This disease is called curly top in English, which is very important in the world.Curly top disease in Iran was first reported in 1345 by the American entomologist Gibson from Marvdasht and Razzaq Fars regions. So far, this disease has been reported in most beet growing areas in Iran. The damage of this disease in Iran is sometimes estimated up to ninety percent. Has been.
In addition to beets, other crops such as tomatoes, eggplants, watermelons, cantaloupes, beans and a number of ornamental plants and weeds are affected by this disease. In total, more than 200 plant species from 42 families have been reported susceptible to the disease.
Symptoms:
In beets, diseased seedlings are often destroyed. In older plants, the leaves are folded or tubed parallel to the main vein, or the leaves stand upright. The veins on the underside of the leaf are swollen, and the leaves turn dark green and brittle. Sometimes sap-like droplets appear on the veins and petioles and after a while they harden in the air and turn brown. In the cross section of beet roots, concentric brown circles are observed, which are the result of necrosis of phloem tissues.
In tomatoes, the leaflets are tubed upwards, but their main veins are bent downwards. Tomato plants take on a wilted appearance. In some cases, the veins beneath the leaflets turn purple.
In cucumber plants, the distance between internodes on the stem is reduced. Also, infected plants do not produce crops.
cause of disease:
Curly top virus is a rod-shaped virus with a length of 150-200-200 and a diameter of 30-50 nm. It is impossible to transmit this virus by mechanical method and inoculation of infected plant sap. In Iran, the virus is known by the circulifer haematoceps and C. tenellus chains as carriers of the beet plant complexity virus.
The virus is persistent in the body of the insect. A prolonged feeding may infect the insect for the rest of its life. In general, the chain takes 14 to 21 hours to become infected and transmit the virus. The virus travels through the phloem vessels in the plant.
Control:
CTV is controlled by crop methods, vector control, and the use of resistant cultivars.
Also, providing suitable growth conditions for beet plants by providing appropriate fertilizers and timely irrigation are effective in reducing the disease. This operation leads to rapid growth of plants. Chains work better in open, sunny environments, often attacking sparse, less-growing fields.
To control the vector chains, the destruction of their wintering place, the use of various pesticides and biological control have not had a definite effect on the control of CTV. Disinfected with systemic toxins before implantation.
The best and most common way to control CTV is to use resistant cultivars.
