Occurrence Regularity and Comprehensive Prevention and Control Techniques of Sunflower Downy Mildew

This paper examines the occurrence regularity and comprehensive prevention and control techniques for sunflower downy mildew.It provides a detailed discussion of the pathogens,symptoms,and associated risks,as well as the transmission pathways,underlying causes,and prevention and control techniques related to sunflower downy mildew.The aim is to offer valuable references and technical guidance for the effective management of this disease.

Occurrence Regularity and Control Research of Apple Early Defoliation Disease in West Sichuan Plateau

[ Objective ] The research aimed to discuss the occurrence regularity of apple early defoliation disease and control effects of fungicides in west Sichuan plateau. [ Method ] Apple early defoliation disease in west Sichuan plateau was systematically investigated during 2009 and 2011, and the control effects of different fungicides during different spraying periods were studied. [ Result] The species of pathogen mainly was Marssonina ma/i （ P. Henn）, accounting for 32.5%, Phyl-losticta Pirina Sa accounted for 29.9%, and Alternaria mali Roberts accounted for 25.7%. The field fluctuation regularity was as follows ： the disease generally be- gan in the mid-May and ended in early and middle October with only one damage peak during the whole year, the fluctuation had positive correlation with rainfall （ R2 =0.891 8 ＊ ＊ ）. Control test showed that 40% flusilazole had the best control effect （86.5%）, which was best to apply after anthesis. [ Conclusion ] The paper provided theoretical basis for the effective control against apple early defoliation disease.

Study on the Occurrence and Epidemic Regularity and Region Division of Rice Blast in Nanchong City

With the aim to improve the level of monitoring and warning as well as the comprehensive control of rice blast disease, and to feasibly reduce the disease threat in Nanchong City, the methods of GPS and GIS, systematical monitoring and field survey, rice blast resistance identification, physiologic races of rice blast monitoring, and meteorological data analysis were performed to study the occurrence and epidemic region division, precise demarcation and occurrence and epidemic regularity of rice blast in Nanchong City. This study first completed the epidemic region division and precise demarcation; first clarified the initial affection（beginning period） locations, occurrence characteristics, epidemic trends and characteristics; explicated the existence of four epidemic peak periods of rice blast in the field, where the damage areas of first peak period played a decisive role during the blast epidemic years; in late May, the cumulative occurrence areas and annual occurrence areas presented higher positive correlation with the correlation coefficient of 0.817;and established a prediction model of occurrence areas per year based on the disease field rate at the end of boot stages and the diseased plant rate at dough stages. The results of investigation on the impact factors investigation of blast disease in Nanchong in recent years suggested that the internal causes were the decrease or loss of blast resistance of the rice cultivars, as well as the increase of physiological races with strong resistance to rice blast and the emergence of new virulent physiologic varieties; the external causes were suitable temperature, too much rainy, and sunlight shortage. Between 2010 and 2015, the short-term forecast accuracy for rice blast in Nanchong was up to 100%, and medium-and long-term forecast accuracy was also up to 98% and 95%, respectively, which increased by 5-15% than that before 1997, thereby making the control effect of rice blast in Nanchong increased by 15-30%.

Occurrence and Epidemic Regularity of Wheat Stripe Rust in Nanchong City of Sichuan Province

In order to realize monitoring and early warning and comprehensive management of wheat stripe rust and to reduce its occurrence in Nanchong City, the occurrence and epidemic regularity of wheat stripe rust in Nanchong was studied by system monitoring and general survey, resistance identification, physiological race monitoring and meteorological data analysis. The initial occurrence location and spreading pathway of Puccinia striiformis f. sp. tritici （Pst） were first verified; there were two infection peaks of wheat stripe rust in Nanchong and one to three epidemic peaks in fields, in which the occurrence area of the first epidemic peak played a pivotal role in disease prevalence in that year; the cumulative occurrence area in late January was positively correlated with annual occurrence area, with the correlation coefficient of 0.769 ; the prediction model for infected field rate, diseased plant rate and annual occurrence area was established. The internal reason for heavy occurrence and prevalence of wheat stripe rust in Nanchong was the decline or loss of wheat resistance against stripe rust, as well as the appearance of physiological races of Pst, which later became dominant races. Large fluctuation of temperature in warm winter and spring and more fog and dew days were external reasons responsible for prevalence of stripe rust. From 2002 to 2014 ,the accuracy rate of short-term prediction of wheat stripe rust reached 100%, while that of me- dium-term and long-term prediction reached over 98% and 95%, respectively, 5% -15% higher than that of the years before 1998.

