Yield Loss

A new particle defect mode has manifested itself with the introduction of sub-0.25 lm process flows. Device structures can now be damaged as a result of collision of high velocity wafers with lower velocity ''ambient'' particles in the process chamber. This effect has been found in batch implanters where wafers are scanned on a spinning disk or wheel. As feature geometries shrink, yield losses from the ballistic particle collisions increase. The particles may be sourced within the process tool, or brought in on the incoming wafers. It is primarily the motion of the wafer which provides the damaging energy of collision, not the motion of the particle. High scan velocities were thought necessary to achieve implant process uniformity. Avoiding yield loss from these new defect modes requires careful attention to the conceptual and detailed design of the implanter to minimize the likelihood and energy of these collisions.

Weeds generally occur in patches in production fields. Are these patches spatially and temporally stable? Do management recommendations change on the basis of these data? The population density and location of annual grass weeds and common ragweed were examined in a 65-ha corn/soybean production field from 1995 to 2004. Yearly treatment recommendations were developed from field means, medians, and kriging grid cell densities, using the hyperbolic yield loss (YL) equation and published incremental YL values (I), maximum YL values (A), and YL limits of 5, 10, or 15%. Mean plant densities ranged from 12 to 131 annual grasses m−2and < 1 to 37 common ragweed m−2. Median weed densities ranged from 0 to 40 annual grasses m−2and were 0 for common ragweed. The grassIvalues used to estimate corn YL were 0.1 and 2% and treatment was recommended in only 1 yr when the highIvalue and either the mean or median density was used. The grassIvalues used for soybean were 0.7 and 10% and estimated YL...

The pink stem borer (Sesamia nonagrioides Lef.) is the main pest of maize (Zea mays L.) in northwestern Spain. Little is known about combining ability for antibiosis and tolerance to this pest. Therefore, the objectives of this work was the estimation of general combining ability (GCA), specific combining ability (SCA) and reciprocal effects (R) for stem damage traits, yield and yield loss, using a complete diallel of ten inbreds, and to determine the most useful trait for evaluating the level of defense to pink stem borer. The diallel design was evaluated for two years for stem damage traits, yield loss, and for yield under two conditions, infestation with Sesamia nonagrioides and no infestation. For all stem damage traits, general combining ability was significant, while specific combining ability and reciprocal effects were not significant. This indicated that, for this set of inbreds, only additive effects were important for stem antibiosis. GCA and SCA effects were significant, in at least a trial, for yield under both infestation conditions and for yield loss. R effects were significant for yield of infested and no infested plants in 1995. The lack of concordance among lines that exhibited the most favorable GCA effects for stem antibiosis, yield loss, and yield under infestation conditions and the low correlation coefficient between SCA effects for yield under infestation and no infestation conditions showed that yield under infestation conditions is the best trait for evaluating the level of defense against pink stem borer attack. A interpopulational recurrent selection program for yield under infestation conditions appears as the most efficient program to improve the defense level against pink stem borer attack.

Stem canker and Phytophthora pod rot (PPR) or black pod caused by Phytophthora palmivora are serious diseases of cocoa (Theobroma cacao L.) in Sulawesi, Indonesia, causing high yield losses for smallholders, possibly exceeded only by losses due to the cocoa pod borer (CPB), Conopomorpha cramerella. Potassium phosphonate (phosphite) applied by trunk injection has been demonstrated to effectively control canker and PPR in Papua New Guinea. The method was tested in a field trial in south-east Sulawesi. Fifty trees were injected with phosphonate, 50 with water and 50 were left untreated. Phosphonate was applied at a rate of ~16 g active ingredient per tree per year, depending on the size of each tree. Trees were evaluated each month for canker severity, for PPR incidence and for CPB incidence and severity. From 4 months after the initial injection, trees treated with phosphonate had negligible levels of canker. Over a 2.5-year period, phosphonate significantly decreased PPR incidence. Cycles of PPR infection occurred in the wet season with PPR incidence fluctuating from less than 30% to greater than 75%. These fluctuations might have been due to variations in rainfall causing natural cycles of sporulation and infection. CPB incidence did not differ significantly between treatments. Since trunk injection of phosphonate effectively controls stem canker and decreases PPR in the long term it provides a valuable option for the management of these diseases for cocoa smallholders.

Since its introduction, the 'pushepull' technology (PPT) has been promoted as an innovative approach for addressing yield losses caused by Striga weeds and stemborer infestations on farmers' maize fields in western Kenya. The technology has been disseminated through different pathways each of which might have different uptake enhancement capabilities. This study was concerned with how different dissemination pathways impacted on farmers' time to adoption while controlling the effects of selected socio-economic and regional factors. This assessment was necessary in order to recommend which dissemination pathway or combination of pathways that could provide an effective dissemination strategy that speed up adoption, while ensuring continued practice of the technology. Data were analyzed using a parametric (Weibull) functional form to specify time to adoption from the first date of a farmer being aware of the technology. The findings indicate positive duration dependence and a positive rate of change in the adoption process. Field days (FD) had the highest effect on the speed of uptake, followed by Farmer Teachers (FT). Other variables that accelerated adoption were education, household size and high-income level. Gender, Tropical Livestock Units (TLUs), group membership, and district dummy variables had delaying effects on the adoption process. The findings suggest the need to fast track the scale up and uptake of PPT through pathways which allow for interactive information sharing and learning as exemplified through farmer teachers and field days.

