Black knot on Stanley Plum Tree - Ask Extension
1.I have just discovered what I think is an early black knot gall on the growing end of a branch on a 3yr old Stanley plum tree. It is brown at this s...
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Black knot on Stanley Plum Tree #833533
Asked June 03, 2023, 1:09 PM EDT
1.I have just discovered what I think is an early black knot gall on the growing end of a branch on a 3yr old Stanley plum tree. It is brown at this stage, and I only noticed it after flowering and full leafing out. My question is: when is the best time to prune it out? Some references say to do so when the tree is dormant. Should I wait until fall, or prune it out now? Thanks.
2. The same tree is suffering from aphids and white fly, for the first time. What is the best way to deal with this? We generally abhor chemical intervention.
Summit County Ohio
Expert Response
It would really help to see some photos of your plum tree symptoms and insects to confirm the identification of it's disease and/or insect problems.
Below are 3 links regarding black knot to help you confirm your suspected diagnosis on your Stanley plum tree. It is recommended that you do your pruning during the dormant season or late winter.
There are also 2 links regarding management of aphids with a strong stream of water, insecticidal soap, horticultural oils, and sticky tape.
I question whether you have white flies because they are normally found on houseplants.
Please feel free to ask more questions and attach photos for the most accurate answers. I hope these links are helpful!
https://extension.umn.edu › plant-diseases › black-knot https://mortonarb.org › plant-and-protect › tree-plant-care › plant-care-resources › black-knot
https://ask2.extension.org › kb › faq.php?id=760033
(cut 6 to 8 inches below them). Fungicides can be used in combination
with this pruning/sanitation and applied at the white bud and petal fall
growth stages. ... Subject: Black knot fungus on my plum tree (#0029964) Date: Thursday, July 8, 2021, 9:45 AM. To: janet ...
https://ask2.extension.org › kb › faq.php?id=642520
insecticidal soaps help when thoroughly applied in the dormant season.
One ongoing method of control is to remove leaves and other plant tissue
in the fall. Monitoring for them with sticky tapes is necessary in the
spring. I hope this is helpful.
https://hortnews.extension.iastate.edu › whiteflies
of whiteflies. The immobile immature stages are small, flat,
nearly-translucent, and easy to overlook. Consequently large populations
can develop before you notice anything is wrong. Sap feeding by nymphs
and adults can stress the plants and cause decline of plant vigor.
Infested leaves may be stunted or yellow and may drop prematurely.
Below are 3 links regarding black knot to help you confirm your suspected diagnosis on your Stanley plum tree. It is recommended that you do your pruning during the dormant season or late winter.
There are also 2 links regarding management of aphids with a strong stream of water, insecticidal soap, horticultural oils, and sticky tape.
I question whether you have white flies because they are normally found on houseplants.
Please feel free to ask more questions and attach photos for the most accurate answers. I hope these links are helpful!
https://extension.umn.edu › plant-diseases › black-knot
Black knot | UMN Extension
Quick facts Black knot is a common fungal disease of Prunus trees including ornamental, edible, and native plum and cherry trees. Hard swollen black galls (tumor like growths) form on branches and occasionally on trunks. Many Prunus trees tolerate black knot.Black knot | The Morton Arboretum
Management Black knot is a serious disease of plum and cherry trees (Prunus species) throughout the United States. Black knot is a disease that gets progressively worse each year unless controlled, and it will eventually stunt or kill the tree. ... The most obvious signs of the disease are the hard, black, swollen galls, commonly called knotsBlack knot fungus on my plum tree - Ask Extension
Jul 5, 2021Yes, one of the best ways to manage black knot is to prune out all the "knots"(cut 6 to 8 inches below them). Fungicides can be used in combination
with this pruning/sanitation and applied at the white bud and petal fall
growth stages. ... Subject: Black knot fungus on my plum tree (#0029964) Date: Thursday, July 8, 2021, 9:45 AM. To: janet ...
tiny white bugs on plum tree - Ask Extension
Squishing some will often cause others to jump off. Horticultural oils andinsecticidal soaps help when thoroughly applied in the dormant season.
One ongoing method of control is to remove leaves and other plant tissue
in the fall. Monitoring for them with sticky tapes is necessary in the
spring. I hope this is helpful.
Whiteflies | Horticulture and Home Pest News
Damageof whiteflies. The immobile immature stages are small, flat,
nearly-translucent, and easy to overlook. Consequently large populations
can develop before you notice anything is wrong. Sap feeding by nymphs
and adults can stress the plants and cause decline of plant vigor.
Infested leaves may be stunted or yellow and may drop prematurely.
