The Efficiency of Southern rice black-streaked dwarf virus Transmission by the Vector Sogatella furcifera to Different Host Plant Species

Southern rice black-streaked dwarf disease is a new rice disease that severely affects rice production in South China.To understand transmission capacity of the vector Sogatella furcifera to Southern rice black-streaked dwarf virus（SRBSDV） among different host plant species,potential host plants of SRBSDV collected from the diseased rice field and/or adjacent to the field in Hunan Province,China,were determined by RT-PCR,and the transmission rates of SRBSDV by S.furcifera among different host plant species were investigated.The results showed that host plants of SRBSDV in the rice fields were five of family Gramineae（Oryza sativa,Echinochloa crusgalli,Zea mays,Paspalum distichum,Alopecurus aequali） and two of family Cyperaceae（Juncellus serotinus and Cyperus difformis）.S.furcifera could not transmit SRBSDV between gramineous plants and cyperaceous plants,and could not transmit SRBSDV between the gramineous plants,J.serotinus and C.difformis as well.However,SRBSDV could be transmitted by S.furcifera within gramineous plants.S.furcifera could transmit SRBSDV between interspecies among three species plants（O.sativa,E.crusgalli and Z.mays）,and between P.distichum and A.aequali.At 15,20,25,30,and 35°C,both macropterous and brachypterous adult of S.furcifera could transmit SRBSDV from the plants（e.g.,E.crusgalli,Z.mays and O.sativa） infected with SRBSDV to rice seedlings.The transmission rates were first increased and then decreased with the increase of temperature.Macropterous adults transmitted SRBSDV from the viruliferous E.crusgalli,Z.may and rice plants to the healthy rice seedlings,and the infected rates of rice seedlings were 26.2,18.8 and 23.7% at 15°C,56.6,64.6 and 53.6% at 25°C,and was 11.2,10.2 and 7.3% at 35°C,respectively.Transmission capacity of brachypterous adults was significantly higher than that of macropterous adults at 15,20 and 25°C（P0.05）,while transmission capacity of brachypterous adults was relatively lower compared with that of macropterous ones at 35°C.These results offer evidence on the transmission of SRBSDV via the vector S.furcifer among different host plants,which can be helpful to control Southern rice black-streaked dwarf disease by the appropriate cultural measures in South China.

Effect of Rice Sowing Date on Occurrence of Small Brown Planthopper and Epidemics of Planthopper-Transmitted Rice Stripe Viral Disease

To understand the relationship between rice sowing date and occurrence of the rice small brown planthopper （SBPH） Laodelphax striatellus Fallen and the epidemics of the planthopper-transmitted rice stripe viral （RSV） disease, four sowing dates of rice were evaluated in 2006 and 2007. The results showed that the peak density of SBPH and RSV incidence in the nursery and in the transplanted field decreased with the delay of sowing date in single crop of japonica rice in north Zhejiang Province of China. The relationship between seedling RSV incidence at the end of the nursery trial with sowing date was well described by Weibull equation. The area under the curve of population dynamics （AUCPD or planthopper-day accumulation） or the peak density of the planthopper in the nursery could be summarized by a logistic equation. RSV incidence in the transplanted fields could be characterized quantitatively by a multivariate regression equation, including the variables of sowing date, peak density of the vector, and RSV incidence at the end of the nursery trial. That the descriptive model excluded the AUCPD in transplanted field implies that this variable is not necessary in forecasting disease epidemics in the field. The 2-year experiments sufficiently indicated that suitable sowing of rice could be used as one of the effective measures to control the vector population and therefore the planthopper-transmitted RSV on a larger scale. The optimal sowing date for the single-cropped transplanted japonica rice is recommended from late May to early June in north Zhejiang, China.

