help .. asian pear trees 2 yrs old

[motdaugrnds]

I found my two asian pear trees looking like the below pics. Both were planted in fall 2008.

This one is a "Hosui Asian Pear" I was told was got too much water and needed boron, iron & calcium in early spring (leaves streaked with yellow and light green). I added those and its new growth was looking much better. Now I find the black spots.



This one below is "Starking Hardy Giant Asian Pear" & was the one I thought had died; but it put out again this year and was looking real well until just recently when I found all these black spots.



Can anyone identify what I need to do to keep them alive and get them healthy?

[ksfarmer]

It looks like a Anthracnose leaf blight of some sort. I took this info for treatment from a Ohio State University extension fact sheet:


Control of Anthracnose Diseases

Overall tree care program. Use proper fertilization, pruning, watering, and pest control practices to encourage vigorous plant growth. This aids in general tolerance of the effects of disease and in rapid refoliation in years where disease is severe.


Fungicide applications. If significant damage occurs yearly and controls are justified, properly applied fungicides may reduce damage from these diseases. High pressure spray equipment will be needed for large tree applications, and this typically requires the hiring of a professional tree care service.

Fungicides will not be effective unless they are applied before and during infection periods. Typically, three applications are necessary, beginning in early spring, with the first application made before leaf buds open. Applications in the fall have been shown to be useful for sycamore anthracnose control. Fungicide injections have also shown promise for sycamore anthracnose control. These must be applied by professional tree care companies.


Some common product names containing the fungicides mentioned above include: mancozeb (Fore, Dithane, Mancozeb), chlorothalonil (Daconil*, Bravo, otho-multipurpose fungicide*), thiophanate-methyl (Cleary's 3336, Domain) and propiconazole (Banner).

[motdaugrnds]

Thank you ksfarmer. I had some Daconil; so i went out and sprayed them down real good. Hope it is not too late to save them.

[MOgal]

Start from the "ground up" with good soil. Don't have good soil? Then start now making it by layering as much compost and mulch as you can get your hot little hands on around your trees. Pay special attention to the drip line. I don't use chemical fertilizers, fungicides or insecticides but I do spray with aerated compost tea fortified with fish emulsion, liquid kelp and a bit of blackstrap molasses about once a month. I will do spot applications of pyola spray from GardensAlive! if I have a localized infestation of tent caterpillars or other bugs but not a general spraying with any toxic materials.

I have been described as "rabidly organic" and took it as a complement. I grew up in the Deep South--cotton and soybean country--and was exposed to a horrible brew of poisons including most things found in Agent Orange of Vietnam era fame. I don't see exposing myself to those chemicals again since I've already done the cancer gig once. Exposure and cancer may have been related, may not have been but I prefer not take chances. I'll let the tree die, the crop fail rather than handle any of that stuff. So....my approach is much less aggressive than what Extension, et.al, suggests.

Good luck.

[GoatsRus]

Looks like fire blight. My pears had it (removed them) and now my apples have it. They will be removed this year.

Fire blight can easily be cured, no reason to remove the trees. First, it doesn't show up every year, secondly, when you do your dormant pruning, cut back several inches below the blistered area. discard all cuttings well away from the tree. If you have concerns, spray in the spring with agricultural streptomycin, since fire blight is a bacterial disease.
Fire blight tends to show itself fairly early in the season.

[motdaugrnds]

Zong, these trees did not have this dark discoloration 2-3 days ago. It only showed up afer we got much rain. (I also noticed same discoloration on some forestry not too far away.)

Is "agricultural streptomycin" an ingredient in some fruit tree sprays or is something I need to purchase as a singular item? (The sprays I have no longer have the labels and what is there is so tiny I cannot make it out well enough to be sure what contents are.)

When you say "cut back several inches below the blistered area, does that mean take off the top of the main tree trunk or just the leaves? I doubt I should do that at this time; but not sure. Also, is there anything I can do now (already sprayed with Deconil) ... anyway to save these trees or should I just not do anything until they are dormant? (Excuse my ignorance please. I am just so unsure of myself when it comes to my fruit trees/bushes as I have not had enough experiences as yet.)

Fire blight usually shows up in late spring. Streptomycin wont be in any other insecticide or fungicide, but sold by itself. Probably called Agrimycin. Look at the picture. There is a burnt looking spot about middle ways of the limb. Leaves to the left of that spot have turned black. When I prune the tree, this winter, I'll cut that limb back to where my thumb is, and dispose of the infected portion. If you don't have a burnt looking place, you don't have fire blight. Once the tree has fireblight, the damage is done for that year, it wont get worse on its own. However, if you mess with it, you can spread it. I just leave them alone and take care of it when I prune the following winter. I don't think what you have is fire blight. I think its a result of those 102 degree days last week. I have a few leaves on various trees that turned black in the past few days too. I figure its from all that heat.

[motdaugrnds]

Zong, thank you so much for the pic and information.

I do not see any burnt looking spot on any of the limbs. The discoloration is only on the leaves. Yes, we did have extreme heat a few days ago (followed by lots of rain and "cold" weather) and these trees were doing pretty well until then.

I will pick up some Agrimycin when I am able to get to the store this week. It probably won't hurt to go ahead and spray them with it; so will unless you think it best I not do so.

I have hope now for our asian pear trees. Thank you

[GoatsRus]

Originally Posted by zong

Fire blight can easily be cured, no reason to remove the trees. First, it doesn't show up every year, secondly, when you do your dormant pruning, cut back several inches below the blistered area. discard all cuttings well away from the tree. If you have concerns, spray in the spring with agricultural streptomycin, since fire blight is a bacterial disease.
Fire blight tends to show itself fairly early in the season.

Unfortunately, my trees have the blight on lower limbs and close to the base. I pretty much have to cut the tree to a nub. I started cutting back the branches, but the blight just kept coming back on other branches, so I've given up.

Agrimycin would only work as a deterrent, in advance of any infection, at blossom time. Heres an article about the use of agricultural streptomycin in a fire blight plague in Switzerland. http://www.swissinfo.ch/eng/index/Fa...ml?cid=6829978
GoatsRUs.. I feel for you. I am so attached to my fruit trees, it takes a lot of work to get a maximum production. It would be a trauma to me to lose a few of them...