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Ornamental Crops IPM E-newsletter, 2008

For Spring 2008

In this Issue:

Cornell IPM Team for Production Ornamentals

Reducing Weed Growth with Ornamental Groundcovers

Brian Eshenaur

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Cutting back on herbicides. Saving time and work. Landscapers, highway departments, and homeowners all stand to benefit from research out of Cornell University’s horticulture department and Cooperative Extension on weed-suppressive groundcovers.

Eighty five perennials were rated for how well they beat out weeds and how pleasing they look under a range of growing conditions. You can see the top 14—some familiar, others new—in six demo plots scattered around the state. Among the 14 you’ll find something for every growing condition.  One, Walker’s low catmint. began suppressing weeds three weeks after it was planted.

Weed Suppressive Groundcovers:  Clockwise from upper right, butterfly milkweed, blue woodsedge, ‘Walker’s Low’ catmint.

Find out more about this project, including a fact sheet on each of the 14 groundcovers.

The initial research was sponsored by the New York Department of Transportation. Support from the New York Farm Viability Institute helps us get the word out to New York greenhouse and nursery growers.

IPM In-depth: Hands on Workshop, Live and in Color!

Betsy Lamb
Coordinator for Ornamental Crops IPM
Ithaca, NY,

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Would you like to get nose to nose with some thrips? See what that grey fuzzy stuff really looks like?  Find out what’s going on inside your pots?  Come to the workshop for ornamental producers July 21, 2008 from 1:00-5:00 on the Cornell Campus, Ithaca, NY -  the day before the Floriculture Field Day.

You’ll have a chance to get hands-on practice testing container media and looking at Botrytis and thrips.  And bring your own media to test, or any insect or disease pests you need help identifying.  You’ll go home with a folder of materials that relate to the hands-on training sessions.  DEC credits applied for.

- Sessions -

Getting your hands dirty - testing container media for pH and salts

During this session you will get hands on practice using the two most popular methods for media testing (the 1:2 dilution and pour thru methods) and pros and cons of each.  Learn how to use these test results as powerful tools to adjust your fertilizer practices and reduce susceptibility to root-borne pests and pathogens.  You will receive supplemental material with pH and EC guidelines for common greenhouse crops.  Attendees are invited to bring their own container grown plant and a sample of their greenhouse tap water for testing.  Led by Neil Mattson, Floriculture Dept.

Thrips: Up Close and Personal

Learn the details about one of the biggest pests of flower crops: western flower thrips. You’ll see them alive and under a microscope, in all their life stages, and learn about how to detect them, how they live, reproduce, and spread, a little about the viruses they can spread, meet a few of their natural enemies, and think over some ideas about how to control them.  Led by John Sanderson , Entomology Dept.

Spots, Blights and Blasts: Hands-on Plant Disease Workshop

We'll begin this session with an overview of plant diagnostics, and then through hands-on work with Botrytis, we’ll learn how disease problems develop and how to best protect plants.  Hand-lenses and microscopes will be used to see how spores spread, germinate and cause disease.   Led by Brian Eshenaur, NYS IPM.

The cost of the entire program is $45, which will include a campus parking pass for the day.  Registration materials will be available soon.  For more information, please contact Elizabeth Lamb, (607) 254-8800 or

Release Monitoring for Parasitic Wasps

Laurie Mickaliger, Agricultural Stewardship Technician, Cornell Cooperative Extension of Suffolk County

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Quality Control for the Beneficial Insects You Receive

Releasing beneficial insects into a greenhouse operation is becoming increasingly popular. You can now easily purchase biological control agents to aid in the control of greenhouse pests ranging from aphids to thrips to whiteflies.

Staff at Cornell Cooperative Extension on Long Island have been working on several biological control projects, including controlling whiteflies in poinsettia production using parasitic wasps. One result of this study was the development of a monitoring system for parasitic wasps. The only way to really know how many biological control agents were working in the greenhouse environment was to monitor their release in a confined environment.

We recommend that any grower who works with biological controls do the same and as you’ll see, it’s a simple process that can serve you well.  This parasitic wasp monitoring system uses a catch-can method. The supplies used to create the catch can include: a mason jar with a lid, a piece of tightly woven fabric (make sure the fabric mesh is smaller then your beneficials), 1/3 of a 3”x4” sticky card or approximately 1”x2” piece of sticky card, a wire tie (longer than the mouth of the jar is wide), masking tape or a label, a sample of the biological control agent, a marker/pen, a hole punch, and a hand lens - items that you have on hand.

