Unprotected Plots Research Articles

In Vivo Efficacy of Bioagents and Fungitoxicants against False Smut Disease of Rice Caused by Ustilaginoidea virens (Cooke) Takahashi

The present experiment was conducted from June to November 2017 at Crop Research Center, Chirodi, Sardar Vallabhbhai Patel University of Agriculture & Technology, Meerut (U.P.), India to assess the efficacy of six fungicides-propiconazole, strobin, flutolanil, copper oxychloride, azoxystrobin, flusilazol, and two bioagents viz., Trichoderma harzianum and Pseudomonas fluorescens-against false smut of rice under natural epiphytotic field conditions. Once panicle emergence reached 50%, each fungicide and bioagent was sprayed once. The findings of present investigation revealed that spray of propiconazole @ 0.1% reduced the false smut significantly and resulted in the lowest percentage of infected tillers (7.48%) and smutted grains (4.98%) along with maximum yield parameters like number of tillers (294), 10-ears weight (30.10 g), 1000-grain weight (24.50 g) and yield (4903 kg ha-1); it was followed by the spray application of either azoxystrobin @ 0.07% or strobin @ 0.06% with above respective parameters. Apart from the fungicides applied, the application of Trichoderma harzianum also reduced the false smut and increased the yield components significantly over the control plots. However, the lowest 10-ear weight (22.80 g), 1000-grain weight (17.50g), and yield (3100 kg ha-1) along with the highest percentage of infected tillers (23.93%) and smutted grains (21.47%) were recorded in unprotected plots. Therefore, growers can be advised to use a foliar spray of one of three fungicides-propiconazole @ 0.1%, azoxystrobin @ 0.07%, or strobin @ 0.06%–at 50% panicle emergence stage to fungicidal control of false smut of rice.

Exclosure from browsing by invasive ungulates increases species richness and diversity of ground flora in rainforests of New Caledonia

Introduced ungulates can impact forest structure and composition. We tested in rainforests of New Caledonia if exclosure of invasive ungulates (Javan rusa deer Rusa timorensis russa and feral pigs Sus (scrofa) domesticus) increased abundance, species richness and diversity of native plants by comparing 19 plots of 10 m2 in four study areas that were protected from browsing for 7 years with 76 unprotected plots. Abundance, species richness and diversity of native plants of 20–60 cm of height were higher in protected plots compared to unprotected plots. We attribute the measured negative impact mainly to deer as the positive effect of exclosures was highest in the study area with the highest deer abundance and browsing rate. The exclosures were also beneficial in a secondary forest with medium deer abundance whereas in old-growth forest with medium deer abundance we could not detect an effect of the exclosures. We conclude that protecting even small areas from browsing by invasive ungulates can increase biodiversity and that exclosures are most beneficial at high deer abundance and in secondary habitats.

Combined effects of fungicides formulations and potato varieties on late blight management, yield and net farm income in Kenya

