Climate Change and Potato Production in Contrasting South African Agro-Ecosystems 3. Effects on Relative Development Rates of Selected Pathogens and Pests

A set of daily weather data simulations for 1961 to 2050 were used to calculate past and future trends in pest and disease pressure in potato cropping systems at three agro-ecologically distinct sites in South Africa: the Sandveld, the Eastern Free State and Limpopo. The diseases and pests modelled were late blight, early blight and brown spot, blackleg and soft rot, root-knot nematodes and the peach-potato aphid Myzus persicae (as indicator of Potato virus Y and Potato leaf roll virus). The effects of climate on trends in relative development rates of these pathogens and pests were modelled for each pathogen and pest using a set of quantitative parameters, which included specific temperature and moisture requirements for population growth, compiled from literature. Results showed that the cumulative relative development rate (cRDR) of soft rot and blackleg, root-knot nematodes and M. persicae will increase over the 90-year period in the areas under consideration. The cRDR of early blight and brown spot is likely to increase in the wet winter and wet summer crops of the Sandveld and Eastern Free State, respectively, but remains unchanged in the dry summer and dry winter crops of the Sandveld and Limpopo, respectively. Climate change will decrease the cRDR of late blight in all of the cropping systems modelled, except in the wet winter crop of the Sandveld. These results help to set priorities in research and breeding, specifically in relation to management strategies for diseases and pests.     

Effects of pest and soil management systems on potato diseases

Long-term cropping systems research is important in order to reduce production costs, to control crop pests, and to optimize the sustainability of agro-ecosystems. Soil amendment use, improved disease management practices, and careful cultivar choice are some of the potential components for improving potato production systems. This research was conducted in long-term cropping systems plots in order to evaluate the impact of soil amendments, pest management practices, and cultivar on foliar and soil-borne potato diseases and to assess the relationships of soil and pest management practices to disease levels and soil microbial activity. Fungicide applications for management of foliar diseases varied between the pest management systems (e.g., biological, reduced input, and conventional). Incidence of potato foliar diseases was quantified five times during the cropping season. The impact of soil amendment and pest management practices on soil microbial activity and tuber-borne diseases was also investigated. Low incidences of foliar and selected soil-borne diseases were recorded. Disease levels varied between years, cultivars, pest management, and soil amendments. Significant differences between cultivars were detected for early blight, white mold, and black dot. The cultivar Superior had higher incidence of white mold and black dot, while cv Atlantic had higher early blight incidence. Pest management system significantly affected foliar early blight incidence in 1998, but not in 1997. Pest management system did not affect late blight, white mold, or black dot incidence, or tuber disease incidence in either year. The addition of soil amendments significantly impacted tuber black dot incidences. Microbial activity responded to increasing temperature as the season progressed and was significantly enhanced by the addition of manure and compost soil amendments; however, lower disease incidence was not associated with increased microbial activity. While pest management practices were not major determinants of disease levels in these experiments, the results show that soil amendments can increase incidence of selected tuber diseases and microbial activity in soils.     

豫南“籼改粳”理论与技术研究进展

简要介绍了豫南稻区"籼改粳"的基本情况和在理论技术方面的研究进展。高温、稻瘟病和纹枯病、三代三化螟危害是豫南粳稻产量低、品质差的三大障碍因子,而播期早是产生障碍的根源,推迟粳稻播期是"籼改粳"的关键技术;豫南"籼稻-小麦"轮作存在制度缺陷,推迟粳稻播期可以得到修复,因秧龄过长而减产、机插秧以及抛秧难以利用等问题得到解决;增产提质、机械化、轻简化、规模化生产是"籼改粳"的必然选择;"东粳西移"是解决豫南粳稻品种利用的有效途径;机插秧、抛秧有利于实现粳稻推迟播种,而"泥质法"育秧解决了高温条件下育秧的问题,提高了机插秧、抛秧的秧苗素质;粳稻晚播稻瘟病、纹枯病和三化螟已不再是豫南"籼改粳"的毁灭性病虫害,恶苗病、干尖线虫病、稻蓟马、稻曲病上升为主要病虫害;水稻两段栽培技术是根据水稻高产稳产生长发育规律,分别从群体、形态和机能构建三个方面进行栽培设计,按照营养生长和生殖生长两个阶段进行定向培育的一种栽培方法,不仅高产稳产,而且减肥减药。     

A characterization of rice pests and quantification of yield losses in the japonica rice zone of Yunnan,China

