Some frost damage to alfalfa occurred again in late-April, mostly in areas in south-western Ontario. Some of these fields were also frost damaged in late-March. Regrowth of these fields will likely occur, but maturity will be delayed and yields reduced. www.fieldcropnews.com/?p=2236
With dry April weather, most new forage seedings were completed in good time. Once emerged, watch new seedings closely for annual broadleaf weeds and to determine optimum time of spraying. The risk of injury to alfalfa seedlings is greatly increased when 2,4-DB application is made outside of the first- to the third-trifoliate stage window. 2,4-DB can suppress legume growth for a period of 2 – 3 weeks and severe injury can occur under drought or high temperatures. Field experience has demonstrated that reducing the rate of herbicide can reduce the risk of injury to alfalfa seedlings while providing acceptable suppression or control of weed seedlings. Refer to Publication 75, Guide To Weed Control. http://www.omafra.gov.on.ca/english/crops/pub75/chapter10.htm