The Basics of Bio Control of Insects for Greenhouses and Nurseries
These methods are successful when managed properly and control is attainable using BCA's individually and with soft chemicals. The importance of scouting is a significant part of a successful bio control program, and this process is explained along with the methods for implementation.
Bio control of insects is a strategy that is gaining adherents in greenhouses and nurseries currently. Some of the production greenhouses using bio control in Pennsylvania include Creek Hill Nursery, and North Creek Nurseries. Botanic gardens and arboreta also use this insect management strategy (such as Longwood Gardens), and aspects of bio control are utilized at the Penn State Flower Trials as well. Laura Buck, IPM coordinator at Creek Hill Nursery, is interviewed about the success of the bio control program and the scouting procedures that are used at Creek Hill.
Some of the typical greenhouse and nursery pests are shown in this program, including aphids, spider mites, thrips, white flies, and fungus gnats. Selected predatory and parasitizing BCA's that attack these pest insects are also shown in this video as well. The principals of the use of bio control are briefly explained, along with some information on successful application of these pest bio control measures.
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- [Sinclair] Biocontrol is an important tool for greenhouse and nursery use.
A number of commercial firms are using this strategy to successfully control insects, such as perennial plug producer North Creek Nurseries, shown here in Landenberg, Pennsylvania.
Creek Hill Nursery in Leola, Pennsylvania also uses this method of insect control successfully.
Botanic gardens and arboretum can implement biocontrol where collections of plants are permanent to semi-permanent.
At the Penn State flower trials, aspects of biocontrol are used both in the greenhouse and field production of the flowers being tested each season.
Aphids are one of the first insects we typically see in spring.
Over 4,000 species are known and about 250 are serious pests of agricultural, forestry, and horticultural crops.
Aphids can multiply rapidly and two aphids on a plant or crop on Monday can multiply to 100 by Friday of the same week.
These sucking insects are vectors of many plant virus diseases.
Aphis nerii is a specialist and will only attack milkweed and oleander, unlike potato aphid.
Green peach aphid, or Myzus persicae, is another generalist and will attack a wide-range of plant species.
As they grow in population numbers, winged adults will form and move to other plant species.
Macrosiphoniella sanborni, or the chrysanthemum aphid, is a very specialized aphid and will only attack chrysanthemum.
Prompt aphid control is an important aspect of good horticultural practices.
A number of good generalist predators are available commercially, like ladybird beetles.
Not only do they attack aphids, but they will attack other problem insects like mealy bugs.
This picture shows a large number of ladybird beetles found in the United States.
This collection is part of the USDA ladybird species collection.
One ladybird beetle can consume 5,000 aphids in its lifespan.
Larvae are particularly effective as predators in the ladybird species.
Green lacewings are also a useful predator of the generalist type, as they eat many insects.
They can consume scale, spider mites, mealy bugs, and others.
This is an adult lacewing, but the larval stage is very effective in controlling many species of insects.
Usually they have large wings with lacy markings.
Generally they do not reproduce in greenhouses.
Aphidoletes is a delicate midge that lays 100 to 200 eggs per female and the larvae will kill about four to 65 aphids.
Aphelinus is about three thirty-seconds of an inch long and is best used preventatively and can be applied with Aphidius.
Aphidius colemani and ervi are used commercially and are less than one-eighth of an inch long and not affected by day length; controlling cotton aphid, green peach aphid, tobacco aphid and bird cherry oat aphid.
The larger aphids are controlled by Aphidius col ervi.
This is an aphid mummy which is the result of an ervi or colemani attack.
As you can see, the parasitization right here, then the larvae will chew their way out of the backside of the aphid.
Syrphid flies are wonderful beneficials that actually will work their way into the greenhouse.
The adults feed on nectar, but the maggots or larvae feed on aphids.
They are very effective in cleaning up an infestation of aphids in many types of plants.
Scouting is very important as an aspect of a sound biological control strategy and successful implementation is necessary to scout on a weekly basis to determine changes in insect populations.
Two spotted spider mite typically feeds on the lower leaf surfaces and chemical resistance makes this a prime target for biological control.
Phytoseiulus persimilis is a predatory mite and one of the effective biocontrol strategies.
Phytoseiulus moves rapidly, as you can see, seeking out two spotted spider mites in the foliar canopy of the plant.
This is a very common successful control, giving a quick knockdown of spider mites.
Phytoseiulus persimilis will consume 20 spider mites per day, typically, and does a very good job of cleaning up a crop on a foliar canopy.
To deploy these mites is a simple matter, shaking them out over the crop to be treated.
Another way to get them into the canopy is to use a sachet for vertical systems or hanging baskets.
When you have this much flowering material in a greenhouse, likely you will find thrips.
Thrips such as western flower thrips not only transmit virus diseases, but they also damage flowers and foliage of many plant species.
Again, chemical resistance has been shown with thrips and biological control can be a very good alternative strategy.
Typically, thrips feed on nectar and pollen as well as flower petals and foliage.
They're transported on the wind and can move about geographically.
While there are many choices for biocontrol, one effective control is the minute pirate bug.
Orius can survive on nectar and pollen in the absence of thrips.
Poinsettias, a long-term greenhouse crop, are often beleaguered with white flies in the later part of the production cycle.
Greenhouse white flies have also shown chemical resistance and biocontrol has proven to work well.
Delphastus is an excellent consumer of white fly.
Rove beetles are useful in the cleanup of undesirable insects in potting media, consuming a wide range of species.
Fungus gnats are a particular problem in young plants, seedlings and cuttings.
Larvae chew on the root systems of young plants and adults are distinguishable by a Y-shaped vein pattern in the wing.
Fortunately, these are easily controlled using beneficial nematodes.
Steinernema may be applied through the hose injector system or with a watering can.
Simply dissolve the material in the water and apply through the hose and injector.
For a good biological control program, scouting and recordkeeping are paramount.
Work closely with your BCA suppliers, adjust the chemical use to fit your biocontrol strategy and preserve and conserve the naturally occurring BCAs in your environment.
We hope you have enjoyed this video.