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Author Topic: Leaf Miners hammering new leaves, when to fertilize citrus?  (Read 654 times)

JakeFruit

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Leaf Miners hammering new leaves, when to fertilize citrus?
« on: October 23, 2020, 09:06:21 AM »
I have half a dozen lemon & lime seedlings, each maybe 2 feet tall. I've been fertilizing over the summer, but each round of new leaves just serve as hatcheries for moth larvae, leaving the leaves mangled. I've tried spraying new growth with Neem oil with some success, but it's a lot of continuous work. Reading up on the issue, sounds like I either have to use an insecticide or avoid fertilizing during the hot months when the bugs are most active. I'd like to avoid using chemicals (for now, at least), so I'm thinking to only fertilize in months when the larvae is less prevalent. I also read once the trees get larger the Leaf Miners become less of an issue. I'm wondering if that's because there are just more leaves and only so many bugs or if maybe the height of the trees put them out of reach.

Being new to citrus growing, I'm hoping some can share with me their recommendation on when to fertilize or how they deal with this pest.

Thanks in advance!

Mike T

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #1 on: October 23, 2020, 09:30:07 AM »
Sounds like miner damage only. Bad shot at humour there.Doesn't pest oil or neem work or does it have to be timed right? Can you put a bag over the foliage so you see when they emerge and it is time to spray. Are there too many affected leaves to destroy those ones.

JakeFruit

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #2 on: October 23, 2020, 10:16:10 AM »
 :D dad jokes

Neem seems to work, but it has to be applied constantly to new leaves until they mature/harden, especially if it's raining or I irrigate. The trees are healthy with plenty of leaves that emerged before the miners really got after them, but any new growth gets hammered (as of last week).

Millet

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #3 on: October 23, 2020, 11:32:48 AM »
Spray infected plants with Spinosad, an organic insecticide, which will control the leafminer. Spinosad does not kill on contact but will have to be ingested by the leafminer to take effect.  Spinosad is the only program that actually works, or works best.

JakeFruit

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #4 on: October 23, 2020, 12:12:36 PM »
Thanks Millet, I didn't know there was an effective organic insecticide out there. Do you have any opinion on what to do if I don't want to spray anything? Can I just fertilize in the months when the moths are inactive, or are they are big problem year-round (I'm an hour south of Tampa on the Gulf Coast of Florida)?

Millet

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #5 on: October 23, 2020, 02:59:44 PM »
JakeFruit, if you don't want to spray anything, you will just have to continually live with damaged leaves.

pagnr

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #6 on: October 24, 2020, 03:33:21 AM »
Backing off fertilizer to avoid a heavy new leaf flush is a recognized strategy against Leaf Miner in Australia ( same species ?? ),
but maybe more for larger ornamental/container trees.
You have seedlings, you probably want to push growth.
With older trees the % of damaged leaves is less of the total canopy, so less effect on growth.
Have you considered physical barriers, ie insect proof mesh over the plants ? There are various grades for various pests.
Small plastic poly houses can be made from HD irrigation pipe hoops and even large clear mattress bags for a temp cover fix.
Spraying is probably the easiest effective solution, but with a small number of plants, there may be strategies to make it more effective.
You don't want to be as if spraying for flies and mosquitoes with all your doors and windows open at the same time.

laidbackdood

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #7 on: October 24, 2020, 12:19:11 PM »
Well i think i am fully qualified to comment on this subject because i have been tortured by citrus leaf miner here in Perth western Australia....I have done my research and have my 2 cents worth.......there is not much else that terrorizes  young citrus in perth ...except leaf miner.........But i can give you some tips.......they are very hard to pin down and you wont avoid them all together but you can try your best........Knowing your enemy helps....
Firstly.....what are leaf miner up too and what do they seek ?........they tend to come out to coincide with new growth flushes....so spring and autumn....They are after UREA....which just so happens citrus particularly love.....so the key is to feed them towards the end of winter with high urea to give them a good push before spring....to get the big growth surge.......Then you need to spray when u see minute buds starting to form.........They particularly feast on young and tender growth....so dont let new growth grow bigger than 5mm before you spray !...best to start from pin heads ! and then stick to the program.
NEEM oil soaks into the leaf and kills the grub....ECO oil is a surfactant which leaves a coating on the leaf.....therefore making it hard for them to get in.......So i get a 5 litre spray bottle and mix 10ml of Neem oil and 20ml of eco oil and a capful of eco feed(fish emulsion/seaweed).....it all protects the new growth and foliar feeds at the same time...Even fish emulsion has a coating effect on the leaf.....leaves already infiltrated should be pruned off....the key is to get in early when the buds are tiny......I then re spray every 10-14 days....make sure both side of leaves are sprayed and done about 6pm at night...when autumn flush comes......continue with the spray program but avoid high UREA feeds as this is what they seek......dont over feed and and promote autumn growth....the spring burst is where its at.....avoid spraying on open flowers as it will kill them and always spray at the end of the day.......The combo of neem and eco oil has been the most effective for me and i have 30 trees.....CLM can be very demoralizing when you have done everything right and you see lots of new growth.......It drove my friend so mad...he was spraying every 3 days!!!......I have not seen any sign of CLM so far this season and its 34C tomorrow and we are well into spring here............Hope this helps.......Remove all the damaged leaves    and stick to a program...i mark it on my calender every time....This is the organic solution.
« Last Edit: October 24, 2020, 12:32:06 PM by laidbackdood »

strom

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #8 on: October 24, 2020, 04:06:31 PM »
Why remove the damaged leaves?

