Prevention
Clean in and around storage facilities. Grain storage facilities, and the area around storage facilities, should be cleaned thoroughly prior to storing grain.
Clean equipment used to move grain. Grain left in equipment throughout the summer months can result in new grain that is being placed into storage becoming infested. Combines, truck beds, grain wagons, augers and other equipment used to move grain should be cleaned of grain residue. Other potential sources of grain infesting insects include livestock feeds, old seed bags, spilled grain, etc.
Inspect grain storage facilities for signs of deterioration, especially for leaks or holes through which insects or rodents can gain access to the stored grain. Moving and storing the grain in clean facilities will eliminate one source of infestation. However, grain stored for long periods of time still has the potential for renewed infestations.
Treating storage facilities. Depending on the commodity to be stored, storage facilities may additionally be sprayed or dusted, if needed, with a recommended insecticide before storing grain in the bin (e.g. malathion, diatomaceous earth or cyfluthrin – refer to product labels for details). Note: some commodities, such as canola, flax and sunflowers, should not be stored in facilities recently treated with malathion or cyfluthrin (Tempo).
Dry and Cool Grain. Ideally, the grain should be dry before being put into storage, and cooled as quickly as possible. For long-term storage, producers are urged to lower the grain temperature below 15°C as soon as possible after the grain is placed in storage. At 15°C the stored product insects stop laying eggs and development stops. Aeration systems used during the night immediately after harvest should have the grain below 15°C in about 2 weeks. Grain that is not moved or aerated after harvest can remain warm enough to allow insects to survive the winter. Convection currents arising from this warm air can also promote condensation, sprouting (heating) and mould growth in unmanaged grain. These conditions are very attractive to stored product pests and support their development.
Once the grain mass is cooled to the desired temperature, fans should be sealed to prevent unwanted air migration through the mass that could result in early grain mass warm-up. Cold grain has a longer storage life than warm grain.
Note, however, that under cool grain temperatures, insect movement is reduced to the point that some insecticides may not be effective.
Monitoring for Insects
Bin probe and Sieves: Stored grain insects can be monitored by taking grain samples with a bin probe, sieving the grain, and looking in the dockage for Insects.
Probe Traps: Another means of detecting insects in stored grain is through placing probe traps (such as the WB PROBE II Trap from Trece) in the grain and monitoring them. Often the first indication of an infestation will be found near the top centre of a storage bin, and therefore, this is where traps should be placed. Monitoring should take place once every 7-10 days during the onset of storage (first 60 days) and then the frequency of monitoring may be adjusted.
Identifying insects in stored grain
Correct identification of insects found in stored grain is important in determining the most appropriate control methods. Some of the insects found in stored grain feed directly on the grain, referred to as primary pests, while others feed on grain that is damaged or going out of condition, referred to as secondary pests.
Primary insect pests
Insects that feed directly on the grain include rusty grain beetles, red flour beetles, and sawtoothed grain beetles.
The rusty grain beetle is the most common stored product insect. Heavy infestations of this insect cause grain to heat and spoil.
The red flour beetle is another common insect pest of stored grain in the prairies. Red flour beetles cannot feed on undamaged, dry seed with less than 12% moisture content. They prefer grain dust, broken grain and milled stocks.
Sawtoothed grain beetles are more common in stored oats than in stored wheat and barley.
Secondary insect pests:
Insects that feed on fungus in the grain bin or stored grain that is damaged include the foreign grain beetle, hairy fungus beetle, psocids, and grain mites.
Foreign grain beetles resemble the rusty grain beetle, but can be distinguished from it by club-shaped antennae. Also, when placed in a glass jar, foreign grain beetles will climb up the sides, while rusty grain beetles cannot. While foreign grain beetle is considered a fungus feeder, they will feed on grain if the moisture content is in the high end of the acceptable range (eg. 14.5% mc wheat).
Grain mites are whitish, about 0.2 to 0.5 mm long, and can be hard to see with the naked eye. About eight kinds of mites are common in farm granaries and elevators.
Psocids are soft-bodied insects, about 1 mm long, with long antennae relative to the body size.
Fungus feeding insects and mites cannot survive in dry grain. Chemical control is not necessary for fungus feeding pests in stored grain. Practices that result in the grain drying may be all that is needed to control such pests.