Before you monitor your beneficial shipment you need to do a few things. First, check your shipment immediately for any damage to the product. Next, record the batch number of your product so that if there is a problem you can relay all of the pertinent information back to your distributor/supplier.. The batch number is generally a date or code written on the label or on the back of the product. Take one or two samples from each product in the shipment depending on the size of the order. This could be 1-2 release cards or 1-2 blister packs. If you are taking two samples, place each sample in a separate catch can.

Materials used to assemble a simple release monitoring unit. 

Step 1: Place the sample of the beneficial agent at the bottom of the jar/container. (Remember to open the release packaging if necessary.)

Step 2: Punch a hole in the sticky card and place the wire tie through the hole in the sticky card and hang it from the top of the jar/container. (Make sure the sticky card is hanging and not touching the beneficials or the bottom of the jar.)

Step 3: Place the mesh on top of the jar/container followed by the lid.

Step 4: Use the masking tape to make a label for the jar. Label the jar with the following information: date, name of the beneficial, supplier’s name, batch number, contents of the sample (i.e. 1 card) and the distributor (if using multiple distributors).

Step 5: Place the jar in a protected, room temperature area, out of direct sunlight, not in the greenhouse.

Step 6: Monitor for two weeks. This allows for enough time for all of the pupae to hatch.

Step 7: Count your findings on the sticky card.  The hand lens or any magnifying device will come in handy at this time. (The beneficials on the sticky card are ones that considered viable because they were able to fly and travel through the crop.) Once you count your sticky card you will have a rough estimate as to the number of wasps that emerged from the cards or blister packs.

To get a rough estimate of how many wasps were released into the greenhouse, you can use this calculation: the number of wasps on the sticky card X the number of wasps ordered / the number of wasps the package was supposed to contain. An example would be: An order for 10,000 Eretmocerus eremicus wasps was received in 40 blister packs (each blister pack contains 250 wasps). One blister pack was used as a sample and there was a total of 264 wasps on the sticky card. To find the rough estimate of how many wasps were released into the greenhouse we can use our formula: (264 * 10,000)/250 = 10,560. This means that approximately 10,560 wasps were released into the greenhouse.

You should expect the number you catch to be fairly close to the specified amount. If any discrepancies occur, contact your supplier immediately. 

This procedure works well for beneficial wasps sold as pupae on cards or in blister packs. As we continue working with biological controls, we’ll  develop, and report on,  additional monitoring methods for other beneficial insects.

Cornell Guidelines Available for Purchase

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Greenhouse Floral Crops
Item Code: GFC-08, List Price: $25.00 (shipping INCLUDED)
This annual publication provides up-to-date pest management information for those producing greenhouse floral crops in New York State. It has been designed as a practical guide for producers, pesticide dealers, and others who advise those producing greenhouse floral crops or operating a greenhouse.

In addition to the annually revised pesticide and pest management information, highlighted changes in the 2008 Greenhouse Floral Crops Guide include:

  • A reorganization of the insecticide chapter to eliminate repeating product details while providing a simpler method to select appropriate insecticides.
  • The addition of mode of action classification numbers to insecticide listings for use in insecticide resistance management programs.
  • An updated growth regulator discussion, including expanded growth regulator listings.
  • Revised disease and fungicide chapters that include the addition of: cladosporium to diseases of concern, nemesia to the listing of specific floral crops, new fungicides, and new fungicide resistance information for more recent chemistries.
  • A revised biological organism chapter.

Herbaceous Perennials
Item Code: HP-08, List Price:  $25.00 (shipping INCLUDED)
This annual publication provides up-to-date pest management information for those producing and maintaining herbaceous perennials in New York State. It has been designed as a practical guide for producers, landscapers, pesticide dealers, and others who advise those producing or maintaining herbaceous perennials.

In addition to the annually revised pesticide and pest management information, highlighted changes in the 2008 Herbaceous Perennials Guide include: The addition of two new reference tables: one on the mode of action classification for various insecticides/miticides and another on herbicides registered for landscape use.  A new section on herbicide resistance.

Trees and Shrubs
Item Code: TS-08, List Price:  $25.00 (shipping INCLUDED)
This annual publication provides up-to-date pest management information for managing pests in ornamental trees and shrubs. It has been designed as a practical reference for producers, pesticide dealers, and others involved in production and maintenance of ornamental trees and shrubs.

In addition to the annually revised information, highlighted changes for 2008 include:

  • Relocating all general pesticide information into one chapter.
  • Revisions to the insect management chapter that include adding the active ingredients cypermethrin, indoxacarb, iron phosphate, milbemectin, and tebufenozide to the insecticide listings, identification of federally-restricted pesticides to aid in determining supervision requirements, and the addition of insecticide mode of action group numbers.
  • Additions to the weed management chapter including a new herbicide resistance discussion and a new table to identify herbicides registered for use in landscapes.


