Protect Roses With Bugs

Growing Roses with Beneficial Bugs

At Heirloom Roses, we are always looking at more sustainable methods of producing our roses. One of the most exciting changes we have made at the nursery involves our Integrated Pest Management (IPM) program. IPM takes a holistic approach to growing roses, with an increased emphasis on scouting for pests and maintaining healthy plants as ways to minimize the use of chemicals. One of the cornerstones of our IPM program is the use of beneficial predators for pest control.

A New Motto

Avid gardeners are already familiar with the time-honored tradition of releasing ladybugs to control aphids; in essence, we have applied this philosophy within all of our greenhouses. Our first line of defense against harmful pests is now using beneficial insects (“good” bugs that eat the “bad” bugs).

Predatory mites, parasitic wasps, rove beetles and midges now roam our crop, seeking out insect pests to dine on. This has proven to be an effective and earth-friendly growing practice that has dramatically reduced insecticide use. As our beneficial supplier likes to say, “Bugs, not drugs” create healthier plants.

Spraying your roses with a jet of water spray can be an effective alternative to chemicals. Spraying your roses with a jet of water spray can be an effective alternative to chemicals. A high-impact water spray is often enough to injure or knock aphids off of plants.

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Natural Balance

We use a variety of beneficial predators to control pests such as aphids, thrips, whiteflies, spider mites, and fungus gnats. These greenhouse pests are headaches for any grower; they are rarely a problem outdoors where birds and other insects keep them in check. It is this natural balance we seek to imitate in our greenhouses by releasing beneficial predators.

The predatory midge Aphidoletes aphidamyza The predatory midge Aphidoletes aphidamyza, with its long, elegant antennae, takes a rest on a rose leaf as it seeks out aphid populations to lay eggs near. One larva may feed on as many as 80 aphids before dropping to the soil to pupate. Adult midges fly at night and are often seen in dancing swarms at dusk, when mating occurs.

Aphidius: Before Like a scene from a horror movie, the parasitic wasp Aphidius matricariae lays it’s eggs directly inside of a live aphid, creating a “mummy”

Aphidius: After Note the exit hole created when the predator emerged. Other beneficials include Hoverflies and Ladybugs


What has been most interesting, however, is the number of predators in the greenhouses that we never released. It turns out that Mother Nature has been waiting in the wings all along, ready to take over as soon as we reduced the insecticides. The hoverflies, ladybugs, lacewings, and Aphidius all showed up on their own. This has made scouting more challenging, as new arrivals must be studied and categorized as Friend or Foe. We ask our customers to do the same, as our beneficials may be “shared” when they are shipped with the roses. Speed is an indicator: if it moves quickly, chances are it’s a predator chasing a pest.

Ladybug Lady Bug Hard at Work

Hoverfly Hoverfly


larvae of many beneficial insects make for effective predators They may not win any beauty contests, but the larvae of many beneficial insects make for effective predators. Here, a brown lacewing egg has been laid amongst a population of harmful spider mites (note how you can see the eyes of the brown lacewing inside the egg). The inset photo shows what the larva looks like upon hatching. Large, powerful pincers are an indication that this creature eats pests and not plants, making the larva of this predator one of the “good guys.”

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For more information regarding the use of beneficial insects, please visit our suppliers: Evergreen Growers Supply at www.evergreengrowers.com or Applied Bio-nomics, Ltd. at www.appliedbio-nomics.com.