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Topics - KarenRei

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1
I'd always believed that Aztec Sweet Herb (formerly, Lippia dulcis, now Phyla scabberima), the source of the sugarless sweetener hernandulcin, also contains significant amounts of the toxic substance camphor, and thus should only be consumed in small amounts, and in particular be avoided by pregnant women.  However, I just ran into this interesting paper from 1996:

https://www.sciencedirect.com/science/article/pii/S0031942296006917

Apparently the first studies of the plant involved samples collected in Tlayacapan (where they're known for use in treating dysentery and abdominal inflamation), and they identified hernandulcin as the sweetening compound, in significant quantities. A followup study involved a mixture of plants collected in Tlayacapan and herbs purchased in Mexico City, being sold as an abortifacent. They strangely found little hernandulcin (although their analysis method may have been to blame), but also found that the essential oil was 53% camphor, creating the health concerns. This study here analyzed plants collected in Orocovis, Puerto Rico and found ample hernandulcin (36% of the essential oil) and no camphor whatsoever. It also yielded much higher essential oil contents than the Mexican plants had.  In Puerto Rico - and, from what we know of the Aztecs' usage of the herb - there were no abortifacent properties attributed to it.  The author suggests several possibilities, but perhaps the most probable is that the abortifacent-variant sold in Mexico was misidentified and was not L. dulcis / P. scabberima.  It might also answer the paradox of how you could have a sweet-tasting herb containing so much camphor, as camphor is bitter tasting.

I need to research this some more later, but I'll call this good news for fans of natural sugarless sweeteners  :)

2
I'm curious, who here (who sells live plants) is under phytosanitary control and certified for their export?  I know a number of people here as seed sellers (and have purchased from some before), but have not previously had need to purchase live plants so have not looked into it.  I'd much rather to purchase from people here than from elsewhere  :)

In general, we can import pretty much anything tropical.  E.g. nobody's worried about the "Icelandic citrus industry" being hurt by citrus psyllid or about strawberry guava becoming invasive or whatnot  ;)

3
Tropical Fruit Discussion / Aaaargh!
« on: May 02, 2018, 08:39:38 AM »
So, I recently had a number of plants showing signs of potassium deficiency and struggling.  A soil potassium test revealed that it was low (nitrogen was high, phosphate normal).  So, I gave them a nice helping of potassium sulfate from a bag I got on ebay long ago and but had only recently started slowly using up (not in formal product packaging, just a labeled ziplock).  They all got worse, and a few that I'd had for years died. I was baffled, but something had been eating at me.  When I bought a big bag of potassium sulfate at a store here (since I was running low on the ebay stuff), the compound didn't look like the contents of my old ebay potassium sulfate.  So I set up a potassium test and sprinkled some into the test liquid.  No colour change.  Then I set up a nitrogen test and sprinkled some in.  Rapid bright purple, off the charts.  It's some bloody ammonium compound.  Ammonium, a compound that  makes potassium deficiency worse, and when over applied is toxic.  Aaaargh!

Well, this also probably explains the calcium deficiency in one of my bananas too that doesn't seem to want to go away.  I'd been giving it the "potassium sulfate", and yes, excess ammonia causes calcium deficiency too  :

4
Tropical Fruit Discussion / Native habitats spreadsheet
« on: April 30, 2018, 07:55:55 AM »
So, I made a thing  ;)

https://docs.google.com/spreadsheets/d/1P-AoOGdl2ZHcm1Es0p5VLGsLWp3ffKbpYQuhpkcXCSg/edit?usp=sharing

Still very much a work in progress, but I thought I'd share: as a tiny portion of the database project I've been working on, I wrote a program that parses plant habitat descriptions and combines that with climate data to determine what sort of native environments they're grown in (this is combined with some curated data concerning what conditions the plants are known to like growing in.).    It looks at the plant's native altitude range and only includes points within the habitat areas which are within that altitude range.   If it can't find any locations that match the stated altitude in the stated range (e.g. the resolution is too coarse), it uses what data it did find and adjusts temperature, etc for the altitude difference. 

Now, some caveats.

1) It's a computer without a brain having to read text.  Subtlety will pass it by.  I've tried to include common edge cases - for example, "Located in X, not found in Y" - it'll see Y but not parse it.  It also tries to, when it sees "Found in X (Y)", where either X or Y is a subregion of the other, only parsing the subregion, not the whole.  But expect some mistakes.

