traps and replace lure every 3-4 weeks.
Apple maggot fly adult on red sticky trap
Apple maggot fly red sticky ball trap (not all insects on trap are apple
maggot flies)
In
late July, examine leaves for presence of second generation leafhopper
nymphs and adults to determine if threshold has been reached.
Continue
to keep track of the total number of hours, starting ten days past Petal
Fall, that the leaves were wet. Risk of fly speck infection increases
when 270 hours of leaf wetting have accumulated.
Begin
summer pruning in mid- to late-July to open up the canopy, improving
light penetration for better fruit quality, faster drying conditions,
and better spray coverage.
Summer pruning
Mow
grass to discourage vole populations and to aid in air circulation for
disease management.
Monitor
soil moisture conditions and irrigate when necessary.
Collect
leaves for foliar nutrient analysis in late July to early August. Contact
your Extension office for specific instructions. Next year's fertilizer
program should be based on the foliar and soil analyses.
Collecting leaves for foliar nutrient analysis
August
Continue
to examine leaves for presence of second generation leafhopper nymphs
and adults to determine if threshold has been reached.
Examine
middle-age terminal leaves to determine if threshold has been reached
for European red mites.
Check
apple maggot fly traps on a regular basis to determine if threshold
has been reached. Clean traps and replace lure every 3-4 weeks.
Continue
summer pruning.
Clean
and repair harvesting bags and fruit storage containers.
Check
predicted harvest dates.
Monitor
soil moisture conditions and irrigate when necessary.
Mow
grass to discourage vole populations and to aid in air circulation for
disease management.
September
Remove
or mow fruit drops where feasible as they are a source of food for voles.
Note
any pest damage during harvest so it can be addressed in IPM planning
for the next growing season.
Mow
grass to discourage vole activity.
October
Check
trunks (small diameter trees especially) for signs of borers.
Roundheaded borer adult
After
harvest and before leaf fall, estimate the orchard's level of "scab
risk" by following the sequential sampling procedure (Potential
Ascospore Dose assessment).
Check
placement and condition of vole guards; repair and re-position if necessary.
Remove
or mow fruit drops where feasible as they are a source of food for voles.
Mow
grass to discourage vole activity.
Collect
soil for analysis. Contact your Extension office for specific instructions.
Next year's fertilizer program should be based on the foliar and soil
analyses.
How To Take A Soil Sample
Lime
soil if recommended by soil analysis.
November
After
leaves have fallen to ground, perform apple scab sanitation practices,
like leaf removal or flail mowing.
Overwintering scab lesions on fallen leaves
White
paint, which is normally painted on the trunk to protect the tree from
sudden
temperature changes and sunscald, is prohibited by most organic
certifying agencies. Therefore a slurry of kaolin clay and water can
be used instead to cover the bottom of the trunks. However, this solution
is not as permanent as paint and needs multiple reapplications.
Replace
solid plastic vole guards if mesh guards were not put on in the spring.
(These white plastic guards will also help protect the trees from sunscald
like paint would)
White plastic guards on a new high density planting
If
organically approved deer repellents will be used, set them before deer
establish a feeding habit. Inspect and make repairs to deer fence.
Clean,
service and properly store equipment and pesticides.
Photo credits: L.P. Berkett; Integrated Management of Apple Pests in Massachusetts
and New England, Coop. Ext. Sys., University of Massachusetts. 1984.; Instructional
Media Center, Michigan State University, East Lansing, MI.; W. MacHardy;
T.S. Sutton.