Hello Recently my kumquat has been dropping leaves - a lot of them. I am struggling to understand what is wrong and how I should act to save it. Around 1.5-2 weeks ago there was a ton of flowers, most of which seemed to be pollinated at the end. And everything was fine until suddenly it started dropping those, after 2-3 days there was nothing left of the new fruitlets... And I thought that maybe it's just decided that it's too much given that there already are fruits ripening but then in the last days also more and more leaves have been falling - every day it gets even worse. If this continues, very soon it'll have lost around half... Some of them are brown-ish, some seem to be completely fine. About the conditions it had, since october until recently it's been standing on a window sill and watered regurarly, mostly around every 2 days (every second time with biohumus), as it seemed to be the best interval for it and worked just fine. For the last 3-4 weeks I've been taking it outside during the day, as the temparatures were around 20-25 degrees celcius (68-77F). Oh, and every time when I watered it, I was also spraying leaves with water. And that's pretty much how it was. For the last 4 days I haven't watered it and I didn't move it outside, as I first thought that the most probable cause would be overwatering (somehow) but now I am beginning to doubt that this is the reason. I am quite sure that it's also not any insects, as there is nothing to be found. And I already dealt with spider mites so surely not them this time. I am seriously scared that it's not gonna make it so any advice or suggestion will be highly appreciated. Below I attach some photos.
It certainly seems to have been shocked by something. Was it recently repotted? Was anything other than water sprayed on the leaves? Is it possible the biohumus had something unexpected in it or was too strong?
The last and only time it was repotted was back in october when I got it. The only thing I'm spraying it with is water. I used grey soap a few times to get rid of spider mites but again this was around december. And the biohumus I am using is exactly the same one for all these months. I am guessing that the only shock it could experience was getting quite a lot more sunlight and higher than usual temperatures - but could it really cause this much damage? Is there any chance that it's some kind of fungal infection maybe? Would it help it if I removed its fruits and/or pruned it? And is it a good idea to start watering it again now? It's been 5 days without water but the plant doesn't seem to be suffering from lack of it and I'm a bit scared that it could lead to root rot or some infection if it actually is all caused by overwatering somehow.
It does not have the usual signs for a fungus issue as far as I can saee. The few leaf lesions in your photos should not be a cause of concern for the whole plant. You should naturally remove any leaves or branches that have those signs but there is nothing in your photos that I see as a cause of major concern. However, the sudden severe leaf drop indicates there has been a sudden shock, which may not be easy to identify the cause of. Certainly trim back any branches and leaves that look like they have any sign of disease. If it looks dry and the soil feels dry about 1/2 inch below surface you should certainly water it. More sunlight could cause sunburn, but that looks different than your photos. Also, excessive temperatures could cause leaf drop but certainly not in the range you indicate. Above about 52C is when I would expect to start to see some damage, not at 25C. Perhaps inspect the trunk closely and see if you can find discoloration. Sometimes fungus gets inside the plant and causes severe problems, but it does not look like that is the case to me based on the photos.
I think, that the start of shuffling caused this problem. Citruses don't like rapid changes. If your plant was constantly indoors until recently, then exposing it tuo intense UV, could cause the leaf dropping. Watering is another possible cause. You water based on regular intervals, in 2 days cycles. Citruses are susceptible to over watering, so better is to water them according need based intervals. When it's hotter, windier and drier, then more often, when cooler, more humid and without wind, then less often.
Alright, I did water it finally but so far the situation isn't improving. I think there's less than 50% leaves left at this point and new ones are still getting brown and falling. I've checked thorougly for any infections, fungi, insects and yeah, I'm almost 100% sure the only possible reason is some kind of shock, most probably caused by suddenly moving it... I'll just wait and see how it develops further, as I don't think much can be done at this point. Should I remove the fruits when it gets even worse, say when a half of remaining leaves is gone?
Well, I didn't need to wait too long, right now it's only around 25% of leaves left and it started dropping fruits as well. When/if there are no leaves left, are there any chances the plant can regenerate? Or is it already gone?
If its roots are still ok, then dropping all the leaves should not be fatal. So in case of just a sunburn your tree will be green again after some months (or even just couple of weeks). If you boiled its roots by exposing its dark container to the scorching sun (assuming that you had similar heat wave, or even worse, as here in Estonia), or over watered and caused root rot, then your kumquat could be dead. Anyways, less leaves means less transpiration, so less water is needed, so don't over water now!
One of my young mandarins suffers some scorched leaves also, despite being outdoors since the end of April. At the place, where I keep my mandarins, pomegranates and figs, the ambient temperature rises up to +45ºC (dark surfaces even above +50ºC) during current heat wave, thanks to the micro climate in the hot spot near southern wall of my house.
Well, the plant wasn't exposed to the most insane temperatures we are having now and spent the last week indoors so hopefully its root aren't severely damaged. I decided to sacrifice the fruits to increase chances to survive maximally and the first good news is that no new leaves turned brown and/or fell today so maybe the situation will improve. Btw if you kept your mandarines outside since the end of April, do you mean it was there all the time day and night? I'm just curious how did they manage with low temperatures and stuff that cannot be fully controlled, like rainfall that could easily lead to root rot?
They were mostly out. Only in case of night frost risk I moved them indoors. That made maybe 10 nights altogether since April. Springs are the driest part of a year here, so rain caused no issues. My potting mix is mostly coarse sand, it is well draining.
