Pear sensitivity to neem oil?

Communist alert! I'm not 100% sure...but 2 days after applying the third holistic spray ... I found 8 out of 10 comice pears had serious burn (looking very phytotoxicity like) all 5 of Flemish Beauty leaves had turned brown and shrivelled and my one Orca pretty much fried. However 2 Comice were completely unaffected just one row over. All other varieties (Bartlett, Bosc, D'anjou, Winter Nellis, Seckel and Buerre Hardy) completely unscathed. Looking for another cause, I had just spread lime the day before the Pulse spray and it was pretty windy at times and lime dust was flying around--but how to explain those 2 unaffected Comices??? Hot Days? Well, you Eastern types tell me. The day I spread lime (I know---you're supposed to spread it in late Fall, but it is so expensive and we had just enough bucks in Late march) it was a high of 70 F and the day of spray 62--then 62 --52 degrees. I don't think that was too hot.

On a happier note, I have to search high and low to find ANY scab on the pears!!! This is astounding as I had 95% damage on Bartletts last year and plenty (40-60%) on the other varieties. Even on the 15 trees that did not get sprayed with sulphur (the others got 2 Lime sulphur/micronized sulphur combo sprays). And the leaf shine--it's so bright it hurts your eyes on sunny days---really. I have found that pears "respond" to foliar sprays more visibly than apples do.

I am looking for others of you who have a fair amount of pears in your mix (I have an acre and change) to compare notes with.

The Apple Farm
Zone 8b in California



Edited 1 time(s). Last edit at 04/30/2013 03:02PM by Michael Phillips.

I've seen a degree of this, Tim, in that spotting of pear leaves happens more readily than apple following a spray mix that includes neem. Generally, I do put it down to temperature-induced damage but it's also possible to spray too heavily on a particular branch/tree and thus up the gross concentration of fatty oils on plant tissues . But what you describe sounds quite worse. The fact that not all varieties had this issue -- and that Comice actually showed both sides of the cheek -- does make things hard to figure. Maybe you have to use less than a 0.5% concentration for neem oil in the pear spray when foliage and fruitlets alike are fresh and tender? The use of liquid fish also should be considered, for its oil component certainly ups the ante yet again.

The other question to be asked here concerns the time window when oil can cause phytotoxic damage. And here I think we're not just talking about neem oil but any fat and/or horticultural oil. I've assumed four to six hours before temps rebound into the 80s might be "safe" and thus advise growers do evening sprays during warm spells, if really necessary. That time lag factor of damage showing up 24 to 48 hours later is compelling as well. What do we need to understand here?

Lost Nation Orchard
Zone 4b in New Hampshire



Edited 1 time(s). Last edit at 04/30/2013 03:23PM by Michael Phillips.

I have seen this on Flemish Beauty for a few years; only this spring have I started to suspect the neem. This year all the spur leaves on the Flemish Beauty are completely black, vegetative leaves look fine so far, but they came out later, so I am suspecting that it came from the first (april 28) spray: that was 1 oz neem/1 oz natural dish detergent and seaweed in 1 gal water rate at tight cluster. Bosc and Harrow Delight essentially fine (scarce spotting). Weather has been dry and unusually warm/hot. It is leftover neem from last year (Ahimsa), though I don't know as that makes a difference.

Varietal difference is quite dramatic.

I did not take particular notice of these symptoms (or absence of symptoms) before first trying neem several years ago, so can't for sure blame the neem, but next year I will definitely skip the neem on part of the tree to test.

Jim Gallott
New Haven, VT USDA Zone 5a

Interesting. The Flemish Beauty has bounced back much better and faster than Comice--which is recovering---all new growth looking real good. Pretty much lost all Comice fruit, but some still on the Flemish. Will learn more next year. Weather here dry and warm also.

The Apple Farm
Zone 8b in California

Hello, we've had a bad time of it with Neem on pears once it warms up. We don't do this now....Susan

Well, in this second year of a full on Neem and Fish program, the blackening leaves on Comice and Flemish Beauty have returned---this time on all of them instead of a few. But not as severe as last year's damage--only one tree nearly defoliated. Since I have only seen this a very few times in 30 years, I can only suspect the Neem may be the culprit in exacerbating the problem. It happened this year several days after 3rd Neem spray (same as last year except it happened immediately after 3rd spray) and on only 2 trees---but over the next week all trees were afffected. Also from the tractor seat I cannot see a single pear on any of the Comice. Will confirm this later as fruit sizes. Checking on some old soil tests I usually come out a little low on potassium, but not real low. Will reread your comments on that. Next year will mark many of the trees and try to avoid them at least for the 3rd spray. Comments...ideas?

