Synopsis: Finally significant planting progress in corn and soybeans! Rainfall over the last two weeks varied from 0.5” to 3”. Early corn is at 4 to 5 leaf stage while the majority of the corn is emerging to 2 leaves. The most advanced wheat is heading. Weed control is becoming the order of the day. Lots of conventional herbicides are being applied with glyphosate in both roundup ready corn and soybeans to reduce the chance of further resistance developing (excellent!). Weeds are large and require the higher rate of glyphosate when burning down.
Corn: A lot of corn was planted in the last 5 to 6 days, now 50% (Essex, Lambton clays) to 100% planted. Clay soil corn acres may be switched to soybeans soon. Some growers just started planting on May 31st on the clay’s. Many corn fields planted before Mother’s Day have uniformly thin stands ranging from 18,000 to 26,000 ppa, even on lighter soils. Cold wet weather reduced stands: millipedes in these fields may have also reduced stands. Corn that was planted more recently is emerging in 7-10 days. Some stand questions: replanting charts can be found in the OMAF Agronomy Guide Publication 811 and a replant decision aid is available at www.gocorn.net but the stand would have to be horrendous to be replanted now. Pioneer reports that 85% of their seed corn is planted, the delayed inbreds are going in well and overall are in pretty good shape. It may be challenging to get all the detasseling done in a short time.
Black Cutworm: A few early reports of feeding damage, and unconfirmed reports of spraying on tobacco sands. Lynn VanMaanen of the Grower Pesticide Education Program is looking for fields with black cutworm infestations so they can capture video footage. If you know of a field please contact Lynn at (519) 674-1500 ext. 63586 or firstname.lastname@example.org
Wheat: The wheat crop is progressing well with little disease pressure. Many fields were not sprayed with herbicides and will probably require a preharvest glyphosate. There are a number of fields that are still showing poor growth over the tile lines. Thoughts are: nitrogen deficiency due to denitrification losses, or a virus infection (or both). Samples are being sent to the diagnostic lab for viral analysis. With warm saturated soils, up to 5% of the nitrogen can be lost per day. This process can continue inside soil aggregates, even with soils that are almost at field capacity (~3%/day?). In several fields nitrogen overlap areas or split nitrogen trials look significantly better. This suggests N deficiency. However, 25R40 shows more severe symptoms. That suggests virus. Adding 30 lbs N/acre to the yellow strips is recommended. Yield response to late N has generally been good.
Agricorp has damage reports on 22% of their insured winter wheat (140,000 ac). About 5 to 10% of the acres have gone to another crop. A lot of the winter wheat herbicide was sprayed at the flag leaf stage this year. Watch for hormone injury symptoms at heading.
There is huge variability in heading uniformity: making it difficult to time fungicide application. Timing is critical to get the maximum benefit. One option: utilize DONCAST during the heading time frame, and spray when a high risk is present. Alternatively, assess when 25% of the heads have emerged: call this Day 0, and time the spray for day 5. The majority of the rest of the field will have headed by then. Products must cover the head well, and fusarium control drops off rapidly at Day 6. Where T2 fungicides have been applied, there is still a benefit to a T3 fungicide. Research shows about a 10% yield increase to either the T2 or T3 fungicide alone (equal response), and a 15% yield response when T2 + T3 applications are both applied.
Soybeans: Some growers have not started planting soybeans yet but for the area they are about 30 to 70% planted. Albert circulated a new Soybean Vein Necrosis Virus guide with lots of great pictures. It is available from the OMAF & MRA Ridgetown Resource Centre (519) 674-1690.
Forages: There is significant alfalfa weevil in hay fields so get scouting. The hay crop is late compared to normal. Yields are below normal in many fields.
Weed Control: There is some concern that the lack of rainfall will affect weed control of soil applied herbicides. PPI (preplant incorporated) herbicides are working well. A lot of red clover was tilled but not sprayed. This has resulted in many complaints about regrowth. Red clover must be sprayed before tillage for best results. Fleabane controlled looks good with 2, 4-D plus glyphosate. Eragon control has been more variable. A lot of conventional chemistry is being applied to glyphosate tolerant soybeans. The larger operators are resisting this. A lot of questions coming in on horsetail control: in wheat use the high rate of MCPA, in soybeans use glyphosate/Dual/BroadstrikeRC and in corn use Broadstrike RC plus MCPA, and spray only the spots. In corn MCPA MUST be sprayed by the 4 leaf stage or earlier: significant yield loss occurs with later applications (18% at the 8 leaf stage, P Sikkema 2013 trials). The yield impact of an uncontrolled horsetail is difficult to determine.
Can you plant soybeans if dichloroprop or other hormone herbicides were applied in wheat that is now taken out? Best guess would suggest waiting at least 3 to 4 weeks before planting. Peter Sikkema is interested in hearing about any weed control issues you would like him to work on. He can be contacted at (519) 674-1500 ext. 63603 or email@example.com
Horticulture Crops: 100% of the sugarbeet crop is in the ground with the last going in May 31st. 90% of the crop has excellent stands. The earliest planted fields are at the 8 leaf stage. 80% of the tomato crop is planted with some growers done. The early planted fields are in great shape. It may be a challenge to process the tomatoes as they went in over only 8 to 10 days.
Soils and Tillage: There were many comments about the condition of the soil this spring. As the fields dried up many became hard and were difficult to plant into or to till. It is hard to know why it was different this year. One possibility is that more surface tillage is being done and this is breaking down the soil structure allowing it to set up harder. Many are using vertical tillage units as tillage units and doing too many passes. Research has shown that one vertical tillage pass is good but two is detrimental. Wheat stubble is working up much better than soybean stubble: soybean stubble is drying out fast. This resulted in the need for careful monitoring and adjustment of planting depth. When seedbeds are lumpy, seed does not fall to the bottom of the trench well. Adjusting the depth one notch can sometimes result in a 3/4″ difference in depth, as the seed can get below the lumps. Some planting into a stale seedbed thinking that dry surface meant dry seedbed: side wall compaction is significant. In tough fields a rain would be welcome as it is getting hard to get the planter in the ground.
Earthworm counts on the long term tillage and rotation trials at Ridgetown found 4 to 5 times as many earthworms in no-till compared to conventional tillage. They also found a number of millipedes when doing the counts. Soil structure is significantly better where the annual ryegrass was established last fall.
Next Meeting: 7:15 am, June 17th, Willson Hall, University of Guelph, Ridgetown Campus
July 9 and 10, 2014 Southwest Crop Diagnostic Days, Ridgetown www.diagnosticdays.ca
January 6 and 7, 2015 Southwest Agricultural Conference, Ridgetown www.southwestagconference.ca