Hello Danielle,

Unfortunately your image(s) did not come through, and our system cannot accept video files. Can you please re-send the pictures?

As you may already know, Pomegranate is rarely grown in Maryland because it is barely winter-hardy here and we don't often have a long-enough growing season for its fruit to ripen before freezing in autumn. Due to this, we have very little experience with diagnosing Pomegranate ailments. That said, we will see if any of the symptoms appear familiar when your images come through. Our plant pathologist is out of the office today, but we will consult with him as well as soon as he's available.

Additional information to supplement the photos would be helpful. When did you first notice symptoms? If last year was the first time, do you remember what time of year you noticed something wrong? If a stem looked diseased, what were the symptoms? (Off-color or stunted/deformed foliage, cracked or shedding bark, branches that shed leaves early or never leafed-out, or something else?) Can you describe the ailing plant's growing conditions? (Especially if it differs from the other one that's doing ok.) For example, is it in full sun or mostly shade in summer, does the soil drain well and is there a roof downspout nearby, and are you able to check it for water and irrigate periodically when the weather is dry?

Infections from a single species of pathogen usually don't spread to that wide of a host range (the fruits and nuts you listed), but if environmental conditions are stressing the plants, then they may contract similar diseases as a result, since it's the underlying stress that makes them more vulnerable. Botryosphaeria in particular tends to infect plants stressed by drought, heat, or winter injury; given the fact that Pomegranate is vulnerable to cold damage here, this scenario is a possibility. If you still have some available, or the next time you need to trim, examine the wood in a cross-section of any freshly-dead or dying stems (older, decaying wood won't be as useful) and look for any discoloration. Where in the stem plus how it manifests can narrow-down which pathogen may be responsible.

Miri

Thank you for the photos. Our plant pathologist doesn't see any signs of a disease in the pictures. The raised bumps on the bark look like lenticels (pores for gas exchange, which are prominent on an array of tree and shrub species and can change prominence with wood age) or perhaps normal bark development due to branch age, especially in the final picture. If the bark texture differs greatly from your other pomegranate, are they the same cultivar and age?

There is a small circular hole at the base of one branch in your third picture which might indicate a wood-boring insect was present earlier. Some beetles are small enough that their exit holes are only about the diameter of a toothpick. These borers tend to target stressed plants, though, such as from over-watering or drought. It's also possible this hole is not due to a borer, but if you see any holes on wood you trim away, split the cut branch open at this point and look for tunneling either just under the bark or into the stem's interior, or stained areas of wood.

You didn't mention if there were any other symptoms besides lack of fruit and the bark changes on the branches that have already been removed. If the foliage looked normal all season and the branches weren't bare, then there may not be a chronic issue. Univ. of GA does mention on their pomegranate page that "Without irrigation during prolonged periods of drought, fruit production will be lost, and substantial injury to young trees is likely." You do mention you've watered in dry weather, but perhaps the amount of water applied or the moisture retention ability of the soil impacted how well irrigation alleviated the plant's stress.

UGA also says that pomegranates are self-fruitful (which would mean they can fruit without cross-pollination), but also that insects and hummingbirds can fertilize flowers. However, Clemson's pomegranate info. says plants might not fruit without adequate pollination. Since our weather can of course vary from year to year, maybe conditions were too wet or chilly during their bloom period in the years you didn't get fruit, even though they do flower relatively late. This scenario wouldn't necessarily explain whey the other plant is still fruiting well, but perhaps its flowers weren't at the peak of fertility at the exact same time if weather or pollinator availability was the issue. Otherwise, we aren't certain what factors are causing the interruption in fruiting.

Neither reference mentions any disease or pest problems for the wood (branches or main stems). You're welcome to send additional pictures later this season if you find additional symptoms or if dieback develops.

Miri

You're welcome.

Shedding bark normally suggests branch tissue death, but it can be due to just about any cause - environmental, pathogenic, or an insect pest. Some symptoms may not manifest until the damage has progressed to the point where the stem won't recover. If the summer foliage on the individual stems in question looks normal, then it's probably not a serious pest or disease, because any damage caused by either that injures sapwood would cause wilting or leaf loss of the growth beyond that point. The sapwood is located just underneath the bark, not in the stem's center (on older wood, at least). This means that any damage to the center heartwood are not as harmful to the sapwood as damage confined to the shallowest layers of wood. For what it's worth, canker diseases do tend to kill sapwood first, even if they later extend their growth into heartwood.

For some woody plant species, bark shedding is a normal feature of the plant as it ages. We don't know if this is the case for pomegranate, though web resources don't suggest that it is.

Lenticels were an educated guess based on their appearance, but they could also be points where tissues are maturing into additional layers of bark.

The forms of genus Botryospheria we are familiar with cause cankers and branch death but not necessarily bark disintegration in this fashion. A common host for at least one species in our gardens is Rhododendron, which is why our page focuses on that genus and the management tips mainly apply to Rhododendron. When viewing infected tissue under a microscope (it would need to be a compound scope, which has higher magnification than a dissecting scope), fruiting bodies (spores) are needed to verify pathogen ID. Penn State has a page on Botryosphaeria in home landscapes that provides some symptom information: https://extension.psu.edu/botryosphaeria-canker-in-the-home-garden

Your research may have already turned this up, but we do see scientific references online to the pathogen Neofusicoccum parvum that can infect pomegranate wood. Illustrations appear to show new cankers manifesting as subtly darker areas of otherwise-normal bark. This might be a long shot, but maybe you can find a certified arborist or tree-care company to take samples for culturing. While most tree companies don't have their own diagnostic lab, a few do (you'd have to ask); others might be able to have samples tested through a university lab or private lab. Testing might be expensive, but would be more definitive.

Similarly, since you think this plant may have been infected from the start, we suggest you also contact the supplier and ask if they've had crops infected with any of these pathogens before, or what initial symptoms they've seen if they have. Univ. of FL suggests trimming out diseased pomegranate wood in winter or late fall to minimize spore spread, so if this is what you have been doing, that's the best approach for now. We do not have any fungicide recommendations, but if an arborist suggests applying one, make sure they know that this is a cropping tree and not an ornamental (decorative) flowering pomegranate; not all pesticides can be used on harvestable plants.

There's certainly no harm in trying to find more concrete signs of infection with your microscope. The most visible spore growth will probably occur once we warm up more consistently and the weather becomes wetter, as spores disperse and re-infect plants best with ample moisture. Be aware that, if the wood was already dead or has been dying for awhile when it's examined, secondary and unrelated fungi may be present to take advantage of the wood available for decay, which might make singling-out a pathogen more challenging.

Miri

We understand. Hopefully you'll be able to find something. Good luck!