Occurrence Regularity and Sexual Pheromone Trapping Effect of Spodoptera litura in Field in Central Guizhou

The Spodoptera litura occurrence quantity in Tianlong Town,Pingba County,Anshun City was dynamically monitored by an insect sex pheromone electronic measurement and forecast system in 2015 and 2016 and the trapped effect of S. litura was studied by the home-made S. litura sex pheromone traps in Baishiyan Town,Ziyun County and Tianlong Town,Pingba County in 2016 to accurately grasp the occurrence regularity of S. litura and apply insect sex pheromone for controlling S. litura in Central Guizhou tobacco-growing region. There are 5 generations of S. litura in a year in Central Guizhou region. The first generation of S.litura occurs from late April to middle May,the second from middle-to-late July to middle-to-late August,the third from early-to-middle August to the end of September,the fourth is in the end of October and the fifth in the end of November. S. litura emigrates or enters into the overwintering stage in December. S. litura is almost in active in the daytime during the peak occurrence period of S. litura adults. The first mating time of S. litura is at 17: 30 and its peak mating time is about 22: 00. The second mating time of S. litura is at 1: 00-5: 00 and its peak mating time is about 2: 30. The trapped S. litura quantity presents an obvious layer-belt distribution that the number in the outer ring is significantly higher than that in the middle ring,and the number in the middle ring is significantly higher than that in the inner ring. The number of trapped S. litura is higher around the outer ring of the testing field and at the draught position than in the low-lying land and inner flat ground.

Coupling mechanism of THM fields and SLG phases during the gas extraction process and its application in numerical analysis of gas occurrence regularity and effective extraction radius

The analysis of the coupling mechanism of thermal-hydraulic-mechanical(THM)fields,and solid-liquidgas(SLG)phases during gas extraction process is of profound significance to explore its numerical application in the gas occurrence regularity and its effective extraction radius.In this study,the Hudi coal mine in Qinshui basin is taken as the research area,the influencing factors of gas occurrence were analyzed,the differences in overburden load for gas pressure distribution and the factors influencing the effective extraction radius were further discussed by using the COMSOL software.The results show that the derivation of mathematical model in gas extraction shows that the process is a process the THM fields restrict each other,and the SLG phases influence each other.The longer the extraction time,the larger the influencing range of borehole,and the better the extraction effect.The larger the diameter of borehole,the larger the effective extraction radius,and the influence on gas extraction effect is smaller in the early stage and larger in the late stage.The borehole arrangement should be flexibly arranged according to the actual extraction situation.The higher the porosity,the higher the permeability,the better the gas extraction effect.The larger the overburden load of reservoir,the stronger the effective stress,which will result in the more severe the strain,and the closure of pore and fracture,which in turn will lead to the decrease of permeability and slow down the gas extraction.The relationship among extraction time,borehole diameter,negative pressure of gas extraction,permeability with effective extraction radius is exponential.This study has important theoretical and practical significance for clarifying and summarizing the gas occurrence regularity and its engineering practice.

Occurrence characteristics and enrichment regularity of indium in pyrite: A case study of Dachang tin ore-field

To reveal the occurrence state and enrichment regularity of the dispersed element indium in pyrite, the petrology,mineralogy, geochemistry, and mineral physics were researched detailedly. The results suggest that the structure of pyrite is mainlycomposed of massive structure, disseminated structure, vein structure, reticular structure, comb structure and so on. Generally, thepyrite coexists with sphalerite, marmatite, pyrrhotite, chalcopyrite, galena, and arsenopyrite. And the texture of pyrite primarilyconsists of the metasomatic texture, solid solution texture, idiomorphic?hypidiomorphic granular texture, and disseminated texture.The content of indium in pyrite ranges from 0.491×10?6 to 65.1×10?6 with an average value of 14.38×10?6. Yet, the indium content inthe Gaofeng deposit is higher than that in the Dafulou and Tongkeng deposit, showing a particularly significant supernormalenrichment. Besides, the cadmium content in pyrite is also higher than other dispersed elements, and similarly the abnormalenrichment of cadmium in the Gaofeng deposit is also very significant. An obvious positive correlation exists between In and Cd, orTl, but a negative correlation between In and Re. It is difficult to find out a positive or negative correlation between In and Ga. Theelement zinc is of great importance to the enrichment of indium, which can possibly facilitate to the migration and crystallization of dispersed element indium.

