Hello, In a row of plum trees that grow along a fence, some trees grow very well, while others show a stunted growth with yellow leaves, and the fruits are kind of spongy. They all have drip irrigation and most of them look well, while others look like on the attached pics below. Any idea what can be the reason (with this little information)? See attached photos. On the last two photos one can see the difference between unhealthy and healthy looking plants
Sorry Sulev, but I don't think it has anything to do with the roots, I'm almost 100% sure this is the most common disease that we have here on peach trees (not plum trees) : "Leaf curl" (Copper-based mixtures (such as Bordeaux mixture) and lime sulphur are two fungicides commonly used).There are plenty of peach-trees here because the climate is more suitable than in more northern areas. It is advised to apply it shortly before bud break, and a couple of weeks later since it's essentially a preventive treatment. Once the symptoms have appeared, the disease is hard to control. I had one that was about 2 meter tall, it died because of the disease, but not only. But I got kilos of "pêches de vigne" (1) and many of those I couldn't eat or give were put in the compost bin, and many germinated. And of course, since it's a fungus, try to get rid or burn as many leaves or contaminated fruit as possible. (1) "Pêches de vigne" : small peaches with a white flesh and red around the bone. Delicious, so much tastier than the big ones one can buy in supermarkets...
Well, this looked so common to me that I was sure that it only affected peach-trees that you make me doubt. But the slender lanceolate leaves on your photos made me think thee tree was a peach tree (Prunus persica). Plum fruit have smooth stones, while the stones of peaches haves stones with holes in them. What we call here "Plum" (Prunus domestica) have smooth bones like apricot (Prunus armeniaca). Post a photo of the bone of a fruit, it will help determine the species, hence the diagnosis for the leaf curl.
@AlainK Ah! Im quite sure its a Prunus cerasifera , and not a Prunus domestica. We call both plum here, but Prunus cerasifera we call "cherry plum" :) . I should have written that from the start.
It looks exactly like this plum is not able to obtain enough nutrients from the soil. If not root problems, then maybe drought is the cause?
@Sulev Might be as you say! Will check next time i'm there. Although, the dark spots on the leaves look like some kind of fungi I think
My neighbor has a yellow plum (grafted on Prunus cerasifera) growing close to our property border. It has root system partially in our garden territory and last year it grew a vigorous sucker there. As I know how readily P. cerasifera gives coppice shoots from injured roots, so I left it to grow, to prevent rapid spreading of shoots until I have to dig the ground for beds (this part of our garden has been uncultivated for several years, after being over exploited for decades). This June the shoot was already more than 1.5 m high, when suddenly similar symptoms appeared. A few weeks later, on a windy day, this sucker fell over - voles had completely chewed through the stem 20 cm below ground, despite having ca 4 cm diameter. It had similar yellow curling leaves with brown spots. My plums have similar spots, when they drop leaves in the Fall.
Another possibility is Asterula beijerinckii aka Clasteros carpophilum. But it is not very likely - from your photos it seems, that symptoms are stronger with plums that have more fruits on, Fruit bearing puts some additional strain on trees, so any unfavorable soil conditions could appear stronger on those trees.
The leaf damage looks like Coryneum Blight, which I see frequently in some varieties of plum that I grow; however, the fruit damage looks more like Brown Rot or something similar, not Coryneum Blight.
