Selectivity of Three Miticides to Spider Mite Predator,Phytoseius plumifer(Acari:Phytoseiidae) Under Laboratory Conditions

The predatory mite, Phytoseius plumifer （Canestrini ＆ Fanzago）, is one of the most abundant natural enemies and efficient predator of phytophagous mites in Iran. The miticides hexythiazox （Nisorun, EC 10%）, fenpyroximate （Ortus, SC 5%）, and abamectin （Vertimec, EC 1.8%） were tested in the laboratory for their side effects on P. plumifer. The miticides were applied at the highest field recommended concentration （N） to detached leaves using a Potter Tower to deposit 2 mg spray solution per cm2. Percent predator mortality was evaluated from the protonymph up to the adult stage including the first five days of the oviposition period. Analysis of data showed that the total effect values of hexythiazox were below the lower threshold, and thus it could be considered to be a harmless miticide to P. plumifer. In contrast, the total effects of fenpyroximate and abamectin were found harmful to the predatory mite at the highest field recommended concentrations.

Optimizing Nutrient Use Efficiency and Returns from Soybean Production under Smallholders in Three Agro-Ecologies of Malawi

Field trials were conducted to determine the economically optimum fertilizer rates for soybean production and for optimizing net profits in Dedza, Lilongwe and Salima Districts of Malawi. The effects of PK fertilizer rates on rain use efficiency (RUE), harvest index, agronomic use efficiency of phosphorous (AEP) and potassium (AEK), and value cost ratio (VCR) were evaluated. The applied diagnostic PK fertilizer rates significantly improved soybean grain yields, harvest index, rainwater use efficiency, AEP, AEK and returns to fertilizer use expressed as value cost ratio (VCR). However, the results differed significantly

Characterization of Myanmar Paw San Hmwe Accessions Using Functional Genetic Markers

Paw San Hmwe （PSM） rice has been cultivated in many areas of Myanmar for a long time. Strong aroma, good taste and its elongation during cooking are the key characteristics of PSM rice. Thirty-one PSM accessions were genotypically characterized, and their physical grain and cooking quality traits were studied. We used specific gene markers associated with aroma, apparent amylose content （AAC） and alkali spreading value to determine the alleles carried by different PSM accessions. The results revealed that six PSM accessions （PSM10, PSM12, PSM13, PSM21, PSM22 and PSM30） had a 3-bp insertion in Os2AP gene. Gel consistency （GC） allele was predominant among the PSM accessions for gelatinization temperature （GT）, however, the phenotype observed was between low and intermediate GT because of the combination of the GC allele with the presence of low GT allele at heterozygous state from the other loci of the SSIla gene. Intermediate to high AAC was observed among the PSM accessions corresponding to the haplotype identified for the single nucleotide polymorphism G/T and the （Cm）n repeat in the Wx gene. The characterization and grouping data of PSM accessions posted benefits to Myanmar seed banks, and our results will help in maintaining the integrity of PSM rice variety.

Photosynthetic Water Use Efficiency of Heritage and Modern Potatoes under Limited and Unlimited Water Environments

Photosynthetic capacity for heritage (Taewa) and modern potato cultivars were compared at different water and nitrogenregimes in the glasshouse and field. The glasshouse was 2*2*4 factorial design with two irrigation: 100% ET and 60% ET;two applied N: 50 kg N ha-1 and 200 kg N ha-1, two Taewa (Moe Moe, Tutaekuri) and two modern potatoes (Moonlight, Agria). The 2009/2010 field experiment was a split-plot, with irrigation and rain-fed regimes as the main treatments: four potatoes above were sub-treatments. The 2010/2011 field experiment was a split-split-plot, with three water regimes as the main treatments: three cultivars (Moe Moe, Tutaekuri, and Agria) were subplots;two N rates were sub-sub-treatments. Gaseous exchange was measured by CIRAS-2 at different days from emergence. Leaf water potential was measured using pressure chamber method. Taewa achieved high photosynthetic WUE in glasshouse and 2010/2011 experiment by maintaining high An, low gs and low Ci compared to modern cultivars (p The An, gs and T increased with irrigation and N increase while decreasing Ci (p < 0.01). Water stress significantly increased VPD resulting in low An and photosynthetic WUE in Moonlight in the glasshouse. The leaf water potential for Taewa was very tolerant while modern potatoes were weakened by water stress. The study indicated that Taewa can be scheduled at partial irrigation without more detrimental effects on photosynthetic capacity while modern potatoes need full irrigation to avoid detrimental effects on photosynthetic capacity.