Occurrence Regularity and Green Prevention and Control Technology of Bradysia odoriphaga in Shandong Province

The occurrence regularity,damage characteristics and difficulties in prevention and control of Bradysia odoriphaga in Shandong Province were elaborated,and effective,economic,no residue,simple and feasible green prevention and control technology were put forward,in order to better guide the Chinese chive production.The study would also promote benign development of Chinese chive industry in Shandong Province.

Occurrence Regularity and Control of Thrips on Leek

[Objective] The paper was to clear the species and occurrence regularity of thrips severely occurred in leek field, and to study the main control methods. [Methods] The species of thrips on leek were identified in Sichuan Province, and the damage symptoms, occurrence regularity and control methods of thrips in leek field were studied. [Result] The morphological characteristic of thrips on leek was Frankliniella occidentalis(Pergande). ITS molecular identification results showed that the amplified fragment was 520 bp, which shared the similarity of 99.81% with the base se-quence of F. occidentalis. F. occidentalis concentrated at the height of 80 cm from the ground; in sunny days, the occurrence frequency of F. occidentalis was relatively high during 15:00 and 17:00; rainwater had obvious lethal effect on F. occidentalis, and the lethal rate was 29.30%. Field trial showed that 20% dinotefuran SG and 40% acetamiprid GR had good control effect against F. occidentalis. The control effect of 20% dinotefuran SG 1 500 times dilution was the best, up to 92.56%. [Conclusion] The results will provide effective technical support for large-scale control of thrips in leek field.

Preliminary Report on Species and Occurrence Regularity of Diseases,Pests and Weeds of Corn in Angola

[ Objective] The paper was to understand species of diseases, pests and weeds and their occurrence periods and dynamic changes of quantity during corn growing period in rainy and dry seasons in Angola. [ Method] Using systematic investigation method, the species and occurrence regularity of diseases, pests and weeds of corn in Pedras Negras farm （ Malanje）, Sanza Pombo farm （Uige） and Catete farm （Luanda） in the Mrican continent, the Republic of Angola, were studied in two dry seasons and a rainy season from 2011 to 2012. [ Result] The occurrence status of pests and diseases of corn during dry and rainy seasons were basically similar, and only individual diseases and pests had different incidence degrees. The corn varieties from the United States and Brazil had prominent advan- tages in resistance to diseases and barren. Due to different climate environments in dry and rainy seasons, the unearthed rate of weeds in fields was also different. Soil moisture had great impact on weed population and density. Soil layer depth greatly influenced unearthed speed and unearthed rate of weeds. [ Conclusion ] The study cleared species, occurrence period and harmful levels of pests, diseases and weeds of corn in three provinces of Angola.

Occurrence Regularity of Myzus persicae and Aphid- transmitted Virus Disease in Zhenyuan County of Guizhou

[ Objective] The paper provided a reference for establishment of effective prevention mechanism against aphids in Zhenyuan tobacco area. [ Melllod ] The initial population quantity of aphids in early spring, migration of winged aphids, occurrence regularity and damage status of Myzus persicae and aphid-transmit- ted virus （PVY ＋ CMV） were investigated in Zhenyuan County from 2014 to 2015 using 10-point checkerboard sampling method, yellow dish trapping method and 5-point sampling method. [ Result] The total amount of aphids in Brassica campestris was the largest among overwintering hosts, with an average of 18.44 speci- men/plant. The migration of winged aphids presented bimedal pattern; the population dynamics of wingless aphids presented unimodal pattern, and the occurrence peak was from May to June. [ Conclusion] Field control against M. persicae in tobacco fields should be conducted from mid May to early June.

