Getting the Most from Your Graminicides

Now that many areas have had rains, it looks like summer grasses are taking the most advantage of it. Many fields are showing newly emerged grasses. There are several postemergent grass herbicides (known as graminicides) to control these escapes. Here are some suggestions to maximize their performance:

• Apply to actively growing grasses. The chemical must be absorbed into the grass and moved to the growing tip. If it hasn’t rained or been irrigated, the grasses are likely not growing enough yet.
• Wait until a good flush of weeds has emerged. Grasses emerging after treatment will not be controlled.
• Use the correct rate for the type of weed. Generally the low rate on the label will control annual grasses, and the high rate is needed to control quackgrass.
• Apply at the susceptible growth stage of the weed – this is listed on the label. Annual grasses need to have 1 or 2 leaves emerged, and should be sprayed before the 6 leaf stage. Quackgrass needs at least 3 leaves emerged. Grasses that are past this stage should be mowed or cultivated.
• Use an adjuvant if labelled. Poast Ultra requires the addition of Merge, while Venture L has the required adjuvant included.
• Remember that broadleaf weed escapes will not be controlled.
• Note the preharvest interval:

Preharvest Interval (PHI in Days): Fruit Crops

¹Shaded areas represent registered treatments

¹Shaded areas represent registered treatments

NR - not registered
NL - No PHI listed on label
NB - for non-bearing only

Preharvest Interval (PHI in Days): Vegetables

¹Shaded areas represent registered treatments

NR - Not registered
NL – No PHI listed on label
P – Postharvest
HY – not during harvest year
* Broccoli – 44 days; Cabbage – 35 days; Cauliflower – 43 days
** Not registered on Brussels sprouts
*** Registered on cucumbers, pumpkins and squash

| Top of Page |