Loquat fruit issues

[mbmango]

Trying to identify the issue and possible remedies.  Haven't seen this before, but the trees have just started fruiting for the last 3 years, and haven't had many fruit till now.  Sunken areas are dry & stiff rather than mushy.  Would guess more of a scab than a rot, but my google-fu isn't turning up any matching images.  Not seeing any major issues on the foliage.  A few burnt tips here and there. 

This looks like it may be starting on some other fruits

[Tropical Bay Area]

Sunburn?

[Nyuu]

Sunburn?

That's exactly what I was thinking too but I'm not sure so I didn't reply

[spaugh]

Doubtful its sunburn at Manhatten Beach.  Its way hotter inland and thry don't burn at all here. 

I think there's something else going on and the fruit are already screwed up then getting sun scars. 

[mbmango]

I was thinking possibly also sunburn, since all the affected areas are sun-oriented sides mostly.  Cut open a couple and it's just leathery & dried up on the spots.  No rot going through.  We don't normally get a lot of heat, but Monday did hit 88F.  If so, would it just be a matter of shading, or can I prevent it by watering more?  I do tend to stay on the drier side rather than overwatering.  I'd also be bummed to learn that the fruit were that sensitive to such short heat spikes, but it would be better than having to deal with some other infection.

[Plantinyum]

I think if all the spots are on the upper ,sun exposed parts of the fruit and the plant has been kept drier in a relatively hotter period , it may be sun burn . At least thats what It looks to me too ....also the fruits are growing now so they are tender new growths ,which are in general suceptible to sunburn ,especially in a drier environment. Thats my experience with plants in general.. .

[sc4001992]

My vote is sunburn. I had something similar on my loquat fruit a few years back when the temperature was relatively hot for a short period and most of my fruits on one tree had burnt marks only on the fruits facing the late sun (after noon), west facing. Never seen this sunburn on the same tree since. Fruits on my other trees which were partially shaded by some leaves did not have the sunburn.

I would just cut off all the fruits that show the sunburn now so save some energy for the tree to use elsewhere.

[mbmango]

Thanks for the tips!  I had culled out the burnt ones.  This year, most of the fruit is exposed.  Perhaps I'm supposed to push more growth after the set so they get covered more.  I just was cautious with the watering since it's been so cold.  The fruits are generally larger this year compared to previous, but turns out a lot more seeds and less flesh ratio, at least on the culled ones.  Hoping to be able to still plump up the remainder.

[shmojojojo]

I had the same issue last year.

http://tropicalfruitforum.com/index.php?topic=38938

My Big Jim also only rotted on the side exposed to light, including the fruits that didn't get direct sun, which kind of makes me doubt it's sunburn. I watched it slowly happen and the weather was cool and overcast the entire time. I see too many healthy, fruit filled, sitting in full sun Loquat trees around socal for them to be THAT sensitive to sunlight. What variety is yours? How's your weather been? I can't imagine you've had too many days over 70f in MB this year. I seem to remember it starting after we had a few consecutive days of rain. Has any water been sitting on the fruit? I ended up cutting all the fruit off and it decided not to flower this year, but it does look healthy with a lot of new growth. Good luck


Edit: Looking over that old thread and it looks like Jose Spain might have nailed it with Fusicladium eriobotryae. A fungus dispersed by rain and thrives in wet conditions. At least in my case, I think a rain storm dispersed the fungus to the outer exposed fruit. That might explain why even the fruit out of direct sunlight still looked burned. Google image doesn't have the best photos, but you can read the abstract here http://www.actahort.org/members/showpdf?booknrarnr=1092_46

I had hoped a good trimming would be enough, but I think I'm gonna have to spray my tree

[Jose Spain]

Yep, seems the same again. Here more info about Fusicladium eriobrotryae and when and how to treat it (in Spanish)https://www.cajamar.es/pdf/bd/agroalimentario/innovacion/investigacion/documentos-y-programas/boletin-huerto-93-1496059913.pdf

[sc4001992]

If you look closely at the photos in jose's article on fungus, the picture shows fruits which look very bad with spots and looks like sore spots. Its not the same as sunburn fruits.

The sunburn also called "purple spot" is defined as a physiological disorder directly related to the calcium content in the fruit tissues, and those photos looks closer/match with the mbmango's photos posted. Notice his fruit has larger damaged purple color spot, and nothing on leaves. Here's a comparison below of the information presented.

Fungus on leaves and fruits (Jose's information, link photo below):



mbmango fruit photo below:



Here's a brief study on "purple spots" done by  Department of Agricultural Sciences, Biotechnology and Food Science (ABF) at the Cyprus University of Technology (CUT), they study post harvest issues for fresh produce fruits.

[mbmango]

This was pretty much all the culls:


It definitely is more like dehydration than rot.  The spots are all dry and tough like jerky, vs mushy.  I wasn't really thinking purple when looking at them, but perhaps the earlier stages are more purplish.  I wish I would have noticed sooner, but they were mostly on the upper facing sides.  Only when one branch got bent down due to the weight did I spot it and then pulled out the ladder to check them all.

Purple spot gives a lot more google hits, so hopefully I can fix my practices.  This study suggests a correlation with night temperature, https://www.researchgate.net/publication/248478075_Purple_spot_in_loquat_Eriobotrya_japonica_Lindl_is_associated_to_changes_in_flesh-rind_water_relations_during_fruit_development, which has been pretty low.  Even if we recently have been hitting 70s in the day, it's still been 30-40s at night.  Plus, it mentions elevated sugar levels affecting the osmotic balance, and the sugar changes kick in mostly around color break.  Also, thinning increases the risks and I did a little of that this year to see how big some can get.  Like this study found incidence increases with increasing leaf area to fruit ratio: https://www.cabi.org/isc/abstract/20043000289.  Some studies suggest supplements (Ca/N) prior to color break, so perhaps I should be feeding earlier, but not sure on that part yet.  Conversely, could recent rains have diluted levels, particularly since I have very sandy soil. 

The variety is Champagne, but there are a couple of Kaz's Big Jim and some of those fruit were also affected.  I don't see any spots on leaves.  Just some occasional tips and some burnt margins on tender growth.

[shmojojojo]

Interesting. An internal disorder would make sense. There's no broken skin or fungus growing on the fruit. I'll have to read up on it. Maybe change my fertilization and cover when cold. Thanks for the info everyone

[sc4001992]

You tree looks very healthy.

I wouldn't worry to much about the fruits this year. Next year should be good. Funny that you mentioned you thinned your fruits, I did that on my Big Jim for the first time just to see how much larger the fruits will be this year. So far, doesn't seem to make my fruits any bigger. No sunburn or fungus on my trees (luckily).