Within any geographic area where pest management is to be improved or adapted to agricultural changes, there is a need for characterization to define constraints to crop production. The objective of this study was to assess pest injuries (diseases, insects and weeds) in farmers' fields in the japonica rice zone of Yunnan, China, explore characteristics of rice injury profiles, analyse the relationships between injury profiles and yield levels, and estimate yield losses caused by individual injuries. Seven pest injury profiles (abbreviated as IN) were determined using cluster analysis; IN1, IN2 and IN3 were lower injury levels of pest combinations in seven profiles, while IN5, IN6 and IN7 were higher injury levels. Correspondence analysis based on patterns of injury profiles yielded a path of increasing yield levels associated with varying combinations of injuries. The use of principal component analysis with multiple regression generated estimates of yield reductions due to rice diseases, insects and weeds. The analysis indicated that injuries caused by weeds that are taller than the rice canopy, white heads, leaf folder, bacterial leaf blight, army worms, leaf blast and plant hoppers should be considered as potentially most damaging in this region. Results of this study will provide some foundations for developing pest management strategies and improving rice production at the regional scale.     

Establishment rate of direct-seeded rice in the relay-intercropping system in Kanto region of Japan

The relay intercropping system for cultivating direct-seeding rice and winter cereal is a low-cost method particularly for double cropping, because it eliminates the steps of raising seedlings, paddling, and transplanting. However, in this system, the seedling establishment rate (SER) of rice is low and unstable. The objective of this study was to identify the factors affecting SER to highlight the ways to improve SER. Experiments were conducted in experimental fields in Tsukuba City, Ibaraki Prefecture in 2015 and 2016. To determine the time of rice seed death and to calculate seed survival rates, ‘Akidawara’ seeds were embedded in soil (depth: 3 cm) and dug up after defined periods. We then analyzed the correlation between SER and meteorological factors at two sites (Ibaraki Prefecture and Gunma Prefecture) over the same two years. Based on mean air temperature (MT), we divided the period from seeding to June 20 (when irrigation had been initiated in almost all the fields) into four phases. In Phase 1, the number of days with rainfall (≥5 mm) and soil-wetting days (water potential ≥ ?100 kPa) were significantly and negatively correlated with SER. We found that most of the seed deaths occurred after germination, and the germination rates were presumably affected by water absorption during the low temperature phase. Further investigations are needed to understand the occurrences during the seedling emergence period. This study contributes to a better understanding of the factors affecting variations in the SER of direct-seeded rice grown in the relay-intercropping system.

List of Abbreviations: DSR: direct-seeded rice; SER: seedling establishment rate; TT: thiuram treatment; SSR: seed survival rate; DS: dead seeds; AGS: already germinated seeds; DSRI: direct-seeding of rice in the inter-row spaces of winter cereals; VWC: volume water content; WP: water potential     

Cropping Systems and Integrated Pest Management: Examples from Selected Crops

SUMMARY

Cropping systems have been central to managing associated pests for centuries. This treatment focuses on the history, concepts, and the integration of available Integrated Pest Management (IPM) tools/strategies into cropping systems. Pest assessments/diagnoses, IPM-decision-making aids, and examples of pest management in selected crops/cropping systems (wheat, soybean, corn, cotton, potato, and strawberry) as well as emerging opportunities and challenges are discussed. The evolving philosophy of IPM and the recently renewed emphasis on ecologically based pest management address the fact that significant levels of predation and/or parasitism are desirable insofar as they promote diversity and sustainability of agroecosystems. Thus, cropping systems are beginning to focus on soil and crop health as well as specific IPM and production goals. Although extensive efforts have been directed toward modeling the many interactions between crops, associated pests and the environment, the general implementation of a systems approach to integrated crop and pest management remains to be accomplished.     

一份抗纹枯病水稻品种ZH5的抗病虫特性和生物学性状

两年的温室、大田人工接种和自然诱发等抗病虫鉴定结果表明,ZH5除抗纹枯病外,对稻瘟病、白叶枯病和稻飞虱也具有较好的抗性。生育期、株型观察和稻米外观品质分析表明,ZH5综合农艺性状好,具备“理想株型”的特征。由于具有优质、高产、多抗的特性,ZH5是无公害优质稻生产的理想品种,也是优质、多抗育种,特别是抗纹枯病育种的理想抗源材料。     

Evaluation of alternative tillage and crop establishment methods in a rice–wheat rotation in North Western IGP

