I never saw the flowers even though I make it a point of hiking through this area regularly. Due to the chewed off tops, it is quite possible if I had visited a few days or a week later I may not have seen these plants either. bboy - not sure if you are referring to the plant's odd name or if you think they were eaten by horses, but on that note, while I was looking up info about "horse gentain" it was noted that nobody really knows why it was given this name :-)

These types of double leaves are common with citrus. It is normal for kaffir lime to be this way. I have seen it on others, including a Sudachi I have: The other problem I see is the curling of the leaves. Are you watering enough? What kind of fertilizer are you using and how often?

That's a nice tree. That looks like leafminer damage--the key is the silvery tunnels that form within the leaf and the subsequent deformation/curling of the leaf, followed later by browning of those areas. You can have some areas of leaf curl as well with aphid infestations, and browning patches can also be from significant wind damage, but the trails and the substantial browning point to leafminer. As to control: the party line seems to be that if your tree is 'mature', the damage from leafminer is merely of cosmetic importance, and your tree looks like it has plenty of photosynthetic machinery. But, if it starts to look like it is really hampering your tree or if you are worried about it spreading more than it has, then the agent of choice is apparently spinosad. However, I don't have any experience with it whatsover,and a reasonable choice to look into would be neem oil applied properly ( ie--be wary of burn if it is very hot and sunny). Thats what I would start with in fairly frequent application initally, along with manual squishing of larva and pupae in the trails--they're little nasty worms the size of a grain of rice. The ants don't have a lot to do with this particular problem, but eliminating ants helps if you have any concurrent pest problems like aphids and scale and other tasty things. You can try traps laid out (especially near the colony) if you don't have a risk of pets or kids getting into them--if they don't get watered, then they shouldn't leak any pesticides on your soils. If there are just a few, you can also merely hose them off your tree repeatedly. They tend to get the message. Manual removal of any aphids or scale will discourage the ants too--just disrupt that symbiotic relationship somehow. The relative paleness of the leaves could be a number of things, including nitrogen deficiencies, soil temps, watering issues, lots of youthful leaves, etc. I have no idea what kind of soil you have in your garden but since we Californians have had a very dry spring, I would encourage you to make sure you are getting enough water to the roots. If the roots can't get enough moisture or they are drowning in too much, they can't take up any nutrients. Are the surrounding plants brown from winter cold or is it just really dry?--that will give you a clue as to what you might need to do. Also, you can apply some nitrogen-rich fertilizer if that hasnt been done recently. I use an acidifying fertilizer with iron in it, since I have alkaline clay soils. The proper thing to do though is to get a soil test to see what you might need to do with it. It's normal for citrus to lose a substantial amount of forming fruit, and if they don't drop right away it can just dry up and look like what is in your pictures. That is not directly related to the leafminer nor necessarily pathologic. The dried baby fruit can also be from relative dehydration or from buffeting winds as well--your tree will need enough water to properly fruit. HTH.

BT definitely won't cause this. If it is root rot, which I think it is, it might be a good idea to re-"leave" the plant from a few of it's leaves. I've heard of some chemical treatments that are targeted towards phytophthora mold (which is usually what causes root rot) but I've never tried them myself. The best way us home gardeners deal with it is to let the soil dry out a little. The roots that are already rotted are now useless so the plant might have too many leaves to keep itself alive at the moment. I'd prune it back a good amount and only water it again once the top 3ish inches of soil is dry. Obviously there are some roots still alive or the plant would be completely dead by now. If it's a plant you really don't want to lose and don't mind doing a lot of work on it, I'd recommend pruning it back enough that digging it up isn't a huge pain. Then dig it up, and cut off any roots with rot on them at the point they are rotting. then cut off a few more branches (depends on how many roots are left) then pot it up while it recovers. I'd also amend that soil area where it sits while it recovers so there's more drainage.