Ontario Field Crop Report
July 30, 2008
by OMAFRA Field Crop Specialists
For emerging issues, questions or to provide feedback on this report, contact the CropLine at 1-888-449-0937. Technical information can also be obtained at the OMAFRA Field Crops Webpage at www.ontario.ca/crops and Crop Pest Ontario at www.omafra.gov.on.ca/croppest/. Referenced OMAFRA Publications include Publication 811 Agronomy Guide for Field Crops ($20), 812 Field Crop Protection Guide ($15), 75 Guide to Weed Control ($15), and 505 Ontario Weeds ($15). These can be obtained from your OMAFRA Resource Centre, or by calling 1-800-668-9938
Corn
The majority of corn across Ontario is in good to excellent condition, with most of it in
the tassel (VT) to silking (R1) growth stage. Poorly drained fields or heavy textured soils are suffering due to excess moisture. Uneven tasselling is evident this year and indicates that there may be uneven maturity this fall.
Detecting successful pollination without waiting for the kernel blisters to appear, can be done by carefully removing the husks, turning the ear upside down and shaking it. The majority of silks should fall off indicating successful pollination. Silks that remain attached indicate kernels that have not been pollinated.
Rust and northern leaf blight are evident in a few fields and on some hybrids. Frequent storm fronts from the southern US states have deposited rust spores early this year. Both rust and northern leaf blight are economically significant. Some acreage is being considered for leaf disease control products. Target those fields with disease pressure, and hybrids that are known to be more susceptible.
Forage
Summer seeding of alfalfa is seldom as reliable as spring seeding, however, the moist conditions this summer have increased the probability of success. Target planting for the first ten days of August in southern Ontario. Summer seeding has been less successful on fine textured soils than on loams or sands, because the plants need a stronger anchor to resist heaving during the first winter. Use as little tillage as possible to create a fine, firm seedbed, drill the seed rather than broadcast it, and follow with a press wheel or packer to ensure good seed to soil contact. Even with these precautions, consistent rain is necessary for successful stand establishment. Summer seeding has not been successful with trefoil, since it is slower to establish and needs the entire season to produce a plant that will survive the winter.
Monitor new forage seedings and alfalfa re-growth for leafhopper. If thresholds are reached, even leafhopper resistant varieties require control in the seeding year. Frequent rainfall has kept leafhopper numbers low through July in most areas, but numbers can build rapidly if the weather patterns change to hot and dry. For more information on scouting and management, see http://www.omafra.gov.on.ca/english/crops/pub811/5plh.htm.
Pasture
Unlike most summers, when the challenge in pasture management has been to provide enough volume of forage to the livestock, the challenge this year is maintaining the quality of forage. Most pastures have grass that has moved ahead of the livestock, and is now over-mature and unpalatable. Summer clipping, which is not normally recommended, can help to stimulate new vegetative growth on these pastures, and maintain good forage quality and volume into the fall. Clipping at this time will also help to reduce the seed set on perennial and biennial weeds like thistles.
Winter Cereals
Harvest is progressing rapidly, although frequent showers continue to interrupt harvest. Yields range from average to outstanding (50 to 135 bu/ac). Quality is variable, but holding up better than expected in many locations. Soft white quality is hardest hit, with most samples now downgraded due to sprouts, and some growers realizing that they took too many acres of risk in that category. Fusarium levels, mildew, and black point are downgrading some samples of red wheat. Test weights have dropped as harvest has been delayed.
Continue to harvest as soon as possible. Many elevators are offering “sliding scale” discounts, meaning feed wheat is no longer just feed wheat. Shop around, or consider storing the wheat and looking for marketing opportunities. Toxin levels appear relatively low in some samples with fusarium, and falling numbers have held-up in samples of sprouted wheat. There may be marketing opportunities for this wheat if growers can hold and do a little digging after harvest.
Spring Cereals
Barley and oat harvest is beginning. Spring wheat is a week away from harvest.
In wheat, where fusarium levels are of concern, set your combine to maximize fusarium reduction by setting wind at full blast and reducing forward speed. In some areas, frequent rains are allowing the fusarium to develop on large, fully developed wheat kernels. These infected kernels will be impossible to remove. Check wheat grade at harvest to avoid mixing wheat lots of different grades and running the risk of downgrading entire wheat lots.