Five chickpea cultivars, Chitoui, Neyer, Kasseb, Beja 1 and Bouchra, were planted on three sowing dates at two Experimental Stations in Tunisia: Bou Salem in the north and the more Electronic supplementary material The online version of this article (

Rice productivity and sustainability are continually threatened by abiotic stresses, particularly in the era of global climate change. In severe cases, 100% yield loss can be experienced due solely to abiotic stresses, such as drought. The situation may become worse due to climate change that may multiply the frequency and severity of such abiotic stresses. Hence, there is an urgent need to develop improved varieties that are more resilient to abiotic stresses. This article examines the net economic benefit and potential economic impacts of developing and disseminating a drought tolerant rice variety in South Asia. Drought is one of the most destructive abiotic stresses that not only causes major rice yield losses in South Asia, but also in other parts of Asia and Africa. Using the ORYZA2000 crop simulation model, we demonstrate that the new variety can provide yield gains in South Asia both when there is no change in the climate and also under the different climate scenarios projected by CGCM climate model. Moreover, our economic surplus analysis shows that the economic benefits from the successful development and dissemination of a drought tolerant variety more than outweigh the research investments needed to develop the variety. The partial equilibrium models we used also indicate that rice production is higher and rice prices are lower when a drought tolerant variety is adopted in South Asia (as compared to the case without this new variety). This in turn can lead to more sustainable rice production, improved food security, and better nutritional outcomes for the poor.

Citrus huanglongbing (HLB) reduces an affected orchard's economic life. This work aimed to characterize yield loss due to HLB for different sweet orange cultivars and determine the relationship between disease severity and yield. Disease severity and yield were assessed on 949 individual trees distributed in 11 different blocks from sweet orange cultivars Hamlin, Westin, Pera and Valencia. In each block, plants showing a range of HLB severity levels and asymptomatic plants were selected. Total yield (weight of harvested fruit), mean weight of asymptomatic and symptomatic fruit, relative yield (symptomatic tree yield/mean yield of asymptomatic trees from the same block) and relative number of fruits (fruit number from symptomatic tree/mean number of fruits from asymptomatic trees from the same block) were determined. The weight of symptomatic fruit was lower than the weight of asymptomatic fruit, but the weights of asymptomatic and symptomatic fruit were not correlated with disease severity, indicating that the effects of HLB were restricted to symptomatic branches. The relationship of the relative yield with HLB severity can be satisfactorily described by a negative exponential model. The rates of yield decrease as a function of disease severity were similar for all assessed cultivars. A relative yield (up to 19%) was observed even for trees where disease severity was 100%. The strong linear relationship between relative number of fruits per tree and the relative yield per tree suggested that the yield reduction was due primarily to early fruit drop or lack of fruit set on affected branches.

Tomato, cabbage and garden egg (African eggplant, or Solanum Aethiopicum) are important crops for small-scale farmers and migrants in the rural and peri-urban areas of Ghana. Genetic modification (GM) has the potential to alleviate poverty through combating yield losses from pests and diseases in these crops, while reducing health risks from application of hazardous chemicals. This ex-ante study uses farm survey data to gauge the potential for adoption of genetically-engineered varieties, estimate the potential impact of adoption on farm profits, and highlight economic differences among the three crops. Farmer's expenditures on insecticides are below the economic optimum in all three crops, and the estimated function for damage abatement shows that insecticide amounts are significant determinants of cabbage yields only. Nonetheless, yield losses from the pests and diseases affect insecticide use. Stochastic budget analysis also indicates a higher rate of return to vegetable prod...

Liriomyza trifolii (Burgess, 1880) (Diptera:Agromyzidae) is an important insect pest on vegetable areas. A field-experiment was conducted to investigate population densities of Liriomyza trifolii (Burgess, 1880) on two vegetable soybean (Glycine max [L.] Merr.) cultivars in different irrigation levels in the semi-arid conditions. This research was carried out at the Agricultural Experimental Field of the Harran University (Sanliurfa, Turkey) during the growth periods of 2006, and 2007. The irrigation treatments were 33%, 67 %, 100 %, and 133 % ratios of total irrigation water applied (IW)/cumulative pan evaporation (CPE) with four day irrigation interval. The experiment area was checked once a week during the whole production period. Ten leaves were removed randomly from each plot and living larvae counted. Adult counts were made on yellow sticky trap which placed randomly in each plot. Bean yield was also recorded. Differences of adult number and living larvae were significant between varieties, but showed no significant changes in response to irrigation levels within variety. The number of living larvae and adult of L. trifolii were higher on cultivar Toyohomare than Toyokomachi. However, the population was over the economical damage threshold on all irrigation levels. The highest green pod yield was obtained from Toyokomachi, with I 133 irrigation level. Based on the findings, varietal characteristics should be considered and select less sensitive cultivars to L. trifolii and water stress especially in semi-arid and arid areas for successfully growing soybean.

Abstract: A survey of plant parasitic nematodes associated with Zea mays in Kashmir valley was conducted from June 2006 to November 2006 which yielded a number of Tylenchids. Among them, the species Tylenchorhynchus zeae Sethi and G. Swarp, 1968, ...

