| From 1999 to 2002,based on the improvement of former coating material which contained mainly polyethylene alcohol,bio-determination of seed coating( imidacloprid acting as main ingredients of seed coating ) on rice ( Oryza sativa ) was studied in the experiments indoors and outdoors. Effect of seed coating on germinating energy,germination percentage,field emergence rate,seedling stand percent,seedling vigor,biocommunity in field,control effect on insects at seedling stage and harvest yield were studied and analyzed systematically. The main results as follows:1. The dissolution and dropping of imidacloprid ( active ingredients on insects of seedling stage ) on the surface of rice seed coating which contain different dosage formalin was studied. When the dosage of formalin from 3.0ml to 7.0ml,the dissolution and dropping percentage of imidacloprid became more and more smaller. However,when exceed the dosage of 5.0ml,the dissolution and dropping percentage of imidacloprid became much more than that of the former. Among all of coating materials,the effect of M-F4 coating material was the best,the dissolution and dropping percentage of imidacloprid was merely 9.94% after soaking 72h.The result of moisture uptake test indicated that M-F4 coating materials (containing 4.5ml formalin ) didn't affect rice seeds moisture uptake,sprout normally and germination. The characteristic made M-F4 coating material appropriate for seed coating of rice in soaking region.2. The feasibility of Bl,a new insecticide,acting as main ingredient of seed coating was primarily studied in 1999. The result showed that A-B1 seedcoating had no by-side effects on the seed vigor and the quality of rice seedlings. On the contrary,it could enhance seed vigor,accelerate the speed of rice seed germination,elevate the rate of rice seeding and build up the quality of rice seedlings.According to analyzing,the rate of rice seed germination of seed treatment with A-B1 seed-coating,seed-coating type one,seed-coating type two and water (CK) were 95.00%,91.67%,90.33% and 94.67% respectively;the rate of rice seeding were 58.67%,51.47%,57.33% and 57.00% respectively. The result also demonstrated that the synthetic control effect of A-B 1 seed coating was 91.84% on the major rice insects during the rice seeding. In addition,it had a good effect on rice yield,harvest yield was increased by 20.55% compared with that of the CK treatment.3.The influence of A-B2 seed coating,consisted of several active ingredients,applied as a coating material for rice seeds was studied in 2000,both in laboratory and in the field. The result of laboratory experiments showed that A-B2 seed coating had most significant inhibition on Fusarium moniliforme,and its co-toxicity coefficient(CTC) to Fusarium moniliforme was 223.36. A-B2 seed coating didn't influence the moisture absorption and sprout of rice seeds. The seeds coated with A-B2 seed coating showed higher germinating energy (93.83%) and germination percentage (95.17) than any other seeds.Comparison with the check from field test,the seedling emergence rate was increased by 1.75% and the seedling stand percent was increased by 4.83%. A-B2 seed coating could effectively build up the quality of rice seedlings. The result of field experiments also demonstrated that the A-B2 seed coating possessed the best control effect on Stenchaetothrips biformis (Bagnall) with 50.05%-84.63% among all of the treatments and long persistent to control the pests,and that it's harvestyield was increased by 26.47% compared with that of the CK treatment.4. The bio-determination result of A-B3 seed coating in laboratory indicated that A-B3 seed coating's co-toxicity coefficient(CTC) to Fusarium moniliforme was 119.7,and it had most significant inhibition on Fusarium moniliforme.The average germinating energy of rice seeds (coated with A-B3 seed coating) was 92.83%,and the experimental check treated by water was 92.17%;germination percentage with seed dressing by A-B3 seed coating was for 96.50% and check treated b...
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