In this issue
§ White mold (Sclerotinia sp.)
§
The 2007
§ Application technology for small acreage producers
Recently in the diagnostic lab we have seen several cases of disease caused by white mold. Infected plants included lobelia (stem rot) and gazania (blighting) and gerbera (crown rot).
Sclerotinia has a wide host range including many annuals, perennials, vegetables and field crops. Disease symptoms include pre and post-emergent damping off, crown rot, and blighting of foliage and petioles. Small, hard, irregular, black structures called sclerotia may be present on or in plant tissue (especially inside stem and petiole tissue). White fluffy growth is produced on affected plant parts – this is most readily visible in high humidity.
Disease is spread mainly via sclerotia. These are long term survival structures, that are found in soil and on plant debris.
Movement of these structures is the primary means of disease spread. Disease
can also be spread by the movement of infected plant material. Under certain
environmental conditions, mushroom like structures (apothecia) are produced and
they release airborne spores.
Disease management is primarily based on avoidance of the pathogen. Field
soil should be sterilized before using it in growing media. Susceptible crops
should not be grown in areas with a history of white mold problems.
Additionally, good sanitation is important to limit spread. Weeds should be
controlled in production areas, because some weeds are hosts to Sclerotinia. Fungicide
drenches can be used to protect plants from infection. Fungicides labeled for
control of Sclerotinia
in the greenhouse include chlorothalonil, thiophanate-methyl and PCNB.
Six leading young
plant growers in
§ C. Raker and Sons
§ Duwayne’s Greenhouse Inc.
§ Four Star Greenhouse Inc.
§ Glass Corner Greenhouses Inc.
§
§ Pell Greenhouses, Inc., and
§ Walters Gardens, Inc.
Each location showcases
different plant specialties and product
lines. Companies are open Monday through Friday during normal business
hours and the
Visit the Michigan Garden Plant Tour website at www.hrt.msu.edu/planttour or call
Sandy Allen at 517-355-5191 ext. 1339 for more information. Last year, nearly 2,000 people attended
the Michigan Garden Plant Tour and 64 percent spent at least two days visiting
the participating plant producers. An amazing 92 percent of the last year’s
attendees indicated that they would attend the tour this year!
This workshop is designed for pesticide applicators working with nurseries, greenhouses, vegetables, floral, forest and other small acreage settings.
June 14 from 6:00 – 9:00 PM
Northwest Horticultural
Research Station
6686
Dr. John Grande, Snyder Research Farm,
Two core recertification credits for commercial and private applicators have been applied for. The cost is $5. The rest of the program expense is sponsored by a North Region Project GREEEN grant.
To register, send check for $5 to Roberta Dow,