Stored Product Pests

Stored Product Pests

Prevention, Detection, and Gatekeeping for Control

With the amounts and types of food—both ingredients and finished product—that are stored at food and beverage processing plants, it is all too common for stored product pests to invade. Once in your warehouse, these beetles, weevils, and moths can cause extensive damage and product loss. This can be from contamination of the insects in the food; by their feeding on or boring into grains; or by what they leave behind such as webbing and fecal droppings.

“The main damage these stored food pests cause is product loss due to contamination by the insects themselves or cast skins and pupal cases of the immature stages,” said Insects Limited Technical Director Alain VanRyckeghem.

Additionally, stored product pests can cause a variety of damage in bulk stored raw commodities ranging from loss of volume, mold/conditioning issues, and regulatory issues surrounding foreign material. In the processing, manufacturing, distribution, and retail segments, these pests pose a food safety risk for adulterating items produced or stored.

“They can also cause the recall of products due to infestation and high expense in discarding infested or damaged products,” said Trece Market Manager James Miller. “Insects can also cross contaminate production processes and items stored/distributed in close proximity.”

Stored product pests are typically separated into two categories: primary and secondary feeders. “When/if the commodity becomes out of condition these pests reproduce rapidly which can allow for large populations and cause considerable damage within a short period of time,” Miller said.

Defending against stored product pests can be thought of as comprising four key steps: prevention, detection, control, and “gatekeeping.”

1. Prevention.

The first step in prevention is regular and thorough inspection of incoming products and supplies. Having a standard operating procedure for inspecting—with a flashlight—and sampling all incoming trailers and pallets of food will catch a majority of infested materials and prevent their entry, VanRyckeghem said.

Once the products have been accepted, they need to be protected from additional damage. This could be from material handling or movement, but also may include hot temperatures or high moisture, he said. “Damage resulting in spillage should be ‘cleaned as you go.’ This process ensures spills are cleaned up immediately and broken packages are removed. Sanitation is everyone’s job and that is the most effective way of preventing stored product insect infestations.”

The use of a pheromone monitoring system in transit can enhance the effectiveness of the prevention program, Miller said.

2. Detection

Pheromone-monitoring systems also can be placed in the facility to detect stored product pests that got through your first line of defense or came in from outdoors. “A grid-like pattern of both hanging glue-style traps for flight-capable pests and dome-pitfall style for crawling pests are recommended for finding/narrowing hot spots or high density areas of insect activity,” Miller said. This will help drive sanitation needs and serve as a starting point for visual sightings.

Besides seeing live or dead insects flying or crawling on boxes, bags, or pallets, visual signs of an infestation can include webbing, frass, cast skins, larvae, pupae on or around food products or storage areas, and damaged/out of condition packaging. An insect infestation also may cause the food to have a musty smell.

Signs that VanRyckeghem advises one look for when inspecting for specific insects include:

Indianmeal moth larvae are very active and may crawl away from infested food materials to dark areas, so these may be found in crevices and wall/ceiling junctions. Webbing on or in product containers or packaging is a good indication of infestation.

Warehouse beetle larva go through numerous molts and leave delicate hairy cast skins on the surface of food or packaging material.

Cigarette beetle adults emerge from paper-packaged foods or boxboard containers and create multiple tiny exit holes. These look as though someone has poked the package with a pencil tip.

Red flour beetles and sawtoothed grain beetles typically do not fly, so the main signs of infestations are the active adults around the exterior of the food packaging or dead beetles at its base.

Every plant should have a policy in place for response to detection of an infestation—not wait until there is a problem to establish one. This policy should begin with segregation of potentially infested goods, followed by in-depth inspection of surrounding items, immediate involvement of management, and tracking to the source of infestation if possible, Miller said.

If an infestation is detected on incoming materials, it is essential to prevent the product from entering the facility. It may be kept in the trailer and inspected further, rejected and returned to the sender, or accepted and fumigated to eradicate the pest. “The decision is determined on a case-by-case basis,” VanRyckeghem said.