Bu arastirma, bazi arpa cesitlerinde basaklanma doneminde olculen fizyolojik ozellikleri ile verim ve verim unsurlari arasindaki iliskileri degerlendirmek amaciyla yapilmistir. Arazi calismasi, Şirnak ekolojik kosullarinda 2015-2016 yetistirme doneminde tesaduf bloklari deneme desenine gore dort tekrarlamali olarak yurutulmustur. Materyal olarak iki sirali Baris, Pandora ve alti sirali arpa cesitleri kullanilmistir. Calismada, yaprak alani indeksi YAI , SPAD, normalize edilmis vejetasyon indeksi NDVI , bitki ortusu sicakligi BOS , protein icerigi, hektolitre agirligi, bin dane agirligi, nisasta icerigi ve tane verimi ozellikleri degerlendirilmistir. Arastirma bulgularina gore genotipler arasindaki farklar protein icerigi, nisasta icerigi, verim, bin tane agirligi ve hektolitre agirligi acisindan onemli bulunmustur. Arpa cesitlerinde incelenen ozelliklere gore SPAD degeri 30.85-35.43, YAI degeri 1.70-2.30, NDVI degeri 0.505-0.533, BOS degeri 15.45 °C -17.85 °C, tane verimini 1958-309...

Studies were carried out in eastern Uganda to assess the effect of legume flower thrips (Megalurothrips sjostedti) injury on cowpea grain yields and to establish economic injury levels (EILs) and action thresholds for thrips on cowpea. The studies relied on various insecticide spray regimes to obtain different thrips densities per experimental unit and use of exclusion cages in the field to confine defined numbers of thrips populations. A significant negative relationship (y ¼ À0:011x þ 1:77; r ¼ 0:87; P ¼ 0:003) was observed in the field studies between thrips densities and cowpea grain yields. The EIL was established at seven thrips per inflorescence. The study also revealed that three well timed (i.e., applied after bud initiation to minimize flower bud abortion) insecticide sprays are effective in the control of thrips. The three sprays are regarded effective in that thrips densities were kept below the established thresholds. More than three sprays also reduced thrips populations to less than seven per inflorescence but these were not economical.

The e!ectiveness of using seed treatment with imidacloprid (Gaucho ) to reduce the incidence of Bean leaf roll virus (BLRV, family Luteoviridae), Faba bean necrotic yellows virus (FBNYV, genus Nanovirus) and Soybean dwarf virus (SbDV, family Luteoviridae) in faba bean and lentil was investigated, using arti"cial inoculation with an aphid vector, Acyrthosiphon pisum (Harris). Imidacloprid was applied as a seed dressing at the rate of 0.0, 0.35, 0.7, 1.4 and 2.8 g a.i./kg of seeds. Incidence of BLRV, FBNYV and SbDV in faba bean was reduced from 92, 28 and 98% in untreated plots to 23, 2 and 85% in plots treated with 1.4 g a.i./kg and 13, 1 and 85% in plots treated with 2.8 g a.i./kg, respectively. Moreover, the yield loss was reduced from 80, 37 and 56% in untreated plots to 14, 0 and 39% in plots treated with 1.4 g a.i./kg, and to 14, 0 and 34% in plots treated with 2.8 g a.i./kg, for the above three viruses, respectively. Results indicated that imidacloprid at 2.8 g a.i./kg reduced virus incidence in faba bean plants when they were inoculated with BLRV two months after sowing from 91.6% in untreated plots to 0%, but no e!ect was detected when virus inoculation was done three months after sowing. Moreover, imidacloprid seed treatment signi"cantly improved lentil yields of moderately resistant and susceptible lentil genotypes, but had no e!ect on the yield of resistant genotypes. In addition, seed treatment was more e!ective in increasing seed yield of BLRV and FBNYV-inoculated plots compared to SbDV-inoculated plots. Based on these results, seed treatment with imidacloprid at 1.4 g a.i./kg of seeds can e!ectively reduce the incidence of two persistently transmitted aphid-borne viruses, BLRV and FBNYV, a!ecting faba bean and lentil crops.

This report presents the findings and recommendations of the feasibility study for a macro-level index insurance program for the Provincial Government of Chaco (GoC) as part of its natural-disaster risk management strategies for cotton growers located throughout the 25 departments of the province. Two index options were reviewed under this study starting with a macro-level rainfall deficit and excess rainfall cover based on individual rainfall weather stations in Chaco province, but as the rainfall index prototypes modeled produced very poor correlations with departmental average yields of cotton, this option was deemed inappropriate as a risk transfer instrument for GoC. The second index product analyzed was a macro-level area yield index insurance (AYII) cover which uses, as the basis of insurance and indemnity, the departmental average yield of raw cotton and which was designed to protect the GoC's and or lending institutions' financial exposure to severe climate related ...

In the present study, a helical disc mill was used to mill bulgur. Screen analysis (%), colour (lightness, redness, yellowness and yellowness index), yield, loss, energy consumption, capacity, hectolitre-weight (bulk density), ash, and moisture contents of bulgur were followed at the different disc gaps (

Performance and population growth rate of the cotton aphid Aphis gossypii Glover, and the yield losses inflicted by that pest, were studied in relation to varying nitrogen fertilization levels (90, 110, 150 and 190 ppm) on cucumber, Cucumis sativus L., under greenhouse conditions. The results showed that some plant variables, including leaf biomass, water and nitrogen content, increased at higher levels of nitrogen fertilization. Aphids developing on cucumber plants receiving the highest nitrogen fertilization had a significantly shorter development time and produced more offspring per capita than aphids subjected to the other regimes. However, no significant differences were observed in juvenile survivorship under different nitrogen treatments. Aphid adult body weight and mean relative growth rate (MRGR), as well as the intrinsic rate of natural increase (r m), were positively correlated with nitrogen fertilization levels in the treated plants. Additionally, aphid abundance and population growth rate (r) were significantly influenced by interaction between nitrogen fertilization level and sampling date. Plant yield was significantly affected by the interaction between nitrogen fertilization rate and aphid presence. In the absence of aphids, plant yield increased linearly with higher nitrogen fertilization; however, in the presence of aphids yield decreased linearly with nitrogen fertilization, the lowest yield being produced by plants fertilized with 190 ppm nitrogen. We discuss the results in relation to aphid population dynamics and management.

