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Topsfield, Ma.

For the first time in four years cleaning out the garden, I had two sturdy sunflower stalks that were solid, nice white fleshy material. In previous seasons the stalks were brown and hollow inside...I thought it was the norm? Anyone know how to explain this? Some have been planted, and some have been "volunteers" Biggest healthy stalk was approx 3" dia.
Any input greatly appreciated,
Duff

10/19/2005 8:49:55 PM

West Amwell, NJ

Most likely the hollow stalks with brown were infested with stem borers. It's hollow because they ate it, and it's brown because they poop! :-) I'm not sure of the exact species, but if you slit the stems you will find small, yellow worms. They are tiny, but they are very destructive. They just don't go after sunflowers, but you find them in many native weeds as well. I think it's some sort of moth that lays eggs on or around the sunflowers. I've had some rather large sunflowers stall out and then collapse because of those things. I don't like using poison, and even with poison, they are hard to control. I usually assume that I will lose at least 25% of my plants to them, and damage at least 50-75%. Even with the damage, you can still get sunflowers 14-15 feet tall, which is amazing. Some years they are worse than others. I've seen them in my garden in NY, NJ and PA. They are by far the biggest threat to getting large sunflowers.

10/19/2005 9:59:13 PM

Topsfield, Ma.

Thanks for the input. The sunflowers stand in the pumpkin patch which is treated with Merit for borer control, so it obviously doesn't affect the sun flower borers?

10/20/2005 7:09:24 PM

Billerica,Massachusetts

yup stem borers i have them as well, make sure you burn the stalks as they tend to overwinter in them.

Glenn

10/21/2005 8:06:16 AM

West Amwell, NJ

Anyone know the exact name of the species? Anyone know the most common entry points for them? What the eggs look like? One year I was protecting the stalks with borer killer, and they still managed to make it into the stalks. I found the stems of some of the largest leaves were hollowed out.

10/21/2005 3:01:24 PM

Billerica,Massachusetts

Dectes texanus texanus and a related specie Ataxia hubbardi.

10/21/2005 4:05:54 PM

Montoursville, PA

I have been told that the only thing that will get them is a systemic insecticide. I do not know. Never tried. Had none this year but have seen them other years.

10/21/2005 4:29:55 PM

West Amwell, NJ

Any recommendations on an a particular insecticide? I particularly do not like using an poisons, especially since I like to eat the marrows that grow under the plants.

10/21/2005 4:50:44 PM