Item Code:  TG-08, List Price:  $18.00 (shipping INCLUDED)

This annual publication provides up-to-date pest management information for those producing or maintaining turfgrass in New York State. It has been designed as a practical guide for sod  producers, landscapers, turfgrass managers, pesticide dealers, and others who advise those producing or maintaining turfgrass. Highlighted changes for this year include:

In addition to the annually revised information, highlighted changes for 2008 include:

  • Updated Internet resources for insect pest management.
  • Addition of mode of action and risk of resistance table for turfgrass fungicides.
  • Revisions to the disease management options, including organizing listed fungicides and nematicides by restricted-use, general use, and no use in Nassau and Suffolk counties.
  • Addition of a new plant growth regulator chapter and an expanded listing of currently registered plant growth regulators.
  • A brand new weed management chapter.

To order, go to the Cornell University Pesticide Management Education Program Online Store, or call 607-255-7282, or email Many extension offices in NY have them available.  Contact your local office.

Diagnosis Detective: Figuring Out What’s Wrong with Your Plants

Betsy Lamb
Coordinator for Ornamental Crops IPM
Ithaca, NY,

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Successfully treating a plant problem first requires identifying exactly what the problem is.  What you first notice may not be the cause of the problem at all so it is important to begin with an open mind.

1. Symptoms:  What kind of symptoms does the plant have?  This means you need to know what the plant is supposed to look like.  For example, some normal variegated leaf coloration can look like virus symptoms.  Symptoms including wilting, loss of leaves, holes in leaves, and  unusual growth can be caused by insects, diseases, or abiotic – non-living - agents.  Look over the plant carefully to make sure you have seen all the types of symptoms present.  Check  the roots, too, as root damage can also have an effect on the upper parts of the plant.

2. Signs:  Sometimes there are also ‘signs’ present – actual visible evidence of disease organisms or insects.  You might find the insect itself, cast skins, webbing, droppings, fungal growth or fungal fruiting bodies.  Just keep in mind that some insects or diseases are ‘secondary’ – feeding on the damaged tissue caused by another pest. 

3. Development:  When did you first notice symptoms?  Did they spread through the field or from plant to plant? How quickly? You may not notice the first symptoms but try and keep track of what happens as the problem develops.  Of course, you may want to stop the problem rather than watch it get worse, but any information on symptom development is helpful.

4. Patterns: Are there any obvious patterns to the damage?  On a single plant, you might see damage on the top portion, which may or may not be spreading to lower parts of the plant.  Or maybe it is just on one side, or just on the interior, or just at the base, or randomly over the whole plant.  Most pests have specific feeding or infection methods which can cause the plant to react in a particular way, leading to patterns.

If you have a field or bench or garden of the same plant, look for patterns in the group of plants.  Are damaged plants all along one edge of the bench? Are they randomly scattered or down a specific row?  Did the problem spread from one plant outward to others or did it occur all at once in one part of the field?  Insects and diseases can move by themselves or on wind currents or in the soil water and the pattern may indicate which pest it is or if it has an abiotic cause.

Plant diseases and insects are often specific to certain plants.  Check around the plant with symptoms to see if other, non-related plants, even weeds,  have the same kinds of symptoms.  This may indicate that an abiotic factor is causing the problem.

5. Environment: Check the environment.  The other plants growing happily nearby can sometimes indicate if the area is too wet, too dry, or too shady.  Has there been a frost or freeze recently?  Is the plant close to roads that are salted in winter?

6. History: What else has happened recently – or not so recently?  Drift from a herbicide spray can cause symptoms that look like disease.  Drought in a previous year can have effects this year on growth or dieback or flowering.  Even a lightning strike can cause plant symptoms.  Has the site been changed?  Has fertilizer been applied? Random acts of lawnmower or equipment violence? Remember, the effects may be gradual.

7. Get help!  Even with all this information you may not be able to determine the cause of the problem yourself.  But having it all ready will help an expert diagnose your problem – and they will be really impressed!  The first place to check is your County Cornell Cooperative Extension office.  Many offices have educators with lots of experience who can help.  Cornell also runs diagnostic labs for plant diseases and insects.  You will need to send a sample and pay a fee for the diagnosis.  The following websites provide the information you need to properly sample the plant and send in the sample.

Plant Disease Diagnostic Clinic
329 Plant Science   Ithaca, NY 14853
Phone:(607) 255-7850
Fax: (607) 255-4471

Insect Diagnostic Laboratory
4140 Comstock Hall
Cornell University
Ithaca, NY 14853-2601
Telephone Consultations: (607) 255-4777

Cornell IPM Team for Production Ornamentals
Betsy Lamb
New York State Coordinator for Ornamental Crops IPM
Ithaca, NY,
Gary Couch
Eastern New York Specialist
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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