Learning more about plant pathogens
Published on November 19, 2024 at 12:51pm EST | Author: henningmaster
0By Bev Johnson
Master Gardener
Your garden plants are going to sleep for the winter. Unfortunately, so are the pathogens that cause diseases that attack them. Plant pathogens include fungi, bacteria, viruses and nematodes. Bacteria, viruses and some fungi survive in live tissue, live perennial stems, or inside dormant leaf buds. These are darn near impossible to get rid of. Fungi, for instance, survive in a dormant state on plant debris or in the soil as reproductive spores or dominant mycelium. In this state they are capable of surviving the cold for several months without a host plant. Some fungi form hard resting structures called sclerotia that can survive a wide range of temperatures and go years without a host plant to infect. It is impossible to have a garden that is completely free of these pests. That being the case, should you just throw up your hands and go in the house for coffee? Nope. Put on your big girl panties and go to work.
Just some basic clean up can at least reduce the number of pathogens that survive the winter. The stinkers survive very well on plant tissue they have already infected. As the infected leaves and green stems die back for the year, the fungi that caused leaf spots, rots and other problems either go dormant or remain active feeding on plant debris. Come spring the fungi resumes full activity and infect next summer’s shoots and leaves. You need to break this cycle. Start by removing the stems and leaves of any perennial that had a disease this summer. Pull up and bag any annuals that showed signs of disease. Don’t pile up this stuff near your garden. Rain or wind can easily reinfect it. This cleanup includes any trees that had leaf spot. If you can get your compost pile to heat up to 160, compost this stuff. If you aren’t sure, be safe and bag it and send it to the dump.
Are you confused? You are told to “leave it messy” so beneficial insects can winter in the stems of perennials. And now, you must clean it up. Easy, just leave the healthy plant stems. Beneficials also winter in piles of leaves so when you pick up leaves, leave some at the base of trees or shrubs to give them a nice place for their winter nap.
Many diseases can survive on garden stakes, trellises, and your garden tools. Before you put them away for the winter, wipe down any metal surface with Lysol. For wood or plastic, a 10% solution of bleach does the trick. This is very corrosive to metal, thus the Lysol.
Take time to wrap tender barked trees now. Be sure you get the wrap tight against the soil to prevent moles from eating the bark. Go as high as the highest snow piles up in that area. Bunnies have been known to sit on top of the snow to debark your favorite tree. Paint the south-southwest side of the trunk of thicker barked trees with a thinned white latex paint to prevent sunscald.
If the ornamental evergreens become “everbrowns” every winter, wrap them with burlap. This helps reduce the loss of moisture when the ground is frozen, and they can’t pull any water from the soil. This will also reduce winter burn. That happens when the sun reflects off the snow and ‘burns’ the shrub.
It’s not too late to take care of these chores. You will give your plants a healthy start next spring if you take a bit of time now to clean up.