Tropical Fruit Forum - International Tropical Fruit Growers

Citrus => Citrus General Discussion => Topic started by: brian on June 23, 2019, 09:09:34 PM

Title: new growth flushes turning yellow/white
Post by: brian on June 23, 2019, 09:09:34 PM
Recently all my in-ground in-greenhouse citrus had large growth flushes.  The new growth is looking very yellow/white now.  It seems to match up with spider mites, the trees that haven't had much spider mite activity are still nice and green, but the ones with the most spider mites are most affected.  Are spider mites the likely cause, here?  Or is this more likely a nutrient deficiency? 

I just did a ph test and soil is ~6-7ph.  I added a handful of osmocote to each tree a few weeks ago.  Soil doesn't seem wet, at least in the top inch or two I could dig my finger into. 

All my container-grown trees outside are unaffected. 

Here's the Flame grapefruit (I think):
(https://i.imgur.com/0RcgEaI.jpg)

And the Moro has some really bad areas like this:
(https://i.imgur.com/e4JzIwg.jpg)
(https://i.imgur.com/Am1ek9h.jpg)

Even the Valentine Pummelo that Millet sent me is affected, and it is on flying dragon.  The rest either I don't know the rootstocks, or they are some non-optimal ones like C35
Title: Re: new growth flushes turning yellow/white
Post by: TooFarNorth on June 23, 2019, 09:28:11 PM
I believe that I would try some 10-10-10 fertilizer for in ground trees.  It almost looks like sunburn.  Is it only on some new leaves, or pretty much all of them?

TFN
Title: Re: new growth flushes turning yellow/white
Post by: brian on June 23, 2019, 09:39:07 PM
Pretty much all of the new growth on the affected trees.  It gets hot in my greenhouse, BUT all the trees I have sitting outside in unfiltered look fine. 

Im looking at spider mite leaf damage photos and the fine specking looks just like recent damage ive seen.  I wonder if the mites have been active a lot longer than i realized and i didnt notice until webbing appeared?
Title: Re: new growth flushes turning yellow/white
Post by: Millet on June 23, 2019, 11:01:57 PM
it certainly look like spider mite damage.    I have been spraying my trees twice a day with water spray.  Upper and lower leaves.  Evening sprays work well.  Spider mites hate water.    Oil sprays also work well.
Title: Re: new growth flushes turning yellow/white
Post by: brian on June 24, 2019, 09:58:08 AM
Im going to try spraying them more aggressively.  I was reading about spider mites last night and saw that they do not tolerate high humidity, so simple water makes sense.  Also it seems they tend to decline on their own by mid summer, though i dont know how that schedule applies to a northern greenhouse.  All the research reports are from citrus growing states.
Title: Re: new growth flushes turning yellow/white
Post by: Ilya11 on June 24, 2019, 10:04:32 AM
Spraying with horticultural oil emulsions is very efficient against spider mites.
Title: Re: new growth flushes turning yellow/white
Post by: Millet on June 24, 2019, 10:07:26 AM
Yes, the water sprays raises the greenhouse humidity level.  Especially the evening spray keeps the humidity up through the night.  So far spraying has worked very well in my greenhouse.
Title: Re: new growth flushes turning yellow/white
Post by: brian on June 24, 2019, 10:19:00 AM
I have hort oil but Iím really worried about cooking my plants as it is sunny this week and its over 100F in my greenhouse when the sun is out.  How long after spraying dilited hort oil are plants considered back to normal in terms of heat tolerance?
Title: Re: new growth flushes turning yellow/white
Post by: shaneatwell on June 24, 2019, 11:21:20 AM
I have this too, but I don't think mine is mites. Have it on my mamoncillo and peanut butter tree, but only the grafted branch. Also recently grafted mandarin. Last year it was my glycosmis. Seen it on other citrus other years. I think it has more to do with the exact timing of the growth flush and either temperature or soil moisture. Like the flush starts but the temp isn't quite high enough for soil nutrient mobility.
Title: Re: new growth flushes turning yellow/white
Post by: Millet on June 24, 2019, 02:51:01 PM
Brian, you need to find a method to reduce the day time temperature.  Temperatures 100+ for the entire summer months will not be good for your trees.  Before I put a Wet Wall in my greenhouse my fruit level was very low, and growth was non existent.
Title: Re: new growth flushes turning yellow/white
Post by: brian on June 24, 2019, 03:26:49 PM
I just got my fog pump working today.  I discovered two of the fog nozzles are leaking badly so I need to get replacements, and maybe another thermostat.  Hopefully the fogger will keep temps reasonable but them I will see if I have problems with hard water damaging plants.  My TDS meter says 190ppm for my water supply. 

