Rollinia fruit problem

[ofdsurfer]

My rollinia tree is around five years in the ground and should be large enough to hold fruit but it hasn't held one to maturity yet.  It sets what seems like hundreds but when they get to marble size the stem gets black then the fruit does and they fall off.  A friend thinks it's anthracnose and I plan on spraying some copper to see if it helps.  Does anyone have any other suggestions? 

Thanks

[cbss_daviefl]

I have two rollinia trees. One did the same exact thing with over 60 fruit up to 2 inches in diameter turning black. Not a single fruit remains.  On my other tree, right next to the other, I have many fruit holding at 3 inches in diameter. I have no idea why the first tree aborted all the fruit.

[ofdsurfer]

Did the tree grow out of it or does it still abort the fruit?
Thanks

[cbss_daviefl]

My trees are only in the ground for 3.5 years. This is the first year for fruit set.  The tree that is holding fruit is much smaller than the tree that is aborting fruit. It has about 15 fruit at 5 ft tall and 6 ft wide.  The only difference in treatment was that I did prune the smaller tree because it happened to be leafless at the same time that I pruned my other Annona trees in February.  The aborter had dropped leaves in January and was already flushed out again in February so I left it alone.  I doubt pruning would be the reason one is holding fruit.  I suspect that the timing of the flowering may have had more to do with it. I think the aborter flowered in April and the holder flowered in May, closer to the start of the rainy season.

[fisherking73]

Is there a video somewhere that shows hand pollination of Rollinia?

[TheDom]

It is basically the same as any other annona. You'll see the flower turn yellow and there will be a small opening in the middle of the flower on the first day when it opens in female mode. The next day it'll look about the same but be in male mode and drop pollen.

Is there a video somewhere that shows hand pollination of Rollinia?

[DurianLover]

Is there a video somewhere that shows hand pollination of Rollinia?

Not a video, but illustrated guide.
http://tropicalfruitforum.com/index.php?topic=8780.msg112640#msg112640

[DurianLover]

My trees are only in the ground for 3.5 years. This is the first year for fruit set.  The tree that is holding fruit is much smaller than the tree that is aborting fruit. It has about 15 fruit at 5 ft tall and 6 ft wide. 

5 feet tall in 3.5 years sounds awfully slow, but holding 15 fruits is very impressive for it's size. Is this the same tree you were asking about no growth last year?

[cbss_daviefl]

Yes, the one that people recommended I remove   The trunk is pretty hefty for it's height, around 4 - 5 inches

[Guanabanus]

I don't believe pollination could have been an issue.  The bases of unpollinated flowers abort in about a week, when about 1/8th of an inch diameter.
They do not get to be two inches in diameter!

So I suspect your tree has a mineral deficiency (Boron?  Zinc?) or an infection.

[ofdsurfer]

I don't believe pollination could have been an issue.  The bases of unpollinated flowers abort in about a week, when about 1/8th of an inch diameter.
They do not get to be two inches in diameter!

So I suspect your tree has a mineral deficiency (Boron?  Zinc?) or an infection.

Great thank you Har.  I was hoping you would chime in.  Could it be a fungus?  Would copper or sulfur be better and at what rate?  I'll give it some key plex and see if that helps.

[fruitlovers]

Glomerella cingulata causes stem dieback and fruit rot. It;s a type of fungus.
http://www.ctahr.hawaii.edu/oc/freepubs/pdf/F_N-21.pdf