Successfully fighting currant diseases in the garden can be, if you learn to distinguish between their signs, otherwise all your efforts will be in vain, and the harvest will be lost. For correct diagnosis you need to know the main symptoms of the most common diseases.
Sometimes on the leaves and berries of the currant can be seen a whole "bunch" of spots of different colors and shapes. Which of them are indications that the plant lacks nutrients, and which ones are a sign of a serious disease? Is it possible to recognize the disease at an early stage and cure it? Let's find out.
If you notice dark brown spots on currant leaves, which gradually merge, and the leaves turn yellow and fall prematurely - this anthracnose (Pseudopeziza Ribis Kleb.).
Infection may occur at any time during the entire vegetation period. The main damage from it - abundant abscission of leaves, which can begin at the end of July. This will lead to crop loss next year. Spots can also occur on young shoots, leaf stalks, stems and berries.
If carrot-colored pads appeared on the underside of currant leaves, filled with a mass of spores in the form of bristles, and on top of the leaves, opposite these formations, red spots appeared - this indicates columnar rust currants (Cronartium ribicola Ribes). Later, all the leaves on the back side are almost completely covered with an orange "brush" spore and begin to fall prematurely, and the shoots dry out and look underdeveloped.
Measures to combat columnar rust:
If you notice small brown tubercles surrounded by a yellow border on the upper side of the currant leaves, it means that the currant is sick leaf rust (Puccinia ribesii caricis). Over time, in place of the pads there are columns of yellow and red. Gradually the entire sheet is covered with fluffy rust.
Measures to combat leaf rust:
If on the leaves or sprouts of a currant or gooseberry you have found medium-sized roundish pale grayish spots with a dark brown border, and on them are black, randomly scattered dots (pycnidia), know that askokhitoz (Ascochyta). Over time, the affected areas of the leaves dry up, crack and fall out.
Measures to combat ascohitosis:
If a white mealy bloom appeared on the leaves of the currant, which eventually becomes rusty in color, know that powdery mildew (Erysiphaceae). The disease can occur during the entire growing season. Often the edges of the leaves turn brown and black. Severe infection slows the growth of shoots and adversely affects the yield of the next year.
Powdery mildew control measures:
If you notice that the currant leaves are small and dark green, and consist of 3 blades - this is double leaves or reversion (Ribes virus) currants. The veins of the leaves grow coarser, and sometimes chlorosis appears on young leaves, which subsequently disappears. Calyx, corolla, stamens of a flower look like petals of violet color. In this case, the berries are formed ugly or not tied at all, the bushes become abnormally thickened with signs of growth (like witch panicles).
Measures to combat terry:
If you find rounded diffuse pale yellow spots with a light green center on the leaves of red currant, located between large veins, and you see that the leaf plate is growing unevenly - it means the plant is affected mosaic (Mosaica). Over time, the spots merge, the sheet turns completely yellow, the affected tissue between the veins becomes white and dries.
Mosaic control measures:
If the leaves cover small, up to 2-3 mm in diameter, spots of angular shape, first brown, then white with a brown border - this indicates septoria, or white spot (Septoria), currant leaves.
Measures to combat septoria infection:
As you can see, your concern about the variegated color of the leaves of the currant, most likely, justified. There are several dozen varieties of currants in the list of diseases; therefore, it is especially important to detect signs of infection in the early stages in order to start treatment in a timely manner.