PrincessE
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How to control leaf miners?

These pests have taken over my cucumber, tomato, squash and zucchini plants. I saw online to cut the effected leaf which I've been doing but the next day there are even more. I just cut nearly every leaf off of all my plants. At this point the plant is going to die either from shock because of me cutting so much or from the leaf miners. Is there a way to rid my plants of these things without cutting every single leaf? Many thanks!
Debbie

evtubbergh
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Re: How to control leaf miners?

Do you know what leaf miners they are? If you can catch some post a picture. Even better are there flies around these plants? Moths? Moths are active at night. Beetles? Also pictures of the tracks they make could help identify the kind of miner.

If they are moths (Lepidoptera) then you could try Bacillus thuringiensis. Normal poisons, even non-organic, are not usually effective against leaf miner because they are inside the tissue and the poisons stick to the outside of the leaf. But the bacteria gets into wounds in the leaf and just a little will thrive inside the worm and cause death.

The best part is that it really will not kill other kinds of animals as the variety of bacteria is specifically tailored to kill only a specific organism, in this case Lepidoptera larvae.

PrincessE
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Re: How to control leaf miners?

I do not know what kind they are. This is the first time I've ever had a problem with them so it's all new to me. Now that you asked, there did seem to be a difference between the lines on my squash plant versus the lines on my tomato. I'm not sure if it looked different because of the types of leaves or maybe they were different types of leaf miners. I did not even think to get a photo. I have noticed lately very small flies have been landing on the leaves. I have Neem and liquid BT. Maybe now that I've cut all the leaves off I will spray them real good and hopefully be able to prevent any future issues. Thank you so much for your feedback.
Debbie

Juliuskitty
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Re: How to control leaf miners?

I used to have a great deal of trouble with leaf miners, and Whiteflies too. I now use yellow sticky traps and my leaf miner damage is down about 90%. You should see how many flies are on the traps! I get them at Amazon.com.
My definition of insanity; trying to grow heirloom tomatoes in South Florida!

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applestar
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Re: How to control leaf miners?

Keep in mind, Bt infects ALL butterflies and moth caterpillars. I maintain my garden as butterfly sanctuary and plant nectar and larval food plants so Bt is almost last resort in my garden.

Neem can kill off the predatory insects as well as the pests.

It's really hard to get rid of the leafminers once they get an infestation going. I'm having trouble with them for the 2nd winter -- I clip off parts and entire infested leaves. They are easier to spot once they get big enough to see -- I cut them in half inside the leaf -- though I sometimes find a leaf with multiple teeny tiny clear spots and microscopic larvae.

I have some plants positioned several containers deep on the "bench" and the furthest ones are nearly impossible to inspect. Since I have to turn the pots periodically anyway, I try to inspect after each turn and try to get all that I can see from that angle.

I have tried destroying them inside the leaves with most of the leaves intact, but that just gets confusing for spotting later infestations, so I remove any part or whole affected leaves as I find them.

My tools of choice are : pruners, dissection scissors, paper hole punch, bamboo skewer and toothpick.

I encourage spiders among my plants (even indoors) and orb weavers do catch some moths and I think the stalkers get some of the larvae, but pheromone traps might be effective for determining level of infestation?

I was looking up predatory insects for the tomato leafminers, and it seems they are researching Podisus nigrispinus (predatory stinkbugs) for the purpose.
https://onlinelibrary.wiley.com/doi/10.1 ... x/abstract

I couldn't find any source listing in my cursory search so I guess its not an established protocol.

It was intriguing to discover this bit of info because I had managed to introduce pretty bad leaf miner infestation to my summer garden because I was unable to eradicate them from my winter indoor tomatoes last year. ...And this summer I saw one -- a predatory stinkbug. I didn't know what it was and I had one of those rare moments when on seeing an unknown bug I DID NOT catch and ID but actually killed it Felt so bad about it that I remember it clearly -- it looked exactly like the brown Marmorated stinkbugs that are such a garden pest around here, except it had these dangerously pointy shoulders and didn't have the banded legs.

I'm really hoping that wasn't the only one and a new member has joined my Garden Patrol (my name for creatures that hunt and eat the garden pests) . I'm going to go search for more info -- I hope they are indigenous to this area and will be back next season. This summer, the Garden Patrol seemed to keep the leafminers sufficiently in check so that the tomatoes stayed ahead of the infestation.