A soil quality index for subtropical sandy soils under different Eucalyptus harvest residue managements

Eucalyptus harvest residues are attractive energy production resources for the forestry industry.However,their removal can have adverse impacts on soil quality and forest productivity,especially in sandy soils.In this study,we assessed the effects of Eucalyptus harvest residue managements with variable intensity on forest productivity and on physical,chemical,and biological indicators of the soil quality.The experiment was conducted in a Quartzipsamment(33 g kg-1clay)planted with Eucalyptus saligna in Barra do Ribeiro in southern Brazil.Before the Eucalyptus was planted,residues from the previous rotation were subjected to five different management treatments:(1)FRM,in which all forest residues(bark,branches,leaves,and litter)were allowed to remain on the soil and only trunk wood was removed;(2)FRMB,in which was identical to FRM except that bark was also removed;(3)FRMBr,in which only trunk wood and branches were removed;(4)FRR,which involved removing all types of residues(bark,branches,leaves,and litter);and,(5)FRRs,in which all forest residues from the previous rotation were removed,and leaves and branches from the new plantation were prevented from falling onto the soil surface using a shade net.Six years after planting,soil samples were collected at four different depths(0-2.5,2.5-5,5-10,and 10-20 cm)to determine 17 soil chemical,physical,and biological indicators.The results were combined into a soil quality index(SQI)using the principal component analysis approach.The SQI reduced by 30%,in the 0-20 cm layer,due to removal of harvest residues from the previous rotation,and collection of litter before it falls on the ground.The main drivers of SQI reduction were the principal components associated with soil organic matter and biological activity.Furthermore,the SQI was positively linearly related to tree height at P<0.01 and to tree diameter at breast height at P=0.07.The adverse impact on soil quality and forest productivity in our study indicates that removal of Eucalyptus harvest residues from sandy soils should be avoided.

哈密瓜细菌性果斑病菌快速检测方法的建立

【目的】哈密瓜细菌性果斑病在中国为新发生的病害,其病原菌为燕麦食酸菌西瓜亚种(Acidovorax avenae subsp.Citrulli),危害瓜果造成品质下降。该病为典型的种传细菌性病害,因此种子检疫成为防治此病害的重要手段。【方法】通过实验,将生物学、免疫学和分子生物学检测技术有机结合,建立了一套针对哈密瓜果斑病的种子带菌检测方法Bio-IMS-Real-timePCR。【结果】经过人工模拟种子带菌检测实验,结果表明该方法可成功地检测出1000粒种子中的1粒带菌种子(带菌量约为1.04×105CFU/种子,经计算,可以检测的最初浓度为2CFU·ml-1ASCM培养液),且信号较强。【结论】该检测方法的建立,大大提高了对哈密瓜细菌性果斑病菌检测的精度,也为生产实践中哈密瓜果斑病的防治提供了重要的技术支持。

2019年缅甸草地贪夜蛾发生情况考察报告

缅甸是我国草地贪夜蛾的重要境外虫源区,为了掌握草地贪夜蛾在缅甸的发生与防控情况,2019年5月19-25日,云南省农业科学院与缅甸农业研究司专家联合对缅甸南部、中部、中北部和东部草地贪夜蛾开展了实地调查。结果表明:缅甸全境均有草地贪夜蛾发生,为害严重,田间多种虫态并存。其中,南部玉米大部分已经收获,虫株率62.50%~97.50%;中部区域种植少量的商品甜玉米,防治到位,虫株率6.00%~7.50%;中北部曼德勒敏建玉米种植面积最大,达8000hm^2,80%的地块已成熟收获,处于吐丝-乳熟期的田块虫株率达100%,受害严重;东部掸邦虫株率59%,虫口密度2.60头/株。玉米是缅甸第二大种植作物,全年玉米种植面积达47万~52万hm^2,其中与我国云南接壤的东部掸邦是主要种植区。到5月前因无有效降雨,全境玉米尚未大面积种植,仅有零星种植,随着雨季的来临,玉米种植面积将全面增加,草地贪夜蛾种群数量也将随之增加。因此,加强与缅甸相关部门合作,密切掌握缅甸玉米种植及草地贪夜蛾的发生与防控情况,对我国草地贪夜蛾的监测预警及防控有重要的参考价值。

Assessing the Potential to Change Stakeholders Knowledge and Practices on Fertilizer Recommendations in Africa

Africa’s fertilizer use averages only 8 kg per hectare per year. Available fertilizer recommenda-tions in Africa are high, and vary between countries. The recommendations are generally out dated, and/or “blanket” recommendations that are not site, or crop specific. Recommendation developed for one crop is often used for another and possibly unrelated crop. CABI and AGRA designed a project whose goal is “to help improve the capacity of National Research Institutions in developing fertilizer recommendations for efficient and profitable fertilizer use in 13 sub-Saharan African countries within the framework of ISFM practices under smallholder farming by the end of March 2016”. Baseline survey conducted in May 2014 targeted scientists, policy makers, extension workers, agro-dealers, fertilizer companies and farmers/farmer organization. Snowballing and convenience sampling techniques were used to get the sample and emails were used to reach the respondents. A total of 416 respondents were targeted but only 219 responded from 12 countries. Out of the 219, 148 were extension workers and researchers. About half (51%) of the scientists are aware of fertilizer optimization tool, and a lesser proportion have used the tool across all countries (31%). Fewer extension workers (31%) were aware of the fertilizer optimization tool and none reported to have used the tool. On average about 5% of the study participants reported that other stakeholders were involved in the development of fertilizer recommendations including farmers, farmer organizations, policy makers, researchers, extension workers, agro dealers, fertilizer companies and donor organizations. Stakeholder involvement was highest in Nigeria at 15%, followed by Ethiopia (13%) and Malawi (10%) but most of the countries reported <5%. There is a general understanding that development of fertilizer recommendations is a multi-stakeholder initiative and therefore need for involving many stakeholders in the development of fertilizer recommendations across Africa that will fosters greater ownership and sustainability.

