Vegetable Crops: Applications and Timings

Applications and Timings

• Apply all treatments in 100-200 L/ha (40-80 L/ac) water except where otherwise noted.
• Herbicide Application Timings:
  • Soil Applied Treatments include:
    • Preplant (PP) - Also see Chapter 6, Special Methods of Weed Control for details of products, rates and remarks.
    • 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 of 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 improves herbicide activity in the absence of rainfall.
  • Postemergence (POST) - 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 to 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.

Related Links

... on general Weed topics
... on pesticide labels, search the PMRA website
... on weed identification, order OMAFRA Publication 505: Ontario Weeds
... on weed control, order OMAFRA Publication 75: Guide To Weed Control