Management of late blight relies on the use of fungicides and potato varieties which have been associated with loss of efficacy over time. Baseline survey and field studies were conducted to evaluate the effects of fungicide formulations and potato varieties in managing late blight and subsequently on net farm income improvement. Four fungicides formulations (Infinito® (Fluopicolide 62.5g L−1 + propamocarb 625 g L−1), Milraz® (Propineb 700 g kg−1 + cymoxanil 60 g kg−1), Mistress 72® (Mancozeb 640 g kg−1 + cymoxanil 80 g kg−1) and Ridomil® (Metalaxyl 40 g kg−1 + mancozeb 640 g kg−1)), and varieties (Kenya Mpya, Shangi and Dutch Robijn) were evaluated. Survey results revealed that the majority (78%) of the farmers selected varieties to grow based on market dynamics as compared to seed availability (18%), disease resistance (12%) and other factors (8%). The most widely and least used fungicides were Ridomil® (28.8%) and Infinito® (1.7%) respectively. Late blight significantly reduced crop growth (height and stem count) and yield in the unprotected plots in Shangi and Dutch Robijn, but no effect was observed in K. Mpya. Mistress® suppressed blight symptoms by 54%, while Milraz® (lowest effects) reduced the disease by (43%). In unprotected plots, disease severity on K. Mpya was below 1%, while in Shangi and Dutch Robijn varieties, it was 60 and 78% respectively. Reduction in disease by Mistress® resulted in higher yield (30.70 t ha−1) as compared to the unprotected plots (9.25 t ha−1). Maximum yield (28.56 t ha−1) was obtained from K. Mpya, while Dutch Robijn, had the lowest observed yield (20.70 t ha−1) in protected plots. Yet, the highest cost benefit ratio (CBR) was recorded in unprotected plots with K. Mpya. The smallest CBR (1.55) was observed on plots where Milraz® was applied on Dutch Robjn. Results of this study show that, the use of fungicides reduced late blight and improved yield of potato substantially, but the efficacy varied with fungicide formulation and potato variety. However, the use of resistant variety was effective in managing late blight hence a useful tool for minimizing fungicide applications. Therefore, use of resistant variety could enhance a healthy biodiversity and at the same time maximize food production.

Comparative Studies of Lepidopteran Pest Incidence on JL 24 and DH 256 Varieties of Groundnut

This experiment compares the incidence of lepidopteran pests under protected and unprotected groundnut cultivation at AICRP on Groundnut, MARS, Dharwad, Karnataka in the kharif season of 2021–2022. In order to protect the protected plot from pests, protection measures were implemented at 50 DAS using flubendiamide 20 WG @ 0.5g/l for leaf-eating caterpillars. Based on the crop's phenology, observations were made. Spodoptera litura, Thysanoplusia orichalcea, Helicoverpa armigera, and Maruca vitrata, were deemed to be the main pests, with the remaining pests being of less significance based on their population density and type of damage. When comparing unprotected JL-24 and DH-256 crop plots to protected plots, the majority of major and minor pests were infested during the vegetative to maturity stage, with maximum infestation occurring during the pod formation and pod filling stages of the crop. In comparison to unprotected plots, protected plots had the highest pod and haulm yields.

Estimation of Yield Losses Due to Major Insect Pests of Groundnut

A field experiment was carried to estimate the yield losses due to the groundnut leaf miner Aproaerema modicella (Deventer), tobacco caterpillar Spodoptera litura (F), leafhoppers Empoasca kerri (Pruthi) and thrips Scirtothrips dorsalis (Hood). The results showed the insect pests caused a significant reduction in plant height and other yield attributing characters. They caused a mean reduction of plant height (22%), primary branches (29.1%) reduction in pods/ plant (54.6%) and (44.5) reduction of kernels/ plant. There was a higher yield in the protected plots with 2050 kg/ ha due to spray of insecticides when compared to unprotected plots with 1123 kg/ ha, with a yield increase of 82.5%.

Quantitative and qualitative yield loss caused by red deer (Cervus elaphus L.) grazing on permanent organic grasslands

ABSTRACT This paper addresses yield loss due to red deer (Cervus elaphus) grazing on permanent grasslands on three organic farms in SE Slovenia over two consecutive years. Deer graze on permanent grasslands throughout the year, but the resulting crop loss varies during the growing season. Accounting for three mowings, the quantitative yield loss due to deer grazing totalled 48–52%, or 3.9–4.3 t/ha. Deer had the highest consumption capacity in the spring (first mowing: yield loss of 1.7–1.9 t of air-dried hay/ha), and towards the end of the growing season, consumption decreased (third mowing: loss of 0.9 t/ha). A floristic inventory indicated low species diversity and production in permanent grasslands in SE Slovenia. The crude protein content in unprotected plots was generally greater than that in protected plots, but due to a large quantitative yield loss, the yield of crude protein and net energy for lactation on heavily grazed land were much lower than those on protected land in all mowings. The average additional cost per unit of heavily grazed area ranged from 182 to 344 EUR/ha, and the differences are the result of the different intensities of game grazing in individual locations and grassland production capacities.

