Small leaf spot in stone treesis the most common and dangerous disease of cherries. Its culprit is the mushroom Blumeriella jaapi. The disease often causes cherries to shed their leaves prematurely, even before the fruit is harvested. This phenomenon is particularly visible in sensitive cultivars, e.g. Łutówka. Seehow to combat small blotches of stone treeswhich preparations are recommended against this disease and when to spray to work effectively.
Fine leaf spot on stone trees
Small leaf spot on stone trees - symptoms
A fine leaf spot on stone trees attacks plants at the turn of April and May , that is just after flowering. Infection is favored by rainy weather.
The symptoms of small leaf spot on stone treesbegin to be visible from the end of May and are first noticeable on the lowest branches. Small spots appear on the periphery of the leaves, which gradually begin to cover the entire surface of the leaf blade. At first they are gray-green and then red-brown.
On the underside of the leaves, at the spots of , small elevations are formed, in which the spores of the fungus are located. In wet weather, whitish, slimy aggregates of spores ooze from these places. They are the source of secondary infections and the cause of exacerbation of the disease. In the place of the spots, the leaf tissue dies, forming the so-called necroses that merge into large clusters. Eventuallyleaves turn yellow, redden and fall off Fruits on infected trees are small and do not ripen.
Fine blotch of stone tree leaves - upper side of the leaf
Fig. Erazm, forum.PoradnikOgrodniczy.pl
Fine leaf spot of stone trees - the lower side of the leaf
Fig. Erazm, forum.PoradnikOgrodniczy.pl
Fine leaf spot on stone trees - combating
Fighting fine leaf spot on stone treesis quite easy as Blumeriella jaapi is sensitive to chemical protection agents.The trees should be sprayed in mid-MayThe treatment should be repeated 2-3 times at intervals of 10-14 days, especially if the weather is rainy. In addition to chemical protection,the fight against fine leaf spot in stone trees is primarily prophylaxisThe fungus hibernates in fallen leaves, therefore, in order to reduce the primary source of infection, fallen leaves should be raided and removed.
Fine leaf spot on stone trees - spraying
Against the fine spots of stone leaves, spray with Syllit 65 WPSpray should be preventive or when the first symptoms of the disease are noticed. Treatments are performed from the moment the first flowers open, to 2 weeks before harvesting the fruit (there is a grace period of 14 days) and up to 2 weeks after harvesting. The recommended dose is 12 g of Syllit dissolved in 5-15 l of water, which is enough for an area of 100 m2 of cultivation. For single trees, the dose is 1.5 g of the preparation dissolved in 1 liter of water. Treatments with Syllit 65 WP can be performed up to 4 times during the growing season.
Anotheragent for combating small leaf spot in stone treesfor use on plots is Topsin M 500 SC. We use the preparation preventively before flowering or from the beginning of April, until the fruit ripens, when the first symptoms of the disease appear.When performing treatments, remember to keep the grace period, which is 14 days. We use a dose of 15 ml of the agent in 5-7 l of water. This amount of agent is enough to spray 100m² of trees.
Note!Spray Topsin M 500 SC against the fine spots of stone leaves only once a season.
Anothereffective spraying against fine leaf spot in stone treesto Carpene 65 WP. This preparation is recommended for large cherry and sweet cherries cultivations. We use it preventively or when we observe symptoms of the disease. The first spraying with Carpene 65 WP is performed immediately after flowering. In years with a lot of rainfall, we repeat spraying 2-3 times at intervals of 10-14 days. The treatment can be performed no later than 1 month after flowering. The recommended dose is 1.5 kg of the agent in 700l per 1 ha of cultivation - proportionally for smaller crops, the dose is: 15 g in 7l of water per 100m² of cultivation.During the fall of leaves from trees, it is also worth spraying cherry fruit trees in autumn 5% urea solution.The entire crown of the tree and the leaves that have already fallen under the tree are sprayed thoroughly. Spraying fruit trees with urea reduces the number of fungus spores that can survive on the leaves until spring. This reduces the risk of a tree reinfestation in the spring. In the same way, urea is also sprayed on apple and pear trees against scab.
MSc Eng. Agnieszka Lach
