OMAFRA Field Crop Report August 12, 2010

Corn: Greg Stewart


Corn planted in April is as much as two weeks ahead of normal. Typically, corn reaches the kernel dent stage (R5) 35 to 42 days after silking, which mostly occurred between the 10th and 15th of July. Once corn reaches the R5 stage, over a 3 week period the “milk line” moves from the dent end of the kernel to the tip end of the kernel.  With crop maturity advancing rapidly, many corn silage fields will be ready to harvest during the last week of August. Watch silage fields carefully and be ready to harvest when optimal whole-plant moisture is reached for your storage system. For information on “Harvesting Corn Silage At The Right Moisture” refer to http://www.omafra.gov.on.ca/english/crops/facts/07-047.htm .

 Winter Wheat: Peter Johnson


Harvesting of winter cereals is almost complete. The provincial average winter wheat yield reported to date is above average at 85.6 bushels per acre. Variety information for the 2011 winter wheat crop should be available shortly after August 26th at www.gocereals.ca.

 WEATHER SUMMARY: (source: www.weatherinnovations.com/weathersummary.cfm)
 
Edible Beans: Brian Hall


A large portion of the edible bean crop is 5 -10 days ahead of normal in development. Showers and heavy dews have promoted the spread of anthracnose in white and black bean fields. A late fungicide application for anthracnose will not control anthracnose on infected plants but can limit additional pod infection and limit further  spread in the field. Fungicides provide 10 -14 days protection, but growers need to observe the 14 day pre-harvest interval. Common and halo blight are evident in some bean stands as yellowish- brown areas. Infected leaves have brown necrotic areas surrounded by a distinct yellow margin. Pods develop a reddish-brown flecking. At later  stages, seed in infected pods becomes stained. Stormy weather, and equipment, animals or people moving through fields when foliage is wet will spread the disease. Outbreaks are favoured by high temperatures and humidity.

Copper-based bactericides are not generally effective because of high level of inoculums present in fields at this time.

Pod piercing insects are now evident in some bean fields. Injured seeds either shrivel or develop a blemish known as a “dimple” or “sting” resulting in a reduced seed quality which can be a problem for IP soybeans and dry beans. Control may be warranted in edible beans or in food grade, IP and seed soybeans if an average of one stink bug per one linear foot of row is found during the late R5-R6 stages. Also continue to scout fields for bean leaf beetle as they have been found in high numbers in some fields.

The next two weeks are critical for western bean cutworm (WBC) scouting and management in dry beans. Peak WBC moth flight took place at the end of July and pod feeding is expected 10 to 21 days after peak flight. Huron County is particularly at risk given the very high moth count for that county this year, but all dry beans in Ontario should be scouted during the next few weeks to determine if management is necessary. Look in particular for holes and feeding scars starting on the pods. There could also be some leaf feeding

by the younger larvae, however unless you can actually find the larvae, it is difficult to prove that it was western bean cutworm that did the leaf feeding and not another insect. If pod feeding is present, a spray is necessary. Make sure that there are pods and pod feeding present as this is the best stage and timing to achieve good control of

WBC. Matador is registered on dry beans for WBC control.

 Forages: Joel Bagg


The critical fall harvest period for alfalfa begins over the next 2 or 3 weeks in the major forage growing areas of southern Ontario. This is the 6 week period before the average date of killing frost. Cutting during this period reduces the food reserves in the alfalfa roots going into winter, increasing the risk of winterkill. Even when winterkill does not occur, loss of vigour and yield the following spring typically results. Farmers should be scheduling their last harvest to avoid cutting during this period, if possible. A number of factors influence how

much risk there is to harvesting during the critical period. Any additional stress on the alfalfa stand increases the risk of damage from inappropriate cutting schedules, so fields with low fertility, low soil pH, poor drainage, insect or disease pressure or short cutting rotations are not good candidates for harvesting during the critical period. For more information on fall cutting management, refer to “Risk Of Alfalfa Winterkill” at: www.omafra.gov.on.ca/english/crops/facts/91-072.htm 

 Spring Cereals: Scott Banks

Early harvested cereals had good to excellent yields and grain quality; however harvest progress continues to be slow due to frequent rainfall. To maintain grain quality, start to harvest when grain moisture drops to 18%. Where fusarium is a concern, use high fan speeds to blow out infected kernels and operate the combine at slower ground speed to allow more time for air blast to separate infected kernels from good ones. Once harvested, immediately dry the grain to 13% moisture content in a heated-air dryer to stop the spread of infection. Attempt to keep fusarium damaged kernel (FDK) levels below 5%. Grain above 5% FDK will be downgraded from feed to sample grade at a greater price discount. Storing higher FDK wheat usually pays as better markets develop for this wheat later in the season.

 Canola: Brian Hall


Canola harvest is expected to begin this week. Alternaria (black pod) is present in many fields and can lead to  increased pod shatter. Once canola reaches 10% moisture, do not delay harvest in heavily infected fields. Shattering losses can be reduced by combining at higher seed moisture content and drying the crop, or harvesting when there is dew. A crop swathed too early (before 60% seed colour change) may require more curing time in the swath especially if hot, dry conditions occur. If straight cutting and considering a pre-harvest

herbicide application, note that these products can hasten dry down of crop and weeds, but do not hasten maturity. For a fast acting desiccant like Reglone, the recommended maturity stage of the crop is when an average of 65% -75% of seeds on the whole plant have turned brown. Be aware that this is well past the 75% seed colour change on the main stem. Do not delay harvest after application, as Reglone can increase pod shatter if harvest is delayed significantly. If storing canola, the presence of green material (eg insects, weed seeds, chaff) can cause heating even if the seed itself is dry. Aeration is necessary to bring down the temperature of canola as the crop continues to respire for several weeks following harvest. Do not store canola in bins previously treated with malathion, as the oil in canola has a strong attraction for the insecticide and can result in residues in the seed.

Source : OMAFRA