Adaptation and mitigation capacity of wildland forests in the northeastern United States

Managing forests to mitigate climate change and increase their capacity to adapt to future climate-related disturbances and conditions typically involves protecting and enhancing forest carbon stocks and sequestration capacity while promoting structural diversity. While the focus has been on comparing active management approaches for meeting these objectives, there are few empirical assessments of passive management. Here we used quasi-experimental methods to compare carbon and structural complexity within “wildlands,” where harvesting and other land uses are prohibited, to environmentally comparable forests without protection from timber harvesting. Using USDA Forest Inventory and Analysis (FIA) plots from the Adirondack-New England region of the Northeastern U.S., we compared aboveground carbon, total forest basal area increment (our proxy for carbon sequestration), and six forest-level structural variables in forests. To help explain observed differences, we examined (1) the recent history of harvesting within unprotected forests, (2) stand age in wildland and unprotected forests, and (3) the carbon and structural attributes of protected and unprotected plots at the initiation of wildlands protection. Aboveground carbon was 20% higher in wildlands overall (P < 0.0001), with differences greatest in wildlands of New York (+32%; P = 0.0001) and in Maine (+34%; P = 0.01) where recent harvesting intensity and differences in stand age between protection categories were highest. Basal area increment did not differ between protected areas at the regional and sub-regional scale, but was 37% higher in wildlands (P = 0.03) than in recently harvested areas. Structural complexity was generally higher in wildlands, with four structural variables – large live (>60 cm DBH) and large dead (>45 cm DBH) tree density, maximum tree height, and diversity of diameter size classes) – greater in wildlands than in unprotected forests. Two variables (adult tree species richness and standard deviation of tree height) did not differ between protection categories. Both carbon and structural differences were amplified by recent harvesting in unprotected plots. For the subset of plots that allowed for comparison, wildlands did not differ in carbon and structural attributes from unprotected plots at the onset of wildlands protection, suggesting that subsequent management rather than initial differences was the driver of carbon and structural differences between protection categories. Our results highlight the adaptation and mitigation benefits of allowing natural processes to predominate in strictly protected areas.

Tomato late blight yield loss assessment and risk aversion with resistant hybrid

Late blight (Phytophthora infestans) is one of the devastating diseases of tomato worldwide. Field trial was carried out in Kharif 2019 and 2020 in Hesaraghatta, Bengaluru, Karnataka, India, to estimate yield loss due to late blight and to assess extent of protection in resistant genotype during late blight epiphytotics. Yield loss was calculated as per cent difference in yield between fungicides treated and unprotected plots in three F1 hybrids NS501, Arka Rakshak, both susceptible genotypes and Arka Abhed, a resistant genotype. Over two years, average yield loss due to late blight was 79.47 per cent in NS501, 75.53 per cent in Arka Rakshak and 12.84 per cent in Arka Abhed. With lower mean AUDPC values (147.22 in 2019 and 469.17 in 2020) and with low yield loss, Arka Abhed provided affordable protection against late blight. Our findings indicate late blight as an economically important peril to be considered for tomato yield loss coverage under insurance scheme in Bengaluru region. Arka Abhed hybrid can be cultivated to avert yield loss risk associated with late blight epiphytotics.

Damage and yield loss estimate in maize varieties owing to stem borer (Chilo partellus Swinhoe) infestation and insecticidal control