Let's say a guy gets ramped about pear blister mite. In this case, a new tree from a nursery introduces this pest to the farm ... that nursery won't be named ... yet such is how such things happen. Last year this young tree gets 'neemed' hard (now there's a new verb for y'all!) yet dammit it, the mites subsequently move onto a productive tree this new season. So that guy - who also will not be named (smiley thing) - blasts the hell out of the young tree source and the reddened shoot growth on the newly afflicted. Neem, after all, is systemic and will impact the molting cycle of blister mite. Said guy now realizes the result of his newest obsession. Excessive pear spraying means higher fatty acid concentration ... thus pear leaves burn. Oh, indeed, they do burn. Said guy now curses his narrow-sighted idiocy.

My advice: Spray pears "lightly" with the o.5% core recipe, or if you have a significant amount of pears, and have experienced leaf burn, cut the neem rate by half. All the more so after bloom.

And if you feel obsessed, spray the sheep. Or maybe the neighbor. Pears have a sensitivity and that's a fact!

Lost Nation Orchard
Zone 4b in New Hampshire

Update--There are indeed no comice or flemish beauty fruit on the blackened trees--NOthing! Unnoticed from the tractor seat 2 comice did not blacken up and are loaded with fruit--8-10 year olds. Go figure. last year I did not pay enough attention to whether the blackened trees had or tried to set some frui but dropped it early in the game (come to think of it I can't say for sure about this year either). Will need to pay close attention at bloom time in 2015. It makes one wonder if the tree knows it's gonna have it ahead of time and gives up it's potential crop early on. Talk about systemic! Gosh Michael, I don't know nuthin' 'bout pear blister (except on my fingers when thinning too hard) mites, but I didn't know about flatheaded borer until you introduced me in your book---I hope the mite doesn't follow suit and find my farm.

Has anyone tried spraying pears with smaller neem concentrations (0.25-0.5%) after petal fall, with daytime temps in the 80's?

Zone 6a in North Carolina

I would volunteer for that one--except it's too late! Of course I did not reread this thread before the first two neem spring sprays..or I probably would have tried it from Michaels earlier suggestion. Comice and Flemish Beauty are blackening and I have not done 3rd spray yet...but did a competitive boost (no Neem or fish) Of EM, Mollasses, Kelp, and compost tea yesterday and decided to not hit those trees because of nervousness...probably would not have mattered as fatty acids seem to be the culprit. Will begin 2016 notes and ideas today and will hopefully pay heed next year.

The Apple Farm
Zone 8b in California

Several grape varieties may also be sensitive to a .5% dilution including Worden and Allwoods, we noticed this burn after spraying on early green shoots with emerging fruit clusters. Still love the neem/karanja just the same. Will back off to .25%.

I find this all very interesting -- of course I find everything on this site very interesting. First, pears are very resistant to horticultural oils, (standard app cautions apply), and is recommended as an effective preventative against pear psylla at 1% through the summer. But Hort oils tend to be pretty refined and don't have any nasty stuff, much less good stuff like FAs. Second, I've re-read the threads and am wondering what else may have been applied prior to or in tank mix with the neem in addition to any fish. While it seems that the conclusion is that fatty acids are the culprit, Cueva also has fatty acids -- has anyone seen the same effect from Cueva? Oils are known to be penetrants (helps things get into the leaf) and so any number of other materials could also be at work - (yes/no/maybe?) - exacerbated by the oil. Finally, I am wondering whether any of the Aza-type (cleaned up neem) products also promote any of the leaf burn you're seeing with pure neem. Or have they been so stripped of any goodness that they wouldn't hurt a fly? It just seems that 0.5% or less would be harmless (for the most part). And how could anything good, like fatty acids, be bad at such a low concentration. In essence, my question is what makes pears so susceptible to neem oil induced leaf burn, when they are virtually immune to hort oils at higher concentrations? I know more questions than answers......What about karanja?

Mike Biltonen, Know Your Roots
Zone 5b in New York

On 4/19/2016, I applied my second holistic spray in the morning using a 2/3 concentration of Neem. Temps never got above 80. Here are my findings:
Within 3 days, Moonglow and Potomac show extreme leaf burn, Moonglow blossoms are toast. Flemish Beauty experienced some burn but not as bad as the other two.

The unaffected pears (so far) are Harrow Delight, Anjou, Seckel, Magness, Sunrise, and Shenadoah. I missed spraying the Comice pears by mistake which was fortuitous based on comments from previous posts.

The next holistic spray will use 1/3 the recommended amount. Will update my finds post spray #3.

