Greenhouse Update - April 18, 2005

Aphids and thrips continue to plague growers. Don't confuse distortion from aphid feeding with thrips scarring on ivy geraniums or Ipomoea.

Photo: Distortion from foxglove aphids on ivy geraniums. click for larger view

Photo: Thrips scarring on ivy geraniums click for larger view

Shore flies -- can be seen resting on plant leaves. Adults are primarily a nuisance, but can also help spread diseases. Yellow sticky tape can be used to trap out the adults. Manage algae, their food source, with good cultural controls – avoiding overwatering, fertilizer runoff, and with good sanitation.

Photo: Shore Fly adults on peppers
click for larger view

A frequent concern from growers is why a spray application did not work as well as hoped or expected. Some possible reasons include:

• Failure to inspect incoming plugs and other plant material for insects, diseases and general health and vigor
• Failure to scout and detect populations when they are small and easily managed
• It is difficult to get good spray coverage (especially important for contact materials) after the canopy closes
• Poor sanitation contributing to an outbreak situation
  • Weeds in and around greenhouses leading to migration of insects and perhaps insects carrying viruses to your crops
    • Impatiens necrotic spot virus (INSV) symptoms on chickweed, a favorite of thrips, are easy to ignore.

      
      Photo: Weeds may harbor both insects and diseases
      Impatiens necrotic spot virus symptoms on chickweed are easy to overlook.
      

    • When you spray, spray the weeds under your benches!
    • Keeping older plant material near young plant material
  • Poor timing
    • Treating for larvae with an IGR when adults are also present
    • Treating with a preventative fungicide after the disease has reaching epidemic levels
  • Misidentification of pest, disease or cultural problem
  • Wrong choice of material
  • Tank mixing with materials that are not compatible
  • Not keeping spray water slightly acidic with pH 7 or less
  • For more information, see
    • Effect of pH on Pesticides and Growth Regulators http://www.umass.edu/umext/floriculture/fact_sheets/greenhouse_management/ph_pesticides.htm
    • Directions for optimium pesticide performance using phase 5 http://www.griffins.com/tech_service/bulletins.asp#
  • Ignoring resistance issues and relying on only one or two products
  • Using poor rotations with the same active ingredients or materials that work in the same way
    

Previous 2005 Greenhouse Updates

January 7, 2005

February 22, 2005

March 21, 2005

April 1, 2005

April 8, 2005

GREENHOUSE IPM COORDINATOR (commercial interests and growers)	LEANNE PUNDT	860-626-6240
.	.	.
HOME GREENHOUSE QUESTIONS (homeowners)	UCONN HOME & GARDEN INFORMATION CENTER	phone toll free 1-877-486-6271 or email

Information on our site was developed for conditions in the Northeast. Use in other geographical areas may be inappropriate.

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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