Knowledgebase
Apple fungus? #753115
Asked May 31, 2021, 5:19 PM EDT
Chittenden County Vermont
Expert Response
Are you trying to stay organic? This is more difficult because of the limited materials (copper and sulfur, mainly).
This is an excellent publication geared mainly for organic commercial growers but it has great info on fertility, pruning, and controlling insects and diseases. Through pruning is important to allow light and air to circulate around the tree, as this minimizes fungal diseases.
https://ecommons.cornell.edu/bitstream/handle/1813/42886/organic-apples-NYSIPM.pdf?sequence=1
and another for home gardeners: https://extension.umn.edu/fruit/growing-apples#diseases-1143611
The easiest thing may be to purchase a home garden fruit spray that contains both fungicides for apple scab and insect control.
Here is the main fungus disease you will be battling.
Trees need to have the fungicide applied BEFORE the fungus attacks, there is no curative effect of the fungicide.
Good luck!
Ann
Thanks so much for these references. Gardeners Supply recommended All Seasons Horticultural & Dormant Spray Oil for late fall and early spring, and Citrus Fruit & Nut Orchard Spray to use now. Also said I might have some success stabilizing this season using Revitalize.
I meant to ask if it’s unusual for the fungus to travel onto my Concord grape vines? They have a similar rust appearance on many of the leaves.
I am not 100% organic, although I’d prefer to use as little fungicide as possible throughout the growing season. I actually sprayed with a Fruit Tree application just after blossom drop, thinking it might be an insect causing some of the damage until it became clear that it’s more of a fungus or topical disease.
Thanks again,
Lori
From: Ask Extension <<personal data hidden>>
Sent: Wednesday, June 2, 2021 10:53 AM
To: Lori Roberts <<personal data hidden>>
Cc: Ann Hazelrigg <<personal data hidden>>
Subject: Re: Apple fungus? (#0023046)
No, fungi that cause apple diseases will not affect grapes. They have a whole other set of their own fungal diseases! That being said, the conditions that are conducive for fungal diseases (wet cool weather) will increase these diseases in apples and grapes.
I am not sure what is in citrus nut and fruit spray but it is likely a combination of insecticides and fungicides. You need to follow label directions to cover all the bases. It will involve sprays from green tip (just as the leaves are coming out) through June I imagine.
Ann
From: Lori Roberts <<personal data hidden>>
Sent: Wednesday, June 9, 2021 11:44 AM
To: Ask Extension <<personal data hidden>>
Cc: Ann Hazelrigg <<personal data hidden>>
Subject: RE: Apple fungus? (#0023046)
Thanks so much for these references. Gardeners Supply recommended All Seasons Horticultural & Dormant Spray Oil for late fall and early spring, and Citrus Fruit & Nut Orchard Spray to use now. Also said I might have some success stabilizing this season using Revitalize.
I meant to ask if it’s unusual for the fungus to travel onto my Concord grape vines? They have a similar rust appearance on many of the leaves.
I am not 100% organic, although I’d prefer to use as little fungicide as possible throughout the growing season. I actually sprayed with a Fruit Tree application just after blossom drop, thinking it might be an insect causing some of the damage until it became clear that it’s more of a fungus or topical disease.
Thanks again,
Lori
From: Ask Extension <<personal data hidden>>
Sent: Wednesday, June 2, 2021 10:53 AM
To: Lori Roberts <<personal data hidden>>
Cc: Ann Hazelrigg <<personal data hidden>>
Subject: Re: Apple fungus? (#0023046)
No, fungi that cause apple diseases will not affect grapes. They have a whole other set of their own fungal diseases! That being said, the conditions that are conducive for fungal diseases (wet cool weather) will increase these diseases in apples and grapes.
I am not sure what is in citrus nut and fruit spray but it is likely a combination of insecticides and fungicides. You need to follow label directions to cover all the bases. It will involve sprays from green tip (just as the leaves are coming out) through June I imagine.
Ann