2)  A lot of the mistakes are in the habitat description itself. For example: Artocarpus lakucha comes up with an average wintertime low in its range of 6,1C.  Now, we know that it's not native to such cold climates. How did it come up with that?   Well, the range description is "E. Asia - Malaysia, Sumatra, China, India, Nepal, Sikkim, Myanmar, Laos, Vietnam, Indonesia, Philippines".  So it's looking at the climate of all of those - including all of China.  We know in reality that you'd only find it in the warmer parts of China, but that's not what the description says.  So, vaguery = bad  ;)

Feel free to improve habitat descriptions to be more accurate!  You can use countries, subregions, cities, etc.  Just try to make sure that you don't name a place that has a more major (population, significance, etc) area with the same name!  It understands adjectives such as cardinal directions (including e.x. "northeast", but not "northnortheast") as well as "central".  Scattered city listings are just fine.  Let me know when you make any changes of significance and I can re-run it.

3) It does not understand the common wording "through" - e.g. "Portugal through Greece".  It will only look at the endpoints.  Again, feel free to improve this by being more specific.

4) The data behind it is the same data behind this site:

http://climatemaps.romgens.com/

But some of that data doesn't match other sites.  For example, they show a much dimmer winter in Manaus than you get when you punch Manaus into PVWatts.  I'm still trying to reconcile that.  Another example is in humidity; the average humidity figures seem to match the figures you'll see reported for average humidities for cities on Wikipedia, but when you go to daily weather histories on Weather Underground, it feels a bit off, particularly on daytime humidity.  Again, not sure how to reconcile that; this is just coming from the data I'm given.

5) There's still a good number of duplicate / synonym species that I need to work out, and a LOT more curating that needs to be done.  A known bug is that sometimes it'll list "kill temperatures" as "minimum acceptable temperatures", although it's generally very obvious when it does that.

6) It ignores everything up to the first dash (if an "early first dash" is present), to avoid parsing e.g. whole continents.

All that said... enjoy  :)  Don't be too hard on me about errors, this is a first draft (there might even be some alignment errors pasting into Google Docs!  I haven't had much time to go over it). Just point them out, and where you can and/or improve the data (anything at where it says "Known preferred climate" or to the right) and let me know what you changed (otherwise it might accidentally get wiped out when I do future runs!)  I see one issue I'm going to check into this evening, where an acacia is getting a lower temperature rating than I'd expect.  I want to make sure that at least the algorithm is doing everything right, even if some of the habitats are poorly described  :)

(I have a LOT more data I'm collecting, but I'm still going through it)

5
Hi all! I was in a meeting with our project manager the other day discussing various plant possibilities. She likes the idea of having lianas (we have a huge amount of room to fill and want to do so as quickly as possible, with no practical limits on how much weight the (steel, concrete) structure can bear) but she wasn't sure about how quickly we could get them established.  I was able to answer her questions about a lot of other vining species, but I really have no clue with the big liana species like you find in Apocynaceae.  Based on other tropical vines I'd WAG it around 3m a year once established, but what do you growers find?  And how quickly do the vines thicken up?  I know this is a really broad category, but any datapoints you can add would be great  :)  We'll have a mix of full sun, partial shade, and full shade; summer sun is 24/7 here, while winter would receive an artificial "sun" of nearly half a megawatt of lighting  ;)  And we have both dry and wet domes to fill, with various microclimate zones in each. No winter, and dry seasons only where needed..

Note that while the potential of fruit is important, even if it ultimately fails to fruit, that's fine; we just need to get some things large and impressive established in the early years. Actual yields in the earlier years would be from smaller, precocious plants, while plants that need time to grow large get their chance to do so.  Any initial fast-growers that ultimately "fail to perform" would be on the chopping block  down the road to make way for other species that want their sunlight  ;)  Of course, if they yield fruit that goes over well, then they can earn their keep  ;)

6
Tropical Fruit Discussion / Encouraging acerola fruit set
« on: April 21, 2018, 09:49:58 PM »
So, I've finally figured out the recipe to making my acerola flower: fertilize well, calcium-rich / higher-pH soil, good root aeration, significant dry period, then water and prune (no clue why pruning encourages flowering, but it sure seems to).  Right now my acerola has more flowers on it than it's ever had on it in its whole life put together.  Yet at least so far I'm not sure if I've gotten any fruit set. Are there any good tricks for that?  I've done some trying to pollinate with a sponge paintbrush, some tree shaking, and last night I have it a heaping serving of potassium sulfate, hoping that will help.