Joanne Patton, Squire Oaks Farm
Zone 6A, Northern Virginia

I feel like I've seen a thread somewhere else on this forum where folks have reported apple and pear varieties which show neem sensitivity, but have not been able to locate it. We know all about 'Dabinett' apple sensitivity and certain pear varieties (after too many inadvertent leaf-burning episodes, we now sub 100% karanja for neem oil in our holistic mix when spraying our pears. However, for the longest time, I have meant to report an apparent plum sensitivity, as well. We have a small planting of plums, consisting of 'Santa Rosa' and 'Methley' planted alternately (one 'Santa Rosa,' one 'Methley,' one 'Santa Rosa,' etc.). It turns out that 'Methley' plums are more sensitive to BOTH neem and karanja oils than any other fruit we know of. We stopped spraying the plums directly with our holistic mix ages ago when the sensitivity issue became apparent (on 'Methley only; the 'Santa Rosa' plums have never exhibited any sensitivity to our sprays). Subsequently, we found that even the most minor drift of a holistic mix containing neem oil will defoliate the 'Methley' plums. This season, we decided to include the plum planting in our karanja only holistic spray regimen that we utilize on our pears, and have found that this also defoliates the 'Methley' plums, but not the 'Santa Rosa' plums. Say goodbye to the 'Methleys'. Goodbye, goodbye!

Kordick Family Farm
Westfield, NC
Zone 7a

Brittany, concerning pears, do you use 1 oz., or 1/2 oz of Karanja Oil per gallon for your 100 percent Karanja Holistic Spray? Do you include fish as well?

Thanks!
1 acre Mixed Orchard
6a Southwest Ohio

Hi Chad,

We have historically sprayed karanja on our pears equivalent to a rate of 1/2 oz. per gallon. We have a few pears that are particularly sensitive, and even sometimes react adversely to karanja at this rate, so we don't dare go higher at this point. We don't include fish in anything in our orchard, but that's just on principle, not because we don't think it would be beneficial. Hope that helps, and good luck!

Kordick Family Farm
Westfield, NC
Zone 7a

I agree with the principle of no fish hydrolysate or other in the spray tank, but what do you use instead. The oceans are being vaccumed clean of fish, bycatch especially odious. I don't even eat fish for the fact that humans are out-of-control predators.

Old 99 Farm and permaculture site
Dundas ON 5b

Did not mean to introduce any kind of ethical statement about using fish, just wanted to make sure that when I said we didn't use fish in the orchard, that it was understood that there wasn't any direct horticultural reason we don't use it. We don't currently sub in anything for fish, but always keeping our eyes out for a good replacement. Since the value of its inclusion is as much or more about fatty acids as simple fertilizer for the trees, at this point we have opted not to worry about it too much and trust that our trees are getting what they need in that dept. from other components in our spray mixes. Michael has suggested that coconut milk might provide similar benefits, and on homeowner scale that might be feasible, but we have yet to come across barrels of coconut milk and shudder to think what that might cost.

Kordick Family Farm
Westfield, NC
Zone 7a

Thank you Brittany for your reply. I used Karanja at a half oz. with fish hydroslate, seacrop and dipel over the weekend. It burned Potomac’s leaves, little black dots pepper the Ayers, Red Clapp’s leaves seem to have blisters or bumps on several of their leaves. Whether black spots and blistery leaves are a result of the holistic spray, I am not positive. Other than the Potomac no other varieties seem to worse for wear. In the future, I am avoiding all holistic oils on pear trees. I may just use a all season horticultural oil to combat pests and disease. I love the holistic spray on apples and other fruits, but pears seem too sensitive to take the chance on leaf issues. We only get one chance a year to get it right. I will not be taking the holistic spray gamble again on the pears. All other fruits, I have the confidence in the holistic spray’s benefits.

Chad
Zone 6a
Mixed one acre orchard

We were set to spray today, when my father remembered something about pears...oops, that’s right!

In another other post (“How much rain does a rain event make?”), I’d mentioned asking the Ahimsa folks about ideal spray conditions when it is hot. They seemed to imply UV (high/direct sun) was much more important re: leaf burn than temps. But obviously the community experience here is different for pears.

Michael mentions aiming for evening to allow a 4-6 hour cooler window, which I have often tried to do, too. However, here in the sort-of-South, temps are in the high 80s at 7/8pm already; after that gets hard to see in the shadows.

So here is my question: If I follow the UV-is-Most-important model, an evening spray for me is no prob right now. However, if I follow the Temps-are-most-important model, then I spray in early morning...but no way do I get that 4-6 hour window.

Any thoughts on which scheme y’all use? Both generally and for our pear question here. (and thanks to Brittany for your response on the other thread!)

Earthworks
Zone 7a in West-Central MD
Non-commercial, ~100 fruit trees, dwarf to MM106

I just noticed some pear burn on a couple trees for the first time, or at least I'm assuming that's what it is, as we've never had this issue before.

