A weekly report prepared by the staff of the Ministry of Agriculture, Food and Rural Affairs (OMAFRA). If you require further information, regarding this report, call the Elora Resource Centre at 519-846-0941. Office hours: 8:30 a.m. to 4:30 p.m.
For technical information, call the Agricultural Information Contact Centre at 1-877-424-1300 or visit the OMAFRA website: www.ontario.ca/omafra
Dame’s-Rocket
by John C. Benham, Weed Inspector
Some people have been wondering what those patches of mauve flowers along the roadsides are. Most people call them “some kind” of phlox. If the flowers have five-petals they likely will be phlox but if they have four-petals they are Dame’s-rocket.
They are beautiful showy flowers that were brought over from Europe as an ornamental but now has adapted to our conditions and flourished.
Dame’s-rocket is a perennial reproducing only by seed. They grow three to four-feet tall with mauve to pink to white flowers in damp soils in uncultivated areas. Since they are a member of the mustard family the seedpods are similar to the rest of the mustards, one to four-inch long slightly constricted between the seeds. They are not on the noxious weed list.
Permit – guidelines for use in field corn crop talk: Joel Bagg – Forage Specialist
The 2014 registration of Permit (active ingredient: halosulfuron) in Ontario provides a nice tool for the management of yellow nutsedge in corn. Permit will also provide residual control of certain broadleaf weeds. For those two reasons, many growers will consider tank-mixing glyphosate and Permit for use in glyphosate tolerant corn. Here are five key points to consider when using this tank-mix:
When do I apply Permit?
When tank-mixed with glyphosate, it can be applied up to the 8-leaf stage of corn. (Permit can be applied on its own up to the 10-12 leaf stage of corn). Since Permit will often be tank-mixed to improve yellow nutsedge control, application timing should target yellow nutsedge when it is 8 to 30 cm tall.
What rate of Permit should be used for yellow nutsedge?
The label provides two rate ranges depending on the size of yellow nutsedge:
– Nutsedge that is 8-15 cm tall: 35 – 47 g/ha.
– Nutsedge that is 8-31 cm tall: 70 – 93 g/ha.
When control of yellow nutsedge was evaluated at the Elora Research Station, the 47 g/ha rate provided very effective control. More recently, Dr. Peter Sikkema has evaluated yellow nutsedge control at different rates and more consistent control was achieved at the highest labeled rate.
I believe that different field populations of yellow nutsedge vary in their susceptibility to herbicides and therefore you will see a range in their level of control. Ultimately, you may choose to experiment with Permit rates on your farm to come up with a rate that works best.
Lastly, visual control of nutsedge top growth will occur slowly, so don’t be surprised if the control is not impressive two or three weeks after application.
Is an adjuvant required?
The manufacturer (Gowan) is recommending that a non-ionic surfactant (i.e. Agral 90) be added at 0.25% v/v (2.5 L/1,000 L of water) even when tank-mixing with a glyphosate product.
Does Permit provide residual weed control?
Yes, according to the label it will provide control of the following un-emerged species (species that are typically found in corn):
– pigweed species (not group 2 resistant biotypes)
– chickweed
– cocklebur
– hairy galinsoga
– Canada fleabane (not group 2 resistant biotypes)
– jimsonweed
– lady’s-thumb
– lamb’s-quarters
– flower-of-an-hour
– wild mustard
– yellow nutsedge (suppression of un-emerged shoots)
Do I need to worry about crop safety?
2013 University of Guelph trials demonstrated acceptable levels of crop safety with a glyphosate + Permit + 0.25% v/v tank-mix. However, since Permit is a sulfonylurea herbicide (in the same family as Accent, Option, Peak, Ultim etc.) the potential for crop injury may be increased when applications are made:
• During periods of large swings in air temperatures (i.e. going from a low of 7C to a high of 30C).
• Too sensitive hybrids (ask your seed supplier).
• During very hot and humid conditions (above 28° C)
• If a soil or foliar applied organophosphate insecticide has been used (an unlikely scenario).