I love acerola, and they're quite good for you too, so if even a small fraction of these flowers set fruit, I'll be quite happy  ;)

It's weird that I never seem to see any pollen grains.  I can see the anthers in the flowers and they're bright yellow, but no yellow "dust" ever seems to come off of them.  I'd break out the microscope but the eyepieces are a bit messed up at the moment...

7
About to harvest some coffee, and I'm wondering... is there anything worth doing with the flesh of coffee berries?  I've sampled them before, and they're... underwhelming.  Sweet, but a leafy taste.  Wondering if there's any application in which they're actually good. Or whether I should just wet ferment the cherries to try to impart a sweeter flavour to the "beans".

8
Much appreciated by natives in central Australia, particularly the Aranda people. Woody fruits up to 9cm in diameter; flesh inside is sweet, oily and milky, with a taste reminiscent of coconut, and very nutritious.



C. pomiformis seeds are tiny, round, soft, and have a short lifespan.

Shade tolerant. Dioecious. Fertilized by insects. Cannot be grafted or air layered, but comes true from seed.

Available for only a short period of time; get 'em before they fly out the door!

9
I'm finding conflicting information about the odor in the big pom-pom flowers of Parkia biglobosa.



As one would guess, they're primarily bat pollinated (although capable of bee pollination), and so - reportedly - have a strong scent, like most bat-pollinated flowers. However, most bat-pollinated flowers have a strong bad scent.

This paper:
https://watermark.silverchair.com/j.1095-8339.2001.tb01084.x.pdf?token=AQECAHi208BE49Ooan9kkhW_Ercy7Dm3ZL_9Cf3qfKAc485ysgAAAdEwggHNBgkqhkiG9w0BBwagggG-MIIBugIBADCCAbMGCSqGSIb3DQEHATAeBglghkgBZQMEAS4wEQQMotkgRWL250R8q8UrAgEQgIIBhJe6GyzPPjH5mfM8ejeY9HQFvC0Tupjun85RaGjab3VYHpoyPlNPFSxUpcAKidgmpjfTrfG7aPg8a4-1M3C6d4vBgF0G-tKD6ID3jUq2ebGjuk4BGYKMpEwwNTbDEZhha1MI3I4vodg8tOmW8xlK1WIKnK4MkvrK0h9h2MAvgDD52vA7oDHF7VDd8FAnya3MkM7KkyofpoVO04cyeM9zhooB9YpMm6IfhpEt0r6zceEZBeME217C5EayjtrxHYLoWPDBMajZBHvzkSENMUIPWCoW9Lqon-6o1mvSxzyoeM0wk6G_BArMhjLuYnTaDfYCiV-exltG0puZGf__cIlfsCY-k8mADX20XBE4k74hdhAQOoAYrFPfhK361o8Z3pK-6AV7SBhPKyBh_YY5NCCTTYwUFM-DIMW22HvozA6TzAZYPlgDydT7hOcnT5lXPZm9_sZOSedgND4jW45iXdHseCcOJ67d7Gz_vNP9dkvv9cAXAdna21nj8E8mpIgmRF1RQbIk5wY

... describes the scent of other Parkia species as "foetid, fruity or like cow manure", due to sulfur compounds, but finds no sulfur compounds in P. biglobosa. Their description of the "strong floral scent" of P. biglobosa (which peaks in the evenings) is "A heavy, sweet and somewhat stuffy scent".

However... this here:
http://www.worldagroforestry.org/treedb/index.php?theNode=Biology&keyattribute=Hermaphrodite

... says that the flowers "may smell foetid and fruity like cow manure"

My *suspicion*, due to the striking similarity of the wording between the two sources, is that the World Agroforestry site is just getting that from a description of the smell of Parkia species' flowers in general, rather than specific for P. biglobosa. Specifically, the first paper cited "Wee & Rao, 1980; Hopkins, 1983; Gdnmeier, 1990" for that description, so I imagine that World Agroforestry gets that description from them too.  But this is just a suspicion on my part.

Has anyone here ever smelled a P. biglobosa flower?

Also, while were on the topic of P. biglobosa, I've seen conflicting information about how big they are when they start to flower. I've seen one person say "Trees start flowering at 5 - 7 years while still comparatively small.", suggesting that they might even be able to be grown in a pot; while another source says that they're quite large when they fruit, which begins at 5-10 years; and another source says that they grow up to 1 meter in the first year and up to 7m in the first 6 years.  Is that "small size at first flowering" only if you dwarf them?

10
Tropical Fruit Discussion / Coconut deficiency and treatment
« on: March 18, 2018, 08:47:26 PM »
As discussed here, somewhat offtopic:

http://tropicalfruitforum.com/index.php?topic=27233.0

... I've long been rather lax about my fertilizer routine, and am working to amend my wicked ways  ;)  In regards to this, I'm working to treat a deficiency in my Fiji Dwarf coconut.  Symptoms:

 * Deficiency in a mobile nutrient (N P K Mg Cl Mo Ni), as the symptoms are in the oldest leaves, while new leaves are just fine
 * The main symptom is chlorosis, eventually progressing to necrosis.  Chlorisis begins further down the leaflets, yellowing (pure yellow, not spotty/blotchy), affecting the central vein and the edges last.
 * This, I understand, to be a symptom of K deficiency, which I also understand to be the most common deficiency in palms

Leaf that is mostly yellowed, but necrosis is just beginning at the tip:


Zoomed in to the necrotic portions:


Leaf with nearly-full necrosis next to it:


Section of a leaf going chlorotic:


Comparison between the basal portions of the necrotic vs. the yellow leaf:


Older images of an old frond (ignore the cutoff leaflets on the right):



Progression of yellowing up the same old frond, 2 1/2 weeks later (sorry for the red lighting):



Attempts at treatment thusfar:

 * Started out rather half-arsed  ;)
 * First looked up *proper* fertilization for coconut palms, which for a palm the size of mine should be about 200 grams of my fertilizer I had been using** per month, plus extra potassium. I had probably been averaging about 50 grams, with no extra potassium - but it's hard to say because I hadn't been measuring.  The fertilizer is 12-14-14.
 * I started out just giving a proper single monthly dose at the start of the month, but that did nothing to reverse what's clearly been a problem that's built up over time.
 * Over time I made minor, trivial additions of more potassium, magnesium, and trace elements, as well as starting foliar feeding (but AFAIK that was kind of hopeless for macronutrients like potassium)
 * Eventually (~5 days ago?) I looked up how to treat a potassium deficiency, and found out that the amount of fertilizer I should be adding to remedy is huge, something like 1 to 1,5kg, and that it should be a 3:1 ratio of potassium sulfate to magnesium sulfate to avoid inducing magnesium deficiency.  I've so far added about 400g, as I don't want to add it all at once (it's been in two doses so far)
 * Today - although it's doubtful that it's the primary problem - I also added some (maybe ~80g) of sodium chloride (just regular table salt).  Our water isn't chlorinated, so this tree has probably never gotten any added chlorine in its life, and my reading was suggesting that coconut palms are unusual in actually liking chlorine, and that addition of saltwater has been known to help perk them up.  Adding salt to soil goes against every bone in my body, but....

The palm is 3,2m (10' 6") tall to the top of the highest fronds, with the fronds starting to separate at around 80cm up (2' 6"), and a trunk diameter of 10cm (4").  The soil depth is 60cm, and the pot is 80cm wide.  So in gallons, that's probably around 50 gal.  5 fronds - 2 old fronds undergoing chlorosis / necrosis to varying degrees, 2 mature and mostly or completely healthy fronds, and 1 new frond opening up.

The other issue that comes to mind is root health.  Shot suggested soil temperature, pathogens.

Soil temperature should be around 24C (75F), day and night, all seasons, at all depths.  Air temperatures vary, and increase with height, but probably average around 30C (86F), and humid.  I didn't used to, but I've taken to misting my plants several times a day as well.

I did have an outbreak of fungus gnats starting last month and peaking several weeks ago.  Their numbers have been declining of late as I found a place where I could buy predatory insects (yeay!).  They're still around, but not nearly as common.  Apart from fungus gnats, the only other pest that I ever have had problems with is spider mites (they've killed more plants than I care to admit over the years).  No unusual numbers of them of late, and I bought some predators for them as well just in case.

Aeration: the pots have holes drilled at the bottom, but they're such large pots, and plastic, and the soil is so moist, that obviously root rot is something to consider.  Normally I try to prevent this simply by not watering the large pots too often, but now I'm facing conflicting interests; I have to water to rinse fertilizers into the soil (and the more I water, the deeper they'll wash in)... yet if root rot is of concern then I want to water as *little* as possible.  I have no frond wilting, so that's a good start.  I did - 2-3 weeks ago - drill a lot of side holes.  I might go in at some point and double the number of side holes.  I obviously don't want to go so far that I ruin the pot's structural integrity, or I'll have to coat it in fibreglass to reinforce it - but I could probably do more.  Regardless, the soil is very moist right now.  Question of whether I should be relocating the palm to outside the humidity tent to try to dry it out, or just backing off on waterings (aka, washing in nutrients) for a while.  Again, there's no wilting, so maybe it's not a primary concern right now.