Disaster Prevention and Mitigation Technologies of Rice Virus Diseases Spread by Small Brown Planthopper (SBPH)

Rice stripe virus disease （RSVD） and rice black-streaked dwarf virus disease （RBSDVD） are two epidemic diseases in Yancheng City, Jiangsu Province in the last decade. The authors investigated the disaster regularity, prevention and control technology of RSVD and RBSDVD systematically. The occurrence and virus transmission of SBPH and disaster regularity of virus diseases were studied; the resistance of some rice varieties was cleared; the effects of physical and agricultural measures such as insect net blocking, appropriate late sowing and plowing on controlling occurrence and virus transmission of SBPH were figured out; a hatch of chemical agents were screened, providing efficient and harmless pesticides for effective control against SBPH and prevention against virus diseases. A set of disaster control and mitigation technologies was proposed in this paper, which was practical, sustainable, and easy to operate for the local planting patterns.

Possible source and migration pathway for early-summer immigrants of the oriental armyworm, Mythimna separata, arriving in northern Japan

The first generation of the oriental armyworm, Mythimna separata(Walker), arrives every year in northern Japan in mainly late May to early June. Analyses of weather maps suggested that this moth’s immigration source could be eastern China, but the accuracy of those analyses was very limited due to the lack of a current standard trajectory analysis. The management of migratory insect pests such as M. separata benefits from the identification of the migration source(s)and pathway(s) of the pests. The present study provides a trajectory analysis for M. separata. Backward trajectories from trap sites in northern Japan were calculated with the HYSPLIT System developed by the U.S. National Oceanic and Atmospheric Administration, taking the flight speed of M. separata and the limitation of low ambient temperature at flight height into account. The ending times of the moth’s short and long trajectories were set at dusk on the day before and two days before the possible arrival date, respectively. The results suggested two types of possible migration pathway: a multi-step pathway from Northeast China, the Korean Peninsula, and eastern Russia, which are destination areas of the first-generation’s migration, and a direct pathway from seasonal main emigration areas in eastern China such as Jiangsu and Shandong provinces. These findings contribute to our understanding of the migration ecology of M. separata and can be used for the development of methods to predict the migration of this insect.

氨基甲酸酯类杀虫剂及其与阿维菌素的混配制剂对美洲斑潜蝇(Diptera:Agromyzidae)的防治效果

测定了扑蚜威、速灭威、灭蚜威、间乙威等9个氨基甲酸酯类化合物及其 与阿维菌素混剂对美洲斑潜蝇的田间药效，结果发现，当施用有效量075 kg/hm2时，氨 基甲酸酯类单剂对美洲斑潜蝇的防效在75%～92%之间，而扑蚜威、速灭威、灭蚜威与阿维菌 素混剂对该蝇的防效可达85%～92%。表明，氨基甲酸酯类化合物与阿维菌素混配对美洲斑潜 蝇田间防效、速效性均较好，且成本显著降低。

Effect of temperature on the development of sclerotia in Villosiclava virens

The sclerotia of Villosiclava virens were found commonly in high altitude and the temperate regions, where the temperatures are relatively low in rice filling stage. To make sure if low temperature induce the sclerotial formation in V. virens, the inoculated rice panicles in laboratory and the diseased rice panicles cut from paddy fields were treated under different temperatures. The results showed that 3 days of night temperature at 15°C were enough to induce the sclerotial formation. The low temperature was much more effective for young balls with intact membranes. After appearance of chlamydospores on the ball surfaces, the sclerotium could not differentiate anymore. The sclerotia began to differentiate below the chlamydospore layer and gradually grew onto the ball surfaces. This suggests that low temperature in the early development stage of false smut balls is an important factor to induce the sclerotial differentiation, and rice cultivars with long growth periods are able to produce more sclerotium-bearing balls, which will produce mass of spores in paddy field in the coming year.