Stem borer (Chilo partellus Swinhoe) is one of the most damaging and yield reducing pest in maize. Field experiments were organized to assess the extent of damage and yield loss due to the infestation of stem borer in maize following two factors randomized complete block design with three replications at National Maize Research Program, Rampur, Chitwan, Nepal, during two consecutive spring seasons of 2020 and 2021. Maize varieties; Rampur Hybrid (RH)-8, RH-10, RH-12 (CAH-1715), RH-14 (RML-86/RML-96), RH-16 (RML-95/RML-96), TX-369, Arun-2, ZM-401, ZM-627 and Rampur Composite were used as a test variety (First factor) whereas pest control conditions (spray and non-spray) was considered as the second factor in the experiments. The sprayed plots (protected plots) were kept completely free from stem borer infestation by using three application of standard dose of insecticide (spinosad 45% EC@0.4mL/L) at 10 days interval and non spray (unprotected plots) were selected for natural infestation of stem borers. Standard agronomical practices such as time of planting, row spacing, seed rate, irrigation, weeding and fertilizer application and doses were adopted to raise the crop. Among tested varieties Arun-2 was found most susceptible to stem borer attack in both experimental years resulted in higher % dead hearts (6.04%), higher no of exit hole (4.72), higher % foliage damage at before tasseling stage (12.17%) and higher tunnel length (4.62cm). Quantitative yield loss increased with the increase of the borer's infestation. The yield loss was ranged from 25 to 45% in different maize varieties due to the attack of stem borer. Highest yield loss was quantified for the open pollinated varieties, ZM-401(44.61%) followed by Rampur Composite (41.39%) and Arun-2 (41.22%). Spraying of insecticide enabled the recently introduced maize hybrid RH-14 to produce more yield and to be less vulnerable to stem borer damage.

Damage Potential and Management of Sorghum Shoot Fly Atherigona soccata on Sorghum with Seed Treatment

A field experiment conducted at the sorghum research field, College of Agriculture, Indore Madhya Pradesh during kharif 2019-20 evaluated six seed dressing chemicals along with soil application of carbofuran against shoot fly Atherigona soccata (Rondani). Significantly least deadheart (1.36 to 15.95%) was observed with thiamethoxam+ cyantraniliprole followed by thiamethoxam 30FS (1.61 to 21.76%). Soil application of carbofuran resulted in less efficacy (2.96 to 38.21%). The mean yield obtained was 29.13 q/ha in protected plots as against 16.20 q/ha in unprotected plots. Mean deadheart incidence was 11.59% in protected plots and 58.23% in unprotected plots. The avoidable loss in term of deadheart was recorded to be 80.10%.

Estimation of crop loss caused by important insect-pests of mango

A field experiment was conducted at Regional Horticultural Research Station, ASPEE College of Horticulture and Forestry, Navsari Agricultural University, Navsari (Gujarat) during 2009-10 to 2010-11. Application of recommended as well as need based insecticides in protected plots resulted in significantly lower hoppers (3.95 hoppers/twig or panicle), thrips (5.47 thrips/twig or panicle), damages of leaf gall midge (7.24% leaf damage), leaf webber (3.54 web/tree) and fruit fly (7.86% fruit infestation) as compared to the unprotected plots. Number of fruits set at stone (378.54/tree) and harvest stages (232.25/tree) were higher in protected trees giving significantly higher yield in protected (58.06 kg/tree) over untreated (21.82 kg/tree) trees followed by significant lower fruit dropping (38.51%) in the former over the latter (50.58%). The avoidable yield losses due to insect-pests was to the tune of 61.51% resulting into net profit of Rs. 69,780/ ha. in protected trees over control.

Efficacy of insecticide aerial spraying programs to reduce tree mortality during a spruce budworm outbreak (1967–1992) in the province of Quebec

