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Organic Pest Management Overview


Organic Pest Management Overview Hort 390 Fall 2006 Pest Control As Integrated Systems Plan ahead, anticipate, take a design approach to your garden. – PowerPoint PPT presentation

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Title: Organic Pest Management Overview

Organic Pest Management Overview
  • Hort 390
  • Fall 2006

Pest Control As Integrated Systems
  • Plan ahead, anticipate, take a design approach to
    your garden.
  • Prevent as many problems as possible, build
    resilience into the system.
  • Monitor plants and pests on a regular basis.
    Problems that are identified early are easier to
  • Use least toxic methods first, to preserve the
    beneficial insects and microbes as much as
    possible, and maintain system integrity.

Pest Control Possibilities
  • Systems Approach prevention/passive
  • Systems Approach moderate
  • Systems Approach active
  • Note none of these is a business as usual but
    do nothing approach. Also, they all incorporate
    aspects of Integrated Pest Management IPM.

(No Transcript)
Integrating practices
  • Biological Control
  • Cultural Control
  • Mechanical and Physical Control
  • Habitat manipulation
  • Use of resistant varieties
  • Chemical Control

Derived from Kaolin clay, a natural mineral,
forms a barrier film that acts as a broad
spectrum crop protectant. It works to control
insect pests and disease, protect against sunburn
and heat stress. Applied as a water-based slurry
before pests arrive.
Examples of physical pesticides.
D.E. is the fossilized shells of tiny
water-dwelling organisms called diatoms, with
microscopically fine, sharp edges which break the
outer protective layer of the insect and
desiccate them. Applied as a dust or mixed into a
slurry for foliar spraying. Barrier to crawling
pests and soft bodied insects, used in the garden
and as a stored grain additive. Can be used as a
dust on manure for fly control and for intestinal
parasite control.
Other barrier methods can protect crops from
insects, and provide early season growth
enhancement, and some frost protection.
Organic Cropping System in a high tunnel
This is NOT a systems approach - lacks
bio-diversity - no soil improvement plan
- etc.
Organic vs. conventional fruit production in Italy
Green lacewing
Ichneumon wasp
Syrphid Flies
Two-spotted lady beetle
Insects in Kansas
  • The number of species that are harmful to our
    interests is relatively small.
  • Many are beneficial.
  • Most are neutral in their effect on our welfare.
  • It is estimated that there are between 15,000 and
    20,000 species within Kansas, some of which have
    never been identified.
  • Field guide (Insects in Kansas) includes
    photographs of about 850 species.

Economic loss from pest insects is due to
  • Reduced yields
  • Lowered quality of produce
  • Increased costs of production and harvesting
  • Expenditures for control

Approaches to insect management
  • Be prepared by knowing which insects are likely
    to show up in each crop.
  • Know something about each pests life-cycle, when
    it shows up, where it comes from etc
  • Scout regularly. Every 2 to 3 days is
    recommended during critical periods. Have a
    scouting plan (see details later)

Old saying The best fertilizer is the
footsteps of the farmer.
Approaches continued
  • Know the critical thresholds for insects that you
    might find, and how the thresholds might change
    over time (more critical at different life-cycle
  • Use any and all preventative measures that are
    available and practical. see later slides
  • When/if using pesticides, use the ones that will
    have the least impact on you, non-target
    organisms (honey bees, beneficial insects,
    neighbors, etc)

Whats tolerable?

Control applied
Number or damage level
Note threshold will depend on stage of crop,
weather, and has been determined through
empirical research and/or modeling.
Injury and treatment thresholds
  • Injury level
  • Depends on how much damage the users will
  • Economics
  • How much will it cost to treat?
  • Would the losses be greater than the cost of
  • Treatment threshold
  • Control action is taken if a pest problem is
    expected to occur, to prevent crop loss or
  • e.g. weather conditions indicate a disease
    outbreak if no action is taken

Preventing pest problems
  • Plant selection
  • Select variety or crop for location
  • Chose resistant varieties
  • Prepare the site correctly

Cultural control
  • Sanitation
  • Destruction of alternate hosts
  • Habitat modification
  • Smother cover crops
  • Host resistance
  • Crop rotation
  • Intercropping
  • Planting harvest dates
  • Flooding
  • Irrigation and water management
  • Fertilizers soil amendments
  • Mechanical physical control
  • Soil tillage
  • Mowing
  • Mulches, barriers
  • Temperature manipulation, solarization

  • Pest populations exist but the impact is avoided
    through cultural practice
  • Fertilization program to promote rapid plant
  • Not planting in certain areas where pest
    populations are likely to cause problems.
  • Host-free periods.
  • Crop rotation (e.g. rotate sugarbeets on a 3 to
    10 year cycle to reduce sugarbeet cyst nematode).
  • Planting or harvesting date modification (e.g.
    pink bollworm management).
  • Tactics for prevention and avoidance strategies
    may overlap

Two Types of Plant Disease
  • Abiotic diseases/disorders are caused by
    noninfectious agents such as weather stress,
    nutrient deficiency, chemical injury, soil