SUMMARYA simple model is developed to describe crop yield loss as a function of weed density. The model, a rectangular hyperbola, has two agronomically meaningful parameters which together can be used as indices of competitiveness. Examples are given where the model is fitted to experiments from the literature. Seventeen other models are compared through application to 22 data sets. It was found that for the data available two‐parameter yield loss models were generally sufficient.The hyperbolic model gave the best description of data, but this was only marginally better than three other models. This conclusion is discussed with reference to the popular sigmoidal model.

The influence of strategically positioned weeds on the yield of chickpea 9.1 Introduction The relationship between weeds and crops has been examined in many different ways since the time of the first agriculturists. Each weed/crop relationship is unique, and will be dependent on the crop type and density, weed type and density, and the number of weed species present. In recent years, specific studies using empirical models have attempted to mathematically describe what is happening when a single crop competes for resources with a weed at various densities (Cousens 1985a, 1985b). The models derived to explain the relationship between a single weed and a crop do not account for multiple weed species with varying competitive ability (Van Acker et al. 1997). A leaf-area model can describe multiple weed competition by the damage coefficients for each weed being combined in an additive fashion (Kropff & Spitters 1991, Van Acker et al. 1997). The process of adding weed species does not allow for interactions between weeds increasing or decreasing the competitive ability of the weed burden (Van Acker et al.

Common bacterial blight, caused by Xanthomonas axonopodis pv. phaseoli, is an important disease affecting beans causing considerable yield losses in many producing areas. Our aim was to investigate Xap-beans interactions in the first 48 h after infection analyzing structurally relevant changes by electron microscopy. Scanning electron microscopy analysis demonstrated morphological changes on leaf surfaces of both species. Transmission electron microscopy showed different types of chloroplast structural disorganization in both parenchyma and bundle sheath cells of Vigna unguiculata which were only observed in parenchyma cells of Phaseolus vulgaris. Additionally, we report an unexpected physical association between the chloroplasts and mitochondria observed only to P. vulgaris-infected plants. Keywords Mitochondria-chloroplasts association Á Xanthomonas axonopodis pv. phaseoli Á Vigna unguiculata Á Phaseolus vulgaris Communicated by B. Barna.

Gibberella zeae is a pathogen of wheat and other small-grain cereals, causing yield losses and reducing grain quality by producing the trichothecene deoxynivalenol (DON) which is harmful to animals and humans. One hundred and fifty three progeny from a cross between two European DON-producing isolates of G. zeae were analyzed for aggressiveness and DON production in three environments (location-year combinations) in Germany. Aggressiveness, measured as head blight rating and relative plot yield, and DON production showed continuous distribution for each environment and across environments. There was significant (P ¼ 0.01) genotypic variation for all three traits. Transgressive segregants occurred for all three traits. Both repeatability estimates within an environment and heritability estimates on an entry-mean basis for head blight rating and DON production were medium to high (0.5-0.7). Progeny-environment interaction accounted for about 29% of the total variance for the two aggressiveness traits and 19% for DON production. The large genetic variation derived from a cross between two rather similar European parents indicates a potential for increasing fungal aggressiveness in the G. zeae population.

Results o f farm-level experiments with pearl millet are reported from four villages in semi-arid Niger in 1982 and 1983. Crop establishment, yield loss factors (insects, diseases, striga) and economics o f new practices were studied in a randomized design which included density, fer tility, cultivar, and intercropping with cowpea as treatments. Improved cultivars did not estab lish significantly better than local ones, but fertilizer occasionally improved establishment. Incidence o f yield loss factors was low , and only small effects o f cultivar and fertilizer were seen. Fertilizer increased grain yields o f the local cultivar b y as much as 153%. The use o f ferti lizer and improved cultivars increased grain yields b y as much as 171% over an unfertilized local millet. Even without government subsidies, fertilizer use was profitable for 56% o f farmers on all cultivars. In general, fertilizers and improved cultivars had a small positive impact on profita bility, with little adverse impact on grain yield variability, so that they could be recommended to farmers with some prospect o f success. The intercropping treatment failed in both years, and would have to be m odified before extension.

Fruit discards due to physiological disorders and mechanical damage can exceed 50% of apple production in neotropical climate zones such as Uruguay. These damages become generally visible during ripening and storage, but they depend on factors that occur in the field. Sunburn is a major quality defect in fruit, known to be related to high radiation and temperatures, and, more recently, it has also been related to the water status of tissues in fruit and trees. This study aimed to evaluate the relationship between fruit damage and fruit tissue water status in “Brasil Gala”, “Cripps Pink” and “Granny Smith”, as well as the effect of treatments to avoid sun damage (50% black net, 20% translucent white net and kaolinite application) on stemwater potential in “Granny Smith”. Fruit water potential decreased throughout the growth cycle. The exposed sides of fruits located outside the tree crown showed lower water potential than the non-exposed sides. Only the 50% black net of the sunburn avoidance treatments modified the water potential.