First report of the South American tomato leafminer, Tuta absoluta (Meyrick), in China

Tuta absoluta(Meyrick) originated in South America and is one of the most serious pests of tomatoes. It is also known to attack other solanaceous crops, including potato, eggplant, pepper, tobacco, and weedy species such as black nightshade. After accidental introduction into Spain in 2006, this pest spread rapidly throughout Afro-Eurasia and has become a major threat to tomato production worldwide. Here, we report the first record of T. absoluta as an invasive pest in China. It was found in tomato fields in Ili Kazakg Autonomous Prefecture, Xinjiang Uygur Autonomous Region(Ili, Xinjiang), China, and its occurrence was confirmed by both morphological and molecular approaches. In Ili, T. absoluta has been found to attack eggplant, potato, and black nightshade. We found the larvae generally mining and feeding on leaves and boring into tomato fruits, with multiple larvae sometimes observed in a single fruit. Its infestation levels differ among the tomato fields and host species. In all of the surveyed tomato fields, T. absoluta infested 100% of plants. In some of the fields, up to 90% of the eggplant and 100% of the potato plants were infested. Since no natural enemies were found under field conditions, suitable management practices are urgently needed to stop the further spread of this destructive pest in China.

The effects of fermentation and adsorption using lactic acid bacteria culture broth on the feed quality of rice straw

To improve the nutritional value and the palatability of air-dried rice straw, culture broth of the lactic acid bacteria community SFC-2 was used to examine the effects of two different treatments, fermentation and adsorption. Air-dried and chopped rice straw was treated with either fermentation for 30 d after adding 1.5 L nutrient solution（50 m L inocula L–1, 1.2×1012 CFU m L–1 inocula） kg–1 straw dry matter, or spraying a large amount of culture broth（1.5 L kg–1 straw dry matter, 1.5×1011 CFU m L–1 culture broth） on the straw and allowing it to adsorb for 30 min. The feed quality and aerobic stability of the resulting forage were examined. Both treatments improved the feed quality of rice straw, and adsorption was better than fermentation for preserving nutrients and improving digestibility, as evidenced by higher dry matter（DM） and crude protein（CP） concentrations, lower neutral detergent fiber（NDF）, acid detergent fiber（ADF） and NH3-N concentrations, as well as higher lactic acid production and in vitro digestibility of DM（IVDMD）. The aerobic stability of the adsorbed straw and the fermented straw was 392 and 480 h, respectively. After being exposed to air, chemical components and microbial community of the fermented straw were more stable than the adsorbed straw.

New geographic distribution and molecular diversity of Citrus chlorotic dwarf-associated virus in China

In 2009, an emerging citrus viral disease caused by Citrus chlorotic dwarf-associated virus(CCDaV) was discovered in Yunnan Province of China. However, the occurrence and spread of CCDaV in other citrus-growing provinces in China is unknown to date. To better understand the distribution and molecular diversity of CCDaV in China, a total of 1 772 citrus samples were collected from 11 major citrus-growing provinces and were tested for CCDaV by PCR. Among these, 134 citrus samples from Guangxi, Yunnan and Guangdong were tested positive for CCDaV, demonstrating that the occurrence and spread of CCDaV are increasing in China. The complete genome sequences of 17 CCDaV isolates from different provinces and hosts were sequenced. Comparisons of the whole-genome sequences of the 17 CCDaV isolates as well as the 15 isolates available in GenBank revealed that the sequence identity was about 99–100%, showing that the CCDaV isolates were highly conserved. Phylogenetic studies showed that the 32 CCDaV isolates belonged to four different groups based on geographical origins and host species, and that CCDaV isolates from China and Turkey were clustered into different groups. The results provide important information for clarifying the distribution and genetic diversity of CCDaV in China.

