Sensing a Food Plant — An Insect’s Perspective

©vasekk | iStock

Insects have a keen sense for the unusual extremes that make food plants attractive, especially as warm weather arrives. When outside temperatures exceed 80^° F, insects actively search for food, water, and shelter and show up in great numbers. Looking at a food plant through the insects’ senses might reinforce some Integrated Pest Management (IPM) issues to the obvious and provide some practical solutions to the oblivious. How do food plants make themselves less attractive? What are practical solutions?

To determine these, it’s important to understand the insects’ senses:

• Sight. Many insects have a remarkable sense of sight, very important to their survival in eluding enemies and searching for food. An insect’s eyes are of two kinds: compound eyes adapted to long-range vision and simple eyes for close-range vision. The compound eyes are dominant and more important. Insects need light to search for food, and most insects are attracted to light.
• Smell. An insect’s sense of smell also is highly developed. Insects deposit eggs in organic matter which they find with ease, even at distances concealed from sight.
• Touch. Its touch is well developed in its extremities, especially the antennae. Many insects also have sensitive organs (palps) around their mouthparts to feel for food; and its feel for temperature is remarkable.
• Hearing. Its hearing is quite variable; some with no sense of hearing and others with the power to hear just one sex.
• Taste. Its taste is not well developed, likely dominated by the sense of smell.

Thus, the insect’s senses of sight, smell, and touch/feel should be of concern to food plants, but are often overlooked. (Its hearing and taste are not of much concern.) For example, most stored product insects fly with a strong sense of sight and smell, navigating by light in search of food, water, and warmth (shelter), and often will find a food plant. Although insects tend to fly with the wind, they might smell a food plant from the wind arriving in both directions. Some common exterior problems for food plants and solutions to prevent insect attraction include:

1. Odor (e.g., compactors, dumpsters, large trash bins). Clean these areas whenever containers are being serviced and/or through a master cleaning schedule. Chlorine is an effective sanitizer and deodorizer with apparent fly repellent tendencies.
2. White lights especially near entries (e.g., above doors, on the building, near air intakes). Replace with high-pressure sodium lighting with overhead shielding and position it away from the building with lights aimed toward entries. Disable white lights, especially above doors and air intakes.
3. Temperature at or above 80^°F. Maximum development for insects occurs in the 80°F zone. Modifying environments to less than 75^°F will reduce insect attraction, slow insect development, enhance employee productivity, and likely extend product shelf life in warehouses.
4. Open, unscreened entries. If open doors or windows are necessary for air flow, durable nylon screening should be installed. Quick roll-up nylon screens are effective on dock doors. Quick automatic closures are excellent for frequently used dock and pedestrian doors.
5. Negative air pressure (outside to inside, inside from dirty to clean). Sourcing dirty air into clean zones is a microbial hazard. Establishing clean, cleaner, and cleanest zones within a building will help provide beneficial positive air pressure, and show positive results on air flow studies.
6. An “insect buffet.” Traveling from sewage treatment to dumpsters to roof drains to wet mulch to waste compactors to trash containers to floor drains to food spillage to food production — an insect can have a feeding buffet, ending with contamination of your facility or even a population explosion.

Looking at a food plant through an insect’s senses might put a different perspective on common problems and solutions. Managing flying insects is an important activity and requires intelligent effort, especially during warmer times.

As the famous quote by ancient Chinese Military General Sun Tzu says, “If you know the enemy and know yourself, you need not fear the results of a hundred battles.” The core of knowing the pest enemy is knowing its senses of sight, smell, and touch/feel. The core of knowing ourselves is using IPM effectively to manage exclusion, sanitation, and temperature. One fly inside a food plant is one fly too many and a sign of a lost battle.