For the control of perennial weeds such as milkweed, Canada thistle, quack grass and perennial sow thistle in cereals, glyphosate can be applied preharvest when the grain is less than 30% moisture. For wheat and barley, this is the hard-dough stage, when a thumbnail impression stays on the grains. Apply at least seven days prior to harvest. Do not apply to seed crops. Note that not all glyphosate products are registered on all crops. Refer to product labels.
Soybeans
Soybean growth stage varies from R1 (early flowering) to R3 (beginning pod set). Very late planted fields have just started to flower, while most fields have full canopies with early pod set. With ample moisture, pod set should be excellent. Root rot is evident in some fields. White mould is also evident in fields with a lush canopy. Beans will continue to flower and set pods for the next 3-4 weeks, so growing conditions during the month of August will be critical for optimum yields. Investigate areas with yellowing or stunting of plants. Knowing the cause (e.g. soybean cyst, phythohora) will help to develop management strategies for the future. If soybean cyst is suspected, collect a soil sample for analysis. Sample the affected and non-affected areas for comparison, collecting one sample for every 25 acres.
Soybean rust sentinel plots have captured rust spores in rainfall. However, the presence of spores does not mean that any disease has infected plants. So far no soybean plants in plots or fields have tested positive for the disease. Scouting of fields should begin to detect any signs of the disease. Rust is an aggressive disease that is favoured by cool, cloudy wet weather. Check on the underside of leaves in the middle to lower canopy. No fungicide is recommended, at this time, for rust since no disease has been found in the province.
Spring Canola
Early canola looks excellent with a heavy crop canopy. Differences in standability between varieties are evident, with stalk breakage occurring in some heavy canopies. Cool nighttime temperatures and adequate soil moisture should minimize the risk of brown ‘heat’ damaged seed.
Second-generation cabbage seedpod weevil and diamond back moth are now emerging. Scout canola that is flowering or at early pod fill to decide if control is warranted. Significant swede midge injury is evident in some late planted canola, and is past the stage for control.
Decide at early pod fill on the harvest method and if a desiccant is necessary. Direct harvest is most successful when the crop maturity and density are uniform and the crop is relatively heavy or partially lodged. These conditions reduce the risk of shelling and pod drop due to wind. Pre-harvest herbicides do not speed up maturity of the crop, but work as a desiccant (reglone), or as harvest aid (glyphosate). Application will help to ‘even out’ the crop and dry down weeds which will reduce the amount of green dockage. If significant black pod spot disease (alternaria) is present, canola will be more prone to pod shelling, and swathing may be the preferred method to minimize losses. The optimum stage to swath for both yield and quality is 30-60% seed colour change on the main stem. For more information on swathing, refer to the Canola Council ‘Time of Swathing’ guide at http://www.canola-council.org/pub_swathing.aspx
Edible Beans
Edible beans are highly variable with some stands in poor condition because of the rain. Yellow stunted areas within fields are most likely the result of saturated soils, root rot, and/or soil compaction. Initially, root rot appears as a reddish–brown discolouration on the main and lateral roots. Inside the root, the discolouration gradually progresses up the central portion of the stem. Above ground, lower leaves turn yellow and wilt, which can eventually result in complete defoliation. There is no good control for root rot once plants are infected. Infected plants try to compensate by producing new lateral roots above the existing root system. In wide row beans where the harvest method is pulling and windrowing, inter-row cultivation to hill up loose soil around plants can help.
Unconfirmed cases of anthracnose have been reported in a few commercial fields of white beans. Early leaf symptoms of anthracnose can be easily confused with other causes (insect feeding, sand blasting, and group 2-herbicide injury). High daytime temperatures above 28°C, will slow development of the disease, although moderate temperatures at night and heavy dews will allow the disease to develop. Anthracnose can develop quite rapidly under moderate temperatures and with driving rains, which spread the disease. Initial leaf symptoms first appear on trifoliates in the lower canopy. Flag suspect areas and monitor plants for spread of the disease. Report suspect cases of anthracnose to the OMAFRA office in Stratford (519-271-0280). Optimum timing of fungicide application is recommended at the early-bloom stage to minimize yield losses and seed infection. Applications at late flower or pod fill are not always effective in reducing yield losses or preventing a high level of seed infection.
Bacterial blight is also evident on isolated plants in white bean fields. Fungicides will not control or prevent infection from blight, and copper based bactericides have been ineffective or inconsistent in providing control.