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Ornamental Crops IPM E-newsletter, 2009

For Summer 2009

In this Issue:

  1. IPM In-Depth Workshop
  2. Helping the Good Guys Finish First: Biological Control of Insects in Nurseries
  3. Disease Vectors: When Insect Feeding is Just the Beginning

Cornell IPM Team for Production Ornamentals

IPM In-Depth Workshop


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NYS IPM will hold their second IPM In-depth workshop from 12:30-5:00 on July 20, 2009. This year's hands-on topics are:

  • Aphid identification
  • Beneficial and damaging nematodes in the greenhouse and nursery
  • All about alkalinity - testing your water

Program details:

Aphid ABC's

Aphids may not be your #1 pest, but they often seem to blow up out of nowhere at really inconvenient times. How does that happen? Where do they come from? What kinds of aphids are common in greenhouses, why can it be important to know which kinds of aphids are on your crop, and how do you tell them apart? How can you detect an infestation before it gets serious? What pesticides are best for which aphids, and why? What sorts of predators and parasitoids can be used against aphids, and how do they work? We'll try to cover these topics. Feel free to bring in some aphid-infested plants and we'll see if we can identify which species you have.

Nematodes in the Greenhouse and Nursery

In this session we'll take a look at the increasing problems with foliar nematodes and root knot nematodes, we’ll look at the symptoms and the tiny, squirmy worms under microscopes! We'll also take a look at the very common free-living nematodes that can be found in all soils and beneficial nematodes that can be used to help control greenhouse pests.

All About Alkalinity

What is my water’s alkalinity? Why is alkalinity, not pH, the #1 factor affecting nutritional disorders? How come my alkalinity changes throughout the year? What is the best fertilizer choice for my alkalinity? How does alkalinity reduce effectiveness of some pesticides and how can you correct for this? In this session, we’ll learn the answer to these questions through ‘pHun’ hands-on chemistry exercises. Be sure to bring a water sample from your operation (rinsed 20 ounce plastic soda bottles work fine).

The Doctor is IN

Bring in plants that have ‘issues’ you can’t identify and our team of experts, and your fellow growers, will diagnose what the problem might be. We’ll all learn something!

The day after the IPM-In-Depth is Cornell's annual Floriculture Field Day (July 21).

Registration form - Combination form allows you to register for IPM In-Depth and/or Floriculture Field Day and Container Competition. Cost for the IPM In-Depth is $45 and attendance is limited to 45 participants. Pre-registration required.

Questions? Contact Betsy Lamb at or (607)254-8800.

Helping the Good Guys Finish First: Biological Control of Insects in Nurseries

Betsy Lamb, NYS IPM

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You can read articles on using biological control in greenhouses in every trade journal. But what about nurseries? How can they get in on the act? Actually, nurseries have the advantage as there is naturally occurring biocontrol happening all the time – for free!

You may have seen ladybugs and lacewings around your plants, but you may not notice the minute pirate bugs, rove beetles, parasitic wasps, hover flies and spiders happily chowing down on pest insects. There are several guides to beneficial insects that can help you identify the good guys you already have (see list below). Just remember, if there is nothing for them to eat, they won’t hang around - so not seeing huge populations of beneficial insects doesn’t mean that they haven’t been there.

You can help the good guys out by using basic IPM practices in the nursery. Natural enemies have a hard time getting ahead of huge pest populations – there is always a lag in getting the biocontrol numbers up. So keep pest populations low using cultural controls like optimum nutrition and water, and good air flow around the plants. If a pest hot spot develops, use spot treatments of pesticides rather than treating the whole nursery.

While there are a few instances where adding natural enemies to the nursery can work (augmentation), a more common method is to keep the naturally occurring beneficials there by making them happy – conservation and enhancement to biocontrol aficionados.

One way of doing that is by choosing chemical pesticides that have the least effect on beneficial insects. What you are looking for is a pesticide with a low immediate impact and short duration of impact on beneficials. You can check pesticide compatibility with some natural enemies on biocontrol companies ‘side effects’ lists (see below). Different life stages may be affected differently and different application methods may have different effects, so keep all those variables in mind.

Another way to encourage the good guys to hang around your nursery is to create a place for them to live, reproduce and feed. Some beneficial insects need, or can survive on, pollen or nectar. Pest insects may also live in this refuge and feed the natural enemies. A refuge can also provide a place for beneficials to escape from pesticide applications. A good refuge has a diversity of plants so there is something flowering all the time, in an area that is close enough for the good guys to move into the production area but not close enough to create a weed problem. And you may not need to create a new area. If your nursery has an unsprayed demonstration garden with plants blooming throughout the season, you may already have a refuge for your beneficial insects.

It always helps to have a few resources to back yourself up. There are many out there, but here are a few to get you started:

Identifying beneficial insects

Creating refuges for natural enemies

Pesticide compatibility

*** These tables are created for other states so the pesticides listed may not be labeled in NYS

Some Beneficial Nematode Suppliers:

Disease Vectors: When Insect Feeding is Just the Beginning

Brian Eshenaur, NYSIPM,

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Certain insects can act as vectors and are capable of spreading diseases. In fact with some diseases, movement by insects is the only means of spread. In some parts of the world mosquitoes can pick up the malaria pathogen and spread it from person to person. In New York, ticks can move Lyme disease and other pathogens from wildlife to people in a similar manner.

Insects in the greenhouse also vector some plant diseases of ornamentals. Impatiens Necrotic Spot Virus (INSV) is a particularly troublesome virus on many ornamental crops. Western flower thrips are the exclusive vector of this disease. These thrips can acquire INSV only when they are immature by feeding on an infected plant. Once inside the thrips, the virus multiplies within the salivary glands and the thrips can transmit it to other plants through adulthood. It is the adult thrips that are more mobile and more likely to spread the virus to healthy plants. Monitoring for thrips in the greenhouse using yellow sticky cards is an important tool for thrips management. Inspecting new plugs arriving in the greenhouse for both thrips and symptoms of INSV is also key. Reducing thrips numbers and their movement among plants is necessary to controlling this disease. Some growers have found using the quick on-site ELISA test kits to be an important tool for confirming the virus’ presence.

Many of us think of fungus gnats and shore flies as just a nuisance in the greenhouse but these insects have also been known to carry certain pathogens. They may pick up fungi on the surface of their body or consume spores while eating that are later passed through their digestive systems and onto other plants. Shore flies have also been shown to move bacteria from plant to plant. Spores of Verticillium, Fusarium and Thielaviopsis can be transported by fungus gnats. The fungus-like organisms Pythium and Phytophthora may also interact with fungus gnats and shore flies—insects’ role in the spread and severity of these diseases is an area of active research. In any case, removing infected plants as well as monitoring and controlling fungus gnats and shore flies could help control many root and stem pathogens.

Having an awareness of disease carrying insects will help growers minimize disease spread within a greenhouse. Insect vector management is an important consideration when developing an integrated pest management plan for greenhouse crops.

Cornell IPM Team for Production Ornamentals
Betsy Lamb
State Coordinator for Ornamental Crops IPM
Ithaca, NY,
Brian Eshenaur
Western New York Specialist
Rochester NY
Disclaimer: Pesticide recommendations are for informational purposes only and manufacturers' recommendations change. Read the manufacturers' instructions carefully before use. Cornell Cooperative Extension and Cornell University assume no responsibility for the use of any pesticide or chemicals.
Some of the links provided are not maintained by Cornell Cooperative Extension and Cornell University. Cornell Cooperative Extension and Cornell University are not responsible for information on these websites. They are included for information purposes only and no endorsement by Cornell Cooperative Extension or Cornell University is implied.
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