Newspaper article The Florida Times Union

Witches' Broom Can Be Caused by Insects, Fungus and More

Newspaper article The Florida Times Union

Witches' Broom Can Be Caused by Insects, Fungus and More

Article excerpt

Byline: Becky Wern

One of my plants has developed witches' broom for the second time. How can I control it?

Witches' broom is a fascinating plant anomaly. It's not uncommon at all and can have a lot of causes. When a plant develops it, it begins to grow a clump of twigs in a tight cluster. The kinds of things that cause it are amazingly diverse: insects, mistletoe, mites, viruses, fungus and bacteria.

When any of these things attack a plant bud, the bud below it responds by growing a tight clump of branches. This might be a hormonal reaction - the growing tip of the plant contains a high level of growth hormone, and maybe the sudden influx of growth hormones into the bud below the tip just triggers wild growth levels. This deformation is found in many shrubs and trees, although it may not be all that noticeable until the leaves fall off the plant.

While it may not be a serious problem, the University of Florida recommends pruning out the pieces 6 inches below the distorted growth, cleaning the clippers after each cut. In the case of fungal or bacterial causes, using an unclean cutter will transfer the pathogen right on down to the next level.

A 1:9 dilution of bleach or an alcohol rinse for a full 30 seconds will clean the clippers between cuts and ensure that you don't spread the problem.

In some cases, the causal problem can continue and kill the plant. Since your plant has now developed it in many locations, I would consider digging it up and discarding it before the problem spreads to the rest of your shrubs.

I back up to an undeveloped area and have been dealing with air potato for years. I've heard there is a new way to get rid of them. Do you know anything about it?

The air potato beetle is just getting started in North Florida, but it promises to be a great thing for gaining control of this invasive vine. It's a red, brownish or orange beetle, about 9 mm long and 4 mm wide.

The vine was brought to Florida from Asia in 1905. By the 1980s, it had draped itself over a lot of previously natural areas and, by 1999, it was recognized as an invasive. …

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