This is typical of many of these in Florida. The hot, humid conditions lead to several diseases, with Cercosporidium causing lower foliage to die like this. The only thing you can do is to make sure there is no irrigation water hitting the foliage, apply fungicides and also use granite pebbles as a mulch to prevent rainsplash and increase drying of the foliage..

where are you how long have they been in the ground they are conifers ... there is a forum for such... though i do NOT care where you post.. using the GW search engine should get you many posts on these conifers ... interior browning and loss of needles is ENTIRELY NORMAL .... and increased by stressors such as recent planting ... and abnormal winters ... and weather .... no conifer hold the interior needles forever ... as far as the spider web.. its summer... unless you find a specific bug.. FIND IT ... i would defer to mr spider.. and many.... are beneficial ... no matter how much some of us hate them ... its not an issue sans proper ID of something else ... i will defer on the canker issue.. i dont do these plants. in my zone.. but from what i have read.. there is no real great upside to them ... fast growing.. fast to get problems.. and fast to die ... ergo ... i agree with dan.. that replacement is on the books... especially while they are small enough for you to do it yourself .... however.. when and how this has to be done is the issue ... this could easily be a 5 year project.. replacing 1 or 2... while maintaining the privacy hedge... ken

is the one in the pic still in a pot.. or did you really plant it 6 inches from one wall.. and 12 inches from the other??? .. i bet that wall is cooking it with reflected and retained heat ... what are you going to do when it is 25 feet tall and 8 feet wide??? .; see link I'm spraying the trees every time I water them and it gets pretty windy up here in the desert, ===>>> is that the only water.. or are you actually watering the roots also?? ken Here is a link that might be useful: they are monsters

i'll chime in and agree, and confirm the fast growth. I grew a crop from seed (a friend brought them back from Corsica) about 5-6 years ago and they are over the eaves of a one-story house already. So if you are attached to this species, you can get a couple of new ones and get decent-sized trees in short order.