VERMONT VEGETABLE AND BERRY NEWS
March 15, 2001
Compiled by Vern Grubinger, University of Vermont Extension
(802) 257-7967 or vernon.grubinger@uvm.edu

NORTHEAST PEPPER IPM MANUAL IS NOW AVAILABLE

This 136-page, full-color manual has 23 chapters, 200 color photographs, and many easy to read tables and figures. It provides detailed descriptions of all major pests of peppers in the northeast, and most of the minor pests, too. It covers weeds, diseases, insects and other pests. In addition, it comes with an 8-page pesticide supplement that provides information on conventional as well as microbial products. The manual delivers the message that alternative techniques are now available to eliminate or dramatically reduce pesticide use without sacrificing crop quality, and that preservation of natural enemies is an important component in achieving these goals. To order, send $19.95 payable to ‘UConn' to: UConn Communications and Information, 1376 Storrs Rd., U-4035, Storrs CT 06269-4035. Price includes postage. Bulk discount is available.

GRAY MOLD AND POWDERY MILDEW ON GREENHOUSE CROPS

(Adapted from an article by Dr. John Hartman, University of Kentucky)
Greenhouses producing ornamental floral and foliage crops  provide an ideal environment for many fungal diseases. Fungal diseases such as gray mold and powdery mildew can occur seemingly without warning and quickly cause widespread damage to these crops.  Gray mold is caused by the fungus Botrytis cinerea, and is very common and widespread on the flowers and buds of many greenhouse flower crops. It is sometimes associated with stem and leaf rots or other damage. Symptoms may include rotting of buds, flowers, or flower stalks, or an off-white or brown petal spotting. These symptoms are often associated with tan or gray moldy growth of the fungus. The fungus spreads rapidly by means of airborne conidia and can persist in soil as survival bodies called sclerotia or as a saprophyte on plant debris. The fungus produces spores and causes infections when greenhouse humidity is very high and when leaves are moist.  Disease development is rapid when plants are crowded and poorly ventilated.

Powdery mildew is a fungus seen on greenhouse crops. There are several different powdery mildews. The specific powdery mildew fungus for each crop is usually different even though the symptoms of each type are pretty much the same. Disease symptoms are very distinct and powdery fungal signs are readily seen on leaves, shoots, buds, flowers, and poinsettia bracts.  Fungal mycelium and conidia may be found on both tops and undersides of the leaves. Once the
disease gets started, it is capable of "exploding" so rapidly that plants appear to be "flocked" within just a few weeks. Cool (daytime temperatures remaining less than 85 F) and moist greenhouse environments, with crowded plants favor rapid disease development.  Based on work done in Michigan, large numbers of powdery mildew spores are released in mid-day as the relative humidity fluctuates in the greenhouse. Greenhouse relative humidity fluctuations are often associated with watering.

Control of gray mold and powdery mildew is mostly synonymous with good cultural practices.
1) Inspect plants frequently, carefully examining at least one in thirty for disease symptoms and signs, or one in ten if conditions favor the disease.
2) Remove and destroy dead and dying plant material since moribund tissues are easily colonized by Botrytis and the fungus spreads more easily to green, healthy tissues. Significant gray mold control can occur by picking off and discarding dead leaves and spent flowers.
3) Carefully remove powdery mildew infected leaves while disease levels are still low.
4) Provide good spacing between plants on the greenhouse bench.
5) Move air through the crop with the ventilation system. Improved ventilation reduces both gray mold and powdery mildew.
6) Avoid splashing water on foliage.
7) Use heat in the evening to reduce relative humidity. Gray mold development requires high humidity in the greenhouse. As air cools at night, moisture in the air condenses on the plants unless it is heated.

PHYTOPHTHORA WORKSHOP  Tuesday March 27, 2001
Comfort Inn, Chicopee MA  (One hour south of Brattleboro. Take I-91 to I-90, go east one exit to Exit 5. After the toll booth, bear right at the fork and then bear right on Memorial Ave. As soon as you turn, look for Comfort Inn on the right. Meeting room is downstairs.)

Phytophthora capsici has grown more severe in cucurbits, peppers, eggplant and tomatoes in recent years. Some growers and researchers feel this is the toughest and most destructive vegetable pest that exists. For the past two years, this disease has caused significant crop losses around New England. More and more fields have become infected. So have irrigation ponds.
What do we know about this disease?  How can we manage it and prevent its spread?  What more do we need to know?  Does anything work to control it? This workshop will bring together plant pathologists, Extension specialists, industry field people, crop consultants and growers to try to answer these questions. Current strategies, the latest research results, and new ideas will be explored. The format will be informal and discussion oriented. The schedule is flexible: participants are encouraged to question speakers and contribute to discussion at anytime.

9:00:   Registration, Coffee, Snacks
9:15   Welcome
9:30   What We've Seen, What We've Tried, What Seems to Work and What Doesn't Work: the  Farmer's  Perspective. Walter Czajkowski, Hadley MA ‘Experiences with vine crops'.
 Gary Gemme, Whately MA. ‘Peppers and tomatoes; observations with trickle irrigation'
10:00  ‘Phytophthora: Symptoms, Host Range, Spores, Disease Development' Rob Wick,UMass
10:30   Break
10:45  ‘Living with Phytophthora in N.J. Pepper Production'. Steve Johnston, Rutgers Univ.
11:30  ‘Vine Crops: What Works and What Doesn't'. Meg McGrath, Cornell Univ.
12:15   Lunch and hands-on lab: microscopes will be available to look at spores and symptoms.
1:15    More reports and reactions from growers: Tom Calabrese, Southwick, MA.   ‘Contamination from irrigation ponds and experience with raised beds'.
 Nelson Cecarelli, Northford, CT. ‘Site selection, resistant varieties, planting   considerations to prevent Phytophthora in peppers'
1:45  ‘Highlights from Michigan's Phytophthora projects' Ruth Hazzard, UMass.
2:00   Discussion: growers, plant pathologists, Extension, industry staff and crop consultants.

Three hours of pesticide applicator re-certification credit will be offered for this workshop. To pre-register and reserve lunch, your registration must be received by March 20. Send $30 per person, payable to UMass, to: Marilyn Kuzmeskus, Dept of Entomology, Ag. Engineering Bldg., UMass, Amherst, MA 01003. Walk-in registration will cost $35. For more information contact Ruth Hazzard at 413-545-3696 or John Howell at 413-545-5307.