Cole Crops, Root, Bulb and Leafy Vegetable Edition
by Jennifer Allen, Vegetable Crop Specialist, OMAFRA, Guelph 

ONTARIO LEAFY BRASSICA GREENS PRODUCERS Receive Urgently Needed Emergency Use Registration for DOWNY MILDEW

J. Chaput, OMAFRA, Minor Use Coordinator, Guelph

The Pest Management Regulatory Agency (PMRA) recently announced the approval of an emergency use registration for  RAMPART Fungicide (potassium salts of phosphorous acid) for suppression of downy mildew on leafy Brassica greens (crop subgroup 5B) in Ontario.  Crop subgroup 5B includes crop such as mustard greens, bok choy, pak choy, yow choy, gai choy, collards, kale, mizuna, mustard spinach and rape greens.  Rampart Fungicide was registered under the emergency use program in late 2008 in Canada for control of late blight as a post-harvest use on potatoes.  A full registration submission for Rampart Fungicide is also underway by UAP Canada.  

Because of a severe downy mildew outbreak on leafy Brassicas in Ontario combined with a low supply of registered fungicides in eastern North America an emergency use for RAMPART Fungicide was submitted by OMAFRA and the Fresh Vegetable Growers of Ontario (FVGO).

Ontario leafy Brassica producers have identified downy mildew as a top disease priority for several years.  Although there are a few registered downy mildew fungicides, the supplies of the key fungicides were used up very quickly in 2009 due to widespread disease outbreaks on several major crops.  Canadian leafy Brassica producers do not have access to as many products to manage downy mildew including products like Rampart Fungicide.  This represents a significant area of concern in the current pest control product technology gap as identified by the North American Free Trade Agreement (NAFTA) technical working group on pesticides.

Without access to Rampart Fungicide, the Ontario leafy Brassica crops industry faced the risk of very serious losses to downy mildew in 2009 and in fact the risk of serious losses remains critical.

The emergency use registration of Rampart Fungicide will help in the interim to manage the current downy mildew outbreak; however management of downy mildew requires a comprehensive IPM and resistance management program with access to all available tools and strategies.  The following is provided as general information only.  Users should consult the complete label before using Rampart Fungicide.   

Rampart Fungicide can be used for suppression of downy mildew on leafy Brassicas in Ontario until December 31, 2009 only.  Rampart can be applied at a rate of 3 - 7 L product per hectare in 300 – 500 L water per hectare.   Use the higher rate when disease pressure is severe.  Apply at 2 – 3 week intervals and more frequently if disease pressure is severe, however do not apply at less than 3 day intervals.  A pre-harvest interval of 0 days is permitted for Rampart Fungicide on leafy Brassicas.

Follow all other precautions and directions for use on the Rampart Fungicide label carefully.

Rampart Fungicide should be used in an IPM program and in rotation with other management strategies to adequately manage resistance.

We wish to thank Dr. Jennifer Allen, OMAFRA, Guelph and the FVGO for helping to prepare the submission and the rationale documents on behalf of Ontario leafy Brassica producers.  We also wish to thank the Ontario Ministry of the Environment, Loveland Products Inc. and UAP Canada Inc.  for their support of this registration and the personnel of the Pest Management Regulatory Agency for evaluating and approving this important pest management tool.  

For copies of the emergency use label contact Dr. Jennifer Allen, OMAFRA Vegetable Crop Specialist at Guelph (519) 826-4963, Jim Chaput, OMAFRA, Guelph (519) 826-3539 or contact UAP Canada Inc. at 1-800-265-4624 or www.uap.ca  

Degree Days

Here are the degree and growing degree-day accumulations for April 1 – August 30, 2009. Orange highlighted cells indicate pests that have reached 3rd generation status.  

Area	Onion Maggot	Cabbage Maggot	Carrot Rust Fly	Carrot Weevil	Tarnished Plant Bug	Leaf-hopper	GDD
Bradford/ Holland Marsh*	1591	n/a	1731.6	1178.2	591.1	928.1	1451
Sarnia	1691.5	1358.9	1413.8	1814.9	1834.7	1206.9	1549
London	1735.5	1416.3	1451.2	1872.3	1881.0	1264.3	1568
Waterloo	1570.3	1242.3	1293.2	1695.3	1713.6	1081.3	1433
Windsor	2067.8	1756.2	1776.0	2212.2	2216.7	1604.2	1924

Degree-day information for pests.

	Degree Days
	1st Generation	2nd Generation	3rd Generation
Onion Maggot	210	1025	1772
Cabbage Maggot	314-398	847-960	1446-1604
Carrot Rust Fly	329 – 395	1399-1711	n/a
Carrot Weevil	138 – 156 455  (90% oviposition)	No model available	n/a
Tarnished Plant Bug	40	n/a	n/a
Aster Leafhopper	128	390	n/a

DISEASE FORECASTS  

DOWNCAST— Predicted sporulation infection periods.  Risk of downy mildew on onions is high for fields still standing.  

BREMCAST—Predicted sporulation infection periods over the past few days.   Risk of downy mildew on lettuce is high  at this time.    

Data provided thanks to funding from the Holland Marsh Growers’ Association, Bradford Co-op Storage Ltd., Muck Crops Research Station, Department of Plant Agriculture, University of Guelph., Lake Simcoe Conservation Authority, Bayer CropScience, BASF, DuPont, Engage Agro and Syngenta.