Information to help identify insect pests of stored grain can be found at: http://www.grainscanada.gc.ca/storage- entrepose/ keys-cles/sgp-irg/sgp-irg-eng.htm.
Control Techniques:
The Canada Grain Act states that an elevator operator may reject any grain if the operator has reason to believe it is infested or contaminated. Outlined below are some control techniques and when and how these techniques can be best used.
Cold Temperatures
Rusty grain beetles are cold hardy and can survive subzero temperatures. Rusty grain beetles and other stored grain insects can be killed by reducing core grain temperatures as follows:
Time Required to Kill Insects at Various Grain Temperatures
| Grain Temperature | Time required to kill insects |
|---|---|
| -5°C | 12 weeks |
| -10°C | 8 weeks |
| -15°C | 4 weeks |
| -20°C | 1 week |
Cooling the grain, through aeration or moving the grain several times during mid-winter, should provide effective control of rusty grain beetles.
Moving Grain
Moving grain using cyclone-based pneumatic conveyors (grain vacs) at about 200 bushels per hour has been shown to be an effective means of controlling insects in stored grain. However, moving too large a volume of grain at a time using a pneumatic conveyor results in the grain protecting the insects and reduces kill of stored grain insects. Loading the grain using a pneumatic grain conveyor removes insects from grain being delivered to elevators.
Phostoxin, Fumitoxin
Company: Degesch America Inc. (Phostoxin round tablets – PCP# 15736; Phostoxin pellets – PCP# 15735; Fumitoxin tablets – PCP# 19227).
Formulation: 55% aluminum phosphide.
| Formulation | Primary Use | Container Size |
|---|---|---|
| Phostoxin tablets (3g each) Fumitoxin tablets (3g each) | On the farm or country elevator | 333 tablets (1kg) (Phostoxin) 500 tablets (1.5kg) (Fumitoxin) |
| Phostoxin pellets (0.6g each) Fumitoxin pellets (0.6g each) | On the farm or country elevator | 1,666 pellets (1kg) (Phostoxin) 2,490 pellets (1.5kg) (Fumitoxin) |
| Phostoxin tablets prepac | Containers | 1-4 strips of 33 tablets to a pouch |
Insects and other pests controlled: Rusty grain beetle, red flour beetle, saw-toothed grain beetle, granary weevil, yellow mealworm, lesser grain borer, spider beetles, hairy fungus beetles, Indian meal moth, Hessian fly, nematodes, mice and rodents.
Approved for use on the following stored grains: Barley, corn, dried peas, lentils, millet, oats, rye, soybeans, sunflower seeds, triticale, wheat, straw and hay.
Restricted Product: The use and sale of Aluminum Phosphide (Phostoxin or Fumitoxin) is restricted to licensed pesticide applicators possessing a valid fumigation license (Saskatchewan) or stored agricultural products license (Manitoba).
Phostoxin or Fumitoxin can only be used in conjunction with a detailed fumigation management plan.
Rate and Minimum Exposure Period: Refer to labels to determine rate. For grain bins a dosage of 250-500 tablets (or 880-2560 pellets) per 100 m3 of bin space being treated (not volume of grain) is recommended. It is important to ensure that bins are relatively secure. It is not advisable to use phosphine products in bins that are leaky or not well sealed.
The following table may be used as a guide to determine the minimum length of exposure period to phostoxin or fumitoxin at the indicated temperatures:
| Temperature | Exposure Period |
|---|---|
| Below 5°C (40°F) | Do not fumigate |
| 5°C-12°C (40°-53°F) | 10 days |
| 13°-15°C (54°-59°F) | 5 days |
| 16°-20°C (60°-68°F) | 4 days |
| above 20°C (68°F) | 3 days |
Aluminum phosphide can not be used when the grain temperature is below 5°C as the tablets release the gas too slowly. Very dry grain will also slow the release of the gas from the pellets. A shortened exposure period cannot be compensated for by increased dosage. Also ensure that storage is well ventilated for at least 24 hours after the required time for fumigation.
Environmental Hazards: Toxic to birds and mammals. Carefully inspect the outside and inside of the structure prior to application to ensure the absence of nesting or roosting birds. Avoid application if birds are present.
