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水稻瘤矮病主要为害晚季稻,尤以杂优稻受害特重,这与杂优稻秧苗田播种量和大田插植苗数较少有关。目前病区未有免疫或高抗品种。早季稻一般受害较轻,仅零星发病,但成为晚季稻的主要侵染源。晚季稻播种后从秧针期开始(播后4—5天)即受侵染。特别是在7月中旬早季稻收割时介体叶蝉被迫大量迁移,秧田的虫数激增,秧苗感染率也激增。愈靠近早稻病田的秧苗感染率愈高。早播早植比迟播迟植发病重。秧苗在6叶龄前最易感染发病,苗龄愈小受害愈重,9叶龄后感染的不发病,所以大田的发病率基本上就是秧苗期的感染率。防治本病主要抓晚稻秧田下述两项措施:(1)播植期适当推迟7—10天,即在7月中旬播种,8月上旬移植;(2)秧苗田从秧针期开始每4—5天喷药1次,共4—5次,如结合迟播则只需喷药2—3次。1983年的2,670亩防治试验和1984年病区全面推广防治结果,防效极为显著。1984年发病面积仅3.36万亩,为1982年发病面积50万亩的6.7%;发病率在0.5%以下,(1982年一般发病率为20—30%,严重的达98%)基本不造成为害,保产约2,500万公斤。
Rice dwarf disease mainly infects late season rice, especially special crop damage, which is related to the seeding rate of hybrid rice seedling and field planting seedlings less. At present, the ward is not immune or highly resistant. Early season rice generally suffered less damage, only sporadic disease, but became the main source of late rice. Late season rice sowing from the beginning after sowing (4-5 days after sowing) that is infested. In particular, during the early rice harvest in mid-July, the leafhoppers were forced to migrate in large numbers, the number of insects in the seedling fields surged and the infection rate of the seedlings increased sharply. The higher the infection rate of the seedlings closer to the early rice cropland. Early sowing and early sowing than late sowing later onset. Seedlings in the 6-leaf age before the most susceptible to infection, the younger the younger victims, the 9-leaf-age infection is not disease, so the incidence of the field is basically seedling infection rate. Prevention and treatment of the disease mainly in the late rice seedling two measures: (1) sowing period appropriate postponed 7-10 days, that is sown in mid July, early August transplant; (2) -5 days spraying 1, a total of 4-5 times, such as combined with late broadcast only spraying 2-3 times. The 2,670 mu of prevention and control test in 1983 and the comprehensive promotion of prevention and cure results in the ward in 1984 have achieved remarkable results. In 1984, the disease area was only 33,600 mu, which was 6.7% of the disease area of 500,000 mu in 1982; the incidence was below 0.5% (the general incidence was 20-30% in 1982 and 98% in severe cases) basically did not cause harm , About 25 million kilograms of production.