How to diagnose plant virus diseases based on symptom characteristics

Symptoms of 4 peanut virus diseases.

The symptoms of viral disease are easy to identify. Often.

Self-dwarf plant bai or atrophy, diseased plant du terminal bud inhibited, lateral.

A large number of buds sprouted, and the branches were clustered and grew deformed. Leaves, flowers, fruits change color. The leaves are mostly dark green and light green mosaic flowers, or there are faded green spots on the diseased leaves, the spots are large, the edges are not obvious, and the distribution is uneven.

The whole plant or part of the organ is light green or yellow, or it is manifested as necrotic spots, necrotic streaks, green spots, green streaks, etc., or the growth of leaf veins is inhibited, the mesophyll still grows, the leaves become wrinkled, and the leaf margins roll up or down. The petals are broken and green. However, there is very little decay and wilting.

Onset is localized first, and symptoms appear later or earlier on the whole plant. Different viruses will have differences in different host species and varieties, and some viral diseases will appear hidden due to changes in temperature, etc.

Fungi: The asexual stage tends to produce a large number of asexual spores several times in a row during the growing season, which plays an important role in the spread of the disease.

Nematodes: In addition to directly causing damage and predation of nutrients, it is mainly the saliva secreted by nematodes when they puncture the host that contains many enzymes or toxins, causing various lesions.

Parasitic plants: The pathogenic effect on the host plant is mainly manifested in the competition for nutrients. In general, holoparasitic plants are more pathogenic than semi-parasitic plants.

In addition to competing for nutrients, some parasitic plants such as dodder can also act as a bridge to transmit viruses and phytoplasma from diseased plants to healthy plants. Some parasitic algae can cause algal spot or red rust in horticultural plants, which can affect the commodity value of fruits in addition to tree strength.

Plant viruses are non-cellular organisms with a very simple structure, mainly composed of nucleic acids and protective protein coats, and have a molecular weight of less than that.

3×103u。

The basic form of plant viruses is the chondria, and the granules of most plant viruses are globular, rod-shaped, linear and elastic. Cylviruses are common.

11—30nm×

750nm, individually achievable.

2000nm。

The main components of plant viruses are nucleic acids and proteins, and some viruses also contain small amounts of glycoproteins and lipids. Generally rod-shaped or linear plant viruses, medium.

Between is a helical nucleic acid strand and the outer part is a capsid composed of many protein subunits.

A plant virus is a strictly intracellular obligate parasite. As a molecular parasite, it has no cellular structure and does not have complex reproduction like fungi.

Organs, unlike bacteria, do not undergo fission growth, but synthesize nucleic acids and protein components separately and then assemble into daughter chondria. This particular mode of reproduction is called.

Replication proliferation.

Infested plants often exhibit the following symptoms: Discoloration. Due to the use of nutrients by viruses, or the necrosis of vascular bundles caused by viruses hinders the transport of nutrients, the chlorophyll formation of leaves is blocked or accumulated, resulting in mosaic leaves, spots, ring spots, veins and yellowingThe anthocyanins of the flowers can also be changed, so that the flower color becomes green or variegated, and the common symptoms are dark green and light green mosaic disease such as tobacco mosaic disease.

Necrosis. The allergic reaction of plants to viruses can cause cells and tissues to die, turning yellow to brown, and sometimes dimpling. Necrotic spots, necrotic rings and vein necrosis are often present on leaves, and necrotic strips often appear on the surface of stems, fruits and roots.

Malformation. Due to the disturbance of normal plant metabolism, the production of auxin and other hormones in the body and the normal growth and development of plants can lead to organ deformation, such as shortening of stems, dwarfing of plants, abnormal differentiation of growth points to form clumps or clusters, and local cell deformation of leaves to appear blistering, curling, fern leaves and yellowing.

The most superficial parietal lobe is the first to occur, qualitative, and almost stops growing. There are several scenarios.