Published on Wednesday, 30 November -0001 00:00
Flower crabs losing leaves Our office has had many calls regarding flowering crabapple trees losing their leaves. A disease called apple scab is responsible. The disease infects certain apple and flowering crabapple trees. Apple scab infections look like brown to black blotches. Some trees have lost the majority of their leaves. These trees may partially leaf out again but tree specialists are uncertain. All that can be done is to rake up leaves that have fallen and remove them from the area. This may reduce further infections. Foliar diseases are rarely life threatening to trees. Trees can loose up to 1/3 of their leaves annually and have very little effect on the tree's health. A great deal of research has been done on apple scab. Apple varieties such as Honeycrisp have good resistance. Some newer flowering crabapple resistant varieties include Prairie fire, Profusion, Red Jewel, White Cascade and Redbud. If you would like more information, call our office and ask for the two information sheets we have on apple scab and resistant flowering crabapple varieties. Herbicide haying and grazing restrictions Livestock producers occasionally spray pastures with herbicide to get rid of thistles. Restrictions are put on pesticides to make sure no residue remains on the crop that may contaminate food in any way. 2,4-D is one of the most common herbicide used for pastures. It's most effective on annual weeds if applied in the fall. For lactating dairy animals, there is a 7-14 day waiting period when grazing pastures and a 30-day waiting period if the forage is harvested as hay. The waiting period is similar for beef and non-lactating dairy animals (0 - 7 days for grazing and 30 days for harvesting hay). Banvel, another good perennial broadleaf herbicide also has restrictions. At the one-pint rate, the waiting period for lactating dairy animals grazing is 7 days and 37 days if hay is harvested. For beef and non-lactating dairy animals there is no waiting period. The waiting period for harvesting hay increases up to 70 days for Banvel applied at the 4 pint per acre rate. Pursuit is another popular herbicide used by alfalfa growers to control weeds in established alfalfa fields. The waiting period for feeding alfalfa following the application of Pursuit is 30 days.