The Cropwalker - Volume 7 Issue 28

By Jonathan Zettler CPA, CMA, CCA-ON and Patrick Lynch CCA-ON
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CONFIDENTIAL NOT FOR PUBLICATION
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General
Another week with so much happening it is hard to be brief and cover the main topics.
Crop conditions Weather This week last year we were significantly behind an average year. And we were wet. This year is not as bad for most of the province. Some areas have unseeded acres and we feel for those farmers. The weather below shows we are on average about 4 days ahead of long term CHUs. We are averaging about 25 CHUs per day. Winter wheat harvest is still ongoing in central Ontario and Grey, Bruce, and Simcoe. Corn 60-70% of the crop planted by May 20-24th crop is tasseling. Most of the rest of those planting dates will tassel by end of the week. I like to see corn tassel by August 1st. Last year about 40-60% of the corn was in tassel by August 1st so we are a bit ahead of last year.

Things to Do This Week
1. Scout soybeans for insects, soybean aphids, (250 per plant and increasing) spider mites, Japanese Beetle. Probably no need to spray Japanese Beetle but become familiar with them.
2. Web site for Western Bean Cutworm
https://experience.arcgis.com/experience/7164d23d488246d198dcf7a07d8c9021
3. Website for tar spot- it is moving https://cropprotectionnetwork.org/maps/tar-spot-of-corn
Below is a map showing spread of Tar Spot this year

4. Check corn fields for corn rootworm and western bean cutworm. Corn rootworm adults will be emerging now and feeding on silks. Dekalb have a new hybrid line using RNAi breeding to control rootworm. Wet weather means shallow roots and means more lodging later this season in rootworm fields.
5. Check wheat stubble for weeds. Check around outside of field for invasive species.
6. If planning a cover crop, consider spraying off weeds/volunteer wheat, mainly for weeds.
7. Plan wheat seed and fertilizer for the 2024 winter wheat.
8. Order cereal rye seed for planting after soybeans and corn silage
Weed Control
Q – What should I use right now on my wheat stubble for burndowns? (JZ)
A – In my mind you have three, maybe four options.
1) No glyphosate resistant weeds or no weeds not controlled by -> glyphosate?2) Perennials but no glyphosate resistant weeds? -> glyphosate plus Express SG
3) Perennials and glyphosate resistant weeds and going to corn -> glyphosate plus Lontrel
4) Perennials and glyphosate resistant weeds and need crop rotation flexibility -> glyphosate plus 2,4-D Choline (Enlist 1)
5) Glyphosate resistant weeds and sensitive crops -> glyphosate + high rate Eragon/Merge
Regardless of the product you use, you will need to ensure the weather conditions are appropriate for the application being made. If you are going to September/October with the application, consider Express FX in place of Express SG (Express FX is Express SG + dicamba), or you could look at using the dicamba based products (Engenia/Xtendimax 2 or Distinct).
Q - What is Express FX.
A - It is a group 2 AND group 4 herbicide used as a burndown. Active ingredient is Tribenuron methyl + dicamba. You can plant crops such as cereals 24 hours after application; legumes not until next spring. If using for the first time you must read the label. Since Express FX contains dicamba use cautiously, avoiding drift. It has Canada Fleabane, dandelion and rosette Canada Thistle on the label as well as a lot of other weeds. You cannot plant canola until 2 months after application.
Cover crop management
1. If you have double cut red clover, consider clipping to set back weeds and get the red clover growing
2. If planting no till, be sure to use a burn down, to remove weeds and volunteer wheat.
3. If you have manure to apply you must incorporate it. This incorporation will also get rid of some weeds. If you have perennial weeds, it is better to spray glyphosate, wait at least 48 hours for perennials, 24 hours for annual, spread manure and work in.
4. If your cover crop is already up, check to see if weed control is necessary.
Soybeans
Two Spotted Spider Mites
The symptoms from this pest aren’t evident before you find them unless you are doing some serious scouting. Typically, they show up first around the outside of a field where the grass has died (usually the high and dry areas of the field). Damage is visible in the form of white stippling (dots) on the upper leaf surface from the sucking mouth parts, and plants appear sand blasted or dusty on the underside of the leaves. From the road, a soybean field may look grey if there is an infestation, or brown if the leaves are dropping off and the plants are shutting down and dying. If you check the underside, you may see two spotted spider mites if you have good eyes. Two spotted spider mites are yellow-brown with two dark spots on their abdomen, to help with identification shake the leaf over a white piece of paper. Life cycle They typically move from the edge of a field or from a harvested wheat field to the edge of a soybean field, then be moved further into fields with the wind, using a “balloon” made of spun webbing. A single, un-mated spider mite can be the start of a new colony and under hot conditions infestations can grow quickly. Spider mite females can reproduce without mating. There can be 5-7 generations per year. Rain will also help plants by reducing drought stress but will not reduce numbers if you are already at threshold. The only product registered for control is dimethoate (Lagon/Cygon/Dimethoate 480), of which there are some resistant populations.
Comment from Tracey Baute on dry bean control - “Oberon (spiromesifen) is registered for dry beans, though it is for high-value horticulture crops. To be more cost-effective, spot-spraying pockets of mite activity, when caught early, could be enough to keep them from spreading throughout the field. The product is not currently registered for soybeans.”
https://ontariograinfarmer.ca/2023/06/01/spider-mite-populations/
Japanese beetles. The Japanese beetle is about ½” (13 mm) long. It has metallic green- and bronze-coloured wings. Tufts of white hair are visible around its abdomen. The larva overwinters in the soil; the adult emerges from mid-June to September. The adult skeletonizes soybean leaves, eating tissue between veins. You need 25% defoliation from insects to warrant control. This is a picture of a Japanese beetle eating a shrub.

