My Dieffenbachias tend to lose their lower leaves. I don't think that's unusual as long as the tops are healthy and growing. Often plants in low light will lose their lower leaves. And with Dieffenbachias you can't really put them in the sun.

Alright, Al has spoken, lol. Apparently those two leaves are getting yellow because that greedy lemon at the end of the branch is grabbing all of the available food nearby. He didn't say anything about the back of the leaf, but I'm sure if it was worrisome he would have, Al is nothing if not thorough :) And, John, I think you're right, it probably was a critter earlier this year, because I really seem to remember seeing that damage a while ago while they were on the deck for the summer.

m-mm..:) your ag's roots are quite nice. so, why do you have a problem with them? may be just older leaves go yellow? that's normal though. they branch, grow new shoots from soil after a few years, as they get older. but usually they keep growing only at the tip, dropping older leaves. it's how they grow...I just cut and reroot then ev 3-4 years. and it's best to keep them in smallest pots that can fit the roots. I keep mine on water-wicks: so that I don't have to deal with them drying out, as I travel for 2-3 weeks or more and they keep going by themselves. yah! but for that you need 40% perlite and some peat (1/3?) in the mix for wicking. but cactus mix usually contains peat by the way :). I root best in flooded perlite: fill the cup (no holes) with perlite, fill with water to 1/3 approx. add a few drops of 3% peroxide to keep water from going sour. tent. stick yr cutting in. wait. ag's take very long -5-8 weeks normal. may be 3 mo too :(. same with Dieffs unless you use heat-mat: then 4-5 weeks and u'll have roots. without the leaves is problematic. you could try, but that can take 6 mo :). ag's are VERY slow. and sometimes canes will just die. Dieffs are very slow too. yr mix looks good. large perlite is better then gravel. more functional, it actually holds onto water so to speak..better then gravel. gravel is heavy - better for outdoor pots. since you dislike the look, put some gravel in mix instead of perlite for top 1 " for looks, instead of perlite. I cover the soil of my sucs with aquarium gravel. it allows air thru - no problem. I use coco-chips instead of bark in mixes : they re-wet very fast (no need to soak if dry) and aerate better then bark. also for rewetting the mix adding coir dust (peat) is good : it's very fine coco shell fragments : 10-20-30% . I use half AV soiles (peat) half coco-peat for 'soil portion' of the mix.

"Ignorant"? Moi? I'm thinking you may be the ignorant party in this discussion :-) These are only the first few articles that turn up with a Google search but there are dozens more out there. But then it appears that you do not believe what plant pathologists across the country have come to a pretty firm consensus about. ISU Extension Serivce: "Once a tree is diagnosed with Rhizosphaera needle cast, the management tactics aim to reduce the spread of the disease to healthy tissue. One common misunderstanding about this disease is that once needles become infected they cannot be “cured”. Once needles are infected they cannot be healed or cured and will eventually fall off of the tree. One option for management of this disease is to simply not plant susceptible trees. In situations where spruce is the tree of choice, try to avoid blue spruce and take a look at Norway spruce as an alternative." University of Minnesota extension publication: " Colorado blue spruce (Picea pungens) is highly susceptible and is commonly affected. Do not plant Colorado blue spruce (Picea pungens) or other spruce that are not well adapted to the environmental conditions in your area. Damage typically starts on the lower branches and moves up the tree. If the majority of needles are infected for 3 to 4 years in a row, the branch will die." NMSU extension publication: " Rhizosphaera needle cast, a fungus disease caused by Rhizosphaera kalkhoffii, is primarily a disease of blue spruce (Picea pungens) trees in New Mexico. Infected needles turn yellow in July and then reddish-purple in August. The needles eventually turn brown and fall off one or more branches. A severely affected tree will have many bare branches. Premature needle drop is the primary damage, causing the tree to become unsightly. Branches that defoliate for four or five years may die. The disease usually attacks the oldest needles on branches in the lower portion of the tree canopy first and progresses upward, giving the appearance of death from the bottom up and inside out. If left uncontrolled, the disease can eventually kill the tree. " Wisconsin Horticulture publication: " What is Rhizosphaera needle cast? Rhizosphaera needle cast is one of the most common fungal diseases of Colorado blue spruce. It can make Colorado blue spruce unsightly and unusable in many landscape settings. How do I avoid problems with Rhizosphaera needle cast in the future? The easiest way to avoid Rhizosphaera needle cast is to avoid planting Colorado blue spruce." Morton Arboretum: " Rhizosphaera needle cast is a common foliar disease of spruces and other conifers caused by the fungus Rhizosphaera kalkhoffii. Colorado blue spruce is particularly susceptible and can be severely damaged by this disease. Heavily infected trees can suffer severe needle loss and branches may die as they become defoliated. Trees are rarely killed by Rhizosphaera needle cast, but several years of attack will take its toll and only the current season needles may remain. This disease can be frustrating because severe defoliation can occur quite rapidly and without indication that the disease is even present." Penn Sate Extension publication: "Spruce often tend to lose lower branches and become unattractive with age, especially during periods of environmental stress, caused by drought and frequent rain. Recent wet weather years have been especially hard on spruce trees, as evidenced by the number of dying trees visible in local landscapes. A fungal disease affecting spruces is Rhizosphaera needlecast. Symptoms may first appear in mid- to late-summer as yellowing of the innermost needles on the middle to lower sections of the tree. These needles change from yellow, to brown, or purplish-brown and eventually fall off the tree. Because of susceptibility to this disease, less vulnerable conifers including concolor fir (Abies concolor), Oriental spruce (Picea orientalis), Serbian spruce (Picea omorika), and cultivars of Eastern red-cedar (Juniperus virginiana) should be used in preference to Colorado blue spruce." And from an arborist website: " Sprays control the disease but do not cure it. The goal of treatment is to protect each season’s new growth from re-infection."