Biotic diseases/disorders are caused by
infectious agents such as fungi, bacteria,
viruses, nematodes
Biotic/infectious diseases Disease
Pathogen fungi bacteria nematodes
Host Species Cultivar Age
Environment Temp, RH, wetness
Infectious agents pathogens
Viruses Bacteria Fungi Nematodes most
microbes are not pathogens
Biological controls antagonistic fungi,
bacteria Green manures Plant growth
promoters Compost teas Copper, sulfur,
potassium bicarbonate
Boost crop vigorIncreased crop vigor will reduce
the impact of competition by weeds on yields.
Crop vigor can be enhanced through variety
selection and management practices that favor the
crop over the weeds. Favorable variety and
hybrid traits to look for include Rapid
emergence Planting hybrids/varieties that
emerge quickly will give the crop a head start
over emerging weeds, helping them to establish
and better compete. Quick canopy closure Once
the canopy closes it reduces the amount of light
that reaches the soil surface which some small
seeded weed seeds need to initiate germination.
The faster the canopy closes the more weeds it
shuts out. Efficient nutrient scavenging
Logically, crop varieties that are efficient in
utilizing nutrients will perform better and they
may help prevent weeds from taking up nutrients.
Indeterminate growth habit Because
indeterminate crops continue to grow throughout
the season, they are less likely to be shaded out
by weeds. Drought tolerance Drought tolerant
plants that are better water scavengers will be
better equipped to compete with weeds.
Management practices that favor crop vigor over
weed vigor Appropriate placement and timing of
fertilizers for the crop Banded fertilizer
applications applied at times when the crop
demands it most will favor the nutrients reaching
the target crop instead of feeding the weeds.
Increase plant density or populations
Increasing your planting density will provide
quicker canopy closure and deprive weed seeds and
seedlings of light. Early-season weed control
Getting a jump on weed control when the crop is
most vulnerable will increase plant health and
help the crop compete against future weeds.
Adjust planting dates By delaying planting
until after the first flush of weeds, new weed
seedlings can be killed with a light cultivation
or flaming. This practice can help deplete the
seed bank in the top layer of soil, resulting in
reduced competition later in the growing season.
This technique is referred to as a false seedbed
Avoid additions to the seedbank do not let weeds
go to seed Weeds can disperse several hundred to
several hundred thousand seeds each year by way
of wind, water, animals and humans. The number of
seeds produced depends on the weed species and
its environment. As you can imagine, if left
uncontrolled, weed seed production and subsequent
weed infestations could increase exponentially
for the years to come. More information on weed
seedbank management can be found in Managing
weed seed banks throughout the growing season by
Adam Davis, in the April 29, 2004 issue of the
New Ag Network (http//
Increase favorable habitats for weed seed
predators Though we mainly view weeds as a
nuisance, there are several animals that use weed
seeds as a food source. Mice, insects, worms and
birds that are already in your fields are all
example of weed seed feeders or predators. The
exploitation of predator feeding can help reduce
the weed seedbank a tactic that is referred to
as conservation biological control. Certain crop
management strategies, such as tillage and the
use of pesticides, can disrupt the habitat and
lifecycles of these creatures, ultimately
reducing the weed management benefits realized
from predator feeding. To aid in increasing weed
seed predator populations consider the following
Plant cover crops In addition to suppressing
off-season weeds, cover crops can provide weed
seed feeders with protection from predators.
Leave border strips around fields Border
strips can serve as overwintering sites and
refuges for weed seed predators. Reduce fall
tillage Reducing fall tillage leaves more weed
seeds on the soil surface, where most seed
predation occurs. It also increases the
persistence of crop residues which provides
shelter and refuge to weed seed predators similar
to a cover crop.  
General Strategies Ways to diversify
production Crop rotation Certain weeds are
often affiliated with certain crops based on
their growth habit and management. For example,
there is more likely to be a problem controlling
weedy grass species in corn than in soybeans. A
diverse crop rotation with several different
growth habits does not favor the buildup of any
one particular weed. Incorporating fall and/or
spring seeded cover crops into your rotation can
help add diversity. Variations in postemergence
control Increasing the variety of postemergence
control practices used will help suppress a
larger spectrum of weeds than relying on one
tactic. Herbicide (organic or non-organic) mode
of action rotation Consistently relying on the
same herbicides or organically acceptable
compounds for weed control promotes resistance.
If even one weed is naturally resistant, the over
reliance of that strategy increases the selection
pressure on that weed population and can go on to
build an entire population of resistant weeds.
One way to avoid this pressure is by alternating
herbicide modes of action and practices. It is
less likely that a weed will be resistant to
multiple modes of action.
Tillage and weed control
  • Pre-plant
  • Primary tillage (destroy last years weeds)
  • Secondary tillage one or more times (prepare
    seed bed)
  • Post-plant
  • Pre-emergence culTIvation
  • Post-emergence shallow cultivation usually 1 to
    3 times (rotary hoeing, etc)
  • Post-emergence cultivation between rows, between
    plants, etc(see novel examples in video)

Non-tillage weed control
  • Crop rotation will rotate weeds too
  • Allelopathic cover crops rye, oats, crimson
    clover, etc.will suppress weed seed germination,
  • Mulches grow in place, or apply later. Depth
    and timing matter.
  • Flame weeding but not in a high-mulch
  • Mow weeds, graze, etc..

