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Author Topic: Lost a lot of leaves all at once, leaving petioles attached  (Read 200 times)

brian

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Lost a lot of leaves all at once, leaving petioles attached
« on: March 13, 2017, 02:32:41 PM »
A bunch of old leaves one of my minneolas and an adjacent tree dropped at once, leaving their petiole stubs behind.  These trees seem quite healthy otherwise, and have large new growth flushes that are currently expanding.  I understand that old leaves normally drop entirely, and leaving the petiole stub indicates stress of some kind.  The temperature has made some drastic swings lately, but all the other trees are fine.  I'm wondering if perhaps they are too close to the propane backup heater.



Millet

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Re: Lost a lot of leaves all at once, leaving petioles attached
« Reply #1 on: March 13, 2017, 03:17:12 PM »
Looking at the top picture you can see a lot of spider mites and their webbing.  Looks like there is enough to cause damage.

brian

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Re: Lost a lot of leaves all at once, leaving petioles attached
« Reply #2 on: March 13, 2017, 03:38:10 PM »
Hmm I saw that but thought it looked very minor.  I'm not very familiar with spider mites.  I will wipe them off and apply a soap spray, thanks.

Citradia

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Re: Lost a lot of leaves all at once, leaving petioles attached
« Reply #3 on: March 13, 2017, 09:42:03 PM »
When you see webs like that it's not a minor problem. Good you're going to treat for mites. Mites like dry places especially when we bring potted trees inside for winter I've noticed. I try to take mine outside when not freezing and blast trees with water hose to get mites off.

Millet

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Re: Lost a lot of leaves all at once, leaving petioles attached
« Reply #4 on: March 13, 2017, 09:59:22 PM »
It also makes sense that the adjacent tree also lost leaves.  Mites evidently started on one of the trees, and as mites do, quickly moved to its neighbor. Now that the days are getting longer, and warmer I have also found a couple spots where mites have begun. I sprayed them with horticultural oil.
« Last Edit: March 13, 2017, 10:01:36 PM by Millet »

Millet

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Re: Lost a lot of leaves all at once, leaving petioles attached
« Reply #5 on: March 15, 2017, 03:04:23 PM »
At 70-F (21-C) a generation of spider mites is completed in about 2 weeks, and above 86-F (30-C) it just a week.  Below 50-F (10-C) mites go dormant.   Hibernation is also triggered as days become short in the fall.  They crawl off to sleep through the winter in cracks and crevices. A warm heated greenhouse will counteract this impulse in a few mites as some damage may be seen during winter.
« Last Edit: March 15, 2017, 03:08:38 PM by Millet »

Citradia

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Re: Lost a lot of leaves all at once, leaving petioles attached
« Reply #6 on: March 15, 2017, 09:10:58 PM »
Yep. I'd say definitely a spider mite problem: I can now see the stippling or discoloration on the leaves that indicate mite damage. I'd clean out all the dead infected leaves off the ground and out of the pots and spray with horticulture oil like Millet said. Will probably have to spray once a week for a while to kill off several generations of mites and eggs: follow label instructions for frequency of sprays.

 

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