Rust spots on loquats
I have a loquat tree that is about 8 years old and has provided fairly large harvests of fruit over the last several years. We have a lot of fruit on the tree this year also, but some of the fruit is covered with patches of rough rust. I'm enclosing a photo. Last year I had a plum tree on the other side of the yard that developed some yellow spots that turned black on the leaves and the tree died. We removed and bagged it, but I'm worried my other fruit trees might be afflicted with something. Nothing else is showing any symptoms. I have Fig, Pomegranate, Peach, 2 Plums, nectarine, black walnut, and some apple trees that seem healthy. Any help will be appreciated - I don't have much hope for this year's crop of loquats, but I want to ensure the tree is healthy. Best regards, John.
The issue with your plum may not have anything to do with your current loquat fruit problems. The loquat tree itself look perfectly healthy, so I would recommend that you remove the damaged fruit and watch for potential further problems. If you notice any twig die-back where the infected fruit were, prune that back to about 6 inches past the damage (damage will be obvious, with discolored stems). If there is a disease issue, it is likely fungal. So you may apply a registered fungicide that is labeled for use on fruit crops. There are many products labeled for organic use that would be safe. Read the label before purchasing, and ask for assistance from your nursery professional if you need any help deciding between various products. Apply according to the label directions.
Thanks so much!
I'm a little worried because we have a 7 or 8 year old Black Walnut at the back of the house and I recently read the roots of that tree would kill other fruit trees nearby.
I'm considering removing that black walnut to safeguard 5 fruit trees that are within 30 feet. Though, after investing that many years, I'm really loath to rip out that black walnut. This loquat, the fig and pomegranate along with one apple are all probably within 30 feet.
Your research about black walnut is correct. The phenomenon is called allelopathy, where a plant inhibits the growth of other plants near it, to cut down on competition. Here is a well-written article, from Virginia Cooperative Extension, on the topic.