Abstract Spruce budworm (Choristoneura fumiferana) is the most important pest of conifer forests in eastern North America. The main approach for protecting forests against this defoliator is aerial spraying of insecticides. Despite the crucial role of aerial insecticide applications in the global forest protection strategy, little is known about its real effects on tree mortality or the stand characteristics that may affect its long‐term efficacy. We evaluated the efficacy of the protection program that was implemented during the 1967–1992 outbreak in Quebec (Canada) in tree mortality reduction. We established 422 plots in eastern Quebec based upon the following parameters: insecticide application; stand composition; drainage quality; and stand age. Unprotected plots exhibited 18 to 44% greater tree mortality than protected plots. Insecticide efficacy was affected by drainage condition. Protected plots that established on sites with poor quality drainage exhibited 67.53% lower balsam fir (Abies balsamea) mortality than did unprotected plots. Stand age did not affect tree mortality. Insecticide application had no substantial effect on spruce mortality. Our study also found that the return on protection investment in terms of mortality reduction may decline after 7 years of aerial spraying, and that it is not necessary to achieve the target protection goal (50% foliage protection) every year to reduce host tree mortality. Our results may be useful for decision‐makers to decide where and when to apply insecticides during a spruce budworm outbreak and may help to determine the appropriateness of treating the forest on an annual basis depending upon the protection goals.

Minimising fungicides by alternating formulations and intervals to improve potato blight management and farm returns

Late blight (Phytophthora infestans) is one of the most devastating and economic disease impacting both ware and the seed potato industry. The disease causes huge crop losses, and its management attracts heavy expenses. Efficacy successes in chemical management, as opposed to biofungicides, has resulted in the development of a number of fungicide formulations to counter emergence of chemically insensitive P. infestans strains. The objective of this study was to evaluate the efficacy and cost-benefits of applying different fungicides in alternate; while varying the spray intervals to manage potato blight and improve on net farm returns. A survey was conducted in Nyandarua County in Kenya, using a structured questionnaire, administered to potato farmers. Milraz® (Propineb 700 g kg-1 + Cymoxanil 60 g kg-1), Ridomil® (Metalaxyl 4% + mancozeb 64%) and Mistress 72® (Cynamoxil 4% + Mancozeb 64%) were used in vitro and field experiments. Plated pea agar and detached leaflets were amended with the fungicides at concentrations of 0, 35, 70 and 100% of the manufacturers recommended rate before inoculating with P. infestans. In the field experiment, the fungicides were applied at intervals of 7, 14 and 21 days spray as single, two or three fungicides in alternations. Results showed that, mycelial and blight lesion growth was curtailed by concentrations of 70 and 100%; while 35% concentration of the fungicides reduced mycelial growth and lesion size by 53 and 2%, respectively. In the field experiment, there were no yield and AUDPC differences (P&lt;0.05) among the fungicides and their combinations. However, spraying the fungicides at weekly and bi-weekly intervals gave the highest yields of 17.65 and 16.4 t ha-1, compared to tri-weekly and unprotected plots that recorded 7.93 and 0.43 t ha-1 , respectively. In addition, application of triple fungicides in alternation reduced late blight severity by 51%; while application of two fungicides in alternation reduced severity by 39% compared to single fungicide application (21%) on average. Maximum net benefit ratio was observed on plots protected using three fungicides (31.58); followed by two fungicides applications (26.81) applied biweekly in alternate relative to single fungicide applied weekly.

Ecofriendly alternative for sustainable management of banded leaf and sheath blight of maize (Zea mays)

Banded leaf and sheath blight (BLSB) of maize (Zea mays L.) caused by Rhizoctonia solani f. sp. sasakii is one of the most important yield-limiting factors faced by growers in India. Therefore, attempts were made to identify promising suitable bioagents for the management of BLSB of maize. Present study was carried out to check the efficacy of two bioformulations, viz. Pusa Th3 (Trichoderma harzianum) and Pusa Cg2 (Chaetomium globosum) against BLSB in the Vivek QPM-9 cultivar under field conditions during kharif 2018 and 2019 using seven different treatments. All the treatments significantly reduced the disease incidence and contributed higher yield of maize as compared to positive control. The lowest per cent disease index (37.87 and 53.17%) was recorded in case of both seedtreatment and foliar spray with T. harzianum. It gave 40.39% disease control and also increased the yield up to 28.47% over unprotected plot. It was concluded that BLSB disease can be managed by seed treatment with T. harzianum @2 g/kg seed, followed by one spray of T. harzianum @0.1% at 30 days after sowing. Sustainable ecofriendly disease management options identified in the study can help maize growers not only in safeguarding the crop but also increase cost: benefit ratio. In addition, the results indicated that bio formulation of Pusa Th3 can be used to substitute chemical fungicides especially in controlling BLSB