The rice–wheat rotation covering 13.5 million ha in the Indo-Gangetic Plains is vital for food security. Its sustainability is at risk as the current production practices are inadequate resulting in high cost of cultivation and inefficient use of inputs (i.e. water, labor and energy). In a field study, we evaluated resource conserving and cost-saving alternative tillage and crop establishment options with an aim to improve system productivity and efficiency. Treatments included transplanting and direct-seeding of rice after reduced and no-tillage, followed by wheat after no-tillage. Conventional-tilled (puddled) transplanted rice followed by conventional-tilled wheat was included as a current practice. Rice yields of transplanted rice were similar irrespective of tillage/puddling. However, both dry and wet direct-seeded rice yielded 0.45–0.61 Mg ha⁻¹ lower than puddled transplanted rice. Wheat yield after no-tillage was either higher or equivalent to conventional practice. Wheat provided more economic return (US $35 ha⁻¹) than rice. No-till wheat was 6% more profitable than the conventional practice (T1). Rice transplanting with or without puddling had similar water application but dry direct-seeded rice had 10–12% lower and wet direct-seeded rice 20–24% higher. Machine labor without tillage was lower by maximum of 51 and 43% in rice and wheat, respectively. Similarly, human labor was also 9–16% lower in no-till rice compared to other practices. Two years results consistently showed $35 more net income when rice was transplanted without puddling than that of conventional practice. Direct-seeded/un-tilled rice had variable response in 2 years; US $16 more in year 1 and similar in year 2 to the puddled transplanted rice. Direct-seeded or transplanted rice after no-tillage can be more efficient and profitable alternatives to current practice (puddled transplanted rice), however, require further refinement in areas of cultivar development for no-till direct-seeding condition, nutrient, water and weed management to harness maximal potential.     

稻秆还田对水稻主要病害发生的影响

通过水稻秸秆还田小区试验,初步探讨了多年秸秆还田对15个水稻品种病害的影响。试验结果表明：秸秆还田的老稻田15个水稻品种的稻瘟病、鞘腐病、纹枯病的病情指数都高于对照稻田的病情指数。黑龙江省农垦总局建三江分局主栽品种空育131,叶瘟病情指数增加了2．3％,穗颈瘟增加了2．6％,鞘腐病增加了2．2％,纹枯病增加了0．4％。     

Characterizing and Estimating Fungal Disease Severity of Rice Brown Spot with Hyperspectral Reflectance Data

Large-scale farming of agriculture crops requires real-time detection of disease for field pest management.Hyperspectral remote sensing data generally have high spectral resolution, which could be very useful for detecting disease stress in green vegetation at the leaf and canopy levels. In this study, hyperspectral reflectances of rice in the laboratory and field were measured to characterize the spectral regions and wavebands, which were the most sensitive to rice brown spot infected by Bipolaris oryzae (Helminthosporium oryzae Breda. de Hann). Leaf reflectance increased at the ranges of 450 to 500 nm and 630 to 680 nm with the increasing percentage of infected leaf surface, and decreased at the ranges of 520 to 580 nm, 760 to 790 nm, 1550 to 1750 nm, and 2080 to 2350 nm with the increasing percentage of infected leaf surface respectively. The sensitivity analysis and derivative technique were used to select the sensitive wavebands for the detection of rice brown spot infected by B. oryzae. Ratios of rice leaf reflectance were evaluated as indicators of brown spot. R669/R746 (the reflectance at 669 nm divided by the reflectance at 746 nm, the following ratios may be deduced by analogy), R702/R718, R692/R530, R692/R732, R535/R746, R521/R718, and R569/R718 increased significantly as the incidence of rice brown spot increased regardless of whether it's at the leaf or canopy level. R702/R718, R692/R530, R692/R732 were the best three ratios for estimating the disease severity of rice brown spot at the leaf and canopy levels. This result not only confirms the capability of hyperspectral remote sensing data in characterizing crop disease for precision pest management in the real world, but also testifies that the ratios of crop reflectance is a useful method to estimate crop disease severity.     

诏安县双季稻高产优化集成技术

福建省诏安县2006—2010年建立＂稻稻薯三熟高产技术研究＂示范片,获得显著增产增收,双季年产量突破1 200 kg/667m2。介绍了双季稻推广双季杂交稻、适期播栽、壮秧密植、定量施肥、合理管水、调控三组叶片和防控病虫草等优化集成技术。     

Disease management of organic tomato under greenhouse conditions in the Jordan Valley

