Issue link: https://read.dmtmag.com/i/635697
www.goodfruit.com Good Fruit Grower FEBRUARY 15, 2016 27 used in orchards, the field tests showed oxytetracycline didn't work as well as the copper programs under the strong disease pressure in southern Pennsylvania. She cautioned that such field tests are site- and weather- specific, so growers may have different results with copper combinations. Growers may not be able to have totally Xap-free peach and nectarine orchards, but Capasso reiterated that they should be able to greatly reduce the impact of bacterial spot if they follow a management strategy that includes removal of cankers. "Overwintering cankers are large sources of inoculum. If you get rid of them, you will get rid of a lot of bacteria and will reduce the initial amount of inoculum in spring and the initial disease severity." • Leslie Mertz, Ph.D., is a freelance writer based in Gaylord, Michigan. PHOTOS COURTESY OF SARAH BARDSLEY CAPASSO Bacterial spot symptoms typically appear about three weeks after petal fall. Early-season fruit lesions may extend all the way to the pit. After pit hardening, bacterial spot causes shallower lesions that may coalesce and cause the skin to crack. The symptoms of bacterial spot on fruit are similar to those of peach scab, which is a fungal disease. On leaves, both copper injury and nitrogen deficiency look similar to bacterial spot. Distinguishing features of bacterial spot on leaves include angular-shaped lesions (rather than round) that are often surrounded by a yellow halo. As the season progresses, bacterial spot lesions may fall out of the leaf, leaving behind holes.