When plants are growing outdoors, it’s no surprise that they are at risk for pest activity. But even once produce is harvested and brought inside for storage and packaging, it can fall victim to pests’ appetites. In fact, pest infestations that are established during storage can put your produce at increased risk, as it is easy for pests to move and spread quickly in the closed environment.While a pest infestation in the field might be obvious as plants show signs of fatigue, develop deformations or die, an infestation in the warehouse can pass under the radar if it is not monitored. So, it’s important for your Integrated Pest Management (IPM) plan to include strategies for protecting your fruits and vegetables as you prepare them for storage and shipment. IPM strategies focus on preventive techniques, like exclusion, maintenance and sanitation and use sustainable, environmentally-friendly practices to manage and control pests.Fresh fruits and vegetables are vulnerable to pest infestations because of their succulence and the aroma they produce. Pests can infest produce items at any point in the supply chain, and improper packaging can make it easier for them to access your produce. Here are some of the most common pests that attack harvested fruits and vegetables:SpidersSpiders prey on insects and are naturally inclined to be found on foliage and vegetation. Therefore, harvested produce will harbour spiders. While in the field, spiders do help keep insect populations in check, but you don’t want them on your produce when it gets packaged and shipped.SpringtailsSpringtails are tiny insects that jump around when disturbed. They are attracted to moisture, dampness and humidity. They normally live in damp soil and feed on mold and fungi. So, naturally they will be found concealed in foliage and on plant stems, especially on vegetables that grow at soil level. As a result, they can easily make their way into packaged produce once harvested.Fruit FliesAs their name suggests, fruit flies are attracted to ripening and fermenting fruits and vegetables. Female fruit flies lay their eggs under the surface of fruits and vegetables. Therefore, a detailed inspection of random samples of fruits and vegetables to detect eggs and larvae is crucial to preventing a pest infestation in your processing and storage facilities. Sampled fruits should be cut through and examined for eggs and larvae, which are visible to the eyes.Indian Meal MothsWhile they only feed on dried fruits and vegetables, Indian meal moths are the most common stored product pest in food-handling facilities, homes and grocery stores. They are primarily attracted to dry foods and can damage products as their larvae spin silk webbing that accumulates fecal pellets and cast skins in the food. Common signs of an Indian meal moth infestation include the silk webbing, buildup of droppings in the food product and pupal cocoons along walls, shelving and ceilings.PreventionOnce harvested and packed, fruits and vegetables must continue to breath to maintain their freshness. So, packaging often has aeration pores that can make produce vulnerable to pest attacks, and it is difficult to find packaging that is impervious to all pest activity. However, there are some packaging materials that should be avoided for produce.Wooden containers can harbour wood boring insects. When exposed to moisture, they also can rot or cause mold and fungal growth that attracts insects which can spread and infect the packed produce. Rough, wooden boxes or bamboo like packaging can cause bruising and damage produce, which attracts insects. Materials less capable of withstanding stress also can damage produce, as they are vulnerable to tears, which can expose or damage the fruits and vegetables. Therefore, it’s important to choose the right type of packaging for your produce.In addition to avoiding these materials, keep an eye out for packaging that doesn’t seal properly. Even the best packaging doesn’t stand a chance if it’s not closed all the way or has a hole. At the end of the day, your goal should be to make it as difficult as possible for pests to reach your fruit and vegetable products.Fruit and vegetables are susceptible to pest infestations while they are growing. And once in storage, it’s easy for a pest infestation to spread quickly – especially with such an abundance of food for the pests to thrive on. So, it’s important to take steps to manage infestations in the field and to establish controls to help prevent infestations from being brought inside and spreading once in storage.In the field:
Pest prevention starts with Good Agriculture Practices (GAP) in the field that reduce conditions conducive to pest infestations.
Extensively monitor for pest activity by inspecting or scouting plants regularly during growing season to catch infestations early.
Reduce pest attractants by practicing good sanitation (phytosanitation) and eliminating onsite harbourage sites such as weeds, piles of compose, standing water and idle unused equipment.
Remove fallen, overripe or rotting fruits from the fields, as this could attract fruit flies and other pests.
At time of harvest, inspect extensively for insects and spiders on produce.
Harvest produce when they are dry. This prevents pest and diseases from clinging on them.
Clean and sanitize harvest equipment, bins and tools before and after harvesting.
Avoid or prevent bruising of produce. The bruising attracts insect pests, especially fruit flies.
In processing and storage:As a first step, implement these post-harvest handling practices:Sanitation
Have written cleaning and sanitation operating procedures for equipment and the facility.
Clean and sanitize packaging, handing bins and equipment regularly to prevent build-ups and habourages.
Regularly clean spills or trapped produce, especially in hard to reach areas and dead voids in packaging conveyer machines and equipment footing, as well as under and inside pallets.
Ensure floor drains have undamaged cover grids or traps to prevent trapping fruits and vegetables in the drain. This creates a breeding ground for fruit flies, drain flies and phorid flies.
Using drain brushes, mechanically clean floor drains at least every two weeks or so.
Ensure the floor is void of cracks and tile gaps. The floor should be smooth and level for effective cleaning.
Practice good fruit and vegetable waste management to avoiding attracting pests and creating harbourage sites.
Air curtains, sensor doors and roll-up doors keep flies from entering into processing or storage areas.
Install pest monitors like insect light traps and pheromone traps.
Repair screens and weather stripping around doors and windows.
Storage and Shipping
Use the first-in, first-out rule for storing and distributing products to avoid fermentation. Keep products off the floor on racked shelves.
Keep products refrigerated when you can. Temperature regulation and maintaining your cold storage system keeps the produce fresh and keeps pests away.
Allow proper illumination and ventilation to keep moisture down and discourage pest activity.
Avoid crisscross movement of packed produce to prevent pest contamination.
Ensure transportation vehicles are clean and temperatures are regulated.
Inspect packaging for pest activity prior to loading and shipping.
In addition to these preventive steps, be sure to monitor pest activity closely – indoors and outdoors. This will help you identify trends and adjust your pest management program to meet the unique needs of your property. You should also talk with your pest management provider about your process for storing and packaging food. They can offer recommendations specific to the types of produce you grow and help adjust your pest control program accordingly.Alice Sinia, Ph.D. is a quality assurance manager with regulatory and lab services with Orkin Canada.