Early infections of the papaya ringspot virus-watermelon strain (PRSV-W) in summer squash Cucurbita pepo may cause marketable yield losses of up to 100%. Because control of the viral disease via management of vector insects is not efficient, incorporation of PRSV-W genetic resistance into C. pepo cultivars would be highly desirable. Although resistant accessions have been described in C. ecuadorensis, C. foetidissima, C. maxima and C. moschata, resistant accessions of C. pepo are rare. This paper reports on interspecific hybridization between C. pepo and a PRSV-W-resistant C. moschata squash accession, and on the early steps in introgression of this resistance into the former species. C. pepo cv. Asmara was crossed with two PRSV-W resistant C. moschata accessions. Immature F 1 (C.pepo × C.moschata) embryos were excised 20 days after pollination, and cultured asseptically in two different culture media, each under two different light regimes. No adult plants could be recovered from immature embryos of the cross C. pepo cv. Asmara × C. moschata cv. Piramoita. From the cross C. pepo cv. Asmara × C. moschata cv. Duda, 4 seedlings were recovered from 6 embryos incubated in a growth chamber [25 • to 28 • C, 16 hours of light with 1500-2000 lux/ 8 h dark period] immediately after excision and inoculation in a culture medium [= Murashige and Skoog (MS) + 0.01 mg/L of IAA (indolacetic acid) + 0.1 mg/L of Kinetin], without an intervening dark period. F 1 (C. pepo × C. moschata) plants were fertile, and upon selfing yielded viable F 2 seeds. PRSV-W resistance was assessed in the F 2 (C. pepo × C. moschata) population, using C. pepo cv. Asmara and C. moschata cv. Duda, respectively, as the susceptible and resistant (tolerant) checks. Plants were mechanically inoculated with a known PRSV-W isolate. The F 2 population showed a PRSV-W response intermediate between those of the parental accessions, and estimates of the mean degree of dominance indicates incomplete dominance in the direction of susceptibility. The mean broad-sense heritability estimate of PRSV-W resistance was 0.48, a medium to high value, indicating the likelihood of a significant response to selection for resistance. The introgression of the resistance to PRSV-W of C. moschata into C. pepo seems to be technically viable.

Field experiments were conducted in 1993 and 1995 in Cameroon to determine the critical period of weed control in common bean (Phaseolus vulgaris L.), and the effect of location and cultivar. Bean yield loss increased with increasing duration of weed interference, and decreased with increasing duration of weed control. The critical period occurred between emergence and second trifoliate leaf for cultivar Maringue, respectively at Dschang (1993) and YaoundC (1995), and between first trifoliate leaf and pod filling stages of bean growth for other trials. Generally, the critical period was less than 25 days at 5% yield loss level, and non-existent in 50% of the trials when 10% yield loss was considered. The short critical period observed suggests that in Cameroon, irrespective of location and cultivar, a single weed removal well timed is sufficient to prevent yield loss in bean.

Insect infestation and low soil fertility are the major constrictions in okra production and various tactics have been recommended for increased production. An experiment was conceived to explore the effects of different levels of pig manure on the performances and severity of damage caused by Podagrica uniforma Jacq. infestation on okra in South Western, Nigeria. The research was arranged in Randomized Complete Block Design (RCBD) with four treatments (0 t.ha-1 , 5 t.ha-1 , 10 t.ha-1 , 15 t.ha-1 and 20 t.ha-1) replicated thrice. Okra growth, fruit yield, insect population and severity of damaged leaves were assessed and exposed to the Analysis of Variance, and Duncan Multiple Range Test (DMRT) at a 5 % level of significance was used to separate significant treatment means. The study outcomes revealed that okra growth and yield parameters were directly proportional as the pig manure rates increase. A similar trend was equally recorded for P. uniforma population in okra plants enriched with variable rates of pig manure, okra supplied with 20 t.ha-1 of pig manure exhibited the highest growth, yield performance and P. uniforma population. While the severity of leaf damage caused by P. uniforma was in descending order, very low in okra enriched with varying levels of pig manure as compared to the damage recorded in control. The trial showed that okra growth and yield was significantly (p<0.05) enhanced by the application of 20 t.ha-1 pig manure with a resultant reduction in the severity of damaged leaves caused by P. uniforma infestation.

Mistletoes, which are plant parasites in the families, Loranthaceae and Viscaceae, have been reported to cause severe damage to cocoa, citrus and many other fruit trees in Ghana. Participatory and field surveys were carried out to assess the prevalence of the parasite on selected orange orchards in the Abura-Asebu-Kwamankese district of the Central Region of Ghana, a major citrus producing area in Ghana. Both structured and unstructured questionnaires were administered to 40 citrus farmers in the district to find out farmers views about the prevalence and control of the parasite in the district. A field assessment of the incidence and severity of the mistletoe in 20 citrus orchards was also conducted. The results revealed high incidence and severe infestation of citrus by the mistletoe. This obligate parasite attacks citrus plants as early as three years after planting and causes severe damage to citrus trees by retarding growth, causing yield loss and mortality. All the respondent ...

The importance of banana (Musa sp) for food and nutrition security Banana is grown in the humid and subhumid tropics, the tropical highlands, and even in the drier subtropics. In terms of production, bananas are the world's fourth most important food crop, mostly grown and consumed in the tropical and subtropical zones. The banana's ability to produce fruits all year round makes it an important food security crop and cash crop in the tropics. The crop is grown in more than 120 countries; around a third each is produced in the African, Asia-Pacific, and Latin American and Caribbean regions. As shown in Table 2.1.1, three categories of bananas are produced. Plantains and cooking bananas are staple foods, while dessert bananas are an important source of calories, minerals (such as potassium) and vitamins consumed as a fruit. The data in the table do not include production of export bananas. The production figures per capita can therefore be considered the production available for domestic consumption. About 87% of all the bananas grown worldwide are produced by small-scale farmers for local consumption as a food security crop, and for local markets rather than for international trade. They provide a staple food for millions of people, particularly in Africa. The regional figures do not highlight the subregions for which bananas are an important staple. Bananas and plantains supply more than 25% of the carbohydrate requirements for over 70 million people in Africa. These include parts of Uganda, Tanzania, Burundi, Rwanda and Eastern DRC for which East Africa Highland bananas are a staple food consumed in some localities two to three times per day. East Africa is the largest banana-producing and consuming region in Africa with Uganda being the world's second leading producer after India, with a total production of about 10.5 Mt. In some African countries such as Uganda the daily consumption of banana may exceed 1.6 kilogrammes per person, which is the highest in the world.