Effects of sesame nectar on longevity and fecundity of seven Lepidoptera and survival of four parasitoid species commonly found in agricultural ecosystems

Ecological engineering involves the use of plants to promote establishment, survival and efficiency of natural enemies in agricultural systems. Some plant species may be hosts or provide resources to some pest species. We assessed the risks and benefits of sesame （Sesamum indicum L.）, as a nectar source for seven economically important Lepidopteran pest and four parasitoid species in a range of vegetable crop systems. Our results showed that the mean Iongevities of arthropod parasitoids Pteromalus puparum （L.）, Encarsia sophia （Girault ＆ Dodd） and male Microplitis tuberculifer （Wesmael） were significantly extended when fed on sesame flowers compared to the water control. Sesame flowers had no effect on adult Iongevities and fecundities of six out of the seven Lepidoptera pest species tested except Plutella xyllostella （L.） females laid more eggs when fed on sesame flowers. It is likely that the increased fecundity is due to accessibility to nectar at the bottom of corolla because of their smaller body sizes. Our findings provide a first step towards better understanding of the risks and benefits of using sesame to implement ecological engineering for the management of vegetable pests.

Proteomics Identification of Differentially Expressed Leaf Proteins in Response to Setosphaeria turcica Infection in Resistant Maize

Northern corn leaf blight （NCLB）, caused by the heterothallic ascomycete fungus Setosphaeria turcica, is a destructive foliar disease of maize and represents a serious threat to maize production worldwide. A comparative proteomic study was conducted to explore the molecular mechanisms underlying the defense responses of the maize resistant line A619 Ht2 to S. turcica race 13. Leaf proteins were extracted from mock and S. turcica-infected leaves after inoculated for 72 h and analyzed for differentially expressed proteins using two-dimensional electrophoresis and mass spectrometry identification. 137 proteins showed reproducible differences in abundance by more than 2-fold at least, including 50 up-regulated proteins and 87 down-regulated proteins. 48 protein spots were successfully identified by MS analysis, which included 10 unique, 6 up-regulated, 20 down-regulated and 12 disappeared protein spots. These identified proteins were classified into 9 functional groups and involved in multiple functions, particularly in energy metabolism （46%）, protein destination and storage （12%）, and disease defense （18%）. Some defense-related proteins were upregulated such as 13-glucosidase, SOD, polyamines oxidase, HSC 70 and PPIases; while the expressions of photosynthesis- and metabolism-related proteins were down-regulated, by inoculation with S. turcica. The results indicated that a complex regulatory network was functioned in interaction between the resistant line A619 Ht2 and S. turcica. The resistance processes of A619 Ht2 mainly resided on directly releasing defense proteins, modulation of primary metabolism, affecting photosyntesis and carbohydrate metabolism.

Analysis on the migration of first-generation Mythimna separata(Walker) in China in 2013

Mythimna separata（Walker） is an important pest which can cause serious damages to cereal crops. In the past two decades, several heavy outbreaks have taken place in northern China. In order to develop a fine-scale method of forecasting outbreaks, population data were collected in northern China using searchlight traps and ground light traps. A background weather pattern analysis and trajectory analysis were performed via the Weather Research and Forecast（WRF） and FLEXPART models. Our results showed that heavy migration of first-generation M. separata appeared in northern China in 2013. In Yanqing District, Beijing, the cumulative number of captured adults in searchlight traps was around 250000 and the daily maximum for trapped moths was 86000. During the peak period, the majority of M. separata moths arrived after 00：00 every night. The sex ratio（female：male） at each monitoring site was greater than 1 and greatly fluctuated with population dynamics. During the migration peak, prevailing downdraft winds benefited M. separata moths to land passively. Trajectory simulation showed that immigrants were from Anhui, Jiangsu and Hubei provinces and most of them could continue to fly into the northeastern regions of China. These results provide technical support for fine-scale forecasting of the outbreak of M. separata at meso-and micro-scale.

