I have a northstar cherry I planted this spring, a lot of leaves have what I think is cherry leaf spot. japaneese beetles are also starting to hit it. I sprayed with some sevin which seems to work well on my grapes, however I saw neem oil at the store and claims it is an effective antifungal and insecticide. anyone ever try it for cherry leap spot and does it also keep beetles/other pests away?

There are many products on the market that claim 'neem' as an ingredient. Often, the 'neem' is combined with other insecticides and a vehicle that makes emulsification and thus delivery/application easier. If these products have used neem oil that was altered or obtained by a process other than cold-pressing, the value or effectiveness of the essential ingredient azadirachtin has likely been reduced or negated entirely. I have read reports in these & other forums about growers using products like Bio-Neem by Bonide (and others) and having less than what they consider stellar results, while I continue to use the cold-pressed product, such as is produced by Dyna-Gro, with what I consider very safe and very good results. Remember that neem oil doesn't deliver a huge initial knockdown punch, but it IS a powerful antifeedant and chemosterilizer, rendering current generations unable to feed or progress through metamorphic stages to adulthood, and rendering adults sterile. Cold-pressed neem oil is excellent on mites & works initially in the same way as hort oils work, with the added benefits of the other properties already noted. This from a recent post @ another forum site: "As I consider the prophylactic use of any insecticide, including systemics, I guess I have to say that about the only compound that fits that description for me is neem oil. I over-winter around 100 tropical plants (most are normally grown as houseplants, but my focus is on bonsai) under lights in my basement. About 2 weeks before bring them in, I apply neem oil - then again a day or two before I bring them in. Normally these applications keep insect levels in check all winter, though I may see some scale or mite populations appearing toward winter's tail. If it gets too bad, I'll do a neem application & hold out until I get the plants outdoors where the increase in the plant's metabolism and thus natural defenses, along with the increase in beneficial predators, usually completely eliminates the trouble. The bio-compounds plants use to repel plants are a by-product of the plant's metabolism. Plants with high energy reserves and plants growing with good vitality are much better protected 'naturally' from insect predation, which is why plants in low light and those that are just limping along are far more likely to be troubled by insects. I very often diagnose the occurrence of insect infestations as the end product of poor cultural conditions, and the greatest, most frequent offender is a poor soil." I'm not implying you're using a poor soil; I know you're not, but others might wish to consider the corollary. Al

Let me expand further on the topic... I use neem oil from Ahimsa alternative - http://www.neemresource.com/ I buy my fish/seaweed hydrolysate from neptune's harvest http://www.neptunesharvest.com/fs-191.html or I buy from brown's for just straight fish hydrolysate http://brownsfishfertilizer.com/products-page/ Some notes about using... Neem - you have to keep it cold, I split the gallon container into smaller bottles (it hardens when cold, so you'll have to either dunk the gallon container in a sink of hot water or leave it sitting out on a warm day) - Shake it thoroughly and divide into very tightly closing smaller bottles. When you plan on spraying - take the bottle out, put it in a sink of hot water until it returns to liquid state. I usually pour the portion I need (.5 fl oz per gallon - a tablespoon) into a bucket and then return the bottle to the fridge, add my 1 ounce (1/8th cup per gallon of water) fish hydrolysate (be sure to thoroughly shake the container before measuring it out - be warned - this stuff is smelly), and scant tablespoon of biodegradable soap - I get 7th generation - it's cheap & readily available. Then I add about half the water I need and stir it several times in one direction and then switch directions with a dedicated whisk. Pour into sprayer add remaining amount of water needed, close your sprayer, shake thoroughly and start spraying (make sure their are no oil droplets at the top of the solution - neem has to be thoroughly mixed to be effective - think like salad dressing - who likes separated salad dressing? yuck. I prefer spraying right before sundown or even at night (with a flashlight... my neighbors naturally think I'm nuts) and to the point of runoff. Be sure to get undersides of leaves. Why near or at night? This is when the stomata are opening up on the plant - in other words, the pores of the plant are open. You'll get the maximum uptake and benefit from spraying at this time and it gives the maximum time for the plant to avoid sunburn. I do this about once a week during times of high disease pressure and then back off to bi-weekly when disease pressure goes down - if it rains, I spray the next day or as soon as possible (assuming it isn't just going to rain the next day... then I wait) As always - be sure to test an inconspicuous area of the plant and allow a week to make sure their aren't burn issues. If you, after a few weeks, aren't seeing an improvement in plant health - up your spray concentration by half a percent. Per gallon, for example, if you started at .5% dilution - go up to 1% (1 fl ounces per gallon, 2 tablespoons). Few other pieces of advice - this stuff is smelly. Neem has a very strong garlic-nutty smell and fish hydrolysate... well it smells like rotten fish (trust me the cold process hydrolysate smells A WHOLE lot better than the cheaper, less effective hot processed stuff... ugh). Be assured it dissipates quickly - if the scent really is bothersome you can add a drop or two of a fragrance oil - peppermint is particularly effective. Neem and fish hydrolysate once mixed - have to be used immediately upon mixing - they break down rapidly in solution - if you sprayed everything and have some left, use it as a soil drench or spray it on something you don't normally spray. It'll be glad for it. Thoroughly rinse your sprayer after every use - I fill mine with water and just use it to water plants, silly to waste the good stuff. I try to think of it as being like licking the brownie batter off the spoon. This should go without saying, but don't spray it on the blooms. Buds are absolutely fine - but blooms and less so buds are much more prone to phytotoxicity (burn). Do not spray during foraging times for beneficials - (shouldn't be too much of a problem at night). DO NOT spray on host plants for butterflies/native endagered insects - Azadirachtin (the main active compound in Neem) interrupts the molting process of insects that consume it. Butterfly caterpillars, that eat and live on their respective host plants that are treated with neem (or any other spray for that matter) will die. If you don't know what that includes, I'd contact your local extension office. You should see improvement in just about any plant you use this on. I pretty much use it on everything that isn't a host plant in my garden and this is also the same basic formulation I spray on my orchard. Also, the fish hydrolysate is more than just a sticker/carrier - it's also a fantastic fertilizer - I use the same spray formulation (1/2 fl oz neem, 1 fl oz fish per gallon) as a soil drench aka fertilizer. Hope that answers some questions Jordan - Organic/Holistic Orchardist and Gardener This post was edited by jjstatz29 on Wed, Mar 26, 14 at 10:18

Not Cercospora. But let me ask you a question. When you touch these yellow with green leaves, do the immediately drop? With BS leaves with significant green portion usually don't drop that easy. Usually leaf should be almost completely yellow before it drops. The reason why I ask I had several plants in my life 9 I grow roses for 30+ years) that had this issues, especially in spring. Very similar look to what you have here. These were all good quite resistant roses like Dortmund, William Baffin, etc, all with kordesii in their genes. When disease just starts, there are usually pin head size spots on the leaves that have different color, sometimes darker green and then yellow color starts appearing and leaves drop. Disease always starts from the bottom and goes up quite fast. It can almost completely defoliate bush in several days. Roses don't die and issue usally dissapears in summer, but comes back often in fall. I tried hard to figure out the name of this disease, I couldn't find anything, except there were several records of such disease. All reported cases I read about, were with kordesii origin roses. Mostly Dortmund was mentioned. I used sulfur as fungicide at that time and it was not effective against this. Olga