Aphid damage to plum tree? - Ask Extension
Hi!
I have a Toka plum tree, purchased two years ago and planted out last summer. Last year it got hit pretty hard by aphids in spring/early summer ...
Knowledgebase
Aphid damage to plum tree? #871831
Asked June 06, 2024, 12:39 AM EDT
Hi!
I have a Toka plum tree, purchased two years ago and planted out last summer. Last year it got hit pretty hard by aphids in spring/early summer (and suffered a devastating leaf curl) and I promised I’d take better care of it this year. I’d heard neem oil could help, and I planned to spray in the fall and early spring.., but of course didn’t get around to it til after I noticed aphid damage/leaf curl this year. It’s gotten out of control and I’ve spent a lot of time squishing aphids but I can’t open every leaf and get them all. Do you have any suggestions, in addition to the neem? Either for now or prevention for next year? We have 9 fruit trees in our orchard, and while I’ve seen a few aphids on the other 2 plums, none are getting destroyed like this one. Also, I’m not sure if this is related, but when it leafed out this year, many of the branches are bare on the bottom two-thirds or so. They’re not dead, because there are leaves and buds on the top, but they are certainly not growing leaves on the bottom. Will it ever leaf out in those bare places again? I’m planning to give it another year, but I’m wondering if this little guy doesn’t belong here. My other trees are looking great. Thanks so much for the advice!!
Wallowa County Oregon
Expert Response
Dear Gardener,
Thank you for writing about your Toka plum tree. These trees normally have a V-shape and should be trained while young. They do not require a lot of pruning, but they need to have an open habit so that air and sunlight can reach each branch.
About 20% of all the new growth should be trimmed each year to rejuvenate the tree. Also, I suggest pruning the longer branches back by about half for one year only to stimulate some new growth closer to the trunk. The best time to prune is after flowering but before leaf buds break.
While your plum tree needs well-draining soil, do not let the soil become bone-dry which may encourage aphids. There are some reports that Toka has more aphid problems than other cultivars especially if they are near natural vegetation (ie. fields, woodlots), or near windbreaks.
You may be able to identify the aphid species by viewing minutes 2:30 to 2:60 on this video:
https://youtu.be/kbm55xeQlWs?t=149
I have attached a spray schedule below. We recommend that you always use the least toxic solutions first. Please note the following:
Thank you for writing about your Toka plum tree. These trees normally have a V-shape and should be trained while young. They do not require a lot of pruning, but they need to have an open habit so that air and sunlight can reach each branch.
About 20% of all the new growth should be trimmed each year to rejuvenate the tree. Also, I suggest pruning the longer branches back by about half for one year only to stimulate some new growth closer to the trunk. The best time to prune is after flowering but before leaf buds break.
While your plum tree needs well-draining soil, do not let the soil become bone-dry which may encourage aphids. There are some reports that Toka has more aphid problems than other cultivars especially if they are near natural vegetation (ie. fields, woodlots), or near windbreaks.
You may be able to identify the aphid species by viewing minutes 2:30 to 2:60 on this video:
https://youtu.be/kbm55xeQlWs?t=149
I have attached a spray schedule below. We recommend that you always use the least toxic solutions first. Please note the following:
- Spray only if you find live pests on the leaves or trunk. Once they move on, they are unlikely to return in the same season.
- Insecticidal sprays work only on contact with the bodies of the pests. They have no effect if sprayed on the leaves.
- Chemical sprays may be used during the dormant or pre-bloom stage. Do not spray once the buds begin to open as this can kill pollinators and other valuable insects.
