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Search Results for ' Fungicides'

PAL Questions: 2 - Garden Tools:

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Keywords: Plant diseases--Control, Fungicides, Powdery mildew diseases, Integrated pest management, Dahlia

PAL Question:

What can I do about powdery mildew on my dahlias? Should I throw the bulbs away, or does it only contaminate the plant above the ground? I have heard both too much water and not enough water cause this problem. Is either true?

View Answer:

The main thing you will need to do is destroy all the foliage affected by the mildew. The mildew can survive the winter on infected foliage, and then spread to new foliage.

Powdery mildew thrives where plants are crowded and there isn't enough air circulation, so give your plants space, a sunny site, and try watering in the morning, and watering from beneath the plants (not over the leaves) so they are able to dry off during the course of the day. As you indicated, too little water can also be a problem.

Here are two websites with additional information:
Univ. of California IPM Online Guide
OSU Extension Plant Disease Control

I did not come across any information specifically saying that powdery mildew will affect bulbs or tubers. I spoke to an experienced dahlia and begonia grower here who said that it should be all right to store and replant your tubers, as long as you thoroughly get rid of all the diseased foliage aboveground.

Colorado State University Cooperative Extension has some information about powdery mildew, including preventative measures and a recipe for making your own baking soda fungicide.

Season All Season
Date 2008-01-10
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Keywords: Rooting, Fungicides, Plant cuttings, Propagation

PAL Question:

What is the purpose of the chemical in store-brand rooting hormone? I'd rather not use anything with chemicals when I'm propagating plants. Are there alternatives?

View Answer:

The chemical in rooting hormone (usually Indole-3-Butyric acid) acts as a growth stimulator. In commercial rooting hormone formulations, it may be combined with fungicide to prevent the development of fungus/fungal diseases during the rooting process, as is the case with a common brand, Rootone, which contains Thiram (a fungicide). The Environmental Protection Agency has more information about Indole-3-Butyric acid.

If you would rather not use synthetic rooting hormone, you can skip this stage altogether, or you can try making willow water to encourage rooting instead. University of Arkansas Extension explains how to do this:
"First cut a double handful of one-inch sections of branches from willows and split each one. Bring a pan of water to a rolling boil (if you can catch rain water, that is best). Dump in the willow pieces and leave them to steep overnight. In the morning, the water should look like weak tea. Remove the willow pieces from the water, and soak the bases of your cuttings in it for several hours or overnight. If it has been more than an hour or so since you made the cuttings, cut about half an inch from the ends before placing them in the willow water."

Season All Season
Date 2006-11-28
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June 24 2013 12:55:25