Joe, the two most common diseases doing what you are seeing are septoria leaf spot and blackberry rust. My guess would be the former since it is more common. My recollection is dormant lime-sulphur is the best treatment. Lime-sulphur is organic. Since you may be past dormant season you could still spray a less potent strength I expect but look up some guidelines for treatment of the disease with Google to get the details. But, before you do anything search for pictures of various blackberry leaf diseases and figure out which one you have for certain. Then search for treatments for that. If you are not sure, ask more questions here :-) Scott

Oedema. Oedema Oedema is a physiological disorder that can affect all plants. It occurs when the plant takes up more water than it can rid itself of via the process of transpiration. The word itself means 'swelling', which is usually the first symptom, and comes in the form of pale blisters or water-filled bumps on foliage. Under a variety of circumstances/cultural conditions, a plant's internal water pressure (turgidity) can become so high that some leaf cells rupture and leak their contents into inter-cellular spaces in leaf tissue, creating wet or weepy areas. Symptoms vary by plant, but as the malady progresses, areas of the leaf turn yellow, brown, brown with reddish overtones or even black, with older damage appearing as corky/ scaly/ ridged patches, or wart/gall-like bumpy growth. Symptoms are seen more frequently in plants that are fleshy, are usually more pronounced on the underside of leaves, and older/lower leaves are more likely to be affected than younger/upper leaves. Oedema is most common in houseplants during the winter/early spring months, is driven primarily by excessive water retention in the soil, and can be intensified via several additional cultural influences. Cool temperatures, high humidity levels, low light conditions, or partial defoliation can individually or collectively act to intensify the problem, as can anything else that slows transpiration. Nutritional deficiencies of Ca and Mg are also known contributors to the malady. Some things that can help you prevent oedema: * Increase light levels and temperature * Monitor water needs carefully – avoid over-watering. I'd heartily recommend a soil with drainage so sharp (fast) that when you to water to beyond the saturation point you needn't worry about prolonged periods of soil saturation wrecking root health/function. Your soil choice should be a key that unlocks the solutions to many potential problems. * Avoid misting or getting water on foliage. It slows transpiration and increases turgidity. * Water as soon as you get up in the AM. When stomata close in preparation for the dark cycle, turgidity builds. If you water early in the day, it gives the plant an opportunity to remove (for its own needs) some of the excess water in the soil. * Put a fan in the room or otherwise increase air flow/circulation. Avoid over-crowding your plants. Al

Hi Toni, The tallest plant, the one with the leaf problems, is about six inches tall. The others are maybe 4.5 and 3 inches respectively. The light is about 15-18 inches from the top of the tallest citrus. The flourescent light puts out almost no heat, so I don't think that's the problem. Is it possible that it's just too bright? It *is* very glaring, but I didn't think flourescent lights were that powerful. In terms of fertilizer, I have been using a Schultz liquid 10-15-10 every two or three weeks, like I do for most of my plants. I recently switched to a top-dress dwarf citrus fertilizer 21-7-12 w/micros that I bought from a citrus farm in Florida. I haven't been misting the leaves, but I will try that. I don't know exactly how accurate my hygrometer is, but it did change when I took it out of my hermit crab tank and placed it near the plants. Thank you so much for your help, Toni! Laura

That looks physiological to me, not pathogenic. There are a couple of possibilities, depending on what you do with your plants. Some nutrient deficiencies can look like that; magnesium, potassium, maybe molybdenum. If you haven't fed them recently, or if you have been feeding them a straight NPK food and your soil isn't the best, consider supplementing with a complete fertilizer or tonic, one which has trace minerals. (I'm fond of Superthrive for hard-to-pinpoint problems like this.) Low pH can also mimic nutrient deficiency. It could be fertilizer burn, though it's not perfectly typical. If you've been feeding them a lot, lay off for a bit and see whether it resolves. The last possibility I can think of is spray burn. Sulfur and some oils can burn foliage at high temperatures (over 85F) and even simple soap at high concentration can burn; it's common for the tips of the leaves to get higher concentrations of the spray as it runs off. You didn't mention any earlier sprays, but if you have done any, watch your temperatures and try to get an even spray without a lot of runoff. Don't mix different sprays together, either. I don't suspect a fungus because the yellowing pattern is so regular, and the dead patches are in the center of the yellow areas which speaks of it either being the center of the toxicity/deficiency, or being a victim of sunburn as the leaves get too pale to handle the sun. I hope some of that helps. :) --Alison