| Rice is the main food crop grown in Sichuan and Chongqing,and is planted in single-season medium rice.Except for the Chengdu Plain,all of them are mainly mountainous paddy fields,whose topography and climate are extremely complex,and the occurrence of rice pests and diseases is more harmful,and the loss of fertilizer from paddy fields is more common.Dry breeding(seedlings),direct seeding,no-till,machine planted rice and other labor-saving,cost-saving and efficient light cultivation techniques in Sichuan and Chongqing rice area to promote the application of a large area,the main pests and diseases of rice occurred in a large change in the law,some of the pests and diseases have a tendency to aggravate the occurrence.Chilo suppressalis(Walker),Sogatella furcifera(Horvath),Nilaparvata lugens,Cnaphalocrocis medinalis,rice blight,Thanatcphorus cucumcris(Frank)Donk,and rice blast pyricutaria oryzae Cav,etc.had expanded areas and higher outbreak frequencies.The irrational and even abusive application of pesticides and fertilizers has led to increased resistance of rice pests and weeds and deterioration of paddy ecological environment,which seriously threaten the safety of rice production.Based on the principle of insect population ecology and pest prediction,this study systematically investigated the population changes of rice pests corresponding to the change of rice cultivation methods,and used light trapping,field survey,biological characteristics research and large field trial demonstration to explore the effective way of pesticide and chemical fertilizer reduction in rice,in order to further optimize the integrated management of pesticide and chemical fertilizer reduction in rice pests and weeds and to provide reference for the comprehensive management of pesticide and chemical fertilizer reduction in Sichuan and Chongqing rice areas.The results are as follows The main results are as follows.1.The effect of the change of planting method on the number of overwintering generation stem borers in Sichuan and Chongqing rice areas was clarifiedWe analyzed the changes in rice transplanting methods,rice cultivation patterns and the number of overwintering and post-winter generation and generation II occurrence of the borer in five key reporting districts and counties in Sichuan Province during 2010-2019.On this basis,we analyzed the effects of different rice cultivation patterns on stem borer population numbers in 15 districts and counties in Sichuan and Chongqing rice areas in 2019 in combination with the occurrence of stem borers in different no-till type fields and stem borer population composition.The results showed that the area of traditional hand-planted rice in each district and county of Sichuan rice area decreased year by year,the area of machine-planted rice increased year by year,and the area of rice-fishery and rice-duck stereoculture rice fields increased year by year.The overwintering population of stem borer and the population of stem borer of the first and second generation are related to the increase of rice transplanting method and the area of rice field cultivation(duck and fishery)year by year.In the traditional hand-planted rice fields with the same area all year round,the pre-winter,post-winter,first-and second-generation stem borer insects increased year by year,while in the rice areas where the area of machine transplanted rice fields and paddy cultivation(ducks and fishery)increased year by year,the pre-winter,post-winter,first-and second-generation stem borer insects showed a stable or decreasing trend,and the insects decreased year by year.Sichuan rice area as a whole has more overwintering numbers of second-generation stem borers than Chongqing rice area.Rice stem borer overwintering is dominated by second-generation stem borers,accounting for 88.36%,greater stem borers 10.14%,and third-generation stem borers 1.40%;several no-till + rice straw return type fields have overwintering numbers of second-generation stem borers respectively: direct seeding field >traditional seeding and harvesting > winter planting and harvesting > mechanical seeding and harvesting > rice and fishery > rice and duck,and characteristic type fields "regenerated rice >winter planting squash".The change of rice transplanting method and the increase of paddy cultivation area have a synergistic effect on the decrease of the overwintering quantity of the borer,and there is a positive feedback effect on the increase of the borer quantity.The overwintering quantity of the borer differs in different no-till type fields,and the amount of the overwintering quantity of the borer is relatively small in the no-till type fields of rice mechanical planting and harvesting and rice fishing(duck)co-culture.2.The occurrence patterns and biological habits of major pests and diseases in the rice area of Chongqing were clarifiedThe results of the 2018-2019 under-light insect trap and field system survey indicate that the main pests of Chongqing rice area,white-backed louse,brown louse and longitudinal leaf borer,were all seen under the lights in Xiushan County in 2018-2019 in mid to