Soils that have a nutrient imbalance can contribute to plant disease problems and there is no real test for the pathogen that causes mildew problems. That pathogen can also travel through the air with the wind. A good, in depth look at your soil can tell you if you have a good, rich soil that will grow strong healthy plants that will be more disease resistant. Start with these simple soil tests; 1)Structure. From that soil sample put enough of the rest to make a 4 inch level in a clear 1 quart jar, with a tight fitting lid. Fill that jar with water and replace the lid, tightly. Shake the jar vigorously and then let it stand for 24 hours. Your soil will settle out according to soil particle size and weight. A good loam will have about 1-3/4 inch (about 45%) of sand on the bottom. about 1 inch (about 25%) of silt next, about 1 inch (25%) of clay above that, and about 1/4 inch (about 5%) of organic matter on the top. Drainage. Dig a hole 1 foot square and 1 foot deep and fill that with water. After that water drains away refill the hole with more water and time how long it takes that to drain away. Anything less than 2 hours and your soil drains too quickly and needs more organic matter to slow that drainage down. Anything over 6 hours and the soil drains too slowly and needs lots of organic matter to speed it up. 3) Tilth. Take a handful of your slightly damp soil and squeeze it tightly. When the pressure is released the soil should hold together in that clump, but when poked with a finger that clump should fall apart. 4) Smell. What does your soil smell like? A pleasant, rich earthy odor? Putrid, offensive, repugnant odor? The more organic matter in your soil the more active the soil bacteria will be and the nicer you soil will smell. 5) Life. How many earthworms per shovel full were there? 5 or more indicates a pretty healthy soil. Fewer than 5, according to the Natural Resources Conservation Service, indicates a soil that is not healthy.

"Some research indicates that sprays using Neem oil extracts, containing azadirachtin-A, are effective against this pest, particularly when applied to the soil, without being detrimental to beneficial insects. Other natural solutions, including the use of predatory nematodes, are currently being investigated." The above is from Canada: http://www.torontobotanicalgarden.ca/mastergardener/newforum/viewtopic.php?f=12&t=39&p=93 ---------------------------------- Canadians have also stated in forums that Neem works: "Try calling any 'hydroponic' store in your area, such as "Yield of Dreams" or "Homegrown Hydroponics" - they'll have it on the shelf - sometimes called "Einstein's Neem Oil". It works on the Rose Midge infestation I had as well." FROM: Http://forums.gardenweb.com/forums/load/cangard/msg062253481951.html ------------------------------ "I caught sight of it really early around mid-May on one particular climber (2 year old William Baffin). The advice I was given was to clip it back (boo hoo had to loose all those newly formed buds), dispose of those buds in the trash and foliar the plant and surrounding earth with diluted neem oil, dish soap and water. It did the trick - and although none of my other roses were affected I gave them the neem foliar spray just to play it safe." FROM: Http://forums.gardenweb.com/forums/load/cangard/msg0607231619365.html ----------------------------------------------- There are other statements on the web that Neem works. "rochester, neem oil applications have been proven to be helpful against rose midges. Read and follow the directions carefully; you'll be able to find neem products in any garden center." FROM: http://forums2.gardenweb.com/forums/load/organic/msg05182252650.html --------------------------------------- "Azadirachtin neem extract, sold as Azatin or Bio-neem, applied to the soil around the roses, stops the midges from being able to feed. They have a very short live span, so this will not kill immediately, but will stop future generations (a generation lasts less than 2 weeks). Also, immediately remove any damaged or suspicious growth you see on your roses and throw the prunings and any fallen leaves away. If you put a plastic cover over the soil under your roses, when the midge larvae drop to the ground they are exposed and unable to pupate. It's not terribly attractive, but a plastic sheet is better than deformed roses. Neem extract, and/or Bayer's Advanced Garden Rose & Flower Insect Killer, or Bayer's Advanced Power Force Multi-insect Killer, have worked best in recent trials since diazinon was removed from the market. They must be applied every 10 days according to directions, for the entire growing season to get rid of the midges. Also, remember to keep any fallen leaves, etc. from your roses removed asap." FROM: http://en.allexperts.com/q/Roses-732/2008/2/rose-midge-infestation.htm -------------------------------- " Prune off and destroy affected buds. Spray with a neem- or spinosad-based insecticide. Rose midge is a fly larva; although it looks like a tiny caterpillar, caterpillar-specific sprays, such as Bt, won't work. " FROM: http://agave.garden.org/~suzanned/matrix/rose-pest/rose-problem-matrix.html -----------------------------------

I don't believe that anyone is suggesting that good 'housekeeping' will prevent PM all on its own, but it is a very helpful tool to use in conjunction with other management activities. ken pretty much nailed it. alice, this pain-in-the-neck disease will stress out your plant, especially if allowed to take over year after year. I think you know how susceptible lilacs are to PM. Anything you can do to prevent it is important. PM hinders normal photosynthesis, and can cause defoliation of seriously infected plants. On lilacs, this can happen pretty early in the season, since that is when conditions are just right for this disease. To add to ken's suggestions, please add a couple of other things to your management chore list, lol. Careful pruning to THIN out the plant can be very helpful. Not topping, which will promote more growth, but thinning, so that you can expose the remaining plant to more sunlight and air circulation. Also, go easy on the fertilizer. Another product in your arsenal should be neem oil. It has shown much promise in the prevention AND control of PM. Get it on early enough and the spores will not be able to infect the cells. Good luck! Fighting this disease of lilacs is a tough battle.

I do use Neem and am quite happy with the control I get. I've also heard about mixing baking soda, baby oil and water but haven't I tried it and don't know what the proportions would be. Apparently the baking soda makes the leaves too acidic for fungus to grow and the baby oil helps the mixture stick to the leaves. You do have to be careful though--too much baking soda will burn the leaves.