Chemical Weed Control
  • Pre-plant options
  • Check publications to see what is allowed for
    vegetable crop of interest. Must be listed on
    the label to be legal.
  • Organic options include corn gluten, but must be
    from non-GMO corn.
  • Post-plant options
  • Again, check publications to see what is
    registered for each crop.
  • Post Emergence options
  • Herbicides may affect some species and not
    others, or be general (like glyphosate)
  • Organic non-specific herbicide is vinegar.

Biological Weed Control
  • Principle is that an insect or disease
    selectively targets a weed without endangering
    non-target plants.
  • Insects released to control weeds include natural
    enemies of musk thistle and St. Johnswort. Have
    kept these weeds at reduced levels, but has not
    resulted in elimination.
  • Under development (mycoherbicides)

Timing as a form of weed control
  • Tillage, then repeat at critical intervals
  • Tillage, then kill subsequent weeds without
    tillage (flame or herbicide) to create a stale
  • Cultivate at night? No light to stimulate
    germination of new seeds (but no sunlight to kill
    cultivated weeds either).
  • Plant later than your neighborssoil is warmer,
    crop comes up quicker than the weeds, easier to
    control the weeds.

Weed-free threshold concept
  • Control early weeds
  • Usually if the weeds are controlled for the first
    6 to 8 weeks the later weeds dont matter
    (except if there is a crop quality problem,
    harvesting problem, or aesthetic issue).

Strategy vs. Tactic
  • from the Dictionary of Sustainable Management
  • http//
  • A complex and ongoing process of organizational
    change which establishes a context for
    accomplishing goals, and provides a framework and
    direction to achieve an organization's desired
    future. A strategic plan differs from a business
    plan in that it focuses more on the overall
    organizational development and not, specifically,
    on financial models, investment, and budgets.

strategic Programs, goals, and projects of
great importance tactical The lowest level of
military operations, the view from the trenches
and the foxholes. Tactical decisions are those
made by the commanders on the spot, on the front
lines. Most miniature games are tactical or
grand-tactical in nature. The opposite of
tactical is strategic. . http//
Pest Control Possibilities
  • Systems Approach prevention/passive
  • Systems Approach moderate
  • Systems Approach active
  • Planning ahead is strategic.
  • The practices you choose are your tactics.

Pest Control Possibilities Insects
  • Systems Approach prevention/passive
  • - resistant/tolerant crops, attract beneficial
    insects to area
  • Systems Approach moderate
  • - row cover/barrier, clay film barrier,
    diatomaceous earth, vacuum or hand pick, sticky
    traps, pheremones (distruptants and traps).
  • Systems Approach active
  • - botanical pesticides (pyrethrum, sabadilla,
    neem, rotenone), microbial pesticides (Nolo bait
    for grasshoppers, Bt for various larvae.

Pest Control Possibilities Diseases
  • Systems Approach prevention/passive
  • - grow species that arent affected in our
    climate, live with it, rotation, compost and soil
    improvement for root diseases.
  • Systems Approach moderate
  • - sanitation (residue management, pruning),
    choose specific varieties for disease resistance,
    disease free seeds and plants.
  • Systems Approach active
  • - sulfur, horticultural oils, baking soda
    (sodium bicarbonate), potassium bicarbonate,
    compost tea foliar spray (still experimental, E.
    coli concerns?).

Pest Control Possibilities- Weeds
  • Systems Approach prevention/passive
  • - high planting density, leafy crops to shade
    weeds, targeted irrigation, rotation
  • Systems Approach moderate
  • -pre-plant tillage, lots of mulch, landscape
    fabric, hand weeding
  • Systems Approach active
  • - corn gluten pre-emergence, flame weeding,
    between row cultivation, soaps as post-emergence,
    livestock grazing

Diagnosing the problem
Seedling wilting from fungi, primarily
  • Caused by a pest
  • Caused by weather
  • (frost, hail, wind)
  • Caused by nutrition deficiency
  • Caused by machinery, inadequate irrigation

Mower damage
Importance of identification
  • Many symptoms look similar.
  • Presence of a pest doesnt mean it caused the
  • Not all damage needs to be treated (thresholds).
  • Pests may no longer be present.
  • Pest may be difficult to find (especially
    soil-borne pathogens/ nematodes).
  • Symptoms may be caused by improper cultural

Stink bug damage
Katydid damage
Below-ground damage from root-knot nematode
Importance of pest identification
Big-eyed bug (beneficial insect) False chinch bug
(sporadic, minor pest) Lygus bug (major
  • Proper identification is essential for choosing
    the right control actions.
  • Requires identifying
  • Pest organisms
  • Beneficial organisms
  • Population levels
  • Requires correlating pests
  • to damage.

Herbicide damage vs. grub damage
Stump the Chump
  • Come to class on Thursday to play!
  • Bring samples if you want.
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