Losses caused by stem rust (Puccinia graminis f.sp tritici) on durum wheat in Ethiopia

Stem rust caused by Puccinia graminis f.sp. tritici is one of the major biotic constraints of wheat production. The disease may cause substantial quantitative and qualitative yield losses but much of the work in Ethiopia on this pathosystem focuses on quantitative yield loss of durum wheat. This work was carried out at Debre Zeit Agriculture Research Centre during 2015/16 and 2016/17 main and off-seasons. Hence the current study was conducted with the objectives to quantify the amount of loss in grain yield due to stem rust and assess the relationship between disease parameters, grain yield, and physical quality parameters of improved durum wheat varieties grown in Ethiopia. Artificial inoculation was performed using a mixture of different dominant stem rust races. There were treated and untreated plots by fungicide that serves as protected and unprotected plots, respectively. Disease severity was recorded each 10 days interval and area under disease progress curve (AUDPC), terminal severity, and coefficient of infection were calculated. The tested cultivars exhibited different disease severity levels, having a mean value of 6.7-76%. High values of area under disease progress curve (AUDPC) were detected on Hitossa, Utuba (1225.7, 585.9). Whereas the lowest values of yield loss were recorded on CVS. Mangudo and Utuba have the mean value of yield loss of 40.2 and 44.8%, respectively. The highest yield loss was observed on susceptible variety Hitosa showing the mean value of 70%. Correlation coefficients were tested between yield losses and values of AUDPC, final stem rust severity, coefficient of infection, and rate of infection of the tested cultivars. There were strong correlation coefficients among disease parameters (r=0.72-0.99). There was also a moderately strong negative correlation coefficient among disease parameters and yield, hectoliter weight, and 1000-kernel weight of the test cultivars (r= -0.53 to -0.81). The current study indicated that the application of Rex Duo can be used in minimizing yield losses caused by the stem rust disease of durum wheat. Therefore, supporting the released durum wheat cultivars with fungicide application is the most pertinent issue in Ethiopia as most of the durum wheat cultivars in farmers' hands were moderately susceptible to susceptible cultivars Pgt races.

Impact of rangeland enclosure and seasonal grazing on protected and unprotected rangelands in Chakwal region, Pakistan

Scrub rangelands support livestock grazing and provide ecosystem services to their inhabitants. The present study was conducted in Chakwal, an important tract of the Pothwar Plateau, which sustains herds of small domestic and nomadic ruminants. Urbanization and uncontrolled grazing practices have reduced rangeland productivity and increased soil erosion and resulted in poor land conditions. This study assessed the influence of two years of rangeland protection on aboveground vegetation biomass and the chemical composition of plants and aimed to determine the influence of seasonal grazing on the live-weight gain of small ewes. Using the line intercept method, vegetation data from protected and unprotected plots in 2015 and 2016 were collected at two sites, Dhulli and Begal. Vegetation cover was assessed from images using VegMeasure. Results showed that protected study sites displayed higher vegetation biomass (834 and 690 kg ha-1) compared to the unprotected study site (477 and 326 kg ha-1) during April and August of both years. In the seasonal grazing trial, the experimental ewes that grazed on protected rangelands showed higher live-weight gain (33–63 g day-1) compared to live weight of ewes (17–21 g day-1) that grazed on unprotected rangelands during the experimental period of 127 days at both sites. The results suggest that the Chakwal rangeland has tremendous potential to improve vegetation productivity but modern livestock management and seasonal grazing practices are needed to improve carrying capacity and livestock productivity.

