I have several columbine plants in my garden, and many of them now look like they have white leaves, the leaf-borers have feasted so much! Will this harm my plants? (I can't imagine it's *good* for them!) Are there any natural/organic solutions that you know of?
Can leaf-borers kill columbine?
I'm having the same problem! Any idea how I should treat them? Should I cut off all the affected leaves (this would be all of them on some plants).
I've never had them do permanent damage. Leaf miners are harder to treat because they are inside the leaf. I wouldn't cut the leaves off - even holy they provide nutrients.
I recently read that you are supposed to squish the leaf with your fingers at then end of the tunnels and this will kill the the borers. I've tried...alot of tunnels..don't know if it works or not, but it is something to do about it.
I think I'll just wait to see if the plants come back next year...call it either scientific experimentation or laziness!
They'll come back just fine.
I had leaf miners in my columbine this year. It was a first year plant that didn't flower, so I cut it back a few weeks ago. I had planted Cleome seeds in the same area and had moved a few of the bigger plants to different beds and got rid of the rest. I had been noticing over the past week that they had holes in the leaves, and just discovered today that they have leaf miners too! I am guessing it's because they were originally planted right next to the columbine and from what I've read the adult leaf miner fly lays the eggs in the soil around the plant. The Heuchera planted on the other side of the columbine does not have the leaf miners, so I guess they don't go for all plants. My books also say that despite the tunneling in the leaves, the leaf miners really do not affect the health of the plant.
If you forget that it's leaf miners, from a distance it just looks like variegated foliage.. lol
I've had leaf miners in my columbine for the last 4 or 5 years. I've tried picking the damaged leaves off, but they end up showing up in all of them. I also tried cutting all the leaves off for a new flush, but that didn't work either. I've finally decided just to pull up the plants as it's just not worth it. The plants do come back, but so do the leaf miners.
Does anyone think using Merit on them would work? I am at least finding out now what is wrong with some of my columbine by reading this thread...Would the Merit be effective on borers? I have not particular knowledge on this, but if Merit is taken up into the plant, would this kill the leaf miners as they are hosting on it? Or is there a spray we can use?
RatherB
I was told that using a systemic insecticide would work, but never tried it.
I think I may try it. I use Merit on my lawn too for the Japanese beetles. I use it around the river birch to keep the leaf miners away, as per the landscape consultant I use. That is why I am thinking it may work for the columbines. Not all of mine have it, just some. I will certainly give an update if it is working, whether it be this year or next year.
RatherB