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Ornamental Crops IPM E-newsletter

The purpose of this e-newsletter is to provide regular integrated pest management updates to commercial horticulture educators in the Cornell Extension system and others that are in the position to use and disseminate information. It is our intent that the content from these updates will be used in newsletters and programs that reach New York growers.

E-newsletters are sent out on a quarterly schedule (Spring, Summer, Fall and Winter). We welcome your feedback on the content and/or format of the information.

We would appreciate it if you would let us know when and where you are using the content. This will help us determine the types of information that are useful for you and your programs, and will give us some information on distribution of the information.

This newsletter is written by Brian Eshenaur and Betsy Lamb; Extension Educators with Cornell University's New York State IPM Program for Ornamentals.

If you would like to be included on the email list, please email Brian Eshenaur and ask to be added to the list.

see previous issues below

Our most recent issue: For Spring 2011

NYS IPM Program Saved by Stakeholders: Thanks to the efforts of concerned NY growers, the IPM Program was funded in the state budget that passed in early April. Thank you for your support!!

In this Issue:

  1. Swiss Needlecast
  2. What's in the Water? Alkalinity and growing conifers
  3. Annual Cornell Floriculture Field Day and IPM In-depth
  4. 2010 New York Greenhouse Production Figures
  5. Ornamental Crop Growers Opinions Needed


Cornell IPM Team for Production Ornamentals

Swiss Needlecast

Brian Eshenaur, NYS IPM Program

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Currently the biggest problem Douglas fir growers in NY are dealing with is Swiss needlecast. It has been more difficult to control than Rhabdocline and has caused some Christmas tree growers and landscapers to stop planting the customer favorite, Douglas fir.

Why Swiss? Swiss researchers noticed this needlecast disease on Douglas Fir trees established there in plantations in 1925. So, although the fungus that causes this disease is native to the Western US, where the Douglas fir grows naturally, it was first identified in Switzerland and the name stuck.

It's a fungus. Swiss needle cast is caused by the fungal pathogen Phaeocryptopus gaeumannii. It grows inside the needles and produces rows of tiny black specks on the undersides of the needles that may make infected needles look sooty. It is these black fruiting structures that produce the fungal spores.

Give it moisture and watch it spread. The majority of spores are released in the spring beginning in April but spore release can continue through September. The newly formed needles are the most susceptible and most infection takes place during wet spring weather. Damp rainy weather creates an environment where the spores can infect foliage so this disease is worse after unusually wet springs. It takes about a year before the infected needles produce the black fungal fruiting structures.

It's often there before you know it. Unlike Rhabdocline and most needlecast diseases, Swiss needlecast can sneak up on growers because infected needles can remain green and attached to the tree. In fact the diseased needles may produce spores for three seasons before they turn off-color and are finally shed. Eventually the needles will fall and in the most severely affected plantings, only the green needles at the tips of the branches are present. When infections reach this level, the tree's growth is severely stunted. It often makes sense to remove the most severely affected trees to reduce sources of the fungus.

Resistant trees and fungicides can help. Not surprisingly research found that tree seedlings originating from drier areas east of the Native Ranges in the Pacific Northwest were more susceptible to Swiss needlecast than seed collected from wet forests near the coast. However disease resistance can't be looked at without considering cold hardiness, postharvest needle retention and other characteristics of a quality tree. Even within a single seed source, growers can see natural variation in levels of susceptibility in the field.

Protecting the new foliage as it emerges with a fungicide can provide good control. The fungicides that are known to be effective include chlorothalonil, mancozeb, or Spectro 90 WDG. Treatments start when about 10% of the trees have broken bud and continue at three to four week intervals until July 1. Follow all product labels for specific instructions.

What's in the Water? Alkalinity and growing conifers

Elizabeth Lamb, NYS IPM Program

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Most of us remember learning about pH in high school chemistry – acids and bases and what happens when you mix them together. That's right – pH is a measure of the concentration of positively charged hydrogen ions dissolved in the water. The higher the concentration, the more acid the water is. Alkalinity is also based on what is dissolved in the water, but in this case it is the concentration of alkalis – compounds like calcium carbonate – which when dissolved form negatively charged ions. So water with high alkalinity tends to neutralize acids and tends to have a basic pH.

Thanks for the chemistry lesson – why do I need to know this? Because the pH and alkalinity of your water can affect your conifers and any other plants you are growing.

All plant species have soil pH ranges that are optimal for growth. Often they match the conditions where the plants are native. Trying to grow a conifer out of its pH range can result in poor growth or yellowing of needles. Finding exact information on ranges can be difficult but the following table should help.