Production of organic tomato under greenhouse conditions has significantly increased in the last few years. Although greenhouse systems provide the option of off-season production and expansion of markets over traditional outdoor field systems, such systems also pose unique challenges with regard to pest management. An experiment was conducted in the Jordan Valley during the fall of 2011/2012 to evaluate the effects of integrated pest management that combines different preventive and control measures, on diseases and pests of tomato grown under greenhouse conditions. The experiment consisted of three treatments (organic farming, conventional farming and integrated pest management (IPM) farming) with four replicates arranged in a randomized complete block design (RCBD). The plant diseases and pests were monitored in all treatments. Powdery mildew disease was recorded at 6 weeks after transplanting in all treatments and at 22 weeks after transplanting, the disease incidence was 74%, 68% and 57% in the IPM, conventional and organic treatments, respectively. However, the disease severity did not exceed 1.5 in any of the treatments. Early blight disease appeared at 16 weeks after transplanting and at 22 weeks after transplanting, the disease incidence was 62%, 54% and 47% in the IPM, conventional and organic treatments, respectively. Neither bacterial symptoms nor nematode symptoms were observed in any of the treatments. Enzyme-linked immunosorbent assay (ELISA) tests revealed the presence of Tomato ring spot virus (ToRSV) and Tomato bushy stunt virus (TBSV). Overall, the study showed that there were no significant differences between the three treatments with regard to tomato plant height, width, circumference, number of flowers/cluster, number of clusters/plant, fruit yield, shoot dry weight and root dry weight. Furthermore, several quality parameters of tomato fruits were studied; dry weight, lycopene content and pH were found to be significantly higher in the organic tomatoes.     

耒阳烟区烟草有害生物调查研究

2012年11月至2013年7月,对耒阳市烟区开展了烟田病虫草害普查。结果表明,危害耒阳市烤烟的主要病害有12种,其中病毒性病害3种：烟草普通花叶病、烟草黄瓜花叶病毒病、马铃薯Y病毒病;烟草真菌性病害5种：黑胫病、炭疽病、蛙眼病、赤星病、根腐病;烟草细菌性病害3种：青枯病、野火病、空茎病;气候型斑点病。耒阳烟田害虫有6种：烟蚜、烟青虫、斜纹夜蛾、小地老虎、野蛞蝓、蜗牛。烟田杂草主要有稗草、看麦娘、蓼草、革命草、马鞭草等。     

Comparison of Different Methods of Rice Establishment and Nitrogen Management Strategies for Lowland Rice

Abstract

Shortage of labor and water are forcing farmers to explore the alternatives of transplanting. A field experiment was conducted at the experimental farm of International Rice Research Institute (IRRI), Philippines during the 2003 wet season and the 2004 dry season to (1) evaluate the effects of different crop-establishment methods and N management on yield and yield parameters of rice; (2) determine N-use efficiency and water-use efficiency under different methods of rice establishment; and (3) analyze the economics of different crop-establishment methods. Crop-establishment method did not influence grain yield during the wet or dry seasons, indicating the potential of the three variants of direct seeding as alternative methods of establishing lowland rice. Direct-seeded rice had shorter crop duration, required less water and therefore had higher water-use efficiency than the transplanting method. Crop establishment did not influence the various indices of nitrogen-utilization efficiency except partial factor productivity of N (PFPN) during the wet season. During the dry season, dry-seeded rice had the lowest recovery efficiency. In contrast, agronomic-use efficiency and recovery efficiency were significantly higher in the SPAD-based (soil plant analyses development) N management strategy during the dry season. PFPN was significantly higher in the SPAD-based N management strategy during the wet and dry seasons. The interaction effect of crop establishment and N management indicated that for smaller N input and higher efficiency of N usage, N requirement for direct-seeded rice should be based on SPAD N technique. The cost-and-return analysis showed that benefit-cost ratio was consistently higher in dry seeding rice than transplanted rice using a SPAD-based N management.     

Yield constraints of rainfed lowland rice in Central Java, Indonesia

The low and unstable yields of rainfed lowland rice in Central Java can be attributed to drought, nutrient stress, pest infestation or a combination of these factors. Field experiments were conducted in six crop seasons from 1997 to 2000 at Jakenan Experiment Station to quantify the yield loss due to these factors. Experimental treatments—two water supply levels (well-watered, rainfed) in the main plots and five fertilizer levels (0-22-90, 120-0-90, 120-22-0, 120-22-90, 144-27-108 kg NPK ha⁻¹) in the subplots—were laid out in a split-plot design with four replications. Crop, soil, and water parameters were recorded and pest infestations were assessed.