A new failure mechanism was studied on high density and high performances 0.25µm SRAM memories. A local anomalous polysilicon grain growth, promoted by a Phosphorus gate predoped implantation, induced a modification of dopant diffusion into N-doped transistor gate. This local variation of small transistor threshold voltage, was responsible for a severe yield loss in large SRAM memory array. This phenomenon was both related to gate material properties and gate predoped implantation conditions. This paper presents a complete characterization of this new failure mechanism, based on physical and electrical measurements. Finally, main results of process experiments, performed to solve the problem, are discussed.

Delayed harvest can improve the quality of miscanthus biomass for combustion and enhance the long-term sustainability of the crop, despite accompanying yield losses. The aim of this study is to identify the optimal harvesting time, which can deliver improved biomass quality for combustion of novel miscanthus genotypes at various sites across Europe, without high yield losses and without compromising their environmental performance. The relevant field trials were established as part of the European project OPTIMISC with 15 genotypes at six sites across Europe. For this study, the five highest yielding genotypes from each germplasm group and three sites with contrasting climatic conditions (Stuttgart, Germany; Adana, Turkey; and Moscow, Russia) were selected for assessment. The biomass samples were collected between August and March (depending on site) and subjected to mineral and ash content analysis. At Stuttgart, the delay in harvesting time led to a significant variation in combus...

Interactions between water and N may impact remote‐sensing‐based N recommendations. The objectives of this study were to determine the influence of water and N stress on reflectance from a corn (Zea mays L.) crop, and to evaluate the impacts of implementing a remote‐sensing‐based model on N recommendations. A replicated N and water treatment factorial experiment was conducted in 2002, 2003, and 2004. Yield losses due to water (YLWS) and N (YLNS) stress were determined using the 13C discrimination (Δ) approach. Reflectance data (400–1800 nm) collected at three growth stages (V8–V9, V11–VT, and R1–R2) were used to calculate six different remote sensing indices (normalized difference vegetation index [NDVI], green normalized vegetation index, normalized difference water index [NDWI], N reflectance index, and chorophyll green and red edge indices). At the V8–V9 growth stage, increasing the N rate from 0 to 112 kg N ha−1 decreased reflectance in the blue (485 nm), green (586 nm), and red...

This paper presents a post-route gate-sizing algorithm for coupling-noise reduction that constrains the yield loss under process variations. Algorithms for coupling-noise reduction which do not consider uncertainty in the manufacturing process can make a circuit susceptible to failure. Using probabilistic models, the coupling-noise reduction problem is solved as a fixpoint computation problem on a lattice. A novel gate-sizing algorithm with low area overhead is proposed for coupling-noise reduction under uncertainty. Experimental results are reported for the ISCAS benchmarks and larger circuits with comparisons to traditional approaches.

Index crop insurance products can eliminate the asymmetric information problem inherent in farm-level multiple peril crop insurance. Purchasers of index insurance products are, however, exposed to basis risk. This study evaluates the efficiency of various index insurance products to reduce farm yield loss for representative corn farms in southern Georgia. Index insurance products considered are based on county yields, cooling degree days, and predicted yields from a crop simulation model.

Faba bean (Vicia faba L.) is one of the important pulse crops grown in many parts of the world. Its production and productivity are affected by different biotic and abiotic stresses. Broomrape (Orobanche and Phelipanche spp.) causes yield losses of 7-80% in major faba bean growing countries mainly in the Mediterranean Basin and Nile Valley countries. Host plant resistance is found to be the most effective and economic method of broomrape control. Efforts made at the International Center for Agriculture Research in the Dry Areas over many years to develop advanced breeding lines with acceptable resistance and tolerance levels to broomrape have resulted in the identification of several useful breeding lines. These lines were shared with National Agricultural Research Systems (Egypt, Sudan, Tunisia and Portugal) as part of the Faba Bean Orobanche International Nursery, in order to test their stability across three seasons (2005, 2006 and 2007). The results showed that Orobanche plant number, dry weight, Orobanche index, flowering date, maturing date and grain yield were significantly different among lines and locations. AMMI analysis showed that some lines derived from hybrid bulk populations "HBP/DS0/2000" and "HBP/ES0/2000" showed acceptable levels of yield stability in the presence of Orobanche infections across all environments compared with susceptible check. In highly infested soils, the tolerant and resistant lines gave acceptable levels of yield compared with the susceptible check. However, the yield potential of resistant and tolerant lines in non-infested soils was lower than the highly susceptible check.

The tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is a devastating pest of tomato originating from South America. After its initial detection in eastern Spain in 2006, it rapidly invaded various other European countries and spread throughout the Mediterranean basin. If no control measures are taken, then the pest can cause up to 80-100% yield losses in tomato crops in recently invaded areas and may pose a threat to both greenhouse and open-field tomato production. The exceptional speed and extent of T. absoluta invasion have called for studies documenting its biology and ecology, while indicating an urgent need for efficient and sustainable management methods. The development of approaches to manage T. absoluta would be facilitated through a detailed revision of information on this pest in its area of origin. This review combines information on the invasion by T. absoluta, its ecology, and potential management strategies, including data that may help the implementation of efficient biological control programs. These programs, together with a variety of other management tactics, may allow efficient integrated pest management of T. absoluta in Europe and Mediterranean Basin countries.