Thoughts, suggestions?

11
http://www.guaycuyacu.net/seed_sell.html

Casearea quinduensis   -   RG   Small tree, green fruits almost identical to those of C. obovata

All well and good.  Except:

http://www.iucnredlist.org/details/35350/0

Red List Category & Criteria:   Extinct ver 2.3

Has anyone asked Jim about this before?  Either his ID is wrong (most probable), or he's selling seeds of a species that's thought to be extinct.

12
I'm finding some rather limited - and perhaps incongruous - data on the yields of jaboticaba species and their relatives (optimum soil / sunlight / feeding conditions), and I'm looking for feedback  :)

So far I've only found two references that seem of utility: one said that Myrciaria dubia / Camu Camu yields 12t/ha in cultivation (rather low by fruit standards, about 40% more than Mangosteen - a standard low-yielding fruit).  The other states that a mature Jaboticaba (apparently Sabara) yields 1000 pounds (~400kg) in Brazil.  Going with the assumption that by mature they mean "huge", and going with 9 meter (30 foot) trees, spaced 9x9 meters apart (from the same source: "He felt that 30 feet was the correct spacing without pruning"), this works out to around 50t/ha, which is a very large yield (say, high density oranges grown under optimal conditions, or double that of high density mango cultivation).

For you growing jaboticabas, what would you estimate yields would be for your various species/varieties, and what said "optimum conditions" would be?  I assume that you don't know t/ha figures, but I can work with any sort of figures - e.g. "The yield is similar to oranges", "I get about X pounds per fruiting and Y fruitings per year on a tree that's Z feet tall", etc.   :)  Even comparisons of annual yields between different jaboticaba varieties would be of use! 

(Note: per year, not per harvest  :)  )

13
Jim West has a species on offer, Clavija longifolia (mongon) (primrose family, Primulaceae), which like many of his species is somewhat difficult to find personal accounts of people growing it  (although not as hard as Casearea (Caesarea?) quinduensis(?)!).

Does anyone have personal experience with C. longifolia?  From extensive googling, I've come up with: it is a very aesthetically attractive plant, with a palmlike growth habit (2-4m) but a rosette of "broadleaf"-style leaves at the top, and cauliflorous fruiting habit.  The orange fruit appear to have a flesh that looks sort of like orange sherbert or caramel in pictures, with a thin, probably easily removed rind. Photos of the plant show it frequently growing (and fruiting) in varying degrees of shade, including some surprisingly deep, although I've found one picture that shows it in at least mostly sun if not full sun. Productivity looks relatively good relative to the size of its crown and the environments it's growing in. I did find one report that scarified seeds soaked for 36 hours took up to 4 months to germinate, with a 2/3rds seedling death rate, and that they apparently like their growing media constantly moist.  It reportedly has a good smell, although it's not clear whether that's the flowers or some other part, and how much of the year that's present. Habitat: "tropical forests in the Andes between 500 and 2000 m from Venezuela to Bolivia "  IUCN status: Near Threatened.

Pictures:
Link

Anyone have anything to add about this species or genus?  The main thing I'm missing is fruit quality, and anything about cultivation difficulty/details, etc.  I know at least one person here has grown it (akanonui).

14
A gorgeous tree, with well rated fruit... yet the information I'm finding on it seems contradictory.  Just some examples here alone:

http://www.tropical.theferns.info/viewtropical.php?id=Eugenia+dysenterica

 * Says it's slow growing, and "doesn't exceed 2 meters height after 2 years".  Putting on a meter of height per year in a plant's first two years isn't slow growing at all.  How fast does it actually grow?
 * Says it succeeds in both sun and partial shade.  Yet I have trouble finding any pictures of it at all growing (let alone fruiting, aka "succeeding" IMHO)  in any sort of shade... pics generally show it growing in the middle of an open field.  Does it truly "succeed" in partial shade, and if so, how much shade?
 * Says it mainly grows in sandy or clayey soils, but also says that it prefers organic soils
 * The claims that large amounts acts as a laxative, and that large amounts cause a mild drunkenness, make for an interesting mental image.  So if you eat a large amount, you end up drunk on the toilet?  ;)

What's the actual deal with this interesting eugenia?