Global wild rice germplasm resources conservation alliance:World Wild-Rice Wiring

Wild relatives of crop are key genetic resources serving as diversity reservoirs for crop improvement under changing environments.Rice(Oryza sativa)is one of the most important crops in the world,providing staple food for half of the world's population.Wild rice is thus a critical germplasm resource for sustained global food security,ensuring high production yields,improved quality,and stress resistance in the face of climate change.Wild rice is closely related to domesticated rice and has a rich genetic diversity and exceptional adaptability to extreme environments.It has played a pivotal role in the history of rice hybridization and has become a key resource for rice breeding programs.The identification of wild-type cytoplasmic male sterility resources paved the way for the achievement of the“three lines”goal in hybrid rice,leading to a significant increase in rice yields.In addition,the use of resistance alleles found in wild rice is making rice production more resilient to losses caused by environmental stresses.However,wild rice germplasm resources are threatened due to habitat destruction and other anthropogenic factors.At the same time,the lack of centralized distribution of wild rice has hampered the sharing of basic information on wild rice resources and the utilization and conservation of wild rice in each country,as well as collaboration among scientists.

LAND-USE INTENSIFICATION TRENDS IN THE RIO DE LA PLATA REGION OF SOUTH AMERICA:TOWARD SPECIALIZATION OR RECOUPLING CROP AND LIVESTOCK PRODUCTION

The Rio de la Plata region comprises central Argentina,Uruguay,and southern Brazil.Modern agriculture developed around 1900 with recent decades being characterized by the advance of cropping areas over native grasslands.Highly specialized agriculture has decoupled crop and livestock production but has succeeded in intensifying yields.However,significant losses of ecosystem services have been reported.Thus,questions have been raised on the sustainability of this pathway.A glance at world regions that have experienced similar trends suggests that an urgent course correction is needed.A major concern has been the lack of diversity in regions with highly specialized agriculture,promoting renewed interest in integrated crop-livestock systems(ICLS),not only because ICLS are more diverse than specialized systems,but also because they are rare examples of reconciliation between agroecosystem intensification and environmental quality.Consequently,this paper discusses alternatives to redesign multifunctional landscapes based on ICLS.Recent data provide evidence that recoupling crop and animal production increases the resilience of nutrient cycling functions and economic indicators to external stressors,enabling these systems to face climate-market uncertainty and reconcile food production with the provision of diverse ecosystem services.Finally,these concepts are exemplified in case studies where this perspective has been successfully applied.

Whole-genome sequencing to detect mutations associated with resistance to insecticides and Bt proteins in Spodoptera frugiperda

The fall armyworm(FAW),Spodoptera frugiperda,is a major pest native to the Americas that has recently invaded the Old World.Point mutations in the target-site proteins acetylcholinesterase-1(ace-1),voltage-gated sodium channel(VGSC)and ryanodine receptor(RyR)have been identified in S.frugiperda as major resistance mechanisms to organophosphate,pyrethroid and diamide insecticides respectively.Mutations in the adenosine triphosphate-binding cassette transporter C2 gene(ABCC2)have also been identified to confer resistance to Cry IF protein.In this study,we applied a whole-genome sequencing(WGS)approach to identify point mutations in the target-site genes in 150 FAW individuals collected from China,Malawi,Uganda and Brazil.This approach revealed three amino acid substitutions(A201S,G227A and F290V)of S.frugiperda ace-1,which are known to be associated with organophosphate resistance.The Brazilian population had all three ace-1 point mutations and the 227A allele(mean frequency=0.54)was the most common.Populations from China,Malawi and Uganda harbored two of the three ace-1 point mutations(A201S and F290V)with the 290V allele(0.47-0.58)as the dominant allele.Point mutations in VGSC(T929I,L932F and L1014F)and RyR(I4790M and G4946E)were not detected in any of the 150 individuals.A novel 12-bp insertion mutation in exon 15 of the ABCC2 gene was identified in some of the Brazilian individuals but absent in the invasive populations.Our results not only demonstrate robustness of the WGS-based genomic approach for detection of resistance mutations,but also provide insights for improvement of resistance management tactics in S.frugiperda.