Greenhouse Update - April 15, 2006
Leanne Pundt, Extension Educator, University of Connecticut 
  

Edema – a physiological disorder, has been observed on various cultivars of Ipomoea, Cleome, Cuphea, and Ivy Geraniums.  Symptoms vary depending upon the plant species affected. On Ipomoea, white, crusty eruptions, like a grain of salt, develop along the leaf veins. On ivy geraniums, water-soaked swellings on the underside of the leaves later turn brown and corky.

For more information, and a slide show of symptoms – See the fact sheet “ Non-infectious plant disorder, oedema” on the Greenhouse IPM Web site.

However, if mites feed on ivy geraniums, the plants develop oedema-like symptoms that spread to the youngest leaves, as the spider mites migrate to those younger leaves. (Stippling from spider mite feeding doesn’t occur on ivy geraniums).  Look on the underside of the leaves, near the veins, for any signs of two-spotted spider mites.

   

Ringspot symptoms on Geraniums – Ringspot symptoms on geranium may be the result of either tomato or tobacco ring spot virus. New leaves produced from midsummer on generally do not show symptoms, as the plants grow more rapidly.  Plant viruses are relatively common in geraniums; however, in most cases they are not responsible for any major economic damage with the plants remaining sellable.   

See this article for more information:  
http://floriculture.osu.edu/archive/apr98/virger.html
 

ringspot on geranium
Ringspot on geranium
L. Pundt photo  click for a larger image

   

Broad Mites – may occur on a number of ornamental crops including Gerbera, New Guinea Impatiens, Salvia, and Verbena to name a few. Growers often see the characteristic symptoms of injury, but rarely the mites themselves because they are so small. Characteristic symptoms include leaf edges curling downward and distorted flowers or buds that do not open. Terminal buds may also be killed.  

Broad mite injury is often confused with herbicide injury, nutritional (boron) deficiencies, or physiological disorders. 

Not all miticides labeled for spider mites are labeled for broad mites.  Translaminar miticides such as Avid, or Pylon may be used on ornamental crops infested with broad mites.

Contact miticides such as Kelthane, Sanmite or Akari (see supplemental label at www.sepro.com) are also labeled.  

Repeated applications are often needed to manage broad mites because they are so hard to contact with foliar sprays as they feed on the underside of the leaves and deep within the buds and flowers. Consult labels for registered uses and plant safety information.  

If only a small number of plants are infected, and they are detected early, growers may consider rogueing infested plants

broad mites broad mite damage on salvia
Broad mites
L. Pundt photo  click for a larger image
Broad mite damage on salvia
L. Pundt photo  click for a larger image


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Previous 2006 UConn IPM Greenhouse Updates

April 10, 2006
April 3, 2006
March 27, 2006
March 20, 2006
March 3, 2006
February 25, 2006
February 17, 2006
January 31, 2006

New England Greenhouse Update now online. University Extension Specialists in New England, in conjunction with USDA's Northeast Sustainable Agriculture Research and Education, contribute information to this new website. Timely updates are provided for commercial growers of greenhouse crops and flowers in Massachusetts, Connecticut and Rhode Island. You can use this additional resource for more information about current observations and recommendations on environmentally safe production practices.
Topics posted April 2006
April 12 - Two-Spotted Spider Mites
April 12 - Thrips & Other Insect Pests on Vegetable Bedding Plants
April 10 - Iron/Manganese Toxicity to Annuals

Topics posted March 2006
March 31 - Preventing Iron Deficiency
March 31 - Preventing Plant Stretch
March 21 - Excess Soluble Salts
March 9 - Pythium Root Rot
March 9 - Algae

Topics posted February 2006
February 27 - Hosta Virus x Identified in Massachusetts
February 24 - Fungus Gnats
February 23 - pH and Fertility Requirements of Spring Annuals
February 17 - Cyclamen Mites Found on Hydrangea Crop
February 16 - Weed Management in Greenhouses
February 14 - Using Soil Probes for pH & EC Measurements
February 10 - Soil Testing & Disease Diagnostic Labs

Topics posted January 2006
January 26 - Growing Plants Cooler



GREENHOUSE IPM COORDINATOR
(commercial interests and growers)
LEANNE PUNDT 860-626-6240
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The information in this material is for educational purposes. The recommendations contained are based on the best available knowledge at the time of printing. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. The Cooperative Extension system does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available.All agrochemicals/pesticides listed are registered for suggested uses in accordance with federal and Connecticut state laws and regulations as of the date of printing. If the information does not agree with current labeling, follow the label instructions. The label is the law.Warning! Agrochemicals/pesticides are dangerous. Read and follow all instructions and safety precautions on labels. Carefully handle and store agrochemicals/pesticides in originally labeled containers immediately in a safe manner and place. Contact the Connecticut Department of Environmental Protection for current regulations.The user of this information assumes all risks for personal injury or property damage.Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Kirklyn M. Kerr, Director, Cooperative Extension System, The University of Connecticut, Storrs. The Connecticut Cooperative Extension System offers its programs to persons regardless of race, color, national origin, sex, age or disability and is an equal opportunity employer.

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