“If an infestation is detected in storage, it may be difficult to determine the origin of the infestation, so the immediate response should be to quarantine or segregate the product from the rest of the stored products,” he added. To help contain the infestation, the product should be segregated in a transport trailer or sealed room with the air temperature set below 60°F, which will suppress the flight and mobile activity of these insects.

Once the product known to be infested is segregated, it is important to inspect the site with a flashlight to determine if the pests were localized or had spread to other materials. Additionally, the area in which the infested product had been sitting should be thoroughly cleaned, with all insects, larvae and eggs vacuumed. “This will allow the plant manager to detect ‘new’ activity on the next inspection, rather than observe ‘old’ signs from the previous occurrence,” VanRyckeghem added. The area also may be treated with residual insecticide, if allowed, and monitoring tools such as pheromone and food traps should be set up to detect activity that escaped the inspections.

3. Control

There are a number of options for control of pests found in stored food products.

Mating disruption can serve as a tool for both prevention and control, Miller said. “Modern advances in mating disruption are reaching new levels daily—ranging from raw commodity storage to retail stores for prevention and control of Indianmeal moth and soon other noted pests.”

Strategically timed, low-impact, insect-growth-regulator treatments or mist/fog applications designed to interrupt the life cycle of the pest also can help to keep pests under control, he said, adding, “In raw commodity storage, monitoring with grain probes and other pheromone systems to determine insect populations is key to treatment intervals and environmental control measures.”

Additionally, all plants should include warehouses in their sanitation and maintenance schedules, with proper training and oversight

The options for controlling pests in stored food products are dependent on where the food/ingredient is within the food production stream. “Raw ingredients may be reprocessed and sifted/filtered or cleaned to remove foreign materials and then repackaged for use,” VanRyckeghem said. “Sometimes a food material could be frozen to kill active stages and then reprocessed.”

The structure that contained the infestation is the target of most pest control activities, he said. In conventional food storage, options include:

Fogging with pyrethrin or a Vapona product can knock down the flying moths or beetles, preventing further spread.

Crack-and-crevice treatment with a residual is important for crawling adults and immature stages.

In organic facilities, cool storage temperatures (60-65°F) and lower relative humidity (40-45%) can stop many of the common stored product pests from laying eggs and developing into adults.

Fumigation with phosphine, which has a wide range of raw and processed food products on its label, can be another option for temperature-sensitive foods. However, VanRyckeghem said, “Most often a food product that is contaminated with insects cannot be salvaged, especially if it is designated for human food, and must be disposed of to the animal feed stream or landfill.”

4. Gatekeeping

Once prevention, detection, and control strategies are put in place, ongoing vigilance and “gatekeeping” will serve to evaluate the efficacy of the program and reduce the potential for infestation. This should include monitoring with pheromone and food traps, detailed flashlight inspections to locate hidden infestations or conditions conducive to infestation, food safety risk assessments performed on as-needed and annual basis, and the use of a pest-sighting logbook with facility schematics for mapping areas of interest or suspected infestation.

Additionally, all facility employees (management and workers) should undergo at least annual training in modern pest prevention and management techniques by a competent instructor, Miller said. This will ensure your workforce is educated and aware of signs and the need for immediate response and control. “The more eyes on the facility the better.”

The author is Editor of QA magazine. She can be reached at

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Winter Pest Prevention Tips from Smithereen

  • Seal cracks and holes on the outside of your home to help prevent pests from getting inside. Be sure to check the areas where utilities and pipes enter the home. A mouse can fit through a hole the size of a dime.
  • Replace loose mortar and weather stripping around the basement foundation and windows.
  • Store firewood at least 20 feet from the home. Pests often take up residence in wood piles and can easily gain access to your home if the pile is nearby.
  • Rodents can hide in clutter, so keep storage areas well organized, and store boxes off of the floor.
  • Eliminate all moisture sites, including leaking pipes and clogged drains. Extra attention should be paid to kitchens and bathrooms as these areas are particularly vulnerable to cockroach infestations.
  • Install door sweeps and repair damaged screens in windows.
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Houseplant pest control: the best ways to control mealybugs, scale and spider mites

Houseplant pest control: the best ways to control mealybugs, scale and spider mites

When purchasing houseplants, look at the foliage carefully. Avoid plants with yellow leaves, brown leaf edges or spots which indicate the plant has been poorly cared for. Look for signs of scale, mealybugs or mites that could infest your other plants at home. (|The Times-Picayune archive)

Indoor plants make our homes pleasant and attractive. They may even help remove pollutants from the air, making the indoor environment healthier.

