Guardian Pest Control - Pest Solutions: Rice Moth

PEST SOLUTION : RICE MOTH
Rice Moth, Corcyra cephalonica (Stainton) (Lepidoptera: Pyralidae) Management

Importance

Rice moth, Corcyra cephalonica (Stainton) is a worldwide-distributed insect adapted to warm humid environments. The larvae are general feeders and considered one of the key pests of rice, cocoa, biscuits, pearl millet, sorghum and seeds. Larvae also contaminate foods by secreting silken threads that web together food particles, dusts and frass “debris or excrement produced by insects”. These will render infested products unaccepted for sale, manufacturing and consumption.

Descriptions

The adult moth has pale buff-brown forewings with ½-1 inch wingspan, hindwings almost transparent and uniform in color. The wing tips are rounded and tightly folded to the body when at rest. There are no distinctive markings on the wings, although veins may be slightly darkened. The larvae are dull white, with long fine hair and dark brown head. Cocoons are white in color.

Biology

Adults do not feed and live for one to two weeks. Through this period and within short-range, rice moth males are attracted to the female abdominal-tip pheromone that causes the male moths to search for a mate and attempt copulation. Mated females lay from 100 to 200 eggs near food sources. Eggs hatch in 4-10 days. Larvae spin silken threads as they feed and web grains, debris and other particles into galleries in which they live and feed. When they are fully-grown, they form dense white cocoons to pupate. Pupae are usually found in food or they may be found between pallets and sacks. Adults emerge from pupae within four to eight weeks and repeat their life cycle. At optimal temperatures of 86 - 90.5°F and relative humidity of 70%, the life cycle lasts 28-35 days. The low minimum temperature and low relative humidity (RH) of the rice moth are 60°F and 20%, respectively. However, there are up to six generations per year in tropical countries and one generation in temperate climate.

Management

Non-Chemical Methods

Prevention

Avoid purchasing old food items and always use older food first.
Store foods in insect-proof containers with tight-fitting lids and keep highly susceptible foods, such as rice, cocoa, biscuits and millet in the refrigerator or in the freezer.
Store food products in a dry, cool, well-ventilated area (below 60°F and less than 20% RH) “rice moth life stages are not active under these environmental conditions”
Regularly inspect and immediately vacuum all spilled foods materials
Clean shelves with soap and hot water, allow to dry and cover with clean, fresh paper or foil before placing any food or cooking utensils.

Heat or Cold Treatments

Place infested foods in a freezer at 0°F for four to seven days or heat at 140°F for one hour or 120°F for two hours. To avoid damaging certain items, check the product’s label before any heat/cold treatments, i.e., seeds saved for planting may have the germination reduced after superheating or cooling. Practically, during the winter, in northern states, or where the daily mean temperature falls and remains below the freezing point (32°F), placing infested materials covered with plastic sheeting outside in a trailer for one to two weeks will provide sufficient elimination of rice moth life stages.

Physical Removal of the Rice Moth Life Stages “discarding infested materials”

Remove Cocoons: Cocoons could be found on the food surface, bin walls or between bags. Remove cocoons around food products by vacuuming, seal the vacuum bag and properly discard outside the building. Infested materials with cocoons should be destroyed as aforementioned in the heat and cold treatment and then property discarded outside the building.
Remove Eggs and Feeding Larvae: All infested materials should be double-bagged, firmly sealed and discarded outside the building.
Capture the flying Adults using pheromone of insect light traps (ILTs): Traps alone are not a control method. They are important tools for detecting, monitoring and pinpointing stored product pests including rice moth. Proper placement of the traps is very crucial for a successful monitoring program and it depends on the understanding of the insect feeding, flying and mating behaviors.

If commercially available, use sex pheromone lure traps to attract and then capture newly emerged males.

Place pheromone traps in a grid pattern at 20 to 60 feet apart in infested and hard-to-clean areas as well as in places conducive to pest infestation such as commonly spillage areas. Avoid placing pheromone traps in the following places:

Near doors, windows, vents, or loading docks where they could attract insects from outside.
In moist and air current areas to avoid attracting insects to non-target areas.

Number each trap and map your traps in each location
Check traps on a regular basis, usually weekly, and locate traps that captured more moths than other traps.
Around tarps with more catch, tighten the grid to pinpoint the source of the infestation. For example, place traps at five to six feet parts around the one with the catch.
Keep a monitoring record of each trap’s location in the grid, the date it was placed, and its catch at each inspection.
Based on the data collected from the pheromone traps, make your pest management decisions.

Adults of rice moth fly mostly at night and are attracted to lights; therefore, install ILTs which use ultraviolet light to lure and capture the flying adults

Place one ILT every 12-25 feet in the entryway or as recommended by the ILT manufacture’s label. When installing the ILTs, note the following:

Do not place ILTs too close to the doorways or the moth will not recognize them.
Do NOT use ceiling mounted ILT’s in food preparation areas. Electric Grid ILT’s should be mounted a minimum of 10 feet from any food preparation surface.
Adhesive ILT’s should be mounted a minimum of three feet horizontally from any food preparation surface.

Mark all the ILTs on a map
Regularly check collecting trays and glue boards, usually weekly, to determine insect ID, insect category (i.e., stored product insects, flies, or occasional invaders) and the source of infestation.
Periodically replace glueboard before it becomes clogged.
Replace the UV lamp twice a year or as needed.
Follow the same recordkeeping measures previously described in the pheromone trapping method.

Chemical Methods

Before treatment, discard all infested products outside the building and remove food, water and clothing materials from areas to be treated.
Apply a space treatment with an EPA approved non-residual insecticide to knock down the adult populations in warehouse and food processing facilities.
Target feeding, breeding and harborage areas using EPA approved residual insecticides as crack, crevice and spot treatments.

Apply crack and crevice treatments in pantries, closets, baseboard, doorframes, window frames and other similar places.
Apply a spot treatment to surfaces near food storage areas, in and around cabinets, under and behind machines, appliances and furniture; remove shelf papers, and treat where food IS NOT present.

If applicable, apply a perimeter treatment to prevent flying adults coming from outdoors.

Precautionary Measures

During the treatment, no people, food, or pets should be present in the room to be treated. Fish tanks should be covered and the air shut off. Plants will not be affected.
Do not enter the treated room or use before applied pesticides are dried.
Anyone with a respiratory condition should notify property manager and the Guardian Pest Control Service Specialist

Post Treatment Information

Follow up evaluation is necessary 7-10 days after the treatment.

Follow prevention methods and keep monitoring to minimize the periodic space treatments