Control Effects of Jinggangmycin and Its Compounded Reagents against Rice Sheath Blight

The control effects of six kinds of reagents against rice sheath blight were compared in the test. The results showed that 24% thifluzamide SC 300 mL/hm2 and 20% Jinggangmycin ~ prochloraz WP 750 g/hm2 had good control effect against rice sheath blight, and their control effects after spraying for 7 and 14 d were 72.16%, 77.91% and 66.52%, 71.08%, respectively. The control effects of both reagents were significantly better than other test reagents and control re- agent Jinggangmycin, and they had no adverse effect on growth and development of rice. Considering from the aspects of control effect and economy, 20% Jinggang- mycin ~ prochloraz WP was suggested to be used to control rice sheath blight, its recommended dosage was 600 -750 g/hm2, and the reagent volume was 750kg with coarse spraying.

Identification of Heterodera schachtii on sugar beet in Xinjiang Uygur Autonomous Region of China

The sugar beet cyst nematode,Heterodera schachtii,is a major parasite of sugar beet which has been recognized and listed as a quarantine nematode in China and more than 20 countries and regions worldwide.A survey for important nematodes was undertaken in the sugar beet planting area of China during 2015-2018,and numerous cysts were collected from sugar beet fields in Xinyuan County,Xinjiang Uygur Autonomous Region of China.The observations of morphological and morphometric characteristics revealed that cysts,vulval cones and second-stage juveniles of the Xinjiang population were in the same range of each other and within those of other reported H.schachtii populations.Molecular analysis of rDNA-ITS,28S-D2/D3 and mtDNA cytochrome c oxidase subunit 1(COI)gene sequences suggested that the Xinjiang population clustered in a branch with those foreign populations,and the sequence similarity was as high as 99.81-100%.Moreover,this result was confirmed by PCR assay with species-specific primer SHF6 and rDNA2 of H.schachtii,and the pathogenicity test confirmed successful Xinjiang population reproduction in both plant hosts.In conclusion,based on morphological and molecular characterization,this study confirmed that the cyst nematode population collected from sugar beet fields in Xinjiang is H.schachtii.As far as we know,this is the first report of H.schachtii on sugar beets in Xinjiang,China.

Survey and examination of the potential alternative hosts of Villosiclava virens, the pathogen of rice false smut, in China

Rice false smut is caused by ascomycete Villosiclava virens, whose potential alternative hosts have been assumed previ- ously. Here its potential alternative hosts were surveyed and identified from 2008 to 2013 in the main rice-growing regions in China. Two common weeds in paddy fields, Digitaria sanguinalis Scop. and Echinochloa crusgalli （L.） Beauv., were found to present the similar symptoms to smut diseases in a few individuals in 2012 and 2013 in Zhejiang and Sichuan provinces of China, respectively. After the examinations of the spore morphology, their infection and extension mode in hosts, pathogen cell wall components, and molecular identification, the two pathogens were identified to be the Basidiomycetes, Ustilago syntherismae and Ustilago trichophora, respectively. So far there has been no alternative host of V. virens to be identified in China. These suggest that the alternative hosts of V. virens, if they do exist, are not possible to play an important role in the pathogen life cycle and the disease epidemics.

Effects of High-Quality Aromatic Rice Varieties on the Fitness of the Striped Stem Borer, Chilo suppressalis (Walker) in Central China

The striped stem borer （SSB）, Chilo suppressalis （Walker） （Lepidoptera： Pyralidae）, is a major pest of rice in China. Variation in host-plant quality may affect the body size of herbivorous insects, which in turn, can determine their life-history parameters such as survival, fecundity and fitness. In this study, we tested the effects of high-quality aromatic rice varieties on the fitness of SSB in China. Results showed that 1st instar larvae had higher penetrating rates and survival rates on the high-quality aromatic rice varieties （EX-1 and WX-988） than that on the non-aromatic rice varieties （EZ-5 and LYP-9）. In addition, shorter developmental periods, greater female pupal weights and higher of other life-history parameters （hatching rate, pupation rate, eclosion rate and increase index） were found on the high-quality aromatic rice varieties, although only female pupal weight showed a significant difference between the two varieties. The highest dead heart rate was found on the aromatic rice variety of EX-1. These results indicate that SSB sustains a lower fitness cost when consuming the high-quality aromatic rice varieties （EX-1 and WX-988） than on the non-aromatic rice varieties （EZ-5 and LYP-9） in Central China.