But keeping houseplants healthy can be a challenge. To thrive indoors (or at least survive), we must provide proper light and water. Sometimes, however, we can do everything right and still see our houseplants succumb to pests.

The indoor environment is ideal for pest outbreaks, which usually get started when an infested plant is brought inside. There is no rain to wash off pests, the temperatures are moderate year round, and there are no natural predators inside to help control pest populations once they get started.

Your best defense against major pest outbreaks is close and regular inspections and prompt action should an infestation occur.

Three of the most common houseplant pests are mealybugs, scales and spider mites.


Mealybugs are common and infest virtually all of the plants typically grown indoors. They are small, oval, soft-bodied insects usually covered with a white powdery or cottony waxy secretion. They feed on the plant’s sap, much the way mosquitoes feed on our blood.

Look for cottony masses in the growing points of plants: in the crowns, under the leaves and where the leaves join the stem of the plant.

Since they don’t move around much, many people mistake mealybugs for some sort of fungus infection.

Plants heavily infested will appear unhealthy. The leaves may have a shiny appearance and feel sticky, and the new growth may appear weak and deformed.

Many older leaves will begin to turn yellow and die.


Scale insects are related to mealybugs and also feed on plant sap. Scale insects often are covered with a waxy coating that’s usually white, tan or brown depending on the type of scale.

Once they are large enough to notice, they have settled in one place, and no longer move. This, along with their waxy covering, makes it difficult to notice them; and once you do see the strange bumps or dots on the plant, you would never think they’re insects.

Like mealybugs, scale-infested plants will often have shiny, sticky leaves. Even the floor or table where the plant sits may become sticky. This is a result of the accumulation of honeydew (a sweet, sticky excretion of the scale) on surfaces under the plant.

If the scale population passes the plant’s tolerance, the plant will begin to lose vigor, and the leaves will yellow and die.

Spider mites

Spider mites are extremely tiny (barely visible to the naked eye), and the damage they cause is initially very subtle.

In the early stages, damage to the foliage causes it to appear dull, faded and unhealthy. With close inspection, tiny, light-colored flecks or spots can be spotted in the leaf tissue, a symptom called “stippling.”

As damage increases, new growth may be stunted and deformed, and older leaves may become faded, develop brown edges and begin to drop off.

High populations of red spider mites will form webbing where the leaves join the main stem.


These three pests attack a tremendous variety of plants. Virtually every plant we grow inside is susceptible to one or more of them.

When a pest problem is detected, prompt action is called for.

First, isolate the infested plant. All three of these pests are contagious.

Always wash your hands after working with an infested plant, especially if you are about to handle healthy plants.

Since there are no natural controls indoors, if the pest is to be eradicated, you’re going to have to do the job yourself.

If you would prefer not to use a pesticide, physical control is worth a try, but it requires effort and persistence.

Spraying a plant every day with a strong stream of water directed under the leaves will usually get rid of spider mites. Continue spraying for at least a week. Indoors, this will work well only for plants small enough to move to a sink or shower.

Otherwise, move plants outside to a shady area (weather permitting) for treatment and use a garden hose with a spray nozzle attached.

Mealybugs are sometimes treated with a cotton swab dipped into rubbing alcohol. This is a tedious process and must be repeated numerous times, but it may work on a light infestation.

If you decide to use pesticides, you must choose materials that are labeled appropriate for indoor plants. Do not use sprays that are meant to be used outside or those for controlling indoor house pests such as roaches or ants.

Mealybugs, scale and spider mites all can be controlled by horticultural oil sprays. These insecticides kill pests by suffocation and are relatively low in toxicity. Year Round Spray Oil is an example. If you can’t find an appropriate indoor-safe product, move the plants outside for treatment and then bring them back inside when the spray has dried.

