What are the specific symptoms and conditions that make apple trees prone to silver leaf disease?

Everyone has eaten apples. But when growing apples, the trees are very easily afflicted by a disease. That is——silver leaf disease. So what are the symptoms of apple silver leaf disease? Under what conditions are apple trees prone to silver leaf disease? Let's take a look together below~

1. Under what conditions are apple trees prone to silver leaf disease?

Answer: Spring and autumn seasons

Spring

1. In spring, apple trees are most susceptible to the disease because the tree body is rich in carbohydrates at this time. After pruning, take care to protect the wounds and do not leave the xylem exposed; otherwise, when rain brings spores, this is the most likely trigger of the disease.

2. In orchards prone to drought in early spring, large wounds after pruning, after months of wind, sun and rain, will develop many kinds of saprophytic miscellaneous fungi on the surface. These miscellaneous fungi interfere with infection by the silver leaf pathogen, so orchards in these early-spring drought areas have no silver leaf disease.

3. In April to May, in areas with heavy precipitation and relatively humid air conditions, such as the old course of the Yellow River and the Jianghuai basin, the pathogen can take the opportunity to invade tree wounds that are suitable for silver leaf pathogen infection and have not been given protective treatment.

Spring and autumn

In spring and autumn, frequent rain and high humidity in the outdoor environment are the main conditions allowing the disease to prevail. When the temperature rises back to around 13°C, if there are also 2 consecutive days of rain, new primary infection source fruiting bodies will appear. In apple orchards in the Jiangsu and Henan areas, fruiting bodies first appear from early April to late June, with slight differences in timing depending on rainfall. The basidiospores released by the fruiting bodies are carried by air currents and eventually land on apple tree wounds; the spores take advantage of the moist environment to rapidly invade apple tree branches and spread up and down along the conductive system. About 90 days after the pathogen invades, the apple tree begins to develop the disease. The newly formed secondary pathogen fruiting bodies appear from September to November, which leads to another round of infection.

2. Symptoms of apple silver leaf disease

Disease onset in summer

1. If one day you find that the leaves of an apple tree have turned somewhat grayish-white, or already show that silvery-white leaf color, then your apple tree has already contracted silver leaf disease

2. The symptoms of silver leaf disease, when discovered early, are a grayish-white color. When discovered late, the color is silvery-white. When the temperature rises and the weather is hot, the diseased leaves also show brown spots.

3. The morphology is smaller than normal leaves, and they lack toughness, are rather brittle, and are lighter in color, somewhat like the look of chlorophyll.

4. In apple trees corroded by silver leaf disease, the dry branches turn light brown, and as the disease develops, the color of the diseased areas deepens little by little, and the tissue becomes drier and drier. It smells somewhat fishy, and when slowly rubbed by hand, the leaf epidermis separates very easily.

Disease onset in autumn

1. After the beginning of autumn, the symptoms of silver leaf disease become more and more obvious. Parts of the epidermis of diseased branches and leaves crack, and the mesophyll disease spots exposed after cracking appear brown. Their shape is mostly elongated and irregular. In the end, the mesophyll disease spots rupture and perforate.

2. At first the symptoms appear only on one or two branches, then spread to other branches. Dissecting an initially infected branch shows that the xylem at the base has already become brown streaks; in severely affected diseased branches, the roots decay, and the tree dies after about two years.

3. Under rainy, continuously overcast conditions, wood branches decayed by the disease grow something resembling wood ear fungus, purple-brown in color, overlapping in several layers, quite attractive, turning gray after drying, with horizontal lines on the back.

Alright, that is all for today on the symptoms of apple silver leaf disease. Friends who like it are welcome to forward, comment and share, and for more information welcome to follow Tuliu.com. See you next time, bye-bye