Managing Weeds in Herbaceous Ornamentals: Introduction

Excerpt from 2010-2011 Chapter 16, Publication 75, Guide to Weed Control, Order this publication

Introduction

In April of 2009, the Ministry of Environmentammended the Pesticides Act with the Cosmetic Pesticides Ban Act, 2008 and Ontario Regulation 63/09. Pesticides are now classified for sale and use under 11 different classes. It should be noted that agriculture (e.g. nursery production) is exempted. For more information on the legislation see the Ministry of the Environment’s
website at www.ontario.ca/pesticideban

To convert kg/ha or L/ha to g/100 m² or
mL/100 m² – Multiply by 10 and change units.
For example – 11 kg/ha becomes 110 g/100 m²

28.4 L/ha becomes 284 mL/100 m²

PREPLANT INCORPORATED (PPI) – Two incorporations at right angles operating at a depth of 10 cm using a double disk (7–10 km/hr) or vibrating shank S-tine cultivator (10–13 km/hr) are required unless otherwise stated. Cultivation-type equipment used for herbicide incorporation is known to spread perennial weeds to previously uninfested areas. Special attention should be directed toward machinery cleanliness, and/or treating fields with perennial weeds last.

PREEMERGENCE (PRE) – Rainfall at 15–20 mm within 7–10 days after application is necessary to activate preemergence treatments. Shallow cultivation, rotary hoeing or harrowing will control weed escapes and improve herbicide activity in the absence of rainfall.

POSTEMERGENCE – Leaf stage of the weeds is critical for good weed control. Smaller weeds are generally easier to kill but there needs to be enough leaf surface to intercept the herbicide. Apply according to recommended leaf stages. Crop stage is important to optimize crop safety. Adjuvants will frequently improve the weed control when used as directed. Weather or other conditions may influence the optimum rate of adjuvant, see the product label for more details. Always use appropriate drift management technology.

WARNING – Refer to manufacturer’s instructions forwaiting period required after planting.

WARNING – Certain species may be injured by the following herbicides. Check manufacturer’s directions for labeled species before use.

For the latest information on Nursery and Ornamental Crops subscribe to the OMAFRA Nursery and Landscape Report by going to http://www.omafra.gov.on.ca/english/crops/podcast/nursery/standard.xml.

Related Links

• Weeds in Ontario
• Nursery and Landscape Plants in Ontario
• Problem Weed Control in Field Crops
• Integrated Pest Management (IPM)
• Pesticide Application and Safety
• Pesticide Companies and Agents
• OMAFRA Sprayer Calibration Calculator
• Search the PMRA website
• OMAFRA Publication 505: Ontario Weeds
• OMAFRA Publication 75: Guide To Weed Control