Highlights from Ontario Field Crop News' latest crop report include another discovery of stripe rust in the Clinton area and edible bean planting expected to complete within the week. Limited rainfall has been good for dry hay production. Corn progress is all over the place in varying stages. For soybeans, thin stands are being observed in many areas but soybeans can compensate. Temperature models suggest alfalfa weevil development is delayed, but alfalfa weevil can still pose a risk.
Corn planting is essentially complete. Due to variability in rainfall and soil fitness this spring, there is a wide range of crop stages. Early planted corn is now past the V6 stage and approaching row closure in some fields, while late planted corn on heavier textured soils is in the emergence to early V stages. Side dressing continues in many areas. While stands look good overall, there have been some comments about non-uniformity now showing up in some fields where soil conditions may have been pushed at planting, particularly in areas which have remained dry. Corn replants, mostly due to excessive rainfall in 2018, are reported to be below normal. There have been reports of some fields with heavy weed pressure where weed control has been delayed due to high demand for other sprayer activities. Good weed control from emergence to 6 leaf stage is critical for protecting from yield loss in corn.
On June 6, OMAFRA completed its annual Pre-Sidedress Nitrogen Test (PSNT) sampling survey at its zero nitrogen trial locations. This survey assesses soil nitrogen status by measuring natural background nitrogen mineralized from the soil. Average soil nitrate results came back at 12.7 ppm. This is slightly above the long term (2011-2017) average of 11.7, suggesting nitrogen mineralization processes appear normal this spring. The full report and details on the nitrogen status in 2018 corn fields is available online. This survey serves as a general guide. Soil nitrate results are highly field specific, and growers are encouraged to sample their own fields before making any nitrogen decisions.
Most areas of the province have completed planting, though some still continues on very heavy soil textured areas such as Niagara. Due to variability in planting date, crop staging ranges from planted to early emergence for later planted field to 3nd trifoliate for early fields. Thin stands are being observed in many areas. Issues range from soil conditions at planting, heavy rains after seeding resulting in crusting, seed corn maggot feeding, root rots, or extremely dry conditions. Fortunately soybeans are able to compensate for thin stands within reason. Leaving a stand of 90,000 plants per acre on medium textured soils is usually more profitable than replanting. (110 000 plants per acre on heavy clays) For those fields with very poor stands replanting is still a viable option at this date. Feeding from Bean Leaf Beetle has been reported so monitoring is recommended.
A large amount of hay has been cut over the past two weeks. While most dairy hay is complete, some first cut continues this week. Limited rainfall has been conducive for dry hay production as well. Yields have been reported to be good. Quality has been good, with the only challenge reported to be early season grass growth staying ahead of alfalfa due to the cool start in April. Alfalfa weevil has been observed in many areas and scouting is encouraged after first cut this year. Temperature models suggest alfalfa weevil development may be delayed, and could still pose a risk to early regrowth. Control is warranted if there are two or more active larvae per crown, or 4–8 larvae per 30 cm by 30 cm (1 ft2).
The winter wheat crop is progressing well; however, some wheat stands are variable and considerable discolouration is still evident. In the driest areas wheat is starting to flare up due to a lack of moisture. Fusarium Head Blight fungicides (T3) have been going on as wheat progresses through the anthesis stage. A number of acres in the far southwest of the province did not receive a T3 fungicide as warm temperatures moved the crop quickly through the ideal application window. Stripe rust was reported on June 5th in the St. Mary’s area on a susceptible variety. A second field has since been reported in the Clinton area. Disease levels continue to remain low and as temperatures continue to increase, stripe rust becomes less of a concern. If growers are still considering a late T3 fungicide application for stripe rust control, pre-harvest intervals must be considered.
Canola is progressing well, with earlier planted fields in southern and eastern canola growing regions now at green bud stage or bolting. In northern regions the crop is approaching full rosette and expected to start bolting in the next week or two. Flea beetle is being reported, though pressure is generally low. Flea beetle must feed on the seedlings to be exposed to seed treatment insecticides. Foliar insecticide application is not warranted until at least 25% foliar feeding is observed, and once the crop is at the 4 leaf stage it can likely outgrow the feeding damage. Swede midge is now being observed, although populations are reported to be relatively low. Swede midge pheromone traps should be in place and checked every few days through to bolting. With some early reports of Cabbage Seedpod weevil, monitoring is recommended.
A large portion of edible bean acres have been planted, with many growers done or expecting to be done within the next week. Planting continues in some localized areas where rainfall had delayed field operations, or for shorter season beans such as Cranberry beans. Early reports suggest good stands in most cases, with the exception where seedbeds were overly dry. Lack of heavy rainfall events over the past two weeks has limited crusting and other rainfall related plant loss issues.