Intensification of tropical agricultural systems by increasing fertilizer input and technology is a current trend in developing regions. Under intensive management, erosion impacts on crop productivity may not be detected in the short term. However, long‐term impacts are expected because erosion rates in tropical agroecosystems are usually greater than the rate of soil formation. A temporal function of soil‐depth change was defined and named life time Conceptually, soil&#39;s life time is the time until a minimum soil depth needed for sustaining crop production is reached. The life‐time function was applied to the Ceveiro watershed (1990 ha) located at the Southeastern part of Brazil, and compared with sugarcane (Saccharum officinarum L.) yield loss estimations. Soil erosion prediction was made employing the Water Erosion Prediction Project. The mean soil erosion rate for the area was 15 Mg ha−1 yr−1, and sugarcane showed the highest mean value of 31 Mg ha−1 yr−1 The half life time ...

Equations for predicting milk and curd loss due to intramammary infection in sheep and goat herds were derived. The empirical equations were derived from previously published studies conducted by this team with Assaf sheep and crossbreeds of goats in Israel. From these equations, it appears that infection of 25, 50 and 75% of the udders in a given herd was associated with loss of 4.1-12.2.5% milk in sheep and 0.8-2.3% in goats; whereas curd loss was 5.2-15.5% in sheep and 3.3-9.8.9% in goats. Based on percent of udder infection and projected SCC, the following categories are suggested for classification of sheep and goat milk: i. High-quality milk <800,000 SCC/mL, associated with infection of ∼25%; ii. Medium quality milk <1,500,000 SCC/mL, associated with infection rate between 25 and 50%; iii. Low-quality milk >1,500,000 SCC/mL, associated with infection rate above 50%; iv. Milk containing >3,500,000 SCC/mL should not be accepted for human consumption.

TUC 550: a new variety of black bean (Phaseolus vulgaris L.) with tolerance to angular leaf spot (ALS)The purpose of this work was to develop a bean cultivar with tolerance to angular leaf spot (ALS) which would replace the susceptible bean cultivars currently used in Northwestem Argentina (NWA). In 2001, 55 lines of black beans were introduced from the International Center for Tropical Agriculture. These presented multiple genes that endowed them with tolerance to the main diseases affecting the crop. In 2002, these lines were cultivated at two sites, La Invernada (La Cocha, Tucumán) and San Agustín (Cruz Alta, Tucumán), in order to compare their yields and disease tolerance, also drawing comparisons with TUC 500 (local cultivar used as a control). Four lines were identified, which were later evaluated as regards their reaction against different pathotypes of ALS causal agent (Phaeoisariopsis griseola), isolated from beans produced in the Argentine Republic. As a result of these st...

Population fluctuation studies on mirid bug were conducted at Main Agricultural Research Station (MARS), Dharwad, Karnataka, India, during kharif 2016-17 and 2017-18. MRC 7351 (Kanaka) Bt cotton crop was raised under unprotected conditions during the the month of June-July. The pooled data of two years indicated that the activity of mirid bug started with the population of 0.89 bugs/ 5 squares during 36 th MSW and steadily increased with a population of 3.03 to 10.50 bugs from 37 th to 45 th MSW, respectively and reached maximum peak at 46 th MSW (12.00). Thereafter the population of bugs started to decreasing trend from 47 th to 7 th MSW. The damaged squares noticed from 37 th MSW with 7.74 per cent and slowly increased from 38 th to 43 rd standard week with 8.49 to 17.62 per cent damage and reached peak at 48th MSW (23.76%). Thereafter the per cent damage decreased from 49 th MSW (19.37) to 8 th MSW (0.31). The coccinellids were noticed throughout the season starting from 33 rd MSW (0.20/ plant) reaching two peaks at 49 th MSW (1.16) and 51 st MSW (1.14). The chrysoperla activity commenced from 36 th MSW (0.20/ plant) with two peaks at 42 nd MSW (1.27) and 45 th MSW (1.02). Similarly, two peak populations of spiders were noticed at 42 nd MSW and 44 th MSW (1.34 and 1.60). Weather parameters and natural enemies correlated with the population of mirid bug showed negative association with maximum temperature, minimum temperature and rainfall and showed no significant relationship with mirid bug. Whereas maximum and minimum relative humidity were positively correlated and showed no significant relationship. Chrysoperla (0.823**) and spiders (0.912**) showed highly significant and positive correlation on mean number of mirid bugs while coccinellid (0.380*) showed positive with significant relationship. Weather parameters and natural enemies had an influence to an extent of 85.40 per cent.

In the savanna zone of West Africa with a prolonged dry season, the successful growth of legumes as short-season fallow necessitates relay establishment of cover crops into the preceding food crop. Inappropriate choice of legume species and establishment dates may result in severe interspeci®c competition for light, water and nutrients and a subsequent yield loss in the main crop. In the current study, the highly competitive Cajanus cajan L. and the weakly competitive Stylosanthes hamata Taub. were relay-seeded into two upland rice cultivars with different competitive ability (WAB56-50, WAB450-24-3-2-P18-HB syn. V4) at different sowing dates, ranging from 0 to 84 days after rice sowing (DARS). Using a logistic function was adequate to describe rice grain yield, ®nal rice biomass and legume biomass at 1 week after rice harvest as a function of legume sowing date. Rice biomass and grain yield were signi®cantly P < 0:001 reduced when legumes were established between 0 and 28 DARS. Beyond 56 DARS no competition effects on rice were observed. At these late sowing dates only relatively low amounts of legume biomass were obtained, due to a combined effect of a more severe competition by the rice crop and a shorter growing period. The derived yield loss±legume biomass relationship showed that C. cajan was the most appropriate legume species of the two under study, to suit a relay intercropping system with upland rice, as it produced reasonable amounts of biomass at low levels of rice grain yield loss. This conclusion was con®rmed by results on the after-effect of the legumes, where only the improved fallow by C. cajan gave a signi®cant increase in the yield of the subsequent rice crop. Optimum sowing time of C. cajan was between 30 and 35 DARS. The effect of selecting a speci®c legume was found to surpass that of choosing either one of the two rice cultivars, for which contrasting results were obtained in 2 years of experimentation.

