Thank you for your valuable input, Rhizo. After reading your post, I reread about neem use against psyllids. "Results have generally been poor against whiteflies, pepper maggots, and psyllids." (Source: www.nysaes.cornell.edu/pp/resourceguide/mfs/08neem.php) Another, albeit specifically mentioning tomato/potato psyllids (not sure if its the same psyllid): "Soap spray results have been disappointing and neem has not worked." (Source: www.colostate.edu/Depts/CoopExt/4DMG/Pests/psyllids.htm) Does anyone have knowledge of neem's ability to have systemic effects on Pepper Psyllid on the Brazilian Pepper tree? I am tempted to mix up a batch of Neem Concentrate (www.greenlightco.com/products/neem/)and water the tree roots. Good idea or bad idea? If good idea, would the Neem mix rate per gallon of water would be the same for systemic application (2 tablespoons per gallon) as it is for foliar spraying? btw, Rhizo, you are so right about Ladybugs. In the past, when I have released thousands in one day, only a few dozen insects stay around. I wish that my neighbors on all sides would release thousands, maybe some would flee to my property... Here is a link that might be useful: Green Light brand Neem Concentrate BOTTLE LABEL (pdf)

Yellowing and dropping of leaves is normal toward the end of the second summer on the small-leaved lepidote rhododendrons. These should have dense enough habit that this doesn't matter. The larger-leaved elepidote rhododendrons keep their leaves for 3 or 4 seasons. Like all evergreen plants, rhododendrons and azaleas periodically lose some of their foliage, and the leaves may turn yellow, red, or purple before they fall. Often the only leaves that remain are those that surround the flower buds at the tips of the branches. This characteristic is linked to the genetics of the parents used to breed garden azaleas. The degree of leaf coloration or loss is a function of parentage and not the severity of the winter. In unusually cold winters, certain azaleas may lose more leaves than they would in mild winters. Most diseases that harm rhododendrons cause the leaves to yellow, droop, curl, and eventually turn brown, but, oddly enough, they usually don't drop the leaves. Some things that can kill individual branches are: DROUGHT: Drought can cause entire branches or entire plants to die. We have had several years of drought here and we observe that if rhododendrons and azaleas are not watered during a drought some plants will die, but others will just have one section of the plant die. It seems to be the plants way to conserve what little moisture it has. Prolonged drought weakens plants and often results in the appearance of fungal cankers on the branches of older azaleas. Look for branches that wilt in hot, dry weather in late summer and be sure to water azaleas if drought drags on more than a few weeks. Prune out the affected branches to stop the spread of fungal canker diseases. BORERS: If a Rhododendron Stem Borer, Oberea myops, or Rhododendron Borer, Synanthedon rhododendri, is in a branch, the entire portions of a plant beyond (away from the roots) will wilt and die. Borers only affect the portion of the plant away from the roots from the borer. If the borer is in the main trunk, then the entire plant will wilt and die. The plant can be save by cutting off the area with the borer and letting the plant regenerate from the roots. There are no conventional insecticides that will kill stem borer larvae once they are inside the branches. The best control option for homeowners with only a few plants is to prune out and destroy wilting branches in early spring or late summer. FUNGUS: Buds and twigs becoming covered with silver-gray scales is caused by one of the water molds: Altenaria Blight or Botrytis Blight or Twig Blight and is easy to control with fungicide sprays and proper sanitation by removing and disposing of all dead material. Phytophthora cactorum causes the central vein of a leaf to turn brown and the discoloration extends to the petiole on tender new growth. The infections spreads outward from the midrib tissue and the leaf wilts. Infections are more severe on azaleas. Some varieties of rhododendrons are vulnerable (Chionoides, Catawbiense Album, Nova Zembla) and some are resistant (Roseum Elegans, Scintillation, PJM). Control of the disease is difficult. Since the infection goes from the roots to the tips, when you see the symptoms it is too late. To prevent it, use a raised bed with lots of sphagnum peat moss. Prevention with fungicides and careful control of exposure to high humidity may be practical. [Return to Problem Menu] Botryosphaeria dothidea causes leaves to turn dull green and then brown and roll and droop. Cankers form on branches which may girdle the branch. This is the most common disease of rhododendron in the landscape. A typical symptom of this fungal disease is scattered dying branches on an otherwise healthy plant. Leaves on infected stems turn brown, then droop and roll inward. These leaves often lay flat against the stem and will remain attached. The pathogen can infect all ages of stem tissue through wounds, pruning cuts, and leaf scars. Heat, drought stress, and winter injury can increase disease incidence. Cankers on branches can gradually grow through the wood until the stem becomes girdled. Diseased wood is reddish brown in appearance. Discolored wood viewed in longitudinal cross section often forms a wedge that points toward the center of the stem, and the pith may be darker brown than the surrounding wood. Sanitation and applying a fungicide such as metalaxyl (Subdue) after pruning my provide some control. Plants should be grown in partial shade, with mulch and kept well watered during dry periods. All dying branches should be promptly pruned out in dry weather and all discolored wood should be removed. Plants should also be protected from rough treatment during maintenance activities to prevent unnecessary wounds. [Return to Problem Menu] Phomopsis rhododendri symptoms vary from leaf spots to chlorosis and then browning of leaves which then wilt. Browning streaks extend down the stem to a wound. Fungicides such as metalaxyl (Subdue) should control an outbreak. Sanitation and applying a fungicide after pruning may provide control. [Return to Problem Menu] Rhizoctonia solani: causes small necrotic spots on leaves, which later become dark brown or black. Defoliation follows severe leaf spotting. The fungus is omnipresent in the soil and appears to be most virulent at high humidity levels. Microscopic examination of roots and crown are the surest diagnosis. Cultural practices to control this disease include improvement of drainage and avoidance of excess irrigation.