Species Optimal pH range
Fraser fir 5.3-5.7 (not above 6)
Balsam fir 4.5-6.0
Canaan fir 5.5-6.5? (higher than Fraser)
Concolor fir 4.5-7.0
Douglas fir 3.7-6.5 (Rocky Mountain 5.5-7.5)
Blue spruce 5.5-6.0
White spruce 4.8-6.5
Scotch pine 5.0-6.0 
E. white pine 4.8-7.4

Soil pH can also affect soil fertility. Some nutrients get tied up in compounds that can't be taken up by the tree's roots at certain pH levels. For example, nitrogen, potassium, calcium and magnesium all become less available to plants at pH's below 6. If you are growing your trees in low pH soils, you might need to take that into consideration when planning a fertilizer program. Different fertilizers also have different effects on soil pH so you may be able to match your soil pH to your fertilizer for best results. Ammonium and urea forms of nitrogen are acidic and nitrate forms are basic. Fertilizers may have a mix of types so check the label.

available elements

The pH and alkalinity of your water source can also affect your production. For example, alkaline water will reduce soil pH over time. Few field grown conifers grown in NY are irrigated, so this may not be a concern but for those grown in pot production, irrigation water may need to be acidified to maintain the low soil pH desired.

The pH and alkalinity of your water can also affect how your pesticide applications work. In some cases, high alkalinity causes the active ingredient to break down. Water pH over 7 can affect the efficacy of glyphosate (Roundup), paraquat (Gramoxone), bentazon (Basagran), clethodim (Envoy), sethoxydim (Poast), and 2,4-D (many products) (from Weed Management In Nursery Crops, Dr. James Altland, Oregon State University). The following table lists the optimum water pH of certain insecticides and miticides and comments from the Cornell Pest Management Guide for Commercial Production and Maintenance of Trees and Shrubs.


Common Name Optimal Water pH Tree and Shrub Guidelines
Abamectin 6.0 to 7.0  
Acephate 5.5 to 6.5  
Acetamiprid 5.0 to 9.0  
Azadirachtin 5.5 to 6.5 Do not mix with alkaline materials, buffer water to pH 3-7
Bifenazate 6.5 to 9.0 Do not mix with alkaline materials, buffer water to pH 7
Bifenthrin 5.0 to 9.0  
Carbaryl   Buffer water to pH 7
Chlorpyrifos 5.0 to 9.0  
Dimethoate   Do not mix with alkaline materials
Dinotefuran 5.0 to 8.0  
Etoxazole  6.0 to 8.0  
Fenpyroximate 5.5 to 6.5  
Flonicamid 4.0 to 6.0  
Fluvalinate 5.0 to 7.0  
Imidacloprid 5.0 to 7.0  
Insecticidal soap* 6.5 to 7.5  
Methidathion   Do not mix with alkaline materials
Neem oil**   5.0 to 7.0  
Phosmet   Do not mix with alkaline materials, buffer water to below pH 6
Pymetrozine 7.0 to 9.0  
Spinosad 6.5 to 7.5  
* Active Ingredient=Potassium salts of fatty acids
** Active Ingredient=Clarified hydrophobic extract of neem oil
Adapted from Ray Cloyd, GrowerTalks.

How do you know what your soil or water pH and alkalinity are?  There are many  reasonably priced($30 to $250) pH meters available  When selecting a pH meter, look for an accuracy of ± 0.1 pH unit and a range of 1 to 14.  Be sure to purchase solutions for calibrating your pH meter and remember to calibrate it before use.  Test kits are available for measuring water alkalinity.  Look for one that measures in a range of 0 to 8 meq/L (0 to 400 ppm alkalinity expressed as CaCO3).   If you don’t want to do it yourself, most labs that do complete water and soil analysis include both pH and alkalinity in their reports, which cost between $30 and $60.

Annual Cornell Floriculture Field Day and IPM In-depth

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4th Annual IPM In-depth – Monday, July 18, 2011

Back again this year, the popular hands-on IPM In-depth where you get to be up close and personal with plants, insects, and diseases. NEW this year – a longer diagnostic session and lunch!

This year's topics are:

Various Viruses:  Greenhouse virus diseases and their control
In this session we'll look at common virus diseases of annuals and perennials.  From spots to mosaics the symptoms of viruses will be reviewed along with virus detection techniques.  Participants will be able to examine infected plants and run their own tests to diagnose virus diseases.   We'll discuss how viruses spread and why insect control can be very important.  Examples of virus outbreaks will be reviewed to prevent this from occurring at your operation.