Occurrence Regularity and Mating Rhythm of Overwintering Adults of Tessaratoma papillosa on Longan Tree

[ Objeodve ] The occurrence regularity and mating rhythm of overwintering adults of Tessaratoma papiUosa on longan tree were studied in the paper, so as to provide scientific reference for effective prevention and control against the pest. [Method] During the mating period of overwintering adults of T. papillosa, mating duration, occurrence regularity and mating rhythm of overwintefing adults within g8 h as well as their occurrence and mating status during April and June were observed. [Result] Mating duration of T. pap///osa adults for$ -9 h accounted for 18.2%, and duration for 10 -ll h and more than 13 h accounted for 54.5% and 27.3%, respectively. According to daily observation, the maximum adult quantity of T. papillosa adults appeared at 9：00 am, followed by 13：00 pm. There were two peaks （9：00 am and 15：00 pm） and troughs （6：00 am and 19：00 pro） for adult quantity of T. papiUosa and its mating pairs within 24 h as times changed. Mating pairs were positively correlated with observed adult quantity. Adult quantity and mating pairs increased since April 1, and reached the maximum value on April 6. Afterwards, they were gradually dropped down, and almost no adults of T. papiUosa were found after June 11. [Conclusion] The mating peak of T. papillosa adults was from April to May, and there were two mating peaks （9：00 am and 13：00 pm） and troughs （6：00 am and 19：00 pm） every day. Adults repeatedly mated and spawned, while mating usually lasted for 10 -11 h either during the daytime or at night.

Occurrence Regularity and Prediction Model of Underground Pest Adults in Hangzhou District of China

To improve forecasting and sustained control level of underground pests, trapping quantity of underground pests （black cutworm,mole cricket and scar-ab） by lamps and their field dynamics in Hangzhou district from 2005 to 2011 were investigated in the paper. The results showed that different pests had obvious differences in population dynamic. The black cutworm （Agrotis ypsilon） had several damage peaks （late May, late June and late July） and the moth amount in early period was relatively high. The mole cricket （ Gryllotalpa africana） had two damage peaks （late May to early July, early September to mid and late October）. The scarab （Anomala corpulenta） had one damage peak （late May to late June）. There were periodic changes in total quantity of underground pests among years, and the peak period appeared in the year of 2005, 2007 to 2009 and 2011, respectively. On this basis, temperature, humidity, rainfall and light were used as forecas- ting factors, using the method of stepwise regression, 19 factors with significant correlation were screened out and prediction models for occurrence quantity and oc- currence period of the three pests were established. By using accuracy degree judge model for verification, the score values of prediction model for occurrence quan-tity and occurrence period of the three underground pests were more than 58 and 70, which indicated that the historical coincident rate and prediction accuracy of estabhshed prediction models were good.

Occurrence Regularity and Prevention and Control Technology of Kiwifruit Root Rot

Kiwifruit root rot is an important root disease of kiwifruit, which has occurred increasingly in recent years. The disease leads to the death of whole kiwifruit plant under severe condition, and has become an important disease restricting kiwi fruit industry development. The characteris-tics, occurrence, etiology and symptoms of kiwifruit root rot were introduced in the paper, and the prevention and control technology against the dis-ease were put forward from the aspects of agriculture, biology and chemistry.

Occurrence Regularity and Ecological Control Technology of Diseases of Hedgerow Commonly Used in Greening in Five Cities of Southern Jiangsu

The disease types, symptom characteristics, pathogenesis and ecological control technology of hedgerow commonly used in landscape greening in Nanjing, Zhenjiang, Changzhou, Wuxi and Suzhou were systematically studied. The results showed that there were 10 kinds of common diseases of flowers and shrubs in landscape greening in five cities of southern Jiangsu. Among them, 8 were caused by deuteromycotina and 2 were caused by subphylum basidiomycetes. It was pointed out that the disease regularity was directly related to the pathogenic bacteria, temperature and humidity, microclimate and hedgerow growth. For the first time, the ecological control method of hedgerow disease which focused on ecological health maintenance was put forward.

Occurrence Regularity of Tobacco Cutworm Moth (Spodoptera Litura) in Low-Altitude Tobacco Cultivation Areas in Lincang

[ Objective ] The paper was to study the occurrence and damage regularity of tobacco cutworm moth （Spodoptera Litura Fabricius） in low-altitude area in Lincang city. [ Method] The adult sex attractant monitoring, field investigation of occurrence and damage, and observation of continuous generation development of natural populations were carried out in natural flue-cured tobacco fields. [ Result] In field growth period of flue-cured tobacco under low-altitude of 1 000 - 1300 m, tobacco cutworm moth occurred for 4 generations, the duration of each generation was about 33 d, and the main injurious generation was the third generation. [ Conclusion] The paper provided reference for comprehensive control of tobacco cutworm moth in the low altitude areas.

