What is eating these leaves and killing the grapes? - Ask Extension
We have a concord grape vine, crab apple tree, and cherry tree that stand next to each other. (This can be somewhat seen in the tree picture) The leav...
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What is eating these leaves and killing the grapes? #587234
Asked August 07, 2019, 5:49 PM EDT
We have a concord grape vine, crab apple tree, and cherry tree that stand next to each other. (This can be somewhat seen in the tree picture) The leaves of all three get eaten. The grapes grow until they are green, and then just shrivel up. What is infesting these plants and how to manage it? thanks
Montgomery County Maryland
Expert Response
It looks like you have several different things going on here. First, the grapes. The fruits look like they are showing signs of black rot, one of the common fungal diseases of grapes. There are no types of grapes that are resistant to this disease, unfortunately. Minimize black rot problems by removing/discarding infected fruit and pruning out leaves that surround fruit clusters. Refer to our webpage for more information. https://extension.umd.edu/hgic/topics/grape-diseases
The holes on the grape leaf are most likely caused by chewing insects: flea beetles and Japanese beetles. Here is more information about those: https://extension.umd.edu/hgic/topics/grape-insects
It is too late in the season to do anything about these problems. Clean up and discard the affected fruit and leaves. To manage the common disease and pest problems of grapes, if you want high-quality fruit, we recommend following the guidelines of the Virginia Tech Home Fruit Preventative Spray Schedule. See table 3.8 spray schedule for grapes.
https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/456/456-018/ENTO-289C.pdf
And here is general information on growing grapes (including good practices for pruning and training).
https://extension.umd.edu/hgic/topics/grapes
It looks like your crabapple tree has symptoms of apple scab. This is a fungal disease that starts out as spots on the foliage. In severe cases, a high amount of leaf loss and branch dieback can occur. This problem tends to be worse when we have wet spring weather and less of a problem when it is drier. Pruning the tree is one step you can take to try to manage the problem (this will increase air circulation/create a drier environment in the tree canopy). To prevent this problem altogether, you might consider replacing the tree with one that is disease-resistant. You can find more information and recommendations on this page: https://extension.umd.edu/hgic/topics/scab-apples-trees.
You also mention a cherry tree. Cherry shot hole disease is fairly common in cherries and may result in early leaf loss. By this time of year, mature trees have enough carbohydrates (food) stored up to recover with new growth in the spring. https://extension.umd.edu/hgic/topics/cherry-shot-hole-flowering-cherries
Christa
The holes on the grape leaf are most likely caused by chewing insects: flea beetles and Japanese beetles. Here is more information about those: https://extension.umd.edu/hgic/topics/grape-insects
It is too late in the season to do anything about these problems. Clean up and discard the affected fruit and leaves. To manage the common disease and pest problems of grapes, if you want high-quality fruit, we recommend following the guidelines of the Virginia Tech Home Fruit Preventative Spray Schedule. See table 3.8 spray schedule for grapes.
https://www.pubs.ext.vt.edu/content/dam/pubs_ext_vt_edu/456/456-018/ENTO-289C.pdf
And here is general information on growing grapes (including good practices for pruning and training).
https://extension.umd.edu/hgic/topics/grapes
It looks like your crabapple tree has symptoms of apple scab. This is a fungal disease that starts out as spots on the foliage. In severe cases, a high amount of leaf loss and branch dieback can occur. This problem tends to be worse when we have wet spring weather and less of a problem when it is drier. Pruning the tree is one step you can take to try to manage the problem (this will increase air circulation/create a drier environment in the tree canopy). To prevent this problem altogether, you might consider replacing the tree with one that is disease-resistant. You can find more information and recommendations on this page: https://extension.umd.edu/hgic/topics/scab-apples-trees.
You also mention a cherry tree. Cherry shot hole disease is fairly common in cherries and may result in early leaf loss. By this time of year, mature trees have enough carbohydrates (food) stored up to recover with new growth in the spring. https://extension.umd.edu/hgic/topics/cherry-shot-hole-flowering-cherries
Christa