15
Tropical Fruit Discussion / Is White Sapote really *this* productive?
« on: March 10, 2018, 07:00:24 PM »
Some comparison numbers: A modern apple plantation, properly managed, yields about 65t per hectare of saleable apples, which is rather high by fruit yields.  Peppers are 20t/ha.  Papayas are 40t/ha.  Mangosteen is 8,5t/ha.  Etc. The highest that comes to mind, as far as fruits go, is babaco, at just over 100t/ha (banana is also huge - 60t/ha in the high intensity fields, 120t/ha in experimental conditions).  Most fruits are somewhere in the 10-20t/ha range.

From this:

https://hort.purdue.edu/newcrop/proceedings1993/V2-479.html

"Mature trees can reach 15 to 18 m in height and produce 900 kg (2,000 lb.) of fruit per year. Thompson, (1972) reported a tree of 'Chestnut' produced nearly 2,700 kg (6,000 lb.) of fruit in 1971 in Vista, California. Grafted trees remain smaller and develop a better canopy than seedlings."

Looking at pictures of large seedling white sapotes shows that they're moderately "vertical" trees, 1,5-2x as tall as they are wide (unlike smaller/grafted trees, which are broader).  Let's say that they're planted on a square grid spaced at a distance of 1,3x their height; that should keep things nice and sunny for each tree.  For a 16m tree that's 130,6m per tree, or 76,5 trees per hectare.  900kg per tree is 69t per hectare - more than apples.  2700kg would be 207t/ha, which is just bonkers. 

Am I doing something wrong, or is white sapote crazy productive?

16
Tropical Fruit Discussion / Annona(ceae) productivity relative to sun
« on: March 06, 2018, 06:38:14 PM »
For most of the species I'm working on I have to do a lot of digging, but when it comes to annonas (and their relatives with traditionally annona-like growth habits, such as biriba), I imagine I can get a lot of great responses here:   In your experience, what's their relationship between sun and productivity?  My general sense - which could be totally off here - is that maximum yield is in full sun; "light shade" (say, a couple/few hours per day) may results in a (halved?) yield, and "partial shade"/"half shade" is little to no yield, with full shade being a dead plant.

Is this generally correct?  Are there any species exceptions to this? Some that yield as much or better in light shade, or can even fruit decently in half/partial shade?  Some that absolutely demand full sun, with a couple/few hours of shade being prohibitive to fruiting?

17
Tropical Fruit Discussion / Are pineapples really this heavy feeders?
« on: March 06, 2018, 06:02:18 AM »
I've been bad for many years about fertilizing, using a "That looks good" approach, that IMHO has generally left a number of my plants nutrient-deprived (but occasionally overdosed others). I'm looking to amend my wicked ways and - in addition to working on my plant db - have also been working on a fertilizer db, starting with some of the more "mundane" plants I grow.

Everyone knows for example that bananas are heavy feeders - my data for them suggests e.g. around 1kg of N per year per plant (1485kg per hectare) at maturity.  Yet, if one can trust this:

http://edis.ifas.ufl.edu/mg055

... it'd seem that pineapples dwarf that.  I find that commercial pineapple plantations are planted densely, 63400 plants per hectare. The data in the above link says to give fertilizer in amounts that equate to 0,086kg N per plant per year at maturity, or 5478kg per hectare per year - 3,6 times that of bananas.  Of course, pineapples don't stay at maturity for a whole year, but that's not the point; neither do bananas.  Are pineapples really such heavy feeders?  It's not just nitrogen - the ratios on phosphorus and potassium come out to be 4,8x and 1,5x, respectively.  By contrast, the figures for most annonas works out to be in the ballpark of 100kg nitrogen per hectare per year - less than 5% that of pineapples.

Is this right?  Are pineapples that hungry?  If so.... I have some pineapples to feed when I get home  ;)

18
Tropical Fruit Discussion / Don't throw away those passionfruit leaves!
« on: February 19, 2018, 04:21:27 AM »
So, the other day I was looking at a mess of old passionfruit leaves and thinking... "I wonder if there's anything I can do with these".  So today I googled it.  Apparently they're quite edible, used fresh, as a cooked green, and dried in tea (credited as being relaxing, as well as a number of other health effects).