It's not supposed to be yellow, is it? Diagnosing Nutrient Disorders
Plants require more than a dozen mineral elements as building blocks for growth and metabolism. We will look at real live plants with nutrient disorders. We will discuss symptoms of common nutrient problems, noting which ones are easy to detect visually and when it's time to send a test into the lab. You'll learn how to read and interpret a nutrient lab report. Finally, many nutrient deficiencies also look like insect or disease problems so we will discuss strategies to figure out what is the real problem.

Whitefly Wars
Whiteflies are a common pest of many greenhouse crops - ornamentals as well as some herbs and edible crops such as tomatoes. Where do these pests come from? Are there different species of whiteflies to be concerned about? What's this I hear about this "Q-biotype" whitefly? How can I tell if they're in my greenhouse before they become a serious problem? What do I need to do to get good control with pesticides? Are there good biocontrol options for whiteflies? These are some of the questions we'll cover in this hands-on, up-close-and-personal encounter so you can win the war with whiteflies!

9th Annual Cornell Floriculture Field Day to be held Tuesday July 19 2011.

Cornell University's annual Floriculture Field Day will be held Tuesday July 19, 2011 at the Cornell campus in Ithaca, NY. The morning program will center around a marketing theme. We will hear from several individuals that have found creative ways to wholesale, retail, and directly market their products.

Lunch and the afternoon program will take place outdoors at the Blue Grass Lane annual and perennial trials facility. Participants can attend guided tours of the trials or view the flower beds at their own leisure. The Kathy Pufahl Container Design competition will also be held in conjunction with Field Day. The afternoon will conclude with an ice cream social and announcement of the container design contest winners.

Rain or shine we'll see you there!

Field Day 2011 Schedule – July 19, 2011

8:00-8:30 Registration

8:30-8:45 Welcome: Neil Mattson, Cornell University

8:45-9:15 Todd Lighthouse: Marketing via Farmers' Markets and organic niche

9:15-9:45 Anna Steinkraus: Successfully selling in On-farm markets

9:45-10:15 Margaret Kelly: Update from NYS Ag and Markets (½ DEC credit)

10:15-10:45 Break

10:45-11:45 Lloyd Traven and Stephanie Whitehouse (Peace Tree Farms): Marketing to retail/what are retailers looking for?

11:45-12:00 Lloyd Traven In Memoriam: Marketing lessons from Jack Williams

12:00-12:15 Evaluation

12:45 – 1:30 Lunch

1:30-1:45 Hot New Annuals: Melissa Kitchen

1:45-2:45 Walkabouts, guided garden tours, choose from:

A) Pests and diseases in the landscape

B) Containers that work and top perennials

2:45-3:00 Announcement of container contest winners

3:00-4:00 Ice cream social, Cool Jazz and Socializing

DEC pesticide credits will be available at Field Day and at the IPM In-depth. More information and registration forms will be posted shortly to Cornell Greenhouse Horticulture.

2010 New York Greenhouse Production Figures

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The most recent figures from the USDA Floriculture Crops 2010 Summary were released with the following postings:

  • The value of both annual bedding and herbaceous perennial plants is up in NY. Combined, their total rose from $100,395,000 in 2009 to $103,009,000 in 2010.
  • Nationally New York rose from the 7th slot to the 6th highest producer of bedding plants based on dollar value.
  • The number of NY producers is down slightly from 298 to 271 at the same time the wholesale value of their products increased from $182,586,000 to $183,122,000
  • The value of most categories of bedding plants as well as potted flowering and foliage plants were down slightly from 2009. However sales of vegetable transplants and hanging baskets of plants such as begonias and geraniums increased.

Ornamental Crop Growers Opinions Needed

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It’s the busiest time of the year for many of you, but the IR-4 Ornamental Horticulture Program needs your input to prioritize pest, disease, weed and plant growth regulator (PGR) research issues. By providing information on your biggest pest and PGR problems, you can shape the IR-4 program’s two-year plan that will ultimately benefit our industry. The survey can be completed online and should take no more than five to seven minutes to complete.

The IR-4 Ornamental Program focuses on greenhouse, nursery, landscape, Christmas tree and forestry producers. The primary objectives of the program are to facilitate new product registrations and to place new diseases, insects and weeds, as well as new crops, on already registered ornamental horticulture product labels. Please complete this survey to identify your biggest challenges so that our industry can move forward to address those issues.

PS.  The Northeast is ahead in submissions of this survey!  Thanks to those of you who have already sent yours in or completed one at an IPM program.

Cornell IPM Team for Production Ornamentals
Betsy Lamb
New York 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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