A 2-year field study was conducted using common vetch (Vicia sativa L.), wheat (Triticum aestivum L.), triticale (xTriticosecale Wittmack), barley (Hordeum vulgare L.), and oat (Avena sativa L.) pure stands as well as two common vetch-cereal mixtures for silage with each of the above four cereals in two seeding ratios (i.e., vetch:cereal 55:45 and 65:35, based on seed numbers) to determine the competition among the different species and the economics of each intercropping system. Intercropping systems were assessed on the basis of several existing intercropping indices such as land equivalent ratio (LER), relative crowding coefficient (RCC or K), aggressivity (A), competitive ratio (CR), actual yield loss (AYL), monetary advantage index (MAI), and intercropping advantage (IA). The LER and K values were greater for the common vetch-wheat (55:45) and the common vetch-oat (65:35) mixtures indicating that in these systems, there was an advantage of intercropping for exploiting the resources of the environment. A similar trend to that of LER and K was also observed for AYL. The aggressivity, CR and partial AYL values were greater for barley and oat than for wheat and triticale, whereas the corresponding values for common vetch were lower in mixtures with barley and oat than in mixtures with wheat and triticale. These findings indicate that barley and oat were more competitive partners than wheat and triticale as common vetch was affected more in mixtures with these two crops. The highest MAI and IA values were recorded for the common vetch-wheat (55:45) and the common vetch-oat (65:35) mixtures indicating that these intercropping systems were the most profitable.

The impact of plant defoliation on the yield of short-season soybean cultivars was evaluated in five trials carried out in two crop seasons (2008/2009 and 2009/2010) in three states in Brazil (Rio Grande do Sul, Goiás and Mato Grosso). In 2008/2009, defoliation was performed by removing one, two or three leaflets (33.3%, 66.6% and 100% defoliation, respectively) from all leaves at different plant developmental stages (V5, V8, R2, from V5 to R2, and from V5 to harvest). In 2009/2010, the defoliation levels studied were 16.7% (half leaflet) and 33.3% (one leaflet), performed weekly during the vegetative or reproductive period, and during the entire cycle in three trials in Goiás. All tested cultivars tolerated defoliation levels equal and sometimes even higher than current Economic Thresholds (ETs) (30% vegetative stage defoliation threshold and 15% reproductive stage defoliation threshold) without significant yield loss. This indicates that even for the new cultivars belonging to shorter maturity groups or of indeterminate growth habit, soybean plants showed high defoliation tolerance. Thus, we conclude that the currently recommended ET for leaf-lamina consumers in the soybean crop is still valid and should be used by growers, even for the newer cultivars belonging to the lower maturity groups with indeterminate growth habit.

The present work entitled : (c Plant Viral Diseases in The lvory Coast)) is a new edition of the document n046, in the collection ((Initiations Documentations Techniques n, edited by the ORSTOM institute in 1980, entitled : (c Viral Diseases of Cultivated Plants in lvory Coast D. This new edition is also written both in French and in English, and it briefly describes 47 different viral, or presurned to be viral, diseases, identified in the lvory Coast, on tuber crops, cereals, vegetables, legumes, industrial crops, fodder plants, ornementals and weeds. Each disease is described within 4 pages : 2 of them are concerned with the updated informations on the disease and the virus, one is a photograph of the typical symptorns and of the virus itself, when it is known, finally a last page is devoted to the localization of the disease in Africa and to the main bibliographic references on the concerned disease. At the end of the booklet, one can find a classification of al1 the viruses, a list of the viruses classified according t o their transmission mode, a table grouping al1 the African viral diseases not identified in the lvory Coast, and an author index of al1 the references cited in the text. Al1 the photographs were done by the authors and the majority of the electron micrographs were realized in the cc Groupe d'Etude et de Recherche.en Microscopie Electronique, GERME >> in Abidjan. This publication is first meant for agricultural experts and agronomists taking a part in the development of agricultural projects in Africa and Who are lacking informations on these misunderstood diseases. It has been written considering first the descriptive aspect of the diseases, instead of the viral aspect, in the aim of helping t o their identification. The people interested will find informations on the different transmission modes of the diseases and the possibilities for their field control. The African phytopathologists are also concerned by this review because, al1 along their work they will have t o identify viral diseases for which the symptomatology is unclear, so we hope this booklet will be helpful and that they will have al1 the references required. This viral listing is also useful t o plant virologists of the world, because the African viruses are usually unknown t o them, and this is the reason why we included technical details in the descriptions. Finally w e expect that the African studients, concerned by agricultural and biological sciences, will have the opportunity to get this booklet, t o help in the diffusion of plant viral knowledge. ((d'origine inconnue D, mais décrites depuis longtemps, étaient des maladies dûes à des virus nouveaux e t la découverte de leur transmission suggérait des solutions pour les éliminer.