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Ontario field crop report: June 20

June 20, 2014, Ontario – Barley and spring wheat should be sprayed just after heading for fusarium control, reminds Peter Johnson in the latest field crop report from OMAF. 

Canola is advancing rapidly and is between second leaf and bolting, according to Brian Hall. Spray weeds prior to the 5 leaf stage of canola to prevent yield loss. Apply Liberty from emergence to early bolting, and glyphosate from seeding to 6 leaf stage. Cabbage seedpod weevil at low levels can be found on flower buds. Control is warranted on early flowering canola at 20 to 30 per cent bloom (two to four days after flowering starts) if two to four weevils are caught per sweep. Control flea beetles prior to 4 leaf stage of canola if 25 per cent leaf feeding injury occurs.

Edible bean planting is 90 per cent complete, with remaining acres waiting on moisture. Emergence has been generally excellent except for very dry areas. Leafhoppers can be found in low numbers in most fields. Seed treatment with thiamethoxam (Cruiser) provides control for four to six weeks following planting. Watch for numbers to build quickly as they move in from harvested alfalfa fields. Continue to scout before deciding to spray. Hot weather speeds development with nymphs hatching in about 10 days. The threshold at the unifoliate stage is 0.25 insects/plant, 0.5/trifoliate and 1/trifoliate at second and fourth trifoliate stages, respectively.

Cereals
Winter cereals are well into grain fill and beyond any management opportunities, reports Peter Johnson. Physiological fleck (sunburn) is at extreme levels in some fields. Severe fleck can mirror tan spot, with yellow halos and dark brown centres. However, fleck is most prevalent on upper leaves, with a concentration where the leaf bends and catches the sun. There is no management option for this. Significant varietal differences exist. Branson is less susceptible to fleck, but is more susceptible to head snag, another question coming up in many discussions. Both conditions rarely cause significant yield loss. Early barley is heading, with spring wheat and oat at the boot stage. Do not forget to spray oat crops with a fungicide at flag leaf to boot stage: crown rust resistance has failed, and control is essential for high yields and acceptable quality. Barley and spring wheat should be sprayed just after heading for fusarium control: barley pollinates in the boot, so spraying Prosaro or Caramba right at full head emergence is critical to achieve fusarium control. Spring wheat should be sprayed at day 2 to day 5, as with winter wheat.

Corn
Corn is advancing well and moving fast with the rainfall received in most areas. Some bare spots in fields are a result of poor soil conditions at planting, or a significant period of dry weather following planting. The 2014 Soil N Survey occurred from June 9 to 11 on more than 70 fields from across Ontario and found numbers lower than long term averages, especially on loam soils. Sampling was targeted to sites with previous wheat or soybean crops which had not received fertilizer nitrogen, manure or red clover. The average for loams, sands and clays this year were 9.8, 9.7 and 10.1 ppm respectively. Results in 2014 are lower on loam soils than from previous surveys (11.0, 9.5, 12.2 ppm for long term average, 2011 (cool spring) and 2012 (warm spring), respectively. In 2014, unlike previous years, soil texture was not a determining factor in average ppm levels of mineralizable soil N observed. The sands and the clays are more sensitive to heavy rainfall resulting in nitrate loss and in many areas of the province these processes were perhaps less active in 2014. Unique to this year despite a slight trend to lower ppm levels, were a significant number of samples with very low numbers suggesting that applied fertilizer N not adjusted for this on some soils may impact yield. If you suspect your fields might be low in mineralizable N, a soil N test is recommended. Fields sampled where fertilizer N had been applied gave no indication that any of this applied N has been lost (see www.gocorn.net for the full report).

Forages/pastures
First-cut continues with variable yields, report Joel Bagg and Jack Kyle. Yields are generally good in eastern Ontario. In western Ontario areas where alfalfa winter injury occurred, stands are thin, with man yields reported at 50 to 80 per cent of normal. There is some concern about adequate forage supplies. Considerable acres were seeded to annual forages such as ryegrass, cereals, cereal-pea mixtures and sorghums. Many of those affected plan to seed cereals and Italian ryegrass following winter wheat harvest (Summer Seeding Oats For Forage). Hay storages should have adequate ventilation to enable moisture and heat to dissipate from bales. Monitor your hay storage. Avoid tightly stacking bales. Using pallets prevents spoilage of the bottom row of bales. If you detect a slight caramel odour or a distinct musty smell, you have a problem. Hand-held moisture and temperature probes are useful for monitoring hay heating. Hay bale temperature two to three days after baling will often be 5 C above what the ambient temperature was at the time of baling, and then should decline. Temperatures above 50 C indicate that there is microbial growth that may be a serious problem (Silo and Hay Mow Fires). Propionate hay preservatives can be used at baling to inhibit mould growth and heating while bales “sweat” and cure over time as moisture dissipates from the bales in storage (Preventing Mouldy Hay Using Propionate Preservatives)

Soybeans
Soybean are now growing rapidly with some early fields at the third trifoliate leaf stage, according to Horst Bohner. Much of the crop is in good shape although considerable replanting has been necessary due to poor emergence. Some areas are extremely dry and seed did not have adequate moisture to germinate while other areas suffered from excess rainfall and crusting. Inadequate down pressure on drills and some planters resulted in shallow planting into dry soil. Although, the general rule of thumb is to plant into moisture putting seed more than 2.5 inches deep is also not recommended. Planting into the soil moisture transition zone should also be avoided, since the seed has enough moisture to start germination but not enough to emerge. If the radical emerges and the seed dries out it will dye. Seed that swells and is below 15 per cent can survive for quite some time before it is rehydrated. If the seed is fully swollen and then drys out it can only survive about five days before it needs a rain. Soil applied herbicide damage is prevalent this year. In most cases the beans will produce new growth from the axillary buds, but in overlap areas the plants may not recover. Yield reduction due to soil applied herbicide burn is not common.

June 20, 2014  By Top Crop Manager