This is the first year that our Timotayo Mango is setting fruit. I've thinned it way down so that it only tries to make what it can handle. About half of the fruit is splitting. Half look OK. Does anyone know what causes this? Or is this just the way the the tree is further thinning itself out?

Matty,

It could be bacterial black spot which is a pretty common problem here in Hawaii. There are copper sprays for this specific problem, but don't know when in the growing season they should be applied. UH has an ag. research lab in Hilo, so we can take samples in to them to test. Does the UC system have anything like that in your area?

Aloha, Karen

Matt--

Are the immature seeds splitting as well?

Offhand, I'd guess that it could be uneven watering or response to hot weather, but I really have no personal experience with these.

Hi Karen,

I'm not sure if UC has those services. I'll look into it.

Ken,

Yes, the seed is splitting as well. I water once a week, deeply, so I suppose it could be drying out and then getting soaked...back and forth, but the area is mulched so it's not like it's going bone dry in only a week. Maybe it's latent damage from the extreme heat wave a few weeks ago.

Matty,

It could be bacterial black spot which is a pretty common problem here in Hawaii. There are copper sprays for this specific problem, but don't know when in the growing season they should be applied. UH has an ag. research lab in Hilo, so we can take samples in to them to test. Does the UC system have anything like that in your area?

Aloha, Karen

Matt - San Diego County has a plant pathology service (SD Plant Path Lab). As of last summer the services were still free to county residents and businesses.

Also, if you have an iPhone or Android, you can download a free plant pathology application (Plant Doctor) to submit pics and history to plant pathologist Scot Nelson at University of Hawaii for evaluation. Am sure Scot has plenty of experience with mangoes.

Hope this is helpful - gmp

Matt,

Did a little research around the intarwebs. . . Is it possible that your once a week deep watering is watering too much? Seems on many of the fruit tree sites that the going advice is to water a fruiting mango as little as possible to avoid splitting.

Anyway, I have zero personal experience, but this tweaked my interest.

Thanks Dr. George! I do have that app. I should give it a try.

I suppose that the once a week watering is too much, especially since I water for 4 hours at a time (with drip). I'm not going to adjust because as the tree gets larger it should grow into it's increased water needs. I guess that's one possibility.

Commercially here mangos are irrigated up to 80% of flowering and then don't get any water from then on. I've seen the odd bit of damage from over watering, but never that bad nor on fruit that small. They've evolved in a savanna climate, no rainfall during flowering and fruiting. That's also why they tend to be more susceptible to fungus.

Matt, here in FL it is a sign of too much water. I did not want to originally post this, because I know you are in a severe drought. I have 6 Mango trees and sometimes with lots of summer rain, some of them split. Especially the Nam Doc Mai and Keitt. Who knows what happens when you alternate between drought and flood. Are you watering consistently at a light to moderate amount?

Mike did someone say Nam Doc Mai? Droooooooool! I've been thinking about those since I took my last bite of one last year. I'm amazed at how many of those I can eat! I could easily down ten of those in one sitting with pleasure!