pear tree black soot - Ask Extension
I have three pear trees that have a black soot on the trunks and limbs. I sprayed Captan and Rally all summer along with my apple trees. I also tried ...
Knowledgebase
pear tree black soot #816588
Asked November 17, 2022, 10:55 AM EST
I have three pear trees that have a black soot on the trunks and limbs. I sprayed Captan and Rally all summer along with my apple trees. I also tried Neem Max Oil and Lime sulfur spray in the fall with no result. Is there any other fungicides I can try?
Leelanau County Michigan
Expert Response
Hello,Frederic
Sooty mold grows on the sticky honeydew secreted by insects on the tree. The exact insect needs to be identified before treatment will be successful. Then, the appropriate insecticide applied at the correct time of year is used to kill the insects. The sooty mold itself eventually wears away once the insects are gone.
Please try attaching some clear, well-lighted pictures of the branches and trunks affected. We may be able to see which insect is present.
Here is more information:
https://extension.psu.edu/sooty-mold-of-pears-in-the-home-fruit-planting
For example, Pear psylla insect nymphs excrete honeydew
https://extension.psu.edu/tree-fruit-insect-pest-pear-psylla
Another example, San Jose scale can excrete honeydew( see section on this insect)
https://extension.entm.purdue.edu/publications/E-274/E-274.html
Treatment of insects on fruit trees; note that specific insect must first be identified:
https://s3.wp.wsu.edu/uploads/sites/2082/2014/01/AppleandPearPestManagementChart11.pdf
Imwill watch for your pictures.
Sooty mold grows on the sticky honeydew secreted by insects on the tree. The exact insect needs to be identified before treatment will be successful. Then, the appropriate insecticide applied at the correct time of year is used to kill the insects. The sooty mold itself eventually wears away once the insects are gone.
Please try attaching some clear, well-lighted pictures of the branches and trunks affected. We may be able to see which insect is present.
Here is more information:
https://extension.psu.edu/sooty-mold-of-pears-in-the-home-fruit-planting
For example, Pear psylla insect nymphs excrete honeydew
https://extension.psu.edu/tree-fruit-insect-pest-pear-psylla
Another example, San Jose scale can excrete honeydew( see section on this insect)
https://extension.entm.purdue.edu/publications/E-274/E-274.html
Treatment of insects on fruit trees; note that specific insect must first be identified:
https://s3.wp.wsu.edu/uploads/sites/2082/2014/01/AppleandPearPestManagementChart11.pdf
Imwill watch for your pictures.
I hope you can see these photos clearly. Light is not the best.
Frederic,
Laura asked me to weigh in.
I am a retired Fruit Educator with 28 years of experience in the Michigan Fruit Industry. I have some questions. Do you see the soot on the fruit and leaves?Do you spray with an insecticide? Pears generally don't need much insecticide protection until the pears soften in late August, when they need to be protected from late Codling moth. Pear Psylla are a common pest in pears and have become resistant to most insecticides. A dormant oil application in the early spring will knock the early population down and avoiding insecticides until late July will allow predators to keep the population down. In my opinion using fungicides to reduce the sooty mold is a losing game and you need to treat the cause.
I am not familiar with the exact fungus causing the mold if it is caused by honeydew. For the mold called sooty blotch which grows on the waxy surface of the fruit, Captan is good but Rally is not effective. The typical spray interval is 2 weeks between sprays.
Let me know what you think.
Laura asked me to weigh in.
I am a retired Fruit Educator with 28 years of experience in the Michigan Fruit Industry. I have some questions. Do you see the soot on the fruit and leaves?Do you spray with an insecticide? Pears generally don't need much insecticide protection until the pears soften in late August, when they need to be protected from late Codling moth. Pear Psylla are a common pest in pears and have become resistant to most insecticides. A dormant oil application in the early spring will knock the early population down and avoiding insecticides until late July will allow predators to keep the population down. In my opinion using fungicides to reduce the sooty mold is a losing game and you need to treat the cause.
I am not familiar with the exact fungus causing the mold if it is caused by honeydew. For the mold called sooty blotch which grows on the waxy surface of the fruit, Captan is good but Rally is not effective. The typical spray interval is 2 weeks between sprays.
Let me know what you think.
Hi, thank you for your input. Yes, I saw a little soot on the fruit and leaves, but not much. I spray Imidan 70-W about every 10 days. I use a backpack sprayer for all 24 trees . Most are apples, but some are plum, peach, and pear trees. I am fairly new to this. Am I supposed to spray the trunks of the trees too? I've been mixing Captan and Imidan together. Bloom stage I use Habour bactericide for apples and pears. Is there another systemic fungicide I should use? Thanks again for your help.
