Tales from the Field, October 24, 2014

Leanne Pundt, Extension Educator, Greenhouse IPM

Poinsettia Scouting, Latex Eruption on Poinsettia, INSV on Cyclamen, Upcoming Programs

Poinsettias are looking good and beginning to show some color. Be sure to look for whiteflies on the underside of the lowermost leaves. For more see, Tips on Scouting Poinsettia Insect and Mite Pests on the UConn IPM website.

Figure 1: Whiteflies on lowermost leaves. Photo by L. Pundt

There have been some reports in the Northeast of powdery mildew on poinsettia. Powdery mildew is more likely to be found in areas of your greenhouse with more changes between day and night temperatures, such as hanging baskets.

See Powdery Mildew on Poinsettias by Nora Catlin on the E-Gro Alert

Latex Eruption on Poinsettia

Figure 2: Yellow spots on upper leaf surface. Photo by Y. Li

Figure 3: Latex eruption on the lower leaf surface. Photo by Y. Li

Yellow eruptions were seen on both the upper and lower leaf surfaces. Upon examination by the CT Agricultural Experiment Station, no pathogens were found. The symptoms suggested that the yellow spots on the leaves may have resulted from latex eruption due to high humidity combined with a sudden drop in greenhouse temperatures.

Impatiens necrotic spot virus (INSV) on Cyclamen

Yellow ring spots, necrotic spots and line patterns on the lower leaves were due to Impatiens necrotic spot virus (INSV). Symptoms were most prevalent on the lowermost leaves, so one needed to look closely for symptoms. The result of ImmunoStrip test showed the sample was positive for INSV.

Figure 4: Concentrate ring spots, Photo by Y. Li

Looking for Pesticide Credits?

Northeast Greenhouse Conference and Expo

November 5 and 6, 2014

New Location: Mass Mutual Center, Springfield, MA

Program and Registration at:

Here’s the Schedule at a glance!

A total of 10 one-hour presentations (credits vary by state) will be offered for the six New England states plus New York. Please check the schedule on the program brochure, as some of the presentations are at the same time.

Growing Container-Grown Greenhouse Vegetables

Dec 16, 2014

Litchfield County Extension Center, 843 University Drive, Torrington, CT.

4.75 pesticide credits

Click here to view the program and registration form.

2015 Spring Bedding Plant Meetings

Feb 3 at the Litchfield County Extension Center, Torrington, CT

Feb 5at the Tolland County Extension Center, Vernon, CT.

½ day educational program repeated at two locations.

4.0 pesticide credits More details coming soon.

Disclaimer for Fact Sheets:

The information in this document is for educational purposes only. The recommendations contained are based on the best available knowledge at the time of publication. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. UConn Extension 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. The University of Connecticut, UConn Extension, College of Agriculture, Health and Natural Resources is an equal opportunity program provider and employer.