INSECT MANAGEMENT

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INSECT MANAGEMENT IN STORED GRAINS
John Van Duyn, Extension Entomologist NC State
University Plymouth, NC
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Stored Grains Insects

• Over 60 species of insects that may infest
  stored grains and products made from grains.
• 14 are most important
• lesser grain borer rice weevil
• confused flour beetle maize weevil
• flat grain beetle rusty grain beetle
• sawtoothed grain beetle mealworm
• red flour beetle cadelle beetle
• Indian meal moth book lice
• foreign grain beetle grain mites
• Granary weevil

Common in NC. Weevils grain borer are most
damaging. Indiam meal moth and grain beetles
feed on damaged grain and parts.
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Lesser Grain Borer
Granary Weevil Maize
Weevil Rice Weevil
Indian Meal Moth
Rusty Grain Beetle Sawtoothed Grain Beetle
Grain Mites
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Stored Grains Insects

• If grain is stored long enough it will become
  infested with insects --- it is just a matter of
  time, more so in the southern US.
• The goal of Stored Grains IPM is to maintain
  insect-free grain for a finite period, until it
  is sold or used.
• How long it is to be stored can be important.

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Stored Grains IPM

• The strategy of Stored Grains IPM is based upon
  on and this talk is based upon these principles
• 1. Avoiding storage insect problems
• 2. Monitoring grain condition and insects in the
  grain, and
• 3. Applying remedial treatment for insect
  infestations that are economically threatening,
  as needed.

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Principle 1. Avoiding storage insect problems
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1. Avoiding Storage Insects Problems

• Maintaining storage facilities
• Sanitation of storage facilities and harvest
  equipment
• Harvesting on time
• Drying the grain appropriately
• Treating grain with protectant insecticide (if
  needed)
• Keeping grain as cool as practical

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1. Avoiding Storage Insects Problems

• Maintaining storage facilities
• Sanitation of storage facilities and harvest
  equipment
• Harvesting on time
• Drying the grain appropriately
• Treating grain with protectant insecticide (if
  needed)
• Keeping grain as cool as practical

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Grain bins come in many sizes --- Large,
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Medium,
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Or small --- yet, the same principles apply to
all.
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BINS

• Should be weather tight, rodent proof, steel, and
  on concrete base.
• Equipped with a perforated-floor aeration system
  and weather-proof vents.
• Should be inspected regularly for leaks,
  condensation, etc.
• Once filled, bottom sides should be sealed /
  resealed.
• Keep legs and remainder of transport system in
  good repair.

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1. Avoiding Storage Insects Problems

• Maintaining storage facilities
• Sanitation of storage facilities and harvest
  equipment
• Harvesting on time
• Drying the grain appropriately
• Treating grain with protectant insecticide (if
  needed)
• Keeping grain as cool as practical

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Sanitation

• Clean-out bins, under bins, in pits, and around
  entire storage bin area.
• Make sure any old, insect infested grain is
  disposed-of.
• Never store new grain on old grain.
• Clean grain and debris accumulation out of
  harvest and transport equipment.
• Spray bin walls and outside footings.
• Is a year around effort.

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1. Avoiding Storage Insects Problems

• Maintaining storage facilities
• Sanitation of storage facilities and harvest
  equipment
• Harvesting on time
• -- Grain left in field can become infested,
  especially wheat, which is harvested stored in
  warm weather
• Drying the grain appropriately
• Treating grain with protectant insecticide (if
  needed)
• Keeping grain as cool as practical

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1. Avoiding Storage Insects Problems

• Maintaining storage facilities
• Sanitation of storage facilities and harvest
  equipment
• Harvesting on time
• Drying the grain appropriately
• Treating grain with protectant insecticide (if
  needed)
• Keeping grain as cool as practical

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Rice Weevil Development Parameters
Range Temp. 68o to 95o F R.H. 10 to 95
Optimum Temp. 89.6o to 95o F R. H. 70
to 75
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Moisture For Aerated GrainStorage In The So. US
(6 Mo.)
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Moisture For Aerated GrainStorage In The So. US
(6 12 Mo.)
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Moisture For Aerated GrainStorage In The So. US
(1 yr )
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1. Avoiding Storage Insects Problems

• Maintaining storage facilities
• Sanitation of storage facilities and harvest
  equipment
• Harvesting on time
• Drying the grain appropriately
• Treating grain with protectant insecticide (if
  needed)
• Keeping grain as cool as practical

