Corn: Greg Stewart Field Observations: CHU accumulations for the first week of May continued higher than the 30 year normal at most locations. However, ground frost with temperatures in the - 1 to - 4 C range on May 9 or 10 damaged much of the emerged corn. Emerged tissue was frozen to the ground in many fields. There are no reports of temperatures getting cold enough to cause frost damage to the growing point of the corn plant, which is located 2 cm below the soil surface until the plant has cleared 30 cm in height. The frozen tissue is first blackened and then turns to straw colour and is sloughed off . Emerging Issues: Seedlings with frozen tissue will almost completely recover; sending out new leaves as temperatures improve. Reseeding and or lost yield potential are very unlikely. Exercise caution in regards to label recommendation for herbicides and corn growth stages. Include any leaves lost to frost when determining leaf number. Soybeans: Horst Bohner Field Observations: Planting progress has been slow over the last week. It's estimated 15% of the soybean crop has been planted to date. Cooler temperatures during the first half of May slowed growth and many planted fields are just now emerging. Significant frost hit some regions on May 10. Fortunately most planted fields had not emerged by then. It takes four to five days to determine the amount of frost damage and the potential for regrowth. Look for new growth from the growing point or where the cotyledons join the stem. Freeze damage extending below the cotyledons translates to complete death of the seedling. Soybeans can tolerate. Winter Cereals: Peter Johnson Field Observations: Scattered injury reported to advanced wheat, winter barley or rye in areas receiving frost. -1 C for 2 hours will kill developing pollen grains and result in floret sterility. In some cases an increased level of ergot can result. Wheat development has slowed slightly with cool temperatures, but continues well ahead of normal, with advanced wheat at boot stage (GS 45). The crop is normal to short for the stage of development with little lodging concern. Calls have started on the value of straw. Crop status remains above average, although a myriad of colours in some fields continues to challenge crop experts. Powdery mildew is increasing rapidly in lush fields or susceptible varieties. Low levels of septoria can be found on lower leaves. Cuticle development on wheat continues to be extremely thin, with ongoing concerns of leaf burn from spray applications, and any mistakes showing serious burn injury. Emerging Issues: Herbicides should not be applied once the flag leaf appears. Yield loss has already occurred, and injury concerns increase dramatically. Fungicide applications should be considered where disease levels are increasing rapidly and lesions can be found on the upper two leaves. Where heading will occur within 10 days, re-assess with the thought of a fusarium fungicide application which will also give good control of foliar leaf diseases. Canola: Brian Hall Field Observations: Canola seeding is 95% complete in all areas. Northern growing areas made excellent progress over the past week completing planting. Cold, wet and windy weather has delayed emergence and early season growth. Early planted fields are in the two leaf stage. Most emerged canola appears to have escaped damage from freezing temperatures (-1 C to -5 C) on May 9-10. Flea beetles are evident at low populations in some areas, but cold weather has held populations in check. Emerging Issues: Critical weed free period (i.e. period of greatest yield loss) is up to 4 leaf stage of canola. Early planted fields need control now. Spring Cereals: Scott Banks Field Observations: Most stands look excellent but growth has slowed with cold nights. Significant leaf injury has occurred where herbicides were applied during periods of low night temperatures. Some yellowing of barley in the wettest areas. Better drainage is the only solution. Emerging Issues: Weed control timing is past the optimum stage in advanced fields, and should be priority one if not yet complete. Most of the crop is tillering (GS 21-24). Annual grasses are slow to develop, but broadleaf weeds are plentiful. Watch night time temperatures below 3 C. If tankmixing grass and broadleaf herbicides, avoid application during cool, cloudy weather to avoid injury. Forages & Pastures: Joel Bagg Field Observations: Recent growth and development of the forage crop has been stalled with reduced heat and accumulation of Growing Degree Days, reducing the chance of an early start to first-cut. Grass maturity has also advanced relative to alfalfa, with orchardgrass at the boot stage. Rainfall has stimulated pasture growth, and livestock have been turned out to grass. Emerging Issues: Dairy producers generally target first-cut harvest at about 40% NDF. Fibre levels can vary by 10% from year to year on the same calendar date or when based on growth stages. Cool, wet conditions can delay the onset of bud and flower while growth continues and NDF increases. "Scissors-cut" sampling and rapid laboratory analysis, Growing Degree Days (GDD), and "PEAQ stick" estimates of NDF are useful indicators of optimum time of alfalfa first-cut harvest. In mixed stands, be sure to watch the maturity of the grasses when making cutting decisions. Recent frosts may have damaged some early, direct-seeded alfalfa. Alfalfa seedlings are fairly frost tolerant up to the cotyledon stage. However, inspect early seeded alfalfa at the trifoliate stages to monitor for frost-damage. Damaged plants will wilt and then die over the next 3 to 5 days. One leaf must escape damage for a recovery. If plants die back to the ground, the plant is dead.