Since the beginning of the 21st century, with the diversification of farming systems, multiple cultivation methods, the complexity of species distribution, the diversification of farmland ecosystems, and the warming of winter climate, some rice growing areas in the south have been spreading rice black-streaked dwarf disease. The crops are single-season hybrid rice and hybrid late rice. The black-streaked dwarf virus that is currently endangered in our province is infected by the rice black-streaked dwarf virus and the Southern rice black-streaked dwarf virus. The former is a permanent transmission of poison by SBPH. However, it does not transmit the virus via eggs. The latter is based on "Smilax glabra + White-backed planthoppers, white-backed planthoppers". Seeds do not transmit poison.
The disease began to sporadically occur. With the accumulation of poisonous sources and the increase in the number of virus-borne mediators, it suddenly broke out. In general, the loss of yield from field crops ranges from 10% to 20%, and the loss from heavy crops is from 30% to 80%. Even severe crop failure will become a catastrophic disease of hybrid rice, posing a serious threat to rice production.
The common characteristics of the hybrid rice black streaked dwarf disease are: the diseased plants are obviously dwarfed, the number of branches is increased, the leaves are dark green, the leaves are stiff, and some new leaves appear twisted and shrunken. However, symptoms in the seedling stage, branching stage, and heading stage have their own characteristics. Due to the fact that their symptoms and prevalence are quite different from those in the early 1960s, they are often misdiagnosed as seed quality problems or herbicides. In fact, they are different.
Seedling symptoms: The diseased plant is dark green in color, and the heart leaves are drawn slowly. The leaves of the heart are short and stiff and the spacing between the leaves is shortened. The leaf sheath is wrapped in the lower leaf sheath and the plants are short and can not be eared. The symptoms caused by the herbicides are yellow; the symptoms caused by the plant growth regulators are twisted; hybrids caused by the impure nature of the hybrid rice are not generally seen in the seedling stage.
Symptoms during the phased period: the diseased plantings increase in clusters, the upper several leaves of the leaf pillows overlap, the heart leaf breaks down the leaf sheaths or spirals out from the lower leaf occipital opening, the leaves are short and stiff, and the tips of the leaves are slightly Distortion. Plants are short, the main stem and early pods are still capable of heading, but the heads are difficult to seed, or spikes, or spikes, which resemble dwarfism. However, in the disease-affected plants, their leaves were all leaf-shaped, their leaves were distorted and their margins were whitened. The hybrids with impure and impure flowers grew relatively normal, and the plants were generally short in shape.
Heading symptoms: The whole plant is dwarfed and clustered, and some can head, but the relative heading is late and small, half wrapped in the leaf sheath, and the flag leaf is short and stiff; vertical folds are visible at the base of the upper middle leaf; internodes and the lower part of the stem The section shows waxy white or dark brown bulging short swells; visible waxy bulges on the susceptible stalks. This is the most prominent symptom of the current black streak dwarf disease.
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