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Insecticide Application At The Auger Inlet
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Residual Insecticides For Grain(not for
existing insect infestations)

• Bt (e.g. Dipel) all grains (cap spray for
  caterpillars)
• Reldan B, O, Sor, W
• Storcide B, O, Sor, W
• Actellic C, Sor
• Diacon II B, C, P, Sor, W
• Malathion B, C, O, Ry (some resistance)
• Silicon dioxide B, C, O, Ri, Ry, Sor, Soy, W
• Spinosad (not labeled yet but coming is
  reported to be very good)

• Applicators are available that mount on top of
  auger
• and spray into the intake (Bbarley, Ccorn,
  Ooats,Sorsorghum,
• Ryrye, Soysoybean, Wwheat)

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1. Avoiding Storage Insects Problems

• Maintaining storage facilities
• Sanitation of storage facilities and harvest
  equipment
• Harvesting on time
• Drying the grain appropriately
• Treating grain with protectant insecticide (if
  needed)
• Keeping grain as cool as practical

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Avoiding Storage Insects Problems

• Maintaining storage facilities
• anitation of storage facilities and harvest
  equipment
• Harvesting on time and grain drying
• Treating grain with residual insecticide _at_ bin
  fill
• Keeping grain as cool as practical

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Aeration -- To Cool Grain (1)

• Insect development slows stops as temp. moves
  below 60oF.
• Manage grain in bins to facilitate air movement.
• Move temperatures to 55oF or lower as soon as
  possible.
• In the south don t start cooling grain until
  cool weather arrives
• Use cold days to further reduce temp

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Excessive Filling of Bins Vs. Air Movement
Best Not So Good Worst
--Take Home -- Fill bins properly to Facilitate
air movement.
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Foreign Material Core Restricts Airflow Leading
To Insects and Spoilage

When bins are filled, fines build-up in center
form a core that restricts air-flow. Restricted
air flow can lead to heat moisture resulting
in insects / spoilage in the core area (center).
Removing some grain will reduce or eliminate the
corn and facilitate air movement (L).
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Aeration -- To Cool Grain (2)

• Insect development slows stops as temp. moves
  below 60oF.
• Manage grain in bins to facilitate air movement.
• In the south dont start cooling grain until cool
  weather arrives
• Move temperatures to 55oF or lower as soon as
  possible.
• Use cold days to further reduce temp

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Principle 2. Monitoring insects and moisture in
the grain.
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2 Monitoring Grain Condition and Insect Levels

• Monitor grain on a regular schedule
• (e.g. every 2 to 4 weeks).
• Inside, monitor for insects, temperature, mold,
  odors, water vapor, sprouting grain.
• Outside check for condensation, uneven frost /
  snow melt, birds, fecal matter.
• Use thresholds for determining an insect problem.

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Sampling Grain

• Use a trier to probe grain
• Mass to collect samples. Get
• 5 to 10 samples mass.
• Sample at differing depth
• label samples.
• Can use probe traps

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Thresholds

• Rye, Triticale, Wheat
• one living insect per quart sample
• Barley, Corn, Oats, Sorghum, Soybean
• One living weevil or five other insects per quart
  sample

• If thresholds are exceeded fumigation
• is recommended.

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Principle 3. Applying remedial treatment for
insect infestations that are economically
threatening, as needed.
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3. Fumigation To RemoveInsects In Stored Grain
(1)

• Fumigants are the only way to control insects
  within bins.
• Fumigation products are very dangerous.
• Fumigation should be done a by trained,
  registered, and experienced applicator.
• Two types of fumigant are registered
• Various formulations of phosphine
• Methyl bromide

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Fumigation To RemoveInsects In Stored Grain (2)

• Bins must be near air tight.
• A comprehensive manual is available on-line and
  must be completely understood and followed when
  using fumigants.
• Using fumigants is serious business.

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Phosphine Fumigants

• Phosphine may be used on most grains.
• Several formulations are available (e.g.
  Weevil-Cide, Phosfume, Phostoxin)
• Are formulated as tablets or pellets
• Also, phosphine is formulated in compressed CO2
  (has benefits).
• Tablets and pellets release gas that may react
  with certain metals (e.g. copper) and may also
  generate hydrogen.

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Methyl Bromide

• Is in process of being phased-out.
• Does the job well and in less time than
  phosphine gas.
• Doesnt react with metals or release hydrogen.

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Questions ???