After some more search, he predatory stinkbug I posted about above was a Brazillian species: https://www.cabi.org/bni/FullTextPDF/200 ... 071083.pdf

The one I saw in my garden was probably our native Spined Soldier Bug....
https://www.stopbmsb.org/stink-bug-basic ... e-insects/
...this link at the bottom of this page was REALLY interesting too even though it's from Ontario...
https://www.biology.ualberta.ca/bsc/ejou ... mmm_24.pdf

Spined Soldier Bugs seem to be readily available:
https://www.google.com/search?q=spined+s ... s+for+sale

Of course in Hawaii the native species is probably different. Is there any research being done by the university there?
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applestar
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Re: How to control leaf miners?

Here we go. Vegetable leafminers which are fly maggots are different from tomato leafminers which are moth caterpillars. Here's a link: https://www.extento.hawaii.edu/kbase/cro ... riom_s.htm

This is pretty much typical as far as I've seen among recommendations from various ag papers and articles in that they place emphasis on importance of predators to help control the infestation.
Learning never ends because we can share what we've learned. And in sharing our collective experiences, we gain deeper understanding of what we learned.

imafan26
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Re: How to control leaf miners?

Leaf miners usually only do minor damage and can be tolerated. If you want to exclude them you can try a cover for the plants. I got tulle from the fabric store and sewed it together to form a net over a frame for my garden at a house I had about 10 years ago. We lived on a perimeter lot and all kinds of leaf legged stink bugs, locust and whatever came and ravaged the garden. The only thing left standing was rosemary until I netted the garden. The net only works if you can make sure the bugs are excluded.

You don't have to pick off every leaf. If you can find the larvae in the leaf at the end of the trail you can squish it and save the leaf. I'd rather tolerate some damage and consume fewer pesticides and by preserving predators, I will have fewer problems that I have to deal with.
Happy gardening in Hawaii. Gardens are where people grow.

Juliuskitty
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Re: How to control leaf miners?

I know that they really aren't supposed to be doing much harm to my tomato plants, but they do leave a hole where they exit the leaf. Doesn't that mean its an opening for a potential pathogen to get in?
Here in South Fla. We have a climate similar to Hawaii, and we have a really bad infestation. Also, our leafminers here come from small flys, i see them by the hundreds on my tomato plants. Sometimes one leaf will have 6 trails!
I found that the yellow sticky traps did the trick here. Easy, and totally organic. Use a paper punch and just twist tie them to your trellis. Some brands already come with the hole in them.
You can also make your own, get bright primary colored yellow solo cups, or laminated construction paper, ur yellow spray paint and paint something, then coat it with Tanglefoot, or even vaseline. Then hang it if you use paper, or pushpin the solo cup into your stake. Put them out every 5 feet or so.
As an added bonus, they will also strongly attract whiteflies if you have any in your area. I LOVE them! :wink:
My definition of insanity; trying to grow heirloom tomatoes in South Florida!

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rainbowgardener
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Re: How to control leaf miners?

Yellow sticky traps sounds like a good idea. Be very vigilant at the beginning of the season, try not to let the infestation get so bad.

What works for me is trap crops. The leaf miners love the soft tender leaves of velvetleaf

Image
https://streamwebs.org/sites/streamwebs/ ... f_wssa.jpg

and will choose them preferably over anything else. Then you can just keep pulling the squiggled leaves off the velvetleaf. I discovered this by accident. I got velvetleaf in a packet of mixed wildflower seeds. Everything else from the packet died out, but the velvetleaf keeps coming back.


Columbine, lambsquarter are also known as trap crops for the leaf miner.
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Juliuskitty
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Re: How to control leaf miners?

[quote="rainbowgardener"]Yellow sticky traps sounds like a good idea. Be very vigilant at the beginning of the season, try not to let the infestation get so bad.quote]

Unfortunately here there is no winter, so the infestation is always present all year. Ijust took this photo.
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Yellow sticky trap in action.
Yellow sticky trap in action.
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My definition of insanity; trying to grow heirloom tomatoes in South Florida!

imafan26
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Re: How to control leaf miners?

I know what you mean. I have the same problem. A 365 day growing year means pests are present year round too. I tried sticky traps and I also use bug lights at night. Some things I have just learned to live with. I have also learned that not spraying has given me much better control since the predators take care of the problems for me. The only thing that is really affecting my "harvest" are thrips since they attack the flowers of the orchids and I don't spray them either.
Happy gardening in Hawaii. Gardens are where people grow.

Juliuskitty
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Re: How to control leaf miners?

Thrips love blue sticky traps. :D
My definition of insanity; trying to grow heirloom tomatoes in South Florida!

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