Trees - Crabapple
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  (March) My husband and I are desperate! We have two beautiful crabapple trees in our front yard, and every year experience the same problem with them. They come out just fine in the spring and bloom. Then about four to six weeks later, the leaves begin to turn black and drop off. They struggle and eventually produce more leaves, but they also turn black drop off. We watch carefully for these, and spray quickly when they appear. We have also used some fertilizer stakes. Would you give us some advice as to this problem?

  It sounds to me like your crabapples are suffering from fireblight. Fireblight is a bacterial disease that is spread during the bloom season by the bees as they are pollinating the trees. It appears shortly after bloom and will look like the tree has been hit with a fire-the leaves will turn black and scorched looking. The ends of the branches will typically get a shepherds crook--or a wilted tip. Once you get the problem, there is no control, except cutting out the damaged wood six to eight inches beneath where damage is visible. The only possible control measure is to spray with streptomycin, or Agri-strep, or fireblight spray, when the trees are in bloom. Spray every three to five days during bloom and hope for the best. Even with spraying, if you have a highly susceptible tree, and conditions are good for fireblight, you may still get it. If you still see black appearing this season, prune out the infected limbs, six to eight inches beneath where the damage has occurred, sterilize your pruning shears in between each cut with a Clorox solution. Once the temperatures warm up to 80 - 85 degrees, the spread of this disease should stop for the season.

  My crabapple tree is five years old. It bloomed earlier this spring, and then the leaves began to curl and die. It really looks poor right now. It has put on some new growth again. Do I have a disease or some other problem?

  The new growth is darker it in appearance than it should be, but it doesn’t appear to be fireblight. Fireblight is a disease that affects the tips of the branches first, giving them a burned or scorched appearance. It progresses down the stem. It attacks pears, apples and crabapples. Some varieties are resistant, while others are highly susceptible. This disease typically stops with warm weather. Some other possibilities could be the site where the tree is planted. What is the drainage like where your tree is planted? Could it be standing it in water during our wet periods? There are some diseases that can defoliate the trees it in the spring, but typically spotting will occur on the leaves before they fall off. Check the site for drainage problems. Has anything been sprayed near the tree or on it? All of these things could be a factor. Keep a close watch on the tree to try to pinpoint the problem.

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