Wondering whether there might be any adverse health effects, I went to scholar.google.com to search for peer-reviewed research... and found just the opposite.  Apparently they're being studied for use as an anti-anxiety medication, with quite positive results.  Examples:

https://www.sciencedirect.com/science/article/pii/S0367326X01003227
http://www.ijppsjournal.com/Vol3Issue1/1002.pdf
https://link.springer.com/article/10.1007/s00216-016-9376-4
http://www.scielo.br/scielo.php?pid=S1516-89132006000500005&script=sci_arttext&tlng=es
https://pdfs.semanticscholar.org/f0d8/23f38ca5039cbd760141d507794ab0d40a20.pdf

Metastudy:

https://www.sciencedirect.com/science/article/pii/S0378874104000856

They're also effective as a cough suppressant and an antiasthmatic in the right doses:

https://www.sciencedirect.com/science/article/pii/S0367326X02001168
http://onlinelibrary.wiley.com/doi/10.1002/ptr.1151/full

Anticonvulsive:

https://www.thieme-connect.com/products/ejournals/abstract/10.1055/s-2007-969715

... and much more... basically a general CNS depressant with some nice effects. And they're quite antioxidant:

https://www.sciencedirect.com/science/article/pii/S0963996913000033
http://europepmc.org/articles/pmc2865792

And antiinflammatory:

https://www.sciencedirect.com/science/article/pii/S0378874106003680
https://www.sciencedirect.com/science/article/pii/S0367326X06002620

P. incarnata (maypop) appears to be the most potent medicinal passiflora, but most species contain the active compounds to come extent (the closest to P. incarnata is P. caerulea, followed by P. lutea and P. capsularis). The compounds are not found in any significant concentration in the roots, stems, or flowers; the leaves appear to be the primary source. Concerning extracts, methanolic extracts are about 10x as potent as aqueous extracts (tea) - but aqueous extracts are still effective.  More to the point, it appears to be the water-soluble fraction of the methanolic extracts that has the effect.

I think when I get  home I'm going to be doing some pruning  ;)  Hopefully the taste is decent.

19
Tropical Fruit Discussion / White sapote seed safety
« on: February 11, 2018, 07:57:44 PM »
White sapote seeds are said to be fatally toxic.  The general public is well known for not reading signs and doing stupid things. How much of a risk is there of a person who paid no attention to information given killing themselves with a white sapote?  E.g.:

 * Are the seeds fatal when eaten uncrushed, and is it possible to accidentally or intentionally swallow them whole?
 * If they're only fatal when crushed / damaged, is it realistic that a person could accidentally or deliberately do so with their teeth?
 * I've found a couple mentions of seedless trees.  Are seedless cultivars commercially available? I've heard that Suebelle is seedless in about half of its fruits...

Also, while we're on the topic, does the fruit actually make you sleepy?

20
Tropical Fruit Discussion / Bignay: flowering and fruiting
« on: February 04, 2018, 05:48:15 PM »
Concerning bignay / Antidesma bunius:

1) Does anyone know the typical flowering and fruiting times?  The exact dates don't matter as much as the length of time in which they're in bloom / time the fruit is on the tree / length of the harvest.  The only thing I've found is one page mentioning that the harvest is 3 months.  The flowering time is particularly of interest as the flowers are foul smelling.

2) How long does the fruit last off the tree (shelf life)?

3) I'm finding mixed information about pollination.  The trees are dioecious, but one source says that female trees fruit abundantly without males, while another recommends one male for every 10-12 females.  What's the reality?

21
One of the fun things about working on a tropical plants database is all of the unusual species you run into in the process.  One of the odder ones I ran into recently is Boleko (Ongokea gore), a tall (up to 50m) African rainforest tree in the family Aptandraceae. 



The fruit is described as sweet but slightly astringent, with a smell reminiscent of apples.  The unusual aspect of this tree, however, is its seed oil, which is unusually made of fatty acids containing diacetyl groups.  As a consequence, the (inedible) oil doesn't dry at room temperature, but as you heat it up past 200-250C, it begins polymerizing in a highly exothermic reaction.  This speeds up the polymerization process; if heat isn't drawn away fast enough, the seed oil will explode. This aggressive polymerization property make it a useful additive to drying oils, converting them to a hard, wear-resistant, heat-resistant and chemical-resistant coating. It's used industrially to make brake pads, as an additive to silicone, and in advnaced adhesives (one has been patented for use in lithium-ion batteries).

