Lorraine P.
Berkett1, Renae E. Moran2 , M. Elena Garcia3,
Heather M. Darby1, Robert L. Parsons1, Terence L.
Bradshaw1, Sarah L. Kingsley-Richards1, and Morgan
C. Griffith1 1University
of Vermont, 2University of Maine, 3University of
Arkansas
. .
Funding
Sources:
-USDA Organic Agriculture Research and Extension Initiative
-University of Vermont
-University of Arkansas Division of Agriculture Cooperative Extension
Service
-University of Maine Cooperative Extension
-NIFA Integrated Pest Management (IPM) Program
-Vermont Tree Fruit Growers' Association
IMPORTANT:
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
federally accredited certifying agency
to know what is acceptable and to ensure compliance with regulations in
your state.
NOTE:Where trade names or commercial products are used for identification,
no discrimination is intended and no endorsement is implied. Always read
the label before using any pesticide.
The label is the legal document for the product use. Disregard any information
in this guide if it is in conflict with the label.
IMPORTANT: 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
federally accredited certifying agency to know what is acceptable
and to ensure compliance with regulations in your state.
What is Organic IPM?
Organic Integrated Pest
Management (IPM) is an approach to managing pests that integrates organically-approved
biological, cultural, physical, and chemical tools in a way that minimizes
economic, health, and environmental risks.
What is a pest?
The Environmental Protection Agency (EPA) defines pests as "living
organisms that occur where they are not wanted or that cause damage to crops
or humans or other animals. Examples include:
arthropods,
mice and other animals,
unwanted plants (weeds),
fungi,
microorganisms such as bacteria and viruses, and prions."
What is an organically
certified pesticide?
The EPA defines a pesticide as "any substance or mixture of substances
intended for:
preventing,
destroying,
repelling, or
mitigating any pest.
Though often misunderstood
to refer only to insecticides, the term pesticide also applies to herbicides,
fungicides, and various other substances used to manage pests.
Under United States
law, a pesticide is also any substance or mixture of substances intended
for use as a plant regulator, defoliant, or desiccant."
(Source: http://www.epa.gov/pesticides/about/index.htm)
The Organic Materials Review Institute (OMRI) provides organic certifiers
and growers with a product list of materials approved for use in certified
organic production systems according to the National Organic Standards.
A material approved for use in organically certified production is generally
derived from natural resources. Directory of
OMRI Approved Organically Certified Products
Pest Management Throughout
the Season
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.
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.
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.
Back to Season Calendar Menu
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.
http://www.hort.uconn.edu/ipm/imgcatlg/homectlg.htm
Meadow vole (top)
Pine vole (bottom)
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 (left) Putting Out Tarnished
Plant Bug Traps(right)
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.
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.
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.
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 (left)
Fire blight damage to tree (right)
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 (left)
Leafhopper nymph (right)
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 (left)
Predatory lacewing eggs on underside of leaf (middle)
Predatory Syrphid larva (right)
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 (left)
Severe scab symptoms on leaf ('sheet' scab) (right)
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.
Back to Season Calendar Menu
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 (left)
Internal damage caused by codling moth larvae (right)
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 (left)
Apple maggot fly red sticky ball trap (not all insects on trap are apple
maggot flies) (right)
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.
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.
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.
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.
Weed Management Strategies
Preventing weed growth is critical during the establishment phase of an
orchard when strong tree growth is needed to build a fruit bearing framework
of trunk and limbs. Weed management following the establishment phase can
be important for dwarf trees and for orchards planted in sandy soils. Orchards
planted to semi-dwarf trees have been shown to be productive with minimal
weed management, but fruit size and flower bud development are likely to
improve where some weed management occurs. Weed management during the first
half of the growing season will have a large impact on tree productivity
because late spring into early summer is the time for rapid growth of shoots
and early development of fruits.
Mowing, cutting back weeds, is commonly employed in established orchards
with deeply rooted trees on semi-dwarfing rootstocks. However, mowing weeds
is insufficient for trees on dwarfing rootstocks and newly planted trees
with shallow roots.
Cover crops that grow in the tree row will act as weeds and compete
with trees. No ideal cover crop has been found for orchards. Additionally,
they create a habitat favorable for voles which can feed on trunks.
Mulching suppresses weeds by blocking sunlight. Different types of
materials can act as mulch, but some types are detrimental to fruit trees.
Hay, straw, plastic and fabric mulches encourage voles. Wood chips and bark
mulch have been shown to effectively reduce weeds for one to three years
depending on depth to which they are spread. A minimum depth of 3-inches
is recommended to block out enough light to prevent weeds. Unless an inexpensive
source can be found, mulching is a costly method of weed management.
Different Types of Weed Management
Herbicides are an option for weed management where organically approved
products are allowed. Herbicides have a temporary effect particularly where
weed pressure is strong and soil moisture is abundant. Corn gluten will
not effectively manage established weeds, but works as a preemergent and
must be applied as weeds are germinating. Weak acids and essentials oils
act as "burn-down" herbicides and kill the above-ground succulent
plant tissue, but will not effectively kill some weeds. Different materials
that act as burn-down herbicides include concentrated vinegar (acetic acid),
citric acid, clove oil and citrus oils. Because the weeds are not entirely
killed by the herbicide, rapid regrowth occurs with these materials. Reapplication
is needed for a sufficient duration of management in most years. Citrus
oil (d-limonene) has been shown to keep weed growth in check for a period
of two weeks at which time visible weed regrowth occurs.
There may be others in addition to these, and very little information is
available on their effectiveness in apple orchards. Many products are available
containing these compounds for use as organic herbicides, so contact your
certifying agency to find out which are allowed for use in your orchard.
These products can irritate and damage skin, eye and respiratory tissues
so protective apparel should be used when applying them.
Flaming weeds can also temporarily kill above-ground weed tissue. It is
typically accomplished with a propane burner, and works best on small weeds.
It may be less costly than other methods, but potential damaging to irrigation
systems and trees if fires start in the orchard and therefore is not recommended.
Shallow cultivation disrupts the surface weeds and roots and can be effective
if performed early in their growth. Disadvantages of surface cultivation
include the need for specialized equipment, the risk of damaging tree trunks,
disruption of surface roots, and increased chance for erosion. To prevent
trunk damage, adopt the "Sandwich System" which is a one-foot
strip of weeds allowed to grow on either side of the tree with an area of
cultivated soil in the rest of the tree row.
In a research comparison of alfalfa hay mulch, flaming and the Sandwich
System, mulches outperformed other weed management methods during the establishment
years, but not subsequent years.
For more information: A
Grower’s Guide to Organic Apples (Cornell University) Apples:
Organic Production Guide (ATTRA) Groundcover
Management (University of Vermont)
Protecting Trees From Wildlife
Voles, or meadow mice,
girdle young trees when they feed on the lower trunk. To prevent feeding,
protect trunks with hardware cloth so that it encircles the lower part of
the trunk. It should be 12-18 inches in height, but not tight against the
trunk. Plastic spiral guards can also be used, but should be removed in
spring since they encourage trunk boring insects.
Deer feed on the new shoots of fruit trees and can severely stunt trees
of short stature. An 8' fence is the most effective method of keeping deer
away from fruit trees, but is also the most costly. A shorter fence is less
expensive, but also less effective.