I'm rather confused b/c I'm pretty sure I didn't spray these pears with any Neem oil, since they were in bloom. It's a real bummer, as I seemed to have toasted a couple of trees blossoms off. If anyone knows, would any of these spray ingredients cause burn? I really don't think they do, but I'm scratching my head trying to figure this out.

4% EM-1
Molasses
1% Kelp
SeaCrop
MicroLeaf (microbials)
Microplenty (minerals)
Molybdenum
Calcium
Spinosad

All at label rates, unless noted otherwise. I specifically did not fill the sprayer with any Neem or Fish until after this spray, so there would be no leftover residue in the sprayer going on the blooms.

My only other thought is if my non-blossom spray that I sprayed the same time, which included the above with also 2% Liquid Fish and 1% Neem + Karanja, drifted onto these two pears. I was using a Mister Blower, so obviously more potential for drift. Even then, I sprayed at dusk, so I would have figured it would be ok by the next day's UV, and temps are not an issue yet. But if that was the problem, then I guess I have to avoid all Neem and Fish during Pear Bloom, which makes for rather awkward timing sometimes.

Earthworks
Zone 7a in West-Central MD
Non-commercial, ~100 fruit trees, dwarf to MM106

As I understand it, some cultivars are sensitive to the azadirachtin in neem oil (and I'm not sure what compound in karanja oil), so it's not just a matter of damage done by spraying oil in hot or high-UV instances. As mentioned in an above post, we have several cultivars of pears and plums that are apparently very, very sensitive to neem and/or karanja, and even the hint of drift will cause them to defoliate, yet different varieties planted right next door do great with the oils. So in your case, my money would indeed by on drift damage from mere exposure to neem and/or karanja, but it's hard to say definitively, especially without pictures. If you only noticed blossom damage, and not any leaf damage, perhaps it was something else entirely; we experience leaf burn, and tender young leaves coming out surrounding bloom would be especially susceptible. It is very strange that if this is indeed neem and/or karanja sensitivity it would show up after it has not previously been an issue (makes me sort of think of allergies in people and animals . . . could the sensitivity show up later in certain instances?). If you want to know for sure if you are dealing with sensitivity to something, perhaps you could try putting any of the different components you suspect in individual spray bottles and spraying just a small area of leaves on the tree and see how the leaves react to each respective component, replicating your dusk, low UV conditions to be sure.

Kordick Family Farm
Westfield, NC
Zone 7a

Which pear varieties seem to be sensitive in your conditions? Which do not seem to be? Also, I'd be interested to learn if the same purported sensitivity to azadirachtin in neem is the same as with an commerical aza product. I may just try that myself unless some has experiences already. I did stop using neem sprays a few years back when I didn't like the phyto problems I was seeing.

Mike Biltonen, Know Your Roots
Zone 5b in New York

We have 13 different pear varieties currently represented in the mature pear orchard that we began maintaining with neem plus karanja based sprays several years ago. After a season of burn issues, we went to exclusively using karanja oil in that orchard. Of those 13 varieties, we only had sensitivity issues with 3: 'Redbirne,' which was far and away the most sensitive (and even occasionally seems to react to karanja oil, but possibly more due to environmental conditions than the karanja itself, but still is affected by karanja when the other varieties are not), 'Seckel,' and 'Louise bon d'Avranche.' The drift sensitivity issues we have only experienced with 'Methley' plum trees. I could be two rows away spraying a neem-based application and the damn things would defoliate, so we gave up on them.

Kordick Family Farm
Westfield, NC
Zone 7a



Edited 1 time(s). Last edit at 04/22/2023 06:43PM by Brittany Kordick.

Brittany, thanks for the reminder that it is a general sensitivty to azadirachtin, not in combination with UV or temps. For us, it was our Crispie that got a main hit, and some Moonglow and Potomac. Keiffer shrugged it off, as it seems to with most everything. This was on early leaves, to your point, that would likely be much more sensitive. Just bad timing that it got the blossoms, too, which completely disappeared.

In the past, I've usually sprayed the entire orchard with the same tank, and so for non-dormant, I've usually dialed down the neem to 0.5% or even 0.25%. Or perhaps when I left the Neem closer to 1%, it was later in the season and the leaves were less sensitive. This year, I've been doing different tank mixes for different parts of the orchard, partly b/c the growth and bloom timing has been so wacky with the unusual temps we've had, and partly trying to fine tune the microbial and nutrient pulsing. That is to say, this is the first year that drift would have been an issue.

Good suggestion to test each of those products. But it sounds like no one sees any issues with the non-oil spray I did, and I also can't see anything there causing issues.

Earthworks
Zone 7a in West-Central MD
Non-commercial, ~100 fruit trees, dwarf to MM106



Edited 2 time(s). Last edit at 04/22/2023 07:22PM by Josh Willis.