In all seasons, rice yield was significantly influenced by fertilizer treatments. Average yield reduction due to N omission was 42%, to K omission 33–36%, and to P omission 3–4%. Water by nutrient interactions did not affect rice yield and biomass production. In two of the three dry seasons, an average of 20% of the panicles were damaged by pests and estimated yield loss from pests was 56–59% in well-watered and well-fertilized treatments. In one out of six seasons, yields under rainfed conditions were 20–23% lower than under well-watered conditions. Drought, N and K deficiencies, and pest infestation are the major determinants for high yields in rainfed environments in Jakenan. Supplying adequate nutrient and good pest control are at least as important as drought management for increasing crop productivity of rainfed rice-growing areas in Central Java. The relative importance of drought, nutrient and pest management may vary in other rainfed areas. Yield constraints analysis should be systematically carried out to identify appropriate management strategies.     

The effects of irrigation method, age of seedling and spacing on crop performance, productivity and water-wise rice production in Japan

A field experiment using system of rice intensification (SRI) techniques was conducted in Chiba, Japan during the 2008 rice-growing season (May–September) with eight treatment combinations in a split–split plot design (S–SPD) to observe the potential of SRI methods under the temperate climatic conditions in Japan. Intermittent irrigation with alternate wetting and drying intervals (AWDI) and continuous flooding throughout the cropping season were the two main-plot factors, while the effects of age of seedlings and plant spacing were evaluated as sub and sub–sub plot factors, respectively. The experiment results revealed that the proposed AWDI can save a significant amount of irrigation water (28%) without reduced grain yield (7.4 t/h compared with 7.37 t/h from normal planting with ordinary water management). Water productivity was observed to be significantly higher in all combinations of practices in the intermittent irrigation plots: 1.74 g/l with SRI management and AWDI as compared to 1.23 g/l from normal planting methods with ordinary water management. In addition, the research outcomes showed a role of AWDI in minimizing pest and disease incidence, shortening the rice crop cycle, and also improving plant stand until harvest. Synergistic effects of younger seedlings and wider spacing were seen in tillering ability, panicle length, and number of filled grains that ultimately led to higher productivity with better grain quality. However, comparatively better crop growth and yields when using the same SRI practices with ordinary water management underscore a need for further investigations in defining what constitute optimum wetting and drying intervals considering local soil properties, prevailing climate, and critical watering stages in rice crop management.     

双季杂交稻“肥促水调”栽培技术的应用

选用优势强、品质优的杂交组合,早季中熟搭配晚季迟熟组合,培育壮秧,控制分蘖肥用量,增大后期施肥量,超前搁田控制苗峰,在一定穗粒基础上,实现总粒数、实粒数和经济系数的大幅度提高,从而提高产量．     

不同耕作方式对超级杂交稻两优培九产量形成和养分吸收的影响

为了探明免耕对杂交水稻产量的影响．在前3年定位试验的基础上,于2006-2007年在长沙以两优培九为材料进行了翻耕移栽、翻耕直播、免耕移栽和免耕直播4种耕作方式的田间比较试验。结果表明在直播条件下,免耕稻与翻耕稻氮素的吸收量相似,而磷素和钾素吸收量分别比翻耕稻高11．52％和10．44％;在移栽条件下,免耕稻氮素和磷素的吸收量分别比翻耕稻高13．52％和0．67％,但钾素的吸收量比翻耕稻低12．36％。无论在移栽或在直播条件下．免耕稻与翻耕稻产量差异不显著．但无论在翻耕或在免耕条件下．直播稻产量略高于移栽稻,2006年和2007年试验结果一致。     

免耕栽培对超级杂交稻两优培九根系特性的影响

为了探明免耕对杂交水稻根系特性的影响．在前3年定位试验的基础上,于2007年在长沙以两优培九为材料,进行了翻耕移栽、翻耕直播、免耕移栽和免耕直播4种耕作方式的田间比较试验。在水稻直播条件下。分蘖中期免耕稻的根冠比和单株根干重均高于翻耕稻,增幅分别为23．42％0和3．33％,幼穗分化期增幅为30．01％和18．75％;在水稻移栽条件下,免耕稻分蘖中期的根冠比和单株根干重均高于翻耕稻．增幅分别为10．24％和10．57％,幼穗分化期增幅分别为22．67％和4．35％。无论直播或移栽．各个时期免耕稻的根系活力和根长均高于翻耕稻,免耕和直播能一定程度地提高水稻根系的活力。     

分子标记辅助选择在水稻抗病虫基因聚合上的应用

 稻瘟病、白叶枯病、褐飞虱和白背飞虱是危害水稻生产的主要病虫害。实践证明,培育抗病虫品种是控制水稻病虫害最经济和有效的途径。总结了目前已报道和定位的抗病虫基因的研究和利用情况,指出利用分子标记辅助选择聚合不同类型抗病虫基因到同一品种,可以提高品种抗性、拓宽抗谱,是水稻抗病虫品种培育的发展方向。