Pear Blossom Blast Caused by Pseudomonas syringae pv. syringae in China

This study was done to determine the causal organism of the pear blossom and bud blast in China. It was identified by a bacteriological test, electro-microscopic observation, Koch＇s postulate test, Biolog, fatty acid methyl esters （FAMEs）, and a polymerase chain reaction （PCR） test, and compared with the standard reference strains. Six representative strains out of 20 pathogenic bacterial isolates from 16 diseased samples showed characteristics similar to three standard strains of Pseudomonas syringae pv. syringae from Belgium. They were identified as P. syringae pv. syringae with a Biolog similarity of 0.57-0.86 and FAMEs similarity of 0.58-0.81. The bacterium was reisolated from the symptomatic plants and blossoms. Identification as P. syringae pv. syringae was confirmed by using PCR primers and sequence tests, and compared with the above-mentioned results. The data supported the fact that the pear blossom and bud blast in China could be caused by P. syringae pv. syringae.

Prevalence Reasons and Monitoring Countermeasures of Scab in Eastern Wheat Area of Jiangsu Province

With the increasing prevalence frequency and aggravating harm degree in the 21st century, wheat scab had become a recurrent disease in eastern wheat area of Jiangsu Province. This paper reviewed general occurrence situation of wheat scab in eastern Jiangsu, and summarized its occurrence characteristics in last decade. The disease prevalence was elaborated from the aspects of fungal source quantity, chmatic conditions, cultivation modes, variety resistance and pesticide resistance. The author put forward a series of measures and countermeasures, including strengthening resistance monitoring and early warning, promoting and cultivating disease-resistant varieties, compressing planting area of direct seeding rice, canting out chemical control scientifically, and realizing unified prevention and control, in order to provide a scientific basis for the control of wheat scab.

Identification and Evaluation of UV-Tolerant Streptomyces araujoniae Strain Isolated from Tibet Plateau Soil as Biocontrol Agent Against Rice Blast

Rice blast is the most important and destructive crop disease in rice paddies and poses a continued threat to the production of rice(Rossman et al,1990;Khush,2005;Wang et al,2018;Chen et al,2019).Biological control is given increasing attentions on the control of rice blast for its outstanding advantages,such as safety,low-cost,and sustainability and environmentally friendly attributes.Streptomyces Waksman&Henrici is an important actinomycete genus that is well known for its biological control potential.S.araujoniae is a relatively new species and known for its antagonistic effects against many phytopathogenic fungi(da Silva et al,2013).However,there is no report about the antagonistic efiect of S.araujoniae on Magnaporthe oryzae,much less the disease control effects at the field experiment level.

Effects of Fenaminosulf on Yield and Benefit of Single Cropping Zizania latifolia

[Objective]The paper was to normalize the application of fenaminosulf in single cropping Zizania latifolia. [Method]Effects of spraying periods,different concentrations and spraying times of fenaminosulf on yield and output value of single cropping Z. latifolia were studied.[Result]In some regions where single cropping Z. latifolia could be harvested twice per year,fenaminosulf significantly promoted formation of swollen gall,and advanced the harvest period for about 50 d. Application of 0.5 g/L（ a.i.） fenaminosulf at 150,160 and 175 d post transplanting promoted swollen gall formation and enhanced the yield of Z. latifolia.In normal single cropping Z. latifolia growing regions,once application of fenaminosulf obviously advanced harvest period and improved yield and benefit of Z. latifolia,but with the increasing frequency of use,yield and benefit of Z. latifolia decreased significantly.[Conclusion]It is recommended that 1.0 g/L（a.i.） fenaminosulf can be applied for just once at 40-60 d post transplanting of Z. latifolia.