VEGETABLE CROP UPDATE

TOMATO & PEPPER EDITION

Janice LeBoeuf, OMAFRA Vegetable Crop Specialist 

·         Late blight alert

 Late blight alert

Late blight has now been found in Chatham-Kent.  The spores can travel long distances in the wind.  Although they are susceptible to ultraviolet radiation, recent cloudy weather could have allowed viable spores to reach our growing area.

With the widespread incidence of late blight in the US northeast and a confirmation of late blight in Chatham-Kent, it is likely that late blight spores could have reached any tomato crop in southern Ontario.  Growers should implement a protectant fungicide program immediately and scout their fields carefully.  Late blight can devastate a tomato crop very quickly if conditions are favourable.

Recommended fungicides for tomato late blight in Ontario:

chlorothalonil (Bravo 500)
mancozeb (eg. Dithane DG, Manzate Pro-Stick, Penncozeb 80 WP)
metiram (Polyram DF)
famoxadone + cymoxanil (Tanos 50 DF) – has some kickback activity
mandipropamid (Revus) – has some translaminar movement

During wet cool periods, a fungicide should be applied every 5 - 7 days to protect against late blight. If the weather conditions become dry, the spray intervals may be extended.

See the July 27 Vegetable Crop Update (Tomato and Pepper) for more information on identifying and managing late blight.  It is available at http://apps.omafra.gov.on.ca/scripts/english/crops/agriphone/article.asp?ID=1738.  It includes links to photos and more information.

Visit the OMAFRA Vegetable Web Pages: ontario.ca/crops - click Vegetables