Australian Finger lime Die back

[CTMIAMI]

I have several AFL. Two in the ground and one 15 gal. The 15 gal has flowered and set fruit. But it seems like every year, at least for the last two years have suffered some serious die back. Is holding about 15 fruit fron the flowering early in the year and has flowered now again.
The ones in the ground a lot less but definetly minor die back. The ones in the ground, one is larger than the potted one,  now around 8 ft tall, also grafted but has not flowered.
I wonder if the die back is normal and more accentuated on potted AFL. Do they flower several times a year?

I wonder in anyone has information about their susceptibility to greening.  Leaf miners do not seem to bother it much.

[starling1]

Hi Carlos,

finger lime dieback is in my experience to lack of soil drainage. They require standing free draining soil, and this can't be allowed to dry out.

I created this thread a while back which covers a lot of areas, including dieback. If I had  to do the thread over again, I'd probably suggest adding a very high amount of coir to the mix as opposed to hardwood chips. I've never experienced greening with finger limes.


http://tropicalfruitforum.com/index.php?topic=10228.0

[CTMIAMI]

Thanks for the info


Do you have GREENING there?

Does anyone know if AFL  resist greening everywhere?

[starling1]

I don't think we have Greening caused by the Asian bug in Australia.

many varieties of finger lime will fruit several times a year.

[BMc]

From the old NSW DPI document about growing finger limes:

'The main disease affecting finger limes is melanose (Diaporthe citri), a fungal disease that causes dark brown to black spots on the foliage, twigs and fruit. Spores of the fungus develop in dead citrus tissue and are released by water and/or rainfall. The fungus affects all citrus varieties and the incidence of melanose usually increases as trees age and the amount of dead wood in the canopy increases. Annual light pruning should aim to remove any dead wood. Experienced finger lime growers recommend not applying any chemical sprays whilst the trees are flowering as the flowers may be damaged.

Finger limes also occasionally suffer twig or branch dieback, but no causal organism has yet been identified. Dieback in other citrus varieties can be caused by a range of factors including frost injury, hot dry or very cold winds, or some other factor resulting in the plant being unable to get sufficient water when needed, such as a lack of soil moisture or damage to the root system. In coastal orchards the melanose fungus can exacerbate twig dieback.'

Growers have suggested everything from heavy soils to over fertilisation as being causes for dieback. windrub is another factor as overcrowding of branches can cause windrub and the branches throw leaves under stress and die back. Even very healthy trees can carry quite a bit of die back and in the wild they carry lots of dead wood due to the very dense nature of the tree. FLs naturally grow in very rich ground sometimes in creek beds. So they handle wet conditions well on their own roots and some wild finger limes have been recorded as the most resistant of all citrus to citrophora (citrus dieback).

[starling1]

From the old NSW DPI document about growing finger limes:

'The main disease affecting finger limes is melanose (Diaporthe citri), a fungal disease that causes dark brown to black spots on the foliage, twigs and fruit. Spores of the fungus develop in dead citrus tissue and are released by water and/or rainfall. The fungus affects all citrus varieties and the incidence of melanose usually increases as trees age and the amount of dead wood in the canopy increases. Annual light pruning should aim to remove any dead wood. Experienced finger lime growers recommend not applying any chemical sprays whilst the trees are flowering as the flowers may be damaged.

Finger limes also occasionally suffer twig or branch dieback, but no causal organism has yet been identified. Dieback in other citrus varieties can be caused by a range of factors including frost injury, hot dry or very cold winds, or some other factor resulting in the plant being unable to get sufficient water when needed, such as a lack of soil moisture or damage to the root system. In coastal orchards the melanose fungus can exacerbate twig dieback.'

