Drying of growing leaf

Controlling pests of bamboo

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Tarzanus
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Drying of growing leaf

Post by Tarzanus »

Anyone else has seen massive leaf death on growing leaves. Before they have a chance to unfold, they just dry out. I have noticed a tiny worm in one of the freshly half dried leaf I plucked. Bamboo doesn't look bad because of it, but it effectively terminates growth of new leaves on the affected branch.

It must be some sort of small fly which lays an egg into growing tip. This year, the issue is really evident on my arcana seedlings. I'm actually thinking about using a systemic pesticide on them.
Alan_L
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Re: Drying of growing leaf

Post by Alan_L »

I've never seen anything like that, but on small plants (seedlings) I wouldn't hesitate to use something -- although I'd probably start with insecticidal soap and escalate as needed.
Tarzanus
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Re: Drying of growing leaf

Post by Tarzanus »

IMG_20180819_194345.jpg
IMG_20180820_174601.jpg
IMG_20180819_194325.jpg
That's how they end up... variegated and non-variegated. They seem to like Phyllostachys more than other bamboos, or perhaps they just need to adjust their taste-buds.

Phyllostachys arcana 'Luteosulcata' seedlings were hit the most, following by Phyllostachys aurea and by some extent Phyllostachys aureosulcata 'Spectabilis'. Spectabilis got infested by spider mites. They don't bother other bamboos much yet, though.
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Glen
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Re: Drying of growing leaf

Post by Glen »

I have seen a similar phenomenon on my bamboos, mostly on Phyllostachys species, but sometimes on other genera.

In my case, it was a physiological stress response to high heat, drought, or both. It has never been a problem, as new leaves have either emerged from the tip of the current leaf fan, or a bud at the base of the fan has initiated growth. I have not had insects involved in the damage, but my symptoms were otherwise identical to yours.

I have never tried to remedy the problem, except in cases where I had underwatered a small plant.
Tarzanus
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Re: Drying of growing leaf

Post by Tarzanus »

If i pull the dry tip it comes out easily and you can see it's been eaten. There are also worm droppings and in one case, I saw a smal larvae that I pulled out with the leaf. It was 2mm long at most - really small. If it would happen on a few culms/branches, I wouldn't mind, but now it looks like 1/3 of everything is affected. New branches will start growing, I already see buds swelling. I just don't know if I can leave it untreated. I don't want to apply pesticides on it, but I guess it will come to that eventually. I'm afraid contact pesticide like insekticidal soap would not get the borers inside and won't keep new flies from laying eggs.

I will wait some more. Bamboos are tough and won't be harmed by the issue a lot.

@glen
I also saw similar damage and I thought it's sign of drouhgt/heat stress. Now I am not certain, perhaps it was the same issue.
I also saw the same symptom, but with one difference - there was physical damage on the sheath under the leaf. It looked like someone would scratch it open to get to the emerging leaf spike. In this case, new leaf usually started growing, but was a bit distorted, after that bamboo acted as if nothing happened. Alll the following leaves were healthy.
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Re: Drying of growing leaf

Post by Tarzanus »

Here it is, took a picture of this little bugger!
IMG_20180822_190358.jpg
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needmore
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Re: Drying of growing leaf

Post by needmore »

My two new acquisitions both are losing all of these leaves, due to 8 days in a box in hot weather I assume, and I assume they'll come out of it.
Brad Salmon, zone 12B Kea'au, HI
http://www.needmorebamboo.com
Tarzanus
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Re: Drying of growing leaf

Post by Tarzanus »

Heat and drought can terminate growing tips, but I have a different problem this year. Flies of some sort. I shook the bamboo during the late evening and there were moths and flies hiding in it. And I mean a lot of flies! I'm almost certain they are responsible for the worm on the picture above which eats the growing leaf from inside out. We now have very wet weather (heavy showers, T-storms and casual rain inbetween) for 3 days with major cooldown of almost 20°C. I will apply mild insecticidal solution when it gets a chance to dry up at least a little bit.

If it doesn't get to the larvae inside the bamboo tissue, it should at least get rid of the adult flies. New branches are already growing, I hope those suckers won't start laying eggs in them as well.
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