I finally figured out how to post photos in the message. I've also attached the Photobucket link, if you want to see more photos. Looking at the photos makes me realize the discoloration of the leaves may be a bit more of a problem than I initially thought. The photos also show just how pronounced is the curl. I've been wondering if this problem could be result of spring sickness, leaf streak, rust, or drought. Photos of those issues online don't seem to show exactly what I'm seeing in my plants, so let me know if this looks like something you recognize. We have had a colder year than usual and it has been very dry. Thanks, Sandra Here is a link that might be useful: daylily leaf curl problem

This post is excerpted from a series of responses posted on pixie_lou's Show us Your Landscape - A photo thread - January 2012 on the New England Gardening Forum. I corrected a few very minor typos. ------------------------------------------------------------------------------------------------------------- Posted by claire z6b Coastal MA on Sat, Jan 14, 12 at 11:40 Suddenly cones and buds become very interesting in this season (I don't want to think about last year's snow). Icy cold is expected for the next few days - two nights bitterly cold and the day in between not much better. It occurred to me that some of the rhododendrons would be curling up their leaves for protection against the cold so I thought I'd take a few photos today before the curl-up. I didn't pay too much attention last year, and I have a few new rhododendrons, so I don't know if they all curl-up or just certain cultivars. I'll check tomorrow to see what happens. Rh. Anah Kruschke (new this year) Rh. Mary Fleming Rh. Percy Wiseman (in his squirrel-proof cage) Rh. roseum with Azalea Gumpo Pink at its feet. Claire ------------------------------------------------------------------------------------------------------------- Posted by nhbabs z4b-5a NH on Sat, Jan 14, 12 at 20:01 I have a huge rhodie that I assume is Roseum Elegans (which needs pruning after bloom next spring) that has been here at my old farmhouse far longer than I have been. Since it lives by one of the kitchen windows, I use it to tell me the level of cold discomfort before I leave the house. I know from experience that if the leaves are curled, it will feel cold enough that I'll need a warm coat, hat and mittens before venturing out - no running out to the car in a light coat with my heavier coat (for walking to work later) in my hand. ------------------------------------------------------------------------------------------------------------- Posted by claire z6b Coastal MA on Sun, Jan 15, 12 at 10:20 nhbabs: That's a great use of a shrub as a temperature indicator! I have to rely on an electronic sensor swaddled in a jar, hung from my wisteria. Your kitchen window view must be lovely when the rhodie is in bloom. My Roseum was just labeled as "Rhododendron Roseum" so I don't know which one it is. This morning the temperature was 10F; not cold for you northern types but chilly here on the coast. Rh. Anah Kruschke leaves were a little curled, but not fully. Mary Fleming, on the other hand, took the cold very very seriously and clamped the leaves shut. Percy Wiseman is somewhat curled up: and Roseum is tightly curled. Tuesday and Wednesday are forecast to be much warmer so I expect all of the leaves to open up again. Claire ------------------------------------------------------------------------------------------------------------- Posted by nhbabs z4b-5a NH on Mon, Jan 16, 12 at 10:04 My goodness what a range between the various rhodies. I only have the one rhodie at the house, but I will have to watch the ones down the road at the shop to see what they do in various temperatures. I know that they are all tightly rolled today as it is only a few degrees above 0. ------------------------------------------------------------------------------------------------------------- Posted by claire z6b Coastal MA (My Page) on Tue, Jan 17, 12 at 13:41 Not to beat this to death, but I checked the rhododendrons again today (temp. about 40 F). Cold? What cold? Rh. Anah Kruschke Rh. Mary Fleming (along with foxglove and geranium leaves) Rh. Percy Wiseman and Rh. Roseum I am impressed, even stunned, by the rhodies' rapid adaptation to temperature. Claire ------------------------------------------------------------------------------------------------------------- Posted by pixie_lou 5 on Wed, Jan 18, 12 at 15:23 Claire - I'm quite impressed with your documentation efforts. I on the other hand would never run out into the cold just to see if my leaves were curled. I'm hoping to see a spread sheet soon - different varieties of rhodies and the particular temperature on which their leaves turn. Do you think wind chill and humidity make a difference? What about moon phase? This should all be documented on the spreadsheet. I'm kidding of course. But I do find the whole phenomenom fascinating and I actually enjoy seeing your photo documentation. ------------------------------------------------------------------------------------------------------------- Posted by claire z6b Coastal MA on Wed, Jan 18, 12 at 15:51 pixie_lou: no way am I going to delve that deeply into the curly leaf phenomenon (spreadsheets? ...snort, snicker...) But I was very curious and I had to go outside anyway, to feed the birds, break the ice on the birdbaths, and get the mail, so I just hung the camera around my neck and shot photos along the way. I also thought there might be some new gardeners who had just planted their first rhododendrons last season and who might panic when they saw the leaves suddenly curl up (oh no, did I screw up somehow? It's OK, rhodies just do that.) There's a very nice article in the Arnold Arboretum magazine, titled "Why Do Rhododendron Leaves Curl?" by Erik Tallak Nilsen. For some reason I can't link directly to it (pdf) but It's the first hit if you google Why Do Rhododendron Leaves Curl? Apparently not just a straightforward response to cold, but also protection from bright sunlight in the cold and also prevention of too quick thawing of the leaf. Claire