Might try shade cloth also/instead.  Still figuring this out.  Do you think this damage could actually be sun burn?  I always assumed sunburn was due to intense UV+heat.  The polycarbonate filters all UV, and maybe 20% light when you include angles, greenhouse frame, etc.   My outdoor trees seem perfectly happy in direct sun 10hrs a day, though outdoor air temps are 80-90F while greenhouse is 100-110F.

I could also run my fans faster, they get loud though.
Title: Re: new growth flushes turning yellow/white
Post by: Laaz on June 24, 2019, 04:59:11 PM
We have temps in the 90's-100's for months here. All my citrus are in full sun & never burn. Usually the only way you'll get sunburn is from moving plants with new growth from shade to full sun without acclimating them to the sun.
Title: Re: new growth flushes turning yellow/white
Post by: brian on June 24, 2019, 06:27:13 PM
Im going to assume it is just the spider mites, then.  My trees have been in ground there for months.  Id still like to be able to keep it reasonably cool, though.  Ill see how effective it is soon
Title: Re: new growth flushes turning yellow/white
Post by: Millet on June 24, 2019, 08:18:12 PM
If the damage to your trees is from spider mites, as bad as your leaves look, you should see some spider mite webbing. Fogging the greenhouse will raise the humidity to a level that will eliminate any mite problems, and make life comfortable for your trees.
Title: Re: new growth flushes turning yellow/white
Post by: brian on June 24, 2019, 09:19:32 PM
I see spider mite webbing and spray it off every day or two, but much like the cottony cushion scale they come back with a vengeance
Title: Re: new growth flushes turning yellow/white
Post by: Millet on June 24, 2019, 10:39:51 PM
We do not have Cotton Cushion scale in Colorado, therefore I have no experience with them.  Can't CCS be blasted off with a strong spray of water using an adjustable brass nozzle?
Title: Re: new growth flushes turning yellow/white
Post by: brian on June 24, 2019, 11:01:54 PM
CCS is very.. sneaky.  They thrive on the underside of leaves and the least accesible areas to spray
Title: Re: new growth flushes turning yellow/white
Post by: Laaz on June 25, 2019, 05:03:07 AM
If humidity was the key to controlling spider mites we wouldn't have them here, but we do...
Title: Re: new growth flushes turning yellow/white
Post by: Oolie on June 25, 2019, 01:26:04 PM
Most mites are put off by humidity, so a humidification regimen, or spraying the undersides of leaves consistently can ward them off, works great on any spider mites we get on solanaceous plants here.

The bleaching of the leaves though likely due to mites, could also be a result of Iron deficiency.

I would foliar feed with Iron rich fertilizer or supplement to cover the bases while they recover. That would also supply humidity to help route the mites.
Title: Re: new growth flushes turning yellow/white
Post by: brian on June 25, 2019, 03:44:58 PM
I've read that foliar feeding iron doesn't work for citrus, though the explanation for why doesn't make sense to me... "citrus does not translocate iron well" was the gist of it.  I don't see why it would need to move if sprayed directly on leaves.  I have chelated iron I can add to the soil which I understand is effective.


Today a breaker tripped in my greenhouse had no power for a half hour or so, and temps reached 130F!  Unfortunately I can't tell what tripped the breaker so I don't know if it will happen again.  Plants looked fine when I switched the breaker back on, few had leaves a bit curled but I think they'll be okay.
Title: Re: new growth flushes turning yellow/white
Post by: brian on June 25, 2019, 03:47:03 PM
If the damage to your trees is from spider mites, as bad as your leaves look, you should see some spider mite webbing. Fogging the greenhouse will raise the humidity to a level that will eliminate any mite problems, and make life comfortable for your trees.

I definitely have spider mite webbing on the affected areas.  I had just sprayed them off with the hose before taking those pictures.  I've been doing this every few days but I think I need to be more persistent.
Title: Re: new growth flushes turning yellow/white
Post by: Millet on June 25, 2019, 08:57:32 PM
brian, temperatures of 100+is spider mite heaven.  Be persistent,  Also spray the ground under the trees.
Title: Re: new growth flushes turning yellow/white
Post by: brian on June 25, 2019, 09:25:17 PM
Just sprayed them as the sun was going down, will try to keep it up for the rest of the week
Title: Re: new growth flushes turning yellow/white
Post by: spaugh on June 27, 2019, 10:29:12 AM
How about some spinosad spray?  I would probably spray the entire GH down with it at this point you have little to lose.  Those plants are looking like goners soon. 
Title: Re: new growth flushes turning yellow/white
Post by: brian on June 27, 2019, 10:45:56 AM
I have tanglefoot on all my tree trunks, so I'm hoping that will cut down on re-infestation if I can get the foliage clear. 

