We all know that true friends cannot be bought with money — but there’s one instance where they can.
Suzanne Wainwright Evans, aka Buglady Consulting, is a horticultural entomologist specializing in Integrated Pest Management and with a focus primarily on biological controls and the responsible use of pesticides. When I attended her biocontrol presentation titled “Rethinking Rose Pest Management,” I discovered that, apparently, true friends can be bought for our gardens. These true friends include parasitoids, predators, predatory mites and beneficial nematodes.
Nature gifts us with many blessings, including the gift of these beneficials, which come to us free of charge. To minimize pesticide use, commercial growers have had an additional option, to use purchased biological controls for pest management. Now, this purchase option to increase nature’s bounty of “good guys” is also available to home gardeners.
But before we invest in purchasing biological controls, aka biocontrols, we need to recognize the importance of growing plants in their optimal cultural conditions, being present in our gardens to monitor and scout for pests, and using mechanical means as our first tier to dealing with pests. Good gardeners always take the time to identify the pest, know its life cycle and mechanically remove observable pests and pest damage. This knowledge is also important in helping us decide which biocontrols to purchase.
Buying biocontrols is just one more layer to augment our pest-control toolkit. We definitely shouldn’t just give up on attracting beneficials to our garden naturally, because biocontrols come with an expensive price tag and are not typically a one-time purchase. However, biocontrols are an environmentally sound way to keep pests in check. They are also a much better approach than buying pesticides, which can be equally or more expensive. In addition, pesticides, unlike biocontrols, hold the potential of harming beneficials and our environment.
Purchasing biocontrols
Some companies have minimum orders, and because biocontrols are alive, delivery is time sensitive and can be expensive. Some buyers purchase in a group to get better pricing and better quality. Suzanne told us there is a not-for-profit Facebook group called DMV Beneficials that enables members to group together to purchase biocontrols (there’s also a local chapter, San Diego Beneficials). With a little organization, clubs or neighbors could order biocontrols and share the cost of delivery.
Companies that raise beneficial insects for purchase are known as insectaries. When we purchase from these insectaries, we have many choices of predatory insects and parasitoids. We can purchase the biocontrols in different life stages depending on the species. Suzanne told us that the majority of insectaries are labs located outside the United States. Some companies Suzanne mentioned are Beneficial Insectary, BioBee, BioBest, Koppert, Bioline AgroSciences and Associates Insectary.
Beneficial Insectary is the only large insectary that has production in the United States (There are a few smaller specialist producers). Some of the insectaries that sell in the United States include Associates Insectary, Beneficial Insectary, Bioline AgroSciences, BioBee and Koppert.
We can also place orders and purchase from companies that are distributors. These companies include Arbico Organics, Nature’s Good Guys, Planet Natural, IPM labs and Evergreen Growers Supply. The disadvantage to purchasing biocontrols through a middleman company is the potential for a delay in delivery; when we receive an order, predatory mites and most other biocontrols must be used right away. Beneficial nematodes and a few other biocontrols can be refrigerated for a few days. Buyers must read and follow directions explicitly.
Biocontrols packaging and application
Packaging of biocontrols can include bottles, bags with carriers, sachets, tubs, trays, egg cards and balls. Gardeners check the list of pests on the insectaries’ website to determine which biological control to buy. The following is a small sample of the types of controls available for purchase.
• Predatory mites, such as Phytoseiulus persimilis, Neoseiulus californicus, Neoseiulus cucumeris, Amblyseius swirskii and Stratiolaelans scimitus. Persimilis must be applied as soon as possible, normally on the same day they arrive. Other species come with food and will be OK as long as you apply them within one to two days after arrival. The product is sprinkled on plant leaves unless the directions say to apply them on the soil. These predatory mites feed on pests including spider mites, thrips and whiteflies.
• Lacewing egg cards. Lacewing larvae are good generalist predators and feed on aphids, spider mites and many other pests. Lacewing egg cards, which have eggs glued on cardboard cards, are relatively cheap, easy to buy and use. The cards have perforations that you separate into individual tabs and hang on a plant. When the lacewing larvae hatch, they begin hunting for pests. Lacewing larvae can be purchased in a tub and need to be kept cool until application.
• Slow-release mite sachets. These sachets can last 4 to 6 weeks. The sachet is a breathable water-resistant paper that attaches to the plant with a hook or stick. There is bran in the sachet for feeder mites to feed on, and a pinhole for the predatory mites to climb out and disperse. The sachets can take overhead water, irrigation or rain, but it is best not to have them in direct sun. A sachet should be hung on each plant unless the plants are touching, because predatory mites cannot fly.
• Beneficial nematodes. These naturally occurring microscopic organisms found in the soil parasitize a wide range of insect pests that have soil dwelling larval or pupal stages. You pinpoint the pests you want to address and select one or all of the three available varieties. The beneficial nematodes arrive in a pouch that you mix with water and agitate frequently while spraying or watering them onto the soil.
• Ladybeetles are great beneficials, but don’t buy ladybeetles in tubs that have been wild harvested. The wild harvested ones are the species Hippodamia convergens, known as the convergent ladybird beetle. Wild harvested lady bugs disrupt ecology and can spread Microsporidia, a pathogen that is killing lady beetles. In a study, 13 of 22 shipments detected Microsporidia and the ladybug parasitoid, Dinocampus coccineliae, was found in beetles from all shipments. In the European Union, it is illegal to buy wild harvested lady beetles. As an aside, Suzanne mentioned that it would be better if Asian lady beetles (Harmonia axyridis) weren’t here, but they are, nonetheless, beneficials.
Importance of plant diversity
Suzanne stressed the importance of growing a diversity of plants, and not a monoculture of roses. She emphasized that by creating a habitat and planting nectar and pollen plants like sweet alyssum, we can naturally attract beneficial insects to our gardens. She warned against growing marigolds close to our roses, as she said they are a draw for spider mites, thrips and powdery mildew.
Fall cleanup
Suzanne pointed out that we can destroy ecology when we rake up leaves in the fall. Beneficials need overwintering places and habitats. Suzanne does her spring cleanup when she starts seeing the spring insects. When you do clean up yarrow, echinacea and other plants attractive to beneficials, she suggests that you leave them on your property. But she stressed that this advice differs for diseased plant material, which should NOT be left to overwinter.
Biological disease controls
Suzanne mentioned two products that are preventive biological disease controls of powdery mildew, blackspot, botrytis, rust and downy mildew. She highly recommended an OMRI-listed product called Magic Gardener Biological Disease Control, which uses a strain of Bacillus amyloliquefaciens and is very safe for beneficials. I have checked and this product is not yet for sale in California. Suzanne also mentioned OMRI-listed Milstop, which is a foliar fungicide that effectively controls and suppresses powdery mildew by killing spores on contact and preventing the spread of the disease. It utilizes potassium bicarbonate as its active ingredient.
Augmenting beneficial populations in our gardens is a great proposition. I really like the free price tag that comes with the “good guys” that are attracted to my garden naturally. They will always continue to be my “besties.” But I was curious, decided to experiment and purchased three varieties of beneficial nematodes, predatory wasps Neoseiulus cucumeris, and lacewing egg cards. I will monitor my garden to see how these purchased friends perform in my garden.
No endorsement of these products or companies is intended, nor is criticism implied of similar products and companies that are not included.
Perwich is a member of the San Diego Rose Society, a Consulting Rosarian and a Master Gardener with UC Cooperative Extension. For more information, visit rose-harmony.com.