Occurrence Regularity and Control of Tobacco Mosaic Virus (TMV) in Wuxi Tobacco Area of China in 2011

On the basis of general situation and new characteristics of tobacco mosaic virus （TMV） in Wuxi tobacco area in 2011, the paper expounded the objec-tive reasons of TMV via systemic investigation, field experiment and date sorting. Meanwhile, combined with mcteorological conditions and results of systemic inves-tigation, the study especially analyzed meteorological conditions, outbreak and prevalence regularity of TMV and control efficacy of chemical reagents against TMV. The results showed that climatic conditions were the main conditions affecting TMV. There were three occurrence peaks of TMV in 2011, as a result of meteorologi-cal conditions of the months from April to June. The peaks were concerned with a wide range of rainfall about half a month before, low temperature, high humidity and scant sunshine and temperature jump after rain. The results of control effects showed that the chemical reagents could obviously prevent TMV, but once tobacco plants were infected, spraying chemical reagents would not have effective control effect against TMV.

Occurrence Regularity of Fruit Physiological Disease Spongy Tissue in Zihua Mango(Mangifera indica L.)

[ Objective ] The aim was to study the occurrence regularity of fruit physiological disease spongy tissue in Zihua mango （Mangifera indica L. ）. [ Meth. od] Main features of disease symptoms of Zihua mango fruit spongy tissue were investigated from 2002 to 2005 ,and the correlation between the incidence of Zihua mango fruit spongy tissue and its external factors （ fruit maturity, fruit size and fruit yield per plant） was analyzed comprehensively. [Result] The main features of disease symptoms appeared depressed cavity in the middle or lower part of fruit, forming spongy-like cavity. Immature fruits basically had no incidence. The dis- ease began to appear before 10 d of maturity. The disease incidence rate had extremely positive correlation with fruit weight, fruit vertical diameter or cross diame- ter. [ Conclusion] The research provides reference for field diagnoses, identification, preharvest and postharvest uninjurous test of fruit physiological disease suonaw tissue.

Occurrence Regularity of Major Damage Generations of Nilaparvata lugens(Stl) in Single Cropping Medium Rice Region in Sandu County of Guizhou Province

In order to clarify occurrence regularity of major damage generations of Nilaparvata lugens( Stl) in Sandu Shui Autonomous County( Sandu County for short),Guizhou Province,a karst single cropping medium rice region,the population dynamics of N. lugens were systematically studied using the methods of light trap and systematic field survey from 2009 to 2011. The results showed that the number of immigration generations caught by light trap and the actual population of N. lugens in fields were different among three years. The daily maximum trapping numbers of N. lugens amounted to 6 688 in 2009,which were 15. 3 and 2. 5 times of that in 2010 and 2011,respectively. The peak numbers in prediction nursery were 10 777,4 630 and 1 615 heads per hundred hills in 2009,2010 and 2011,respectively. The forth and fifth generations of N. lugens were the major damage generations in single cropping medium rice fields,and the initial immigration day was significantly related with primary-peak day. The occurrence degree of adults and nymphs of N. lugens varied with years and transplanting periods,and the peak days of N. lugens nymphs were from late July to early August in 2010 and 2011. The occurrence peaks of adults and nymphs in late transplanting paddy field were later than that in the early one. Meanwhile,the coexisted various growth periods of rice,due to time differences of transplanting,were conducive to inhabitation and reproduction of N. lugens. The population dynamics of spiders and Cyrtohinus lividipennis well synchronied with that of N. lugens,but predatory capacity of spiders and C. lividipennis was not enough to control N. lugens.

Regularity of population occurrence and migration in the oriental armyworm, Mythimna separata(Walker)

The oriental armyworm,Mythimna separata（Walker）（Lepidoptera：Noctuidae）,is a major migrant pest of grain in China and other Asian countries,causing huge crop production and economic losses nationwide annually.Much of the uniquely difficult aspects of managing M.separata arises from its long-distance migratory behavior.For example,direction and timing of winds from its overwintering regions in the south largely determine where and when large influxes of migrants arrive in the north to oviposit,making prediction of infestations difficult.