Millet

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #9 on: October 24, 2020, 04:16:31 PM »
Good point Strom.  The leaves, although damaged, are still producing photosynthates  (the tree's food).  .

Mike T

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #10 on: October 24, 2020, 05:58:37 PM »
You remove the leaves to stop the cycle. If you want to get serious and just be rid of them you can always just use imidacloprid. Neonicotenoids do work.

laidbackdood

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #11 on: October 25, 2020, 10:24:12 AM »
LoL :D

EricSC

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #12 on: October 25, 2020, 06:22:23 PM »
I tried a few organic ways, but were not disciplined enough as laidbackdood so had to go to Imidacloprid.

I applied imidacloprid in last month. Now the new leaves looks good.  Still can see some uneven, bumps, dins, a few of trails, but most leaves are healthy.   I guess it also took care of aphids, scales, mealy flyers. 

Cjpflaumer

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #13 on: October 25, 2020, 11:02:04 PM »
I use Tree Defender tree covers/nets to keep out all insects. Psyllids, leaf miners, etc. Put a PVC pipe in the ground next to the trunk and try to minimize root damage. Zip tie the net to the top of the pipe to keep it center and zip tie loosely on the trunk. You will have no insects. This wonít work if your tree requires pollination however. Or you have to remove it when itís flowering.

Another option which isnít sewn in as nice of a shape, but works, is Mr Garden garden netting. They make them in all sorts of sizes or just bulk netting. No leaf miners fit through that either. It has larger holes than the Tree Defenders but still keeps out just about every insect.

EricSC

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #14 on: October 25, 2020, 11:54:38 PM »
I use Tree Defender tree covers/nets to keep out all insects. Psyllids, leaf miners, etc. Put a PVC pipe in the ground next to the trunk and try to minimize root damage. Zip tie the net to the top of the pipe to keep it center and zip tie loosely on the trunk. You will have no insects. This wonít work if your tree requires pollination however. Or you have to remove it when itís flowering.

Another option which isnít sewn in as nice of a shape, but works, is Mr Garden garden netting. They make them in all sorts of sizes or just bulk netting. No leaf miners fit through that either. It has larger holes than the Tree Defenders but still keeps out just about every insect.

It is definitely a good idea.  I have some net which I bought for vegetables.  I did use them for citrus in spring to prevent cross pollination.  But I don't keep them too long because they don't look great in my small yard.

JakeFruit

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #15 on: October 26, 2020, 09:33:10 AM »
Thanks everybody, some great insights and tips! This is my first year with lemon & lime trees (bought in winter/February); spring didn't coincide with the worst damage, I couldn't get a single clean leaf once summer started. That might have been because the CLM population built up over the spring. I was hoping autumn would bring relief, but the Aussie dude is correct, there has been no relief.

 I was hoping citrus trees would be easy, so I could focus my attention on my mangoes & avocados. I put far more effort into controlling these little bugs than any issues I had with my other trees this year. I'm not the best at staying on spraying/fertilizing schedules (raising children is a real time-suck), but I'll give it a go with the spray combinations and see how it goes. I'll update this thread on my progress.

spaugh

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #16 on: October 27, 2020, 03:40:09 PM »
Just ignore it and don't over fertilize your trees with chemical fertilizers and it really doesn't matter if your tree has some leaf miners.  They don't do enough damage to impact the harvest.  Once your tree is a mature size you will want to avoid using a lot of nitrogen fertilizer on it so it doesn't grow out of control anyway.
Brad Spaugh

JakeFruit

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #17 on: October 29, 2020, 09:41:58 AM »
Oh, believe me, I want to ignore it; that's my standard MO in all things not involving smoke or fire. All leaves since March are so mangled, I think they are more of an energy drain on the tree than they are beneficial. I was hoping I could just fertilize during the months CLM aren't active, but it seems they might always be active in my area...

Millet

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #18 on: October 30, 2020, 12:04:24 PM »
Leaves damaged by Citrus Leaf Miners, are not an energy drain on the tree.  It is true that they don't generate the same amount of energy and a well formed leaf, but they still do generate a lot of energy.  It is best to control the miner and let the damaged leaves remain on the tree.

strom

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #19 on: October 31, 2020, 10:37:00 AM »
I get what JakeFruit is saying, and definitely empathize with him/her/it.  My only two ground-planted citrus are small and young, their new leaves were hit by leaf miners and slugs, and it got a bit worse even after weekly spraying with neem oil+soap last couple months.  It looks ugly and makes the trees look sick, but I've left them on since I'd really like the plants to grow some more before any pruning/shaping.

laidbackdood

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Re: Leaf Miners hammering new leaves, when to fertilize citrus?
« Reply #20 on: November 07, 2020, 12:30:27 PM »
I have found feeding organically through the winter really helps because it breaks down slowly and is available for the spring burst when the trees need it....all my trees starting growing in the last month of winter ....my spring feed consisted of troforte....which is a cheiacl based feed with beneficial bacteria/fungi component and minerals......feeds for 6 months slow release......I am not seeing much CLM at all.... maybe because there is not much urea in the soil now and thats what the CLM are after.

 

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