I've never used spinosad.  I see various miticides recommended for spider mites but I don't know if I can obtain them on my own.  Have you used this before?
Title: Re: new growth flushes turning yellow/white
Post by: spaugh on June 27, 2019, 10:49:14 AM
I have used spinosad for leaf miner.  Its standard treatment on citrus for leaf miners.  The bottles says it kills mites on contact. 
Title: Re: new growth flushes turning yellow/white
Post by: spaugh on June 27, 2019, 10:51:31 AM
"Spinosad products can be used directly to kill spider mites on contact, but can also be used when watering plants to systemically kill spider mites via the roots."


(https://i.postimg.cc/SjCFwMbF/20190627-075540.jpg) (https://postimg.cc/SjCFwMbF)
Title: Re: new growth flushes turning yellow/white
Post by: brian on June 27, 2019, 11:33:09 AM
Thanks, I just ordered a bottle. 
Title: Re: new growth flushes turning yellow/white
Post by: brian on June 28, 2019, 02:21:10 PM
So that damage might have been sunburn after all, or a mix of spider mite damage and sunburn.  After a nice hot day yesterday I noticed a few of my trees had obvious sunburn damage, even ones that have had no spider mites.  Luckily the last of my fogger parts arrived today so I can set this up before everything cooks.
Title: Re: new growth flushes turning yellow/white
Post by: brian on September 23, 2019, 09:13:28 PM
I tried the predator mites again after the spider mites came back even after a couple spinosid sprays.  This time instead of placing the mites around the base of the tree as the instructions said I spinkled them all over the leaves of the affected trees.  This was about two weeks ago and I haven't noticed any new spider mite webs.  I think it is working.
Title: Re: new growth flushes turning yellow/white
Post by: jbclem on September 24, 2019, 12:36:39 AM
I've been dealing with spider mites on vegetable plants for years, fortunately not yet on my citrus.  But you guys seem to be guessing about the spider mites and the effect of the various treatments.  By the time you see webbing, you usually have a huge population of spider mites and their eggs.  By the time the leaves are all stippled, you have many many spider mites.

Here's an easy way to know exactly if you have spider mites and how many are left after you've soaked yourself trying to wash them off the trees (where do they go when they are washed off, and are the eggs also washed off?):

Try a hand held microscope, somewhere between 10x and 20x.  Here are links to the two kinds I've been using for about 5 years.  They work really well.  The first one isn't anywhere near the advertised 60x, but it gets you close enough to count the eggs, see the really young spider mites, watch them all wiggling their feelers/whiskers/front legs as they suck the life out of the plant.  The second one is a little less powerful than the first, but has a larger field of view and is better made.

https://www.amazon.com/Grow-Room-Microscope-Handheld-Magnifier/dp/B01D96ERFU/ref=sr_1_10?crid=33BCDG8EL033Z&keywords=hand+held+microscope+with+light&qid=1569298048&s=gateway&sprefix=hand+held+microscope%2Caps%2C536&sr=8-10 (https://www.amazon.com/Grow-Room-Microscope-Handheld-Magnifier/dp/B01D96ERFU/ref=sr_1_10?crid=33BCDG8EL033Z&keywords=hand+held+microscope+with+light&qid=1569298048&s=gateway&sprefix=hand+held+microscope%2Caps%2C536&sr=8-10)

https://www.amazon.com/gp/product/B015VGEBS4/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1 (https://www.amazon.com/gp/product/B015VGEBS4/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1)

Myself,  I don't use pesticides, so I'm stuck with Safer Soap which kills them dead but you have to be very persistent since the eggs will keep hatching if you don't come back every 3 or 4 days.  I'm also experimenting with a handheld vacuum cleaner, trying to find a way to do it without damaging the leaves. Citrus leaves are much tougher than vegetable leaves, so vacuuming might be easier to use on Citrus.
Title: Re: new growth flushes turning yellow/white
Post by: brian on September 24, 2019, 09:57:10 AM
Turns out I already have a microscope... though it is intended for slides it works fine if I hold a light source above the sample.

I see a bunch of mite corpses, and a couple live mites.  The live ones seem to be investigating the corpses, maybe this is a predator mite.

It's tough to hold my phone camera steady in front of the eye piece... it is much clearer seeing it in person.
(https://i.imgur.com/ZgJ38w4.jpg)