Corn
Q - I have missed the spraying window for Gibb that causes DON in corn. Should I still spray a fungicide?
A - Yes absolutely. The Tar Spot map shows that it is spreading rapidly across western Ontario. For those of you in Central and Eastern Ontario check with your seed dealers on the presence of Tar Spot in your area.
In the Crop Protection Hub Veltyma and Veltyma DLX both have 3-star ratings. Acapela, Delaro Complete and Miravis Neo have 2-star ratings.
Message from Darel Walker CCA IN on spraying late for tar spot
He is addressing the issue of growers who do not want to spray for Tar Spot until corn is at the blister stage
Now, on to the bigger issue: should we be spraying corn later for tar spot than for other foliar diseases? According to Dr. Darcy Telenko, Purdue's plant pathologist, who has researched this very question for several seasons at the Pinney Purdue Farm, the 2-star answer is NO! Her studies have consistently found that spraying a foliar fungicide for tar spot performs the best on yield response when applied between tassel emergence and blister stage. Tar spot has a 2–3-week incubation period. This means it takes 2-3 weeks after infection before a black tar spot lesion is visible. Fungicides do not cure diseases that are already established, they only provide protection from infection for 2-4 weeks after application. Even the best newer fungicides with three modes of action only provide protection for about four weeks. So, if you wait until milk stage to spray, you may already have allowed three weeks of infection before spraying. This advice is for a one-pass approach. Darcy also tested two-pass approaches for tar spot and while a V12 followed by an R3, milk stage, treatment did provide better tar spot control, it did not yield any more than the one pass applied at blister stage.
Editor’s note: you need to maintain green plant tissue at the most critical stages of grain fill (the start of grain fill). Trying to overthink how grain fill works will get you into trouble.
Forages
Q - I have a customer that wants to put 100 lbs of P and 100 lbs of K in the drill when he summer seeds alfalfa. What do you think?
A - (PJL) That is too K. It could burn the seed if it turns dry. Better to broadcast and work in half of the P and all the K and just put half of the P down the tube.
Sulphur on Forages
From a reader
I am emailing in response to your information regarding sulphur and forages in The Cropwalker. Greta Haupt, completed her master's degree back in 2017. Her research was on alfalfa and canola response to sulphur fertilizer. I have attached her thesis. The "Coles notes" version from her is that yield response was similar between a spring application of potassium sulphate and a fall application of elemental S. However elemental sulphur is typically cheaper than potassium sulphate and if a farmer is applying potash in the fall to their hay fields, elemental S should be added. Her opinion would be to apply 50lbs of sulphur per acre. She also found that adding sulphur in the fall seemed to have a larger effect on older stands, improving their winter tolerance.
Below is a link to the OSCIA research.
Response from Jonathan
Thank you for reading and responding with the research. My experience has been different than her research but will share it in the newsletter with some editorial comments. I also find better winter survival with fields that get adequate sulphur applications.
A couple of items to note;
Potassium sulphate can be difficult to source, and that timing encourages luxury potassium consumption in the 1st cut, which can cause milk fever issues if being fed to dry cows with a potassium imbalance.
50 lbs actual S/ac of Elemental sulphur is almost the same price or possibly even more expensive than using 20 lbs actual S /ac of Sulphate sulphur in the spring. I find elemental sources too slow to become available in my mixed stands in cooler soil conditions, and as a result do not recommend them. Even using Ammonium Thiosulphate in winter wheat nitrogen applications will show up as sulphur deficient in my area until we have warmer weather conditions due to the slower release of that form of S. My clients that apply summer and fall dairy manure (which would contain sulphur in the elemental form @ 5-10 lbs/1000 IMP gallons), comment that they see a response to spring applying blends containing ammonium sulphate.
Lastly, at the end of my retail fertilizer career, we would no longer blend elemental sulphur due to dust explosions at a number of fertilizer plants. Not sure if other retailers had adopted the same policy. The sulphur dust in the air caused the explosions, either due to a spark or in some cases from static electricity.
Here’s a pricing example of sulphur materials I had done about 10 years ago, pricing isn’t current.