Premixed, ready-to-use indoor plant insecticides containing insecticidal soap, pyrethrin, pyrethrum or other active ingredients are readily available. They are generally excellent for mites and mealybugs but not very effective on adult scale.

Use pesticides cautiously and follow label directions precisely.

Be prepared to make several applications for complete control. Since spraying can be messy, particularly when spraying larger plants, move plants outside to spray them whenever it’s practical.

As you care for your indoor plants this winter, make sure you check them over regularly for pests, and deal with infestations promptly.

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New Spider Species Discovered

New Species Discovered

Though it looks like a spider, has a web like a spider and moves like a spider, it’s not a spider. It’s actually a decoy built by a newly-discovered species in the Cyclosa genus.


When biologist Phil Torres was leading a group of visitors into a floodplain in Peru, he saw a white inch (2.5cm) long spider sitting its web. Its flaky appearance, seemingly covered in fungus, suggested it had been dead a while – until it started moving. It wasn’t until Torres got closer that he realized the illusion. The actual spider, only 5mm long in body length, was sitting above the decoy and shaking the web to create the illusion of movement.

The spider seems to be a completely new species, but its sculpting abilities have led experts to place it in the genus Cyclosa. Spiders in this genus are known to use debris in their webs to attract or confuse prey, but haven’t been seen to make anything as detailed as these decoys. The web-shaking behavior is also new. However more observations are needed before it can be declared a new species, as there is always the chance that this is a named spider engaging in never-before-seen behavior.

Photo credit: Phil Torres.

Sources (where several more photos are available)

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4 Tips to Avoid Ants!

Eliminate sources of water in and around the home. Indoors, routinely check under sinks for areas of moisture and repair any leaky pipes. Consider using a dehumidifier in damp basements, crawl spaces or attics. Outside, ensure that downspouts and gutters are functioning properly so that water flows away from the home’s foundation.

Keep a clean kitchen. Wipe down counter tops and sweep floors to remove crumbs and residue from spills. Store food in sealed containers, and keep ripe fruit in the refrigerator. Also, make sure to dispose of garbage regularly.

Don’t forget about the pets. After mealtime, keep pet bowls clean and wipe up any spilled food or water around them promptly. Store dry pet food in a sealed plastic container rather than the paper bags they often come in, which can be easily accessed by ants, rodents and other pests.

Work with a pest professional. Eliminating ants can be challenge without the proper treatment. Some species of ants, like carpenter ants, can cause serious property damage while others can pose health threats. If you see ants in your home, contact a licensed pest professional to identify the species and recommend a course of treatment.

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Keys to a Successful Heat Treatment

3 Keys to a Successful Heat Treatment:

  1. Bring Heat. Electric bed bug heaters are placed within the space; introducing and recirculating heated air with a target temperature not to exceed 135°F.
  2. Monitor. Temperatures are monitored in real time from a remote location using wireless sensors to ensure lethal temperatures are reached without damaging the space and its contents.
  3. Move Air. High temperature fans move heated air throughout the space to reach insects in cracks and crevices or high infestation zones.

Advantages to Heat Treatment:

  • Heat Treatment works where chemicals fail. No toxic fumes, no residue.
  • Kills every life stage from egg to adult.
  • Unlike chemicals bed bugs are attracted to heat – they won’t simply move to re-infest another day.
  • Infested items will not need to be thrown away.
  • Our trucks are discrete and the process is completed in one working day.

Heat Treatment is a proven non-chemical method of killing bed bugs. All life stages (adult, larva, and eggs) die within minutes at a temperature of 120 degrees F. Using 460 volt electric heaters powered by a trailer mounted diesel generator. Heat Treatment introduces temperatures greater than 120 degrees F(lethal temperature) and less than 140 degrees F (content damaging temperature).

Heat Treatment monitors temperatures in real time with 24 wireless sensors placed in treated areas to ensure lethal temperatures are reached throughout the area and its contents. High temperature blowers are positioned to move the heated air throughout the space, through mattresses, baseboards, cracks and crevices.

Depending on room furnishings, floor surfaces, clutter and square footage the treatment will take between 7 and 12 hours.

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