late April,with an average annual migration peak of 2-3 times.White-backed louse and brown louse in late April under the lights have scattered insect sources gradually move in,late May-late July continued to move into Chongqing rice area.The rice leaf roller continued to migrate in late June-early August,but the peak of migration was 7-10 d earlier in 2019 than in 2018;the outbreak of whitebacked louse was in early and late June,early and late July,respectively.2108 was 20 d later for whitebacked louse and13 d later for brown louse than the peak under lights in 2019,and the sustained peak of whitebacked louse was 20 d shorter in the field system survey,and the sustained peak of brown louse The peak period is basically the same,but the overall trend of high outbreak of brown fly in 2018.The timing of under-light trapping and field moth catching for the rice leaf roller was basically the same,with the onset of under-light trapping 22 d later in 2018 than in 2019,and the duration of under-light trapping shortened by 15 d.The timing of under-light trapping for the borer was basically the same in both years,but was still early in 2019.The outbreak of insects was related to migration,reproduction and climatic factors;the accumulation of rain from April to July in Chongqing was the key factor leading to the outbreak of insects in late July.the cumulative rain period and rainfall from April to July were the main reasons for the overall early and high source of rice leaf roller and white-backed fly in 2019 compared with 2018.the number of rainy days from April to July in 2018 was 9 days less than that in 2019.3.Propose the light and heavy occurrence zones of rice pests in the rice area of Chongqing with the boundary of the "two migratory pest" channelThe diversity of topography and landscape in Chongqing area leads to a large variation in the occurrence of pests and diseases.Xiushan,Fuling,Nanchuan and other districts and counties in the southeast and south Chongqing rice areas are in the "Wuling Mountain Passage" and "Dalou Mountain Passage" where rice leaf borer and white-backed louse and other "two migrating pests"migrate into the Chongqing rice area,respectively."The degree of occurrence and damage of rice pests and diseases is heavy year-round.Other districts and counties in Chongqing rice area have lighter perennial occurrence and damage of rice pests and diseases.According to the field occurrence,it is proposed that Xiushan,Nanchuan,Fuling and other south and southeast of Chongqing are heavy pest and disease occurrence areas,and Jiangjin,Wanzhou,Kaizhou and other west and northeast of Chongqing are light pest and disease occurrence areas.4.Formed the integrated pesticide and fertilizer reduction and control technology program in Chongqing rice areaThrough two years of integrated paddy pest control technology program,it is clear that the control program of "rice duck(biopesticide)weeding + seedling application + biopesticide +auxiliary radical health + high efficiency,low toxicity and low residual compound pesticide + 4times of integrated control rule" in Chongqing rice pest heavy occurrence area;Chongqing rice pest light occurrence area with borer sex attractant + golden turtles green In the lightly infested rice areas of Chongqing,the control program is based on the combination of borer sex attractant,green fungus CQMa421,1-2 times of integrated prevention and control,and biochemical pesticide.The integrated technology model of "seed,fertilizer,medicine,machine and technology" is a combination of technology and material.5.The effect of the comprehensive experiment of reducing fertilizer and pesticide on the occurrence and yield of rice diseases and insect pests.The results of the core experimental areas for fertilizer and pesticide reduction and efficiency improvement show that in 2019,the pesticide reduction in the six pest control districts and counties of Xiushan,Fuling,Nanchuan,Jiangjin,Wanzhou,and Kaizhou is 8%-53.08%;the main rice pests and diseases control effect is 90% Above,the income per mu has increased by RMB 5.78-158.18.In2020,there will be 8 core demonstration districts and counties for pesticides and fertilizers in Xiushan County,Nanchuan District,Qijiang District,Jiangjin District,Wanzhou District,Hechuan District,Dianjiang County,and Fuling District,with pesticide reduction of 31.99%-80.37% and fertilizer reduction of 14.29%-In 52.39% of cases,rice yield increased by 7.37%-19.39%.Fertilizer reduction can control the occurrence of diseases and insect pests to a certain extent,and the effect of application methods on the occurrence of diseases and insect pests is better than that of fertilization methods.Reduced fertilization application has obvious effect on the control of diseases and insect pests in severely-occurring areas,but not obvious in light-occurring areas.The fertilizer core experimental area has achieved good economic and ecological benefits by increasing production without increasing fertilizer,losing weight without reducing production,green prevention and control of rice diseases and insects and reducing the amount of pesticides. |
