Potato diseases

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Viral diseases belong to the group of infectious diseases, such as sucking insects (lice, thrips, cicadas, caterpillars) or mechanical damage during cultivation, cutting of stems and other cases, ie infected plant cell sap is transferred to a healthy plant. 'occurs as a result of tooth decay. For subsequent reproductions, the viruses pass through the seed pods. When plants are infected with viruses, their appearance (morphology) changes, that is, the leaves become twisted, wrinkled, yellow, wither, die, the ends become smaller, the shape o 'zgaradi and b. Viral diseases can also go unnoticed, but this does not reduce their contagion and harm

Ktwisting of artichoke leaves

Twisting of potato leaves The disease is the M-virus of potatoes (Solanum virus 14) excites. The virus is round in shape, around 25 nm in diameter. The cryptogram of the species belonging to this group of viruses is R / 1; 2 / *; S / S; S / Ap. Among potato viruses, this disease is the most common and most harmful in the world, and due to it, 90 percent of the crop is lost. In the first year, the leaves of the affected plants are pale yellow, in some varieties slightly purple, pink or reddish, often the edges are tubular and bent upwards. At the end of the season, the plants can be damaged without any external signs. Necrosis of conductive tissues is observed in the ends of very resistant varieties.

In the second year of damaged (grown from diseased tubers) potatoes tuberosum The lower leaves of the subspecies are bent upwards from the central root, become tubular and small, whiten, lose elasticity, become skin-like, the underside of the leaves becomes reddish. Potatoes andigena Chlorosis develops in the edges and veins of the leaves of young plants, the leaves become very small. Myzodes persicae) and spread with damaged ends. Plants belonging to the family of alfalfa, sedges, and some others are affected (Vlasov, Larina, 1982; Peresypkin, 1982; Int. Potato Center, 1982). Under natural conditions, Mvirusi or leaf mosaic torsion disease is transmitted by lice or diseased plants and reduces yields by 25-35%.

Potato U-virus

Potato U-virus potato U-virus (Solanum virus 2) excites. The shape of this group of viruses is elongated, length 750 nm, cryptogram R / 1; 3,5 / 5; Ye / Ye; S / Ap. In terms of damage, U-virus ranks second after leaf twisting, causing up to 80 percent crop loss. Symptoms of the disease are associated with crop varieties and the virus strains that infect them, as well as weather conditions and are very variable: leaf fragility, the appearance of rosettes, the edges bend down, the development of necrosis on them, the decline in plant height , necrotic dark-brown streaks and bands may form on rods and stems; in some varieties a light mosaic develops or the plant is damaged without external signs.

The disease is spread through the nodules as well as, if unstable, with syrups. U-virus is widespread in Uzbekistan and has a significant negative impact on potato seed production. In the experience of the staff of the Samarkand Agricultural Institute, in connection with the variety, the latent form of U-virus reduced the yield of seed potatoes by 13,6-24,0% (Ergashev et al., 2005).

A simple mosaic of potatoes

A simple mosaic of potatoes Hvirusi of potatoes (Solanum virus 1) excites. Virions are fibrous, 515 × 13 nm, inactivation temperature 68… 75 ° C, stable (stored up to 250 days in dry leaves), final dilution 1: 1000000, vitro The case is stored for several weeks. Cryptogram R / 1; 2,2 / 6; Ye / Ye; S / 6. Depending on the potato variety and the virus strain that infects it, the disease can reduce yields by up to 10%. The disease is spread in the field mechanically (by contact) and with infected shoots, not transmitted by aphids. Usually, a mosaic develops on the leaves, some varieties are rarely or damaged without external signs. Virulent strains of the virus cause leaf wrinkles.

Wrinkling of leaves.

Wrinkling of leaves. The disease is caused by the L virus. In this case, the lower leaves of the plant are wrapped around the middle root, resembling a spoon or a tube. Usually this condition starts from the lower leaves. As a result of the leaves being filled with starch, they become hard and brittle. Under natural conditions, the L virus spreads only through lice, not through mechanical damage. But in the end, the viruses are stored. Productivity is lost from 30 to 80%, depending on the degree of occurrence of the patient, and starch from 2 to 5%.

Potato other viral and mycoplasma diseases.

S-mosaic potato virus 3 (Solanum virus 7) (R / 1; * / 6; Ye / Ye; S / Ap). Its effect on yield is small. Mechanical contact, through the ends, some strains spread with aphids, causing a slight mosaic on the leaves, or they are damaged without external signs. Potato X, S, M, U and A viruses often co-occur in the soil.

Potato curls

Potato curls (Solanum virus 7), inside the ends arched rust stains (Tobacco rattle virus) (R / 1; 2,3 / 5 + 0,6- 1,3; Ye / Ye; S / Ne) occurrence and aukuba mosaic (Fvirus, Solanum virus 8) (R / 1; 2,2 / 6; Ye / Ye; S / O) are viral diseases, jaundice mycoplasma of yellow disease of astra (Aster yellows) excites. Except for jaundice, these diseases are carriers of mycoplasma microorganisms that have not been reported in Uzbekistan. Symptoms of the initial onset of the disease are the shrinkage of the upper leaves, chlorosis at the edges of the fragments, discoloration of the leaves, slowly the roots begin to dry out. Sometimes the lateral branches grow and form air bubbles in the stem, and after 7–10 days the diseased plants begin to dry out. Stolbur withering or the formation of thin, fibrous tumors at the ends reduces the yield by 70-80%. The plant that sprouts from the end of the fibrous growth is called kudryash.

The main symptom of the disease is an increase in the number of stems (10–15 and more), thin, the plant is short, the leaf shape is changed. The higher the current slopes, the lower the number of slopes. The plant does not bloom and forms small tufts. In addition to stolbur wilting, viral diseases such as gonorrhea, gout, and leaf wrinkles can cause potato blight.

Potato yellow (southern stolbur) disease

Potato yellow (southern stolbur) disease mycoplasma (Aster yellows). This disease is probably born in some countries of the world under the name of astra yellow fever. The height of the diseased plants decreases, the leaves at the top are twisted, take on a tubular shape, turn yellow or reddish. Plants may wither. When the tubers obtained from diseased plants are planted, they grow abnormal, small, ugly, fibrous seedlings, the roots do not appear, usually have little effect on yield. It is spread in the field through nodules and cancers (Peresypkin, 1982; Int. Potato Center, 1982).

Alvasti (jin) broom.

 Alvasti (jin) broom. Similar to Stolbur, but in this case the plant ceases to grow, the stem strongly branches and forms a large number of stolons. In diseased plants, many small, fast-growing nodules are formed. Its causative agent is the mycoplasma, which multiplies through the nodules.

Gotika

Gothic. The causative agent of this disease is a viroid, i.e. a protein-free virus. Diseased plants become shorter, the number of stems in the bush decreases, and the lower side branches begin to grow strongly. The horns and leaves grow at an acute angle to the stem and appear to cling. This gives the plant a unique - gothic shape. Gothic flowering is observed in the attenuation and shortening of the leaf blade. The end of the diseased plant is crushed and takes the form of an elongated or ovate, obtuse. Its folds are many and cracked. The disease is most common in medium and late varieties of potatoes, and is transmitted by insects from infected parts through the tubers. The yield of diseased tubers is reduced by 20–70%, and the quality of the tubers deteriorates significantly.