Insect Control
Life Cycle Western bean cutworm complete one generation per year. Through fall to early summer, pre-pupae lie dormant beneath the soil in chambers until spring when they pupate. Adult moths climb out of the soil beginning in early July though migratory moths from nearby states (e.g. Michigan) can be captured in traps in Ontario as early as the first week of June. Peak moth emergence in Ontario typically occurs during the last week of July, though some counties may peak one week earlier or later than that. Moths are mostly active at night, searching for mates and nectar to feed. Mated females are preferentially attracted to late whorl to early-tassel stage of corn to lay their eggs on the top two or three leaves of the plants. Eggs are white when fresh but turn to a purple colour within a few days of hatching. Egg laying can occur in Ontario anytime from mid-June to the end of August. Once the eggs hatch, the tiny larvae consume their egg shell then climb up to feed on tassel and pollen tissue either enclosed in the whorl or when the tassel is fully emerged. After 2-4 days, the larvae then move down to feed on silk and enter the ear where they spend the rest of their developmental time before dropping to the ground to burrow down and enter the pre-pupal stage in the fall. (Tracy Baute OMAFRA Dr Jocelyn Smith University of Guelph.
WBC in edible beans (from OMAFRA 2020)
Action Threshold for Dry Beans Thresholds are currently not available for WBC in the Ontario dry bean crop. Trapping thresholds established in western U.S. have not been found to be effective for dry beans grown in the Great Lakes region. It is best to focus on determining when peak flight has occurred in the area and focus efforts on scouting for signs of pod feeding and management 10 to 20 days after peak flight. Research indicates that control is still very effective when done shortly after pod feeding is found. A dry edible bean field that is adjacent to a corn field that has reached threshold for WBC will likely need to be sprayed once pods are present and pod feeding is found (approx. 10 to 20 days after peak flight). Spraying too early when pods are not present on the plants will not protect the crop from damage. Spraying too late, when pod feeding has been taking place for some time will not reduce the risk of seed damage and disease incidence. The key is to protect the plants when the larvae are feeding on the young pods.
Check your corn trait before adding Delegate or Coragen to your tassel application (JZ)
There are a number of corn traits that offer control of Western Bean Cutworm. Check your corn hybrid planting list to see if you have fields with these traits. Look for names like the following; Acremax Leptra (AML), Durcade Viptera (DV, DVZ) Leptra (VYHR), Trecepta RIB Complete (TRERIB), Viptera (V, 3110, 3111), VT4 PRO w RNAi Tech (VT4PRO).
Some of these traits may not be available in Canada.
https://www.texasinsects.org/uploads/4/9/3/0/49304017/bttraittable_jan_2024.pdf
“If I am worth anything later, I am worth something now. For wheat is wheat, even if people think it is a grass in the beginning.”
-Vincent Van Gogh