Protect-It, Insecto
Company: Hedley Technologies Ltd. (Protect-It) PCP#24259; Natural Insecto Products Inc. (Insecto) PCP#22489
Formulation: Protect-It: 74% Silicon dioxide, 10% Silica aerogel; Insecto: 90 percent Silicon dioxide
Insects controlled: Beetles – Rusty grain beetle, red flour beetle, rice weevil, granary weevil. Moths – Angoumois grain moth, Mediterranean flour moth, Indian meal moth.
Approved for use on the following stored products: Feed grains, seed, stored grains, wheat, barley, buckwheat, corn, oats, rye, flax, peas, soybeans and sorghum. Also registered for structural treatment of empty grain storage and transportation containers.
How it works: Diatomaceous earth damages the cuticle of the insect, reducing the insect’s ability to retain moisture. The insect eventually dies from dehydration. A 6-week period of treatment above 20°C is needed for maximum efficacy.
Rate, for empty storage structures: Use a dust blower or aeration fan to get diatomaceous earth into the cracks, crevices and void spaces of the structure being treated. Dust areas at a rate of 1 kg per 200 square metres (5 g/m2).
Rate, while grain is being placed into storage:
- Protect-It: The application rate for Protect-It varies by crop and insect species, ranging from 100 g/tonne for control of rusty grain beetle in wheat to 1000 g/tonne for red flour beetle in corn. Refer to the label for details.
- Insecto: Apply to grain at the time of storage at a rate of 0.5 to 1 kg per metric ton of grain (500-1000 ppm).
Precautions: The application of DE will lower the test weight measurement of the grain, but usually not to the point of downgrading. If test weight loss is excessive, the grain can be diluted with untreated grain. DE is non-toxic to humans and animals.
Malathion Grain Protector Dust
Company: Loveland Products Canada (PCP#15896)
Formulation: 2% malathion
Insects controlled: confused flour beetles, flat grain beetles, granary weevil, Indian meal moth, lesser grain borer, rusty grain beetle and sawtoothed grain beetle.
Approved for use on the following stored grains: Wheat, rye, barley and oats as stored grains.
Malathion Grain Dust can be applied to grain as it is being loaded into a bin or being turned by adding gradually at the grain auger. It can also be used to control surface infestations by applying to the grain surface and raking in to 15 cm depth of the grain. Malathion controls insects by ingestion and contact and insects must be active for it to be effective.
Rate:
| Crop | Rate-g/1000 kg (tonne) grain |
|---|---|
| Wheat | 415 |
| Rye | 450 |
| Barley | 520 |
| Oats | 735 |
Do not apply to grain within 7 days of sale.
Be aware that the Canadian Grain Commission allows only 8 ppm of malathion residues in stored grains.
Malathion 500, Malathion 85E
Refer to labels for these products for insect and mite control in empty grain bins, grain elevators, grain box cars and flour mills.
Note – Some commodities, such as canola, should not be stored in facilities recently treated with malathion. Malathion residue can linger in bins for up to six months after treatment and can be transferred from the bin to canola seed. Canola found with malathion residues is unacceptable for export customers.
Malathion 500 (IPCO)
| Insect | Rate | Note |
|---|---|---|
| Rusty grain beetle, sawtoothed grain beetle, confused flour beetle, grain mite, granary weevil, Indian meal moth, lesser grain borer (empty grain bins) | 250-300 ml/5 Lof water on 100 m2 | May be used within 1 day of grainstorage |
Malathion 85E (Loveland Products Canada)
| Insect | Rate | Note |
|---|---|---|
| Rusty grain beetle, red flour beetle, sawtoothed grain beetle, confused flour beetle, grain mite, granary weevil, Indian meal moth, lesser grain borer, flat grain beetles, rice weevils (empty grain storage facilities) | Mix 490 mlin 15 L of water. Apply 5 L of mixture on 100 m2 | Wait until spray has thoroughly dried before storing grain in treated areas. |
Tempo 20 WP
Company: Bayer PCP#25673
Formulation: 20% cyfluthrin. Tempo is a group 3 (pyrethroid) insecticide.
Application: Tempo can be used to control insects in grain storage facilities, truck beds and other areas where grain is stored before filling these areas with grain. Cleaning of all areas prior to use of Tempo 20 WP insecticide will increase levels of control. See the insecticide label for specific mixing instructions.