22
Tropical Fruit Discussion / Apocynaceae pollination
« on: February 01, 2018, 05:53:47 PM »
So, I'm having trouble tracking down data on pollination of Apocynaceae species - in particular, what's monoecious / (functionally) dioecious and (if monoecious) what's self-fertile.  And in particular:

 * Ancylobothrys
 * Carissa
 * Landolphia
 * Saba
 * Tabernaemontana (T. elegans specifically)
 * Willughbeia

So far, I've found lots of references to many species having hermaphroditic flowers, so it's looking like this is a pretty standard feature of Apocynaceae.  I've not yet found a species confirmed to be monoecious.  Of a couple hundred species in thefamily checked, I've found several (but still quite a small fraction of the total) listed as dioecious / functionally dioecious:

 * Rauvolfia sellowii
 * Rauvolfia vomitoria
 * All three Fockea species (F. angustifolia, F. edulis, F. multiflora)
 * Carissa macrocarpa
 * Allamanda cathartica

Should I just assume that as a general rule, Apocynaceae are dioecious?  Does anyone have any more specific info about specific species?  I've seen a number of threads hearing about people complaining about growing landolphias or willughbeias that got huge but never set fruit, and I can't help but wonder if this is the reason.

23
Tropical Fruit Discussion / Feijoa flowering (greenhouse)
« on: January 31, 2018, 05:30:13 PM »
From what I've seen, Feijoa seems to flower on a seasonal basis (May is often cited as a flowering time start).  Does anyone know how flowering behavior would be in a greenhouse environment?  Does feijoa need a cold period, or a low light period, or something else?  Or does it just flower whenever it feels like it if it never gets cold?  Also, how long are the fruit good off the tree?

24
Tropical Fruit Discussion / Annona grafting recommendations
« on: January 24, 2018, 07:31:51 AM »
So, I was noticing that I now have 3 seedling annonas (1x cherimoya, 2x guanabana) which now have base diameters of maybe 7-15mm (1/4-2/5") - the largest being the cherimoya.  So I guess it's time to start thinking about grafting.  :)  This is a field in which I lack experience. What would you all recommend, both in terms of scions (cultivars, species) and techniques? 

 * Compact is desirable (esp. columnar, whether natural or trained). Want to get maximum diversity in minimum space
 * Productivity is obviously very desirable
 * Shade tolerance (particularly with respect to productivity) is desirable, but full sun is also acceptable.
 * Cold tolerance is irrelevant
 * Heat tolerance is desirable
 * Wind tolerance is irrelevant
 * Pest tolerance is generally irrelevant except for spider mites, which are always a pain indoors (other "greenhouse pests" are "potential" problems, but not constant ones).  There's no, say, annona seed borer indoors  ;)
 * Fungus is usually not an issue indoors (at least, hasn't been for me)
 * Humidity is currently "moderate" - higher than California, lower than Florida  ;) If the greenhouse project reaches completion there will be both high and low humidity sections. Otherwise, they'll continue to live in a moderate humidity environ.
 * Fruit preferences: I love cherimoyas. I love guanabana juice, though I've never had one fresh. I've never had a good sugar apple, only ones that were clearly way past their prime and probably shouldn't have been on the market. I've not tasted any other annonas.  I love "creamy" / "custard-like".  I'd rather not overly seedy, but I put up with them.  "Pretty" is a big bonus, because if they end up in the public greenhouses, "curb appeal" definitely matters (on the other hand, if they end up staying home with me, it's not as big of a deal).  A taste that appeals to the general public is good, rather than acquired tastes (thankfully annonas generally aren't "acquired tastes"!  :) ). 
 * "Rare" and "having a good story" are also desirable properties, although not requirements.
 
I have more seedling annonas (several more guanabana, one sugar apple, maybe a reticulata but I'd have to check), but they're not to grafting size yet. So this isn't the only chance I'll have.  :)

25
Tropical Fruit Discussion / Define "dappled shade"...
« on: January 17, 2018, 08:45:36 AM »
How do you interpret the phrase "dappled shade" in cultivation descriptions?  So far I've been working with three shade categories: "full shade" / "deep shade" -> "part shade" / "half shade" / "part sun" / "half sun" -> "full sun".

"Dappled shade" of course means that you have a spot that's shady but light is shining through in patches, as is common beneath trees.  But is that equivalent to "full shade" or "part shade"?  Or is it a new category in-between?  In my mind I picture part shade as being like, you have a plant that has a shadow cast on it by a tree for part of the day (a shadow that's probably in itself dappled), then in full sun for the rest.  With such a perspective, dappled shade would be darker, equivalent to full shade.  But I imagine that people adding the adjective "dappled" are trying to indicate that it's brighter than full shade.  Meaning that full shade would have to be like the forest floor of a deep, dense rainforest where almost no light makes it to the bottom (and thus very few plants would qualify as tolerating full shade)

How do you interpret it?

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