Definitely some form of insect. Possibly slugs. Are your trees grown from seed? Pics of tree and notes on your care would help to get diagnosis/advice from members

i bought these trees around 10yrs ago... they are grown all winter in a south facing window in my greenhouse room - i feed them 2-3 times from march till oct when they are brought in with miracle grow citrus ferts- never had any problem with them, there is always new growth, but as said , never a flower... and this year something is eating the leaves... many thanks for your quick tooo.. here is a picture of each... one is not too bad, but the 2nd one looks terrible

2nd picture

2nd picture

Commercial growers fertilize their trees at regular intervals during the year, PLUS spray their trees with urea (high nitrogen) several months before the suspected bloom date. This is done to promote a good flowering/fruit. You fertilize your trees only twice during the year, and expect your tree to provide you with much fruit. With your nutrition program it isn't going to happen.

The reason I asked if they were seed grown trees is that seed grown Citrus can take what seems forever to flower until they reach a certain node count or height. I'm in NYC and I get grafted trees to bloom that are less than 10 years old. I have 2 seedling trees (Citrangequat and Morton) several years old and they have never bloomed. PIC#2 is hard to tell if its a grafted tree but how long has it been in that pot (2 gal?)? It may be rootbound as well, with circling roots choking itself. Maybe a root inspection possible repot is in order. Do you have a slug/snails problem, usually you see snails they will sleep under a leaf even in the day but slugs hide in the soil until night. You may have to go out and look with a flashlight. It can't hurt to spray with insecticidal soap. As Silica suggested you also have to up your fertilizer game. I use Jacks and/or mitacle grow for acid loving trees plus I sprinkle Osmocote plus in the container to provide micronutrients.

ok , i'm going to spray em today, and going to repot them tomm- i don't see any slugs/other insects , so maybe it is a bit pot-bound- i also have miracle grow citrus 3month which i will sprinkle once i move it into a bigger pot...

slugs probably. Can be other insets also. Spay organic pesticides like sope water or use chemical pesticides for faster response.

One thing that is absolutely true, and that is "a bit pot=bound" does not cause holes in the middle of citrus leaves.

thats for sure true... still looking for the culprit

Careful looking for the culprit. I found out the hard and painful way about the saddleback caterpillar and it's painful stings.... and that they love citrus. Certainly other pests chew holes as well, but be mindful and wear gloves when looking.

thanks