Robotic laser scarecrows: A tool for controlling bird damage in sweet corn

Sweet corn (Zea mays L.) is an important direct retail and local wholesale crop in the United States. Birds have long been recognized as a pest of corn, which they damage by shredding the husks and eating the kernels. This study was performed to evaluate moving green laser beams as a bird control strategy in sweet corn. A portable, battery-powered robotic scarecrow was designed to continuously move a 14 mm diameter, 532 nm wavelength beam from a 50 mW laser. The scarecrow was tested in sweet corn fields in Rhode Island, USA over three years using a split-field design where half of each field was covered by the laser and the other half served as a control. . In 2017, the control sections averaged 48.4 ± 6.9 damaged ears per plot, while the sections covered by the laser averaged 14.6 ± 5.5 damaged ears (P = 0.0002). In 2018, the control sections averaged 23.8% ± 4.1% damaged ears while 13.7% ± 2.1% of ears were damaged in sections covered by the laser (P = 0.0046). In 2019, mean damage values across all planting blocks were 14.9% ± 4.1% for the protected plots and 20.3% ± 5.8% for the unprotected plots (P = 0.0332). The results of this study show that automated laser scarecrows can reduce bird damage to sweet corn under field conditions. Further research, including aviary studies with controlled populations of individually identified birds, are needed to measure efficacy and test for habituation.

Losses Caused by Stem Rust (&amp;lt;i&amp;gt;Puccinia graminis&amp;lt;/i&amp;gt; f.sp. &amp;lt;i&amp;gt;tritici&amp;lt;/i&amp;gt;) on Durum Wheat in Ethiopia

Stem rust caused by <i>Puccinia graminis</i> f.sp. <i>tritici</i> is one of the major biotic constraints of wheat production. The disease may cause substantial quantitative and qualitative yield losses but much of the work in Ethiopia on this pathosystem focuses on quantitative yield loss of durum wheat. This work was carried out at Debre Zeit Agriculture Research Centre during 2015/16 and 2016/17 main and off seasons. Hence the current study was conducted with the objectives to quantify the amount of loss in grain yield due to stem rust and assess the relationship between disease parameters, grain yield and physical quality parameters of improved durum wheat varieties grown in Ethiopia. Artificial inoculation was performed using a mixture of different dominant stem rust races. There were treated and untreated plots by fungicide that serves as protected and unprotected plots, respectively. Disease severity was recorded each 10 days interval and area under disease progress curve (AUDPC), terminal severity and coefficient of infection were calculated. The tested cultivars exhibited different disease severity level, having the mean value of 6.7-76%. High values of area under disease progress curve (AUDPC) were detected on Hitossa, Utuba (1225.7, 585.9). Whereas the lowest values of yield loss were recorded on cvs. Mangudo and Utuba having the mean value of yield loss 40.2 and 44.8%, respectively. The highest yield loss was observed on susceptible variety Hitosa showing the mean value of 70%. Correlation coefficients were tested between yield losses and values of AUDPC, final stem rust severity, coefficient of infection and rate of infection of the tested cultivars. There was strong correlation coefficients among disease parameters (r=0.72-0.99). There was also moderate strong negative correlation coefficient among disease parameters and yield, hectoliter weight and 1000-kernel weight of the test cultivars (r=-0.53 to -0.81). The current study indicated that application of Rex Duo can be used in minimizing yield losses caused by stem rust disease of durum wheat. Therefore, supporting the released durum wheat cultivars with fungicide application is the most pertinent issue in Ethiopia as most of the durum wheat cultivars in farmers hand were moderately susceptible to susceptible cultivars Pgt races.

Effects of livestock on nitrogen and carbon cycling in a savanna in Burkina Faso

The nitrogen and carbon cycles are fundamental ecosystem processes influenced by several factors including soil type and other abiotic factors, plant species, grazing and soil organisms. Herbivores profoundly influence the functioning of ecosystems and the recycling of nutrients in interaction with plants in natural ecosystems. This study focuses on the effects of livestock on carbon and nitrogen cycling in a grazed savanna in Burkina Faso. Dominant grass species (aerial and root parts) and soil samples were collected under grasses and bare soil patches in 48 plots (24 protected and 24 unