ISSUE 3 May 18, 2006
WHITE COCKLE/NIGHTFLOWERING CATCHFLY CONTROL
A question came in about how to control white cockle. White cockle is in the Pink Family (Caryophyllaceae), is a biennial or short lived perennial and can be confused with its more prevalent relative, night-flowering catchfly, which is an annual. Both plants are found more in the northern part of the state. Stems on both plants are erect, branched, and sticky. Seeds of both species are borne in pods that are swollen and have white to pink flowers. Distinguishing differences between small plants of both species may be difficult if they both germinate from seed. Dig up the seedlings and if the shoots arise from under-ground roots then it is white cockle, since it is perennial in nature.
Dr. Alan Dexter, from his sugarbeet weed control research in the northern valley, has observed that pods of night-flowering catchfly are sticky, whereas seed pods of white cockle are not.
Chemical control of both white cockle and night-flowering catchfly is difficult but more difficult with white cockle being a biennial/perennial. Herbicides that list control of night flowering catchfly on the label are Ally Extra, dicamba, and Harmony Extra or Infinity Tankmix. Dr. Dexter reports that UpBeet controls night-flowering catchfly in sugarbeet. There are no herbicides that list white cockle as control or suppression. I did find one Saskatchewan Agriculture Fact Sheet on white cockle written in 1981 that recommended dicamba at 1.2 to 1.8 qt/A for control of patches in non-crop area.
The Canadian weed guide show Banvel + 2,4-D, bromoxynil + MCPA, and Harmony Extra for cow cockle, another annual relative. For night-flowering catchfly their guide shows the same products as the Green Bible plus bromoxynil + MCPA, so it appears there are very few choices for control or suppression of night-flowering catchfly and none for white cockle.
QUESTIONS AND ANSWERS
One of the consultants reported these questions: I wish he would have answered them.
1. How do I control dandelion and absinth wormwood when you want to seed (broadleaf crops I assume) in two days or the crop is planted. It doesnít appear that in no-till country there has been much use of 2,4-D in a fall burndown situation.
Fall application with a glyphosate + 2,4-D would have been one of the best options without any herbicide residue to crops planted the next spring. Both plants are perennial in life cycle so only herbicides that affect perennial broadleaf weeds (2,4-D, dicamba, picloram, glyphosate) will have any activity. Unfortunately, those herbicides will kill planted broadleaf crops and are not labeled for such use. Only 2,4-D is labeled preplant before soybean and users must observe a 7 day interval before planting for the ester formulations and 15 days for the amine formulations (see page 23 in the weed guide).
2. What products can I use with glyphosate in front of peas, flax, wheat, canola etc to help control either wild buckwheat, volunteer canola, dandelion, biennial or absinth wormwood, etc. people using the 1 pint of LV-4 for 7 days rule in some cases (mostly no-till wheat). Need some good info on what to expect for crop response in-front of our crops.
Only glyphosate is labeled early preplant for these crops or paraquat except for flax and canola.
Wheat has many products registered preplant (see page 6) and in-crop to control these weeds (see pages 8-9 in the weed guide).
For pea, Pursuit Plus PPI will control the buckwheat and volunteer canola but will miss dandelion and wormwood. Basagran twice split applied can control the wild buckwheat, volunteer canola, and biennial wormwood but not dandelion. No chemical options for absinth wormwood except tillage.
3. Lots of volunteer canola coming in those fields that got blown around last Aug.
See page 126 of the weed guide.
4. Pretty heavy pressure on emerging wheat from volunteer sunflower.
Sunflower is one of the most competitive weeds in crops (height x girth gives a good index - the greater the number the greater the competitiveness). Early elimination is mandatory to avoid yield loss. Many herbicides listed on pages 123, 125 show good to excellent control.
5. Growers didnít use any 2,4-D or dicamba to kill off last years alfalfa field and are caught in trying to do it this in mainly wheat and corn crops this spring.
The most effective herbicide to kill alfalfa is any product containing clopyrlaid (stinger), such as Curtail, Curtail M, Hornet, and WideMatch. High rates of 2,4-D, dicamba, or MCPA can also kill alfalfa but those rates cannot be used in crop because of crop injury.
6. With fuel pricing, many farmers are wanting to spray more this fall (burndown or pre-harvest) than use tillage. People also wanting to know how low of glyphosate rates they can use this spring and still do the job.
With price of glyphosate at $2 to $4 per acre for the 22 fl oz rate (4.5 lb ae/gal formulation) or 1 qt/A (3 lb ae/gal formulation) even the thought of cut glyphosate rates should be eradicated from our minds. This is specially true in light of weed resistance occurring in many parts of the country. Many of these weeds are common in ND like common lambsquarters, common and giant ragweed, pigweed species (waterhemp). I fear lambsquarters and kochia may be the two that show glyphosate resistance first in ND. By careful reading of page 107 in the weed guide, one may postpone resistant biotypes by killing the resistant gene in your fields (if they are present) by killing all plants that contain the gene. Use labeled rates and rotate modes of action. We do address glyphosate rates by weeds and weed size on pages 68-69 of the weed guide. This information is based on three to four decades of adjuvant research.
7. Winter wheat getting sprayed somewhat. Biggest concern is cool weather and cheat issues.
For cheat issues, see the handy table on bottom of page 11 in the weed guide but make sure you know which brome species you have because ND probably has no true cheat. We have either downy brome or Japanese brome and Japanese brome is easier to control that downy brome. Identification may be hard as grass seedlings. See below for tips for ID. For weather tips and how temperature and environment affect herbicide performance see A4 (right hand column) on page 67 of the weed guide.
8. Seems to be more pre-emerge going onto corn acres. Seems to be Prowl H20 and Spartan moving onto respective crops. Been hearing in pockets some Resolve going out (price attractive).
We at NDSU support the practice of a PRE/POST planned approach to weed control as indicated by the text in the top part of page 22 in the weed guide. NDSU is conducting research at multiple location comparing Resolve with Harness, Surpass, Outlook, Dual, etc, applied as a PRE.
9. Could you give a couple of short sentences on identification characteristics of downy brome, japanese brome and persian darnel. I would imagine some samples will be coming into agents offices soon for id. What would be great is a few sentences that give the key (unique) characteristics of each weed. What to look for when telling them apart.
Dr. Kirk Howatt has answered this question earlier and was sent out on <agdakota> list serve.
Let's consider four species: Persian darnel, Italian ryegrass, downy brome, and Japanese brome.
Persian darnel and Italian ryegrass have auricles (although auricles on Persian darnel are not obvious until about the 5th leaf). Both plants have shiny leaf blades. But Persian darnel appears shiny on the bottom of the leaf while pictures of Italian ryegrass show the tops of leaves to be glossy. Both plants have prominently raised veins, but Persian darnel has more of a keeled leaf blade than Italian ryegrass.
Downy brome and Japanese brome do not have auricles. The plants have very similar characteristics until the seed heads emerge. Environment can vary the amount of pubescence and purple coloring on either plant. The ligule may be the best discerning morphological characteristic of the seedling.
Japanese brome has a short ligule, about 0.5 mm, while downy brome's ligule is longer than 1 mm. Persian darnel - shiny leaves, keeled leaves, auricles on older plants. Italian ryegrass - shiny leaves, flat leaves, auricles present downy brome - no auricles, long ligule, long awns. Japanese brome - no auricles, short ligule, short awns
NDSU Extension Weed Specialist