Child Item

How to treat powdery mildew on grapevines?

Hi All,

My grapevines are heavily infected with powdery mildew and I have spray some eco fungicide twice in the last 30 days with 12 days apart. I have 3 of them, the middle one is the worst and it is slowly spreading to the 2 next to it.

I would like to stop the spread and wondering if I should do a full pruning right to the cordon now even though it is not the pruning season for grapevines ? Or I should leave it as it is and let the fungicide do its thing and let the leaf fall off by itself?

What should I do?

Find more posts tagged with

Gardening

Planting and Growing

Comments

MitchellMc

Hi @alwyntn,

Typically fungicides work best when applied pre-emptively or at the very first signs of infection. All affected material needs to be removed from the plants, and the ground underneath also needs to be cleaned up. You should also spray the ground. In this case, it appears that you might have been too late to control the outbreak and it will likely continue to spread to other plants. Given the extent of the outbreak, it sounds like a hard prune back to the cordon would be appropriate.

Let me mention a couple of our gardening experts @Noelle and @mich1972 to get their thoughts.

Please let me know if you have any questions.

Mitchell

alwyntn

https://www.workshop.bunnings.com.au/discussion/comment/26135#Comment_26135

Thanks Mitchell.

Yea I have sprayed the ground too.

Will do a hard prune back. Should I remove the top soil too or just top layer mulch and do I need to spray fungicide after prune ?

Hopefully will still get some fruit this year.

Cheers.

EricL

https://www.workshop.bunnings.com.au/discussion/comment/75736#Comment_75736

Hello @alwyntn

Look carefully at the mulch and see if it has a layer of powdery mildew on it. If it does, it will need to be removed and thrown in the bin, don't mix it in with your compost. I suggest leaving the soil intact for the moment, I propose staying with your current spraying schedule as too much fungicide could harm the plant and kill the good microbes in the soil as well.

To prevent spreading the fungus further, it's important to maintain good garden housekeeping. Any dead leaf must be removed from the bottom of the plant and thrown in the bin. Infection travels courtesy of the dead leaf as it gets blown towards your healthy plants. Hence it is vital to keep the area clean and free of leaves.

If you need further assistance, please let us know.

Eric

Child Item