Growers have suggested everything from heavy soils to over fertilisation as being causes for dieback. windrub is another factor as overcrowding of branches can cause windrub and the branches throw leaves under stress and die back. Even very healthy trees can carry quite a bit of die back and in the wild they carry lots of dead wood due to the very dense nature of the tree. FLs naturally grow in very rich ground sometimes in creek beds. So they handle wet conditions well on their own roots and some wild finger limes have been recorded as the most resistant of all citrus to citrophora (citrus dieback).

True, but most people will have grafted varieties. The top growth on grafted trees will die off due to overwatering (this is why heavy soils are bad idea--they get waterlogged and promote dieback). This is why all varieties sold in Australia are potted for sale in free running mixtures. The answer could be more complicated and possibly involves oxygen supply to the roots--there are lots of things that will take flooding, but not sitting in sodden cloying soil. Finger limes grow naturally in the upper stratum of forested areas which have very good drainage.

From experience, trial and error and observation, standing free draining soil and the right light and wind exposure conditions seem to be more important than anything else.

seaweed and liquid fish based fertilisers don't seem to go astray either.

[CTMIAMI]

To add to the discussion my potted FL in 15 gal. Has a dry soil mixture. My hand soil meter reads low all the time. It is a spacial mixture for So. Florida where in the summer rains 3 times a day for weeks.  It could be something else, In the winter I hold back on irrigation and that is when it happens. May be the tree is very susceptible to a dry spell. The others citrus showed not problems.

[BMc]

Miami climate and rainfall are quite close to Tamborine Mountain, or Jambrin (Jambreen), which is the name of the mountain where most of the fingerlimes come from and is the name of the fruit also in the local Yugumbeh language. Most rain falls in summer and relatively little in winter. When it does rain in winter though, the soil stays moist, but not wet, for quite long periods and rarely are there 'drought-like' conditions. But again, its probably more reflective of the rootstock than the graft stock.

[CTMIAMI]

I have been thinking about doing a test with 40 tree to see how feasibly they are to grow commercially here. I'm concerned about the picking. Its a very thorny tight bush.
How do they pick these in commercial groves in Australia. Any special way of doing it?

[starling1]

I have been thinking about doing a test with 40 tree to see how feasibly they are to grow commercially here. I'm concerned about the picking. Its a very thorny tight bush.
How do they pick these in commercial groves in Australia. Any special way of doing it?

Not that I'm aware of. Wear gloves.'

The main thing you need to do is get good varieties. There are dozens, some are very good, some are very bad. Can you post pictures of what you have? I might be able to id the variety.

Epsom salts will increase the size, number and quality of fruit you get.

[CTMIAMI]

We are very limited in the choices we have. There is one green long, one round and I heard there is a red around. But besides that there are no varieties to pick from. Mine are 3 CM now very small.   I will post pictures in a few weeks when they get bigger.

[starling1]

We are very limited in the choices we have. There is one green long, one round and I heard there is a red around. But besides that there are no varieties to pick from. Mine are 3 CM now very small.   I will post pictures in a few weeks when they get bigger.

you can buy seeds of very good Australian  varieties here. This variety is extremely good (red champagne)

http://www.ebay.com.au/itm/20-Fresh-Finger-Lime-Seeds-10-Red-Champagne-10-Pink-Best-Buy-Combi-Seed-Mix-/281362318582?pt=AU_Plants_Seeds_Bulbs&hash=item41828044f6

[CTMIAMI]

Do they grow true from seeds. I heard seedlings can take a very long time to fruit. Like 10 years plus

[starling1]

They do not grow true from seeds, and seedlings will take many years to fruit (ten seems a little steep).

[bsbullie]

Carlos - are these all on Flying Dragon rootstock?

[CTMIAMI]

No they are not on FD. I have some on Sour Orange 2, my Big one 15 gal is probably in S.O. and I have two on the ground that are not on FD. I would not get FD for anything that eventually is going in the ground.  I have a giant finger lime tree that I think it was grafted on KH,  that went from a liner to a 8-9 ft tall tree in 18 months. Not flowered so far is just growing like a super weed.