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Messages - matt_citrus

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1
Citrus General Discussion / Re: Winter, indoor citrus, mites, and UV
« on: March 05, 2024, 11:14:21 AM »
The punchline may be -- very low doses of UV (as little as a few minutes a week) inside greenhouse/garage/indoors may suppress mite infestations. It seems this is already being studied commercially with strawberries.

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Citrus General Discussion / Winter, indoor citrus, mites, and UV
« on: March 03, 2024, 10:12:07 PM »
I've always noticed that in the summer, when the trees are outside, I never have issues with mites. I considered that the rain kept the population low but I noticed I would still have mite issues inside (or this year, in a greenhouse) that would start in Jan/Feb even when I would spray the trees with water, soap, or oils.

The timing was puzzling. Mite populations can reproduce quickly (one search says 8.5x in 10 days) yet it took 3-4 inside months before suddenly requiring back-to-back-to-back-to-back endless spraying regimens.

So why absolutely no issues outside with no regimen, but a delayed issue inside?

Two interesting papers that highlight the effect of UV both as a) a direct suppressor of mite populations and, more interestingly, as b) a catalyst for defensive citrus resistance to mites.

This is slightly problematic for greenhouses with UV-blocking polycarbonate! But perhaps there is a time lag after UV is reduced (for example, when plants are moved inside) where the mite-preventing volatiles are still produced within the plant.

Deleterious Effects of Uv-B Radiation on Herbivorous Spider Mites: They Can Avoid It by Remaining on Lower Leaf Surfaces

UV-induced citrus resistance to spider mites (Tetranychus urticae)
  • "Abundances of Tetranychus urticae on Citrus exposed to solar UV decrease compared to seedlings under UV filtered radiation."
  • "Mite induced plant mediated resistance is dependent on exposure to UV radiation."

3
In conclusion...

I raked 15 lbs of dolomitic lime over 700 sq ft to slightly raise pH.
Then spread 6 cu yd of topsoil / compost mix on top, raking in 25 lb of organic bone meal and 25 lb of organic 3-4-4 slow release. Soon spreading 5 cu yd of pine bark to allow the soil to digest slowly.
Trees are in rootmaker pots and will sit on top.

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Citrus General Discussion / Re: Topsoil recommendations inside greenhouse?
« on: September 20, 2023, 02:40:17 PM »
Soil test results:
P 7 lb/A
K 102 lb/A
Ca 716 lb/A
Mg 122 lb/A

Zn 0.4 ppm
Mn 15.9 ppm
Cu 0.4 ppm
Fe 12.3 ppm
B 0.1 ppm

Soluble salts 243 ppm

pH 5.2
Buffer index 6.1
CEC 4.0 meq/100g
Acidity 38.9%
Base Sat. 61.1%
Ca Sat. 45.1%
Mg Sat. 12.7%
K Sat 3.3%

Organic matter 1.2%

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Citrus General Discussion / Topsoil recommendations inside greenhouse?
« on: September 10, 2023, 03:49:50 PM »
I'm in the last stages of greenhouse construction, and my base soil is a fine, but light, clay/silt. Are there any recommendations for topsoil ("normal"? amended with mushroom compost? other?), and if there are citrus-specific adjustments (for example, make more acidic) to mix in to any standard topsoil.

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Citrus General Discussion / Re: Fungal disease on new flushes?
« on: May 23, 2022, 07:13:58 PM »
Coming back to this, I'm fairly certain now that it's Alternaria Brown Spot.

Don't have a good mechanism for control yet given how often it rains.

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Citrus General Discussion / Re: Leaf Cupping & Magnesium Question
« on: November 29, 2021, 06:30:20 PM »
The downward cupping can sometimes mean overwatering (or vapor pressures inconsistent with plant moisture). Plant is trying to shed moisture.

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Citrus General Discussion / Re: Indoor winter growroom
« on: November 07, 2021, 12:15:36 PM »
I'm "only" running ~17 true W/sq ft. Two sets of Kingbrite 650W LED light bar fixtures (10x LED light bars of LM301H + deep red/infrared). The mix tests at 3400K and 175 lumen/W (and ~1660 total PPF). The LED drivers are not 100% efficient; each fixture pulls closer to 750W from the wall to generate 650W LED output. Kingbrite was highly recommended by some of the other research forums.

The original Kingbrite mount was 100mm spacing between light bars. This would have created a more pronounced PPFD spike in the center. I remounted at ~300mm spacing to distribute the light over a substantially larger area and make the PPFD coverage more uniform.

Lumens or foot candles aren't a great measure of PPFD because it's spectrum dependent. But it's easier to measure the former. 1700 FC at the plant bases and 2700 FC a little over a foot below the lights. If it's close to sunlight spectrum, that's 350-540 PPFD.

Running 12hrs on/12 hrs off. Tops of plants are getting DLI in excess of 25, the bottoms are closer to 15. I planned for 21 for healthy growth.

VPD is averaging 0.9-1.0 with range of 0.6-1.2. Trying to keep humidity up to sustain beneficial mite populations.

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Citrus General Discussion / Re: Help for 50 year old backyard lemon tree?
« on: November 06, 2021, 02:18:57 PM »
Underfertilized and possibly overwatered.

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Citrus General Discussion / Re: Indoor winter growroom
« on: November 02, 2021, 10:46:17 PM »
Humidity and airflow - There's an HVAC vent into the room, and a door. The heater is running for the house more frequently now with the lower temperatures, so that's the positive pressure into the room. Between the vent and keeping the door almost all the way closed, the humidity has been in a good range. There are 30 citrus trees transpiring water vapor into the air! (and evaporation from the pots.) I also have a floor fan on a timer to turn on for 30 min every 2-3 hours for more circulation. It's a very relaxing - if bright - space to be in. Lots of blooming now, too.

Agree with all the comments here about the Root Maker pots, especially for up-potting. It's easy to cut the zipties and expand/add panels around the existing root ball. Combined with the 5-1-1 mix (I generally add more perlite to be closer to 5-1-2) it's a forgiving setup. You can get a feel for the watering by the weight of the pots,, and there's a clear relationship between canopy size, growth, and diameter of the pot for how frequently watering is required. Some of the smallest pots get water every day and they're growing like crazy (finger limes in particular). Tricky to think about up-potting again during constant flushes.

Brian, good question and something I stressed over in the months leading up to the transition. I ended up building a wood platform on casters, covered with panda film to catch any water (any sturdy plastic barrier will do). The trees sit on top of this. I also used some existing plastic catch basins on wheels as well for some trees. So, all the water is caught above the floor and I can maneuver around to get into the thick of the trees to sweep/vacuum as needed. Downside is losing 6-8" of allowed height but well worth avoiding water damage. Need to get the greenhouse planned :).

Thankfully, have not had to deal with any scale in the region. Lots of caterpillars and earwigs before they came in, and of course the big cicada emergence. The surprise pest was a single Boxwood Psyllid on the pomelo but that was months ago.

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Citrus General Discussion / Indoor winter growroom
« on: October 30, 2021, 06:42:36 PM »
Brought the trees in about two weeks ago, just before the fall storms. Almost every tree is flushing now.


The lights are creating a 10°F temperature delta.


A few of the trees require almost daily watering. They may overtake the space within a couple months.

12
Citrus General Discussion / Re: Fungal disease on new flushes?
« on: October 19, 2021, 07:26:01 PM »
Does anyone have suggestions for treatment? New growth continues to be affected.

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Citrus General Discussion / Re: Osmocote Plus is cheap on Amazon right now
« on: September 03, 2021, 09:26:51 PM »
Thanks Brian.

John B, that GroPower fertilizer is great for the regions that have it in stock.

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Citrus General Discussion / Re: Fungal disease on new flushes?
« on: August 27, 2021, 10:14:55 PM »
It does not look like Alternaria Brown Spot.

The mystery continues then.

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Citrus General Discussion / Re: Fungal disease on new flushes?
« on: August 24, 2021, 09:27:28 PM »
Perhaps have answered my own question but offer it to the experienced growers for confirmation.

Looks very much like the Alternaria Brown Spot symptoms on young growth in this recent research paper:
Alternaria brown spot on new clones of sweet orange and lemon in Italy



And in this UF publication: Alternaria Brown Spot

16
Citrus General Discussion / Fungal disease on new flushes?
« on: August 24, 2021, 07:23:05 PM »
30 or so trees in very close proximity and the only one experiencing this is a Shiranui. New growth flushes are browning and dying off. Is this one of the common fungal infections?

   

17
Anyone noticing heat/sun wilting sensitivity In the new growth? Seeing some leaf tip dieback in the hottest conditions.

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Citrus Buy, Sell, & Trade / Re: Where to buy citrus online (USA)
« on: June 27, 2021, 12:00:31 PM »
Madison Citrus Nursery ( https://madisoncitrusnursery.com/ )

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Citrus General Discussion / Scion or rootstock? (Baboon lemon)
« on: June 22, 2021, 05:28:19 PM »
Trying to determine if this low growth is scion (Baboon lemon) or rootstock (allegedly US-897).

US-897 should be easy to identify (trifoliate), so I am wondering if there's an interstock. The petiole wing of the low growth is much larger than the top growth.

Any ideas?



Low growth


Scion growth


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Citrus General Discussion / Re: Endangered Bees
« on: April 17, 2021, 06:57:44 AM »



21
Agree with Millet. Looks like ACP on new growth.

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Citrus General Discussion / Re: Tree Dieback??
« on: June 01, 2019, 12:29:30 PM »
Brian, how were you able to defeat the scale?

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Really nice to see the growth over time. Can you share more detail about the sprinkler and irrigation setup, especially for the younger/newly planted trees?

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Citrus General Discussion / Re: Pruning in ground citrus?
« on: June 19, 2018, 12:33:34 AM »
I have found this presentation on citrus pruning techniques to be informative, although I haven't cross-referenced with any academic papers:

https://crfg.org/wp-content/uploads/CITRUS-PRUNING-Presentation.pdf

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Citrus General Discussion / Re: Help with my meyer lemon
« on: January 10, 2018, 01:19:19 AM »
Snek, the symptoms you describe here and in the other thread match my experience so far. Only affecting the Meyer lemon (and mine is in the ground on standard rootstock) and not spreading to any adjacent trees.

I did recently find a contact in the CDFA Plant Pathology office that offered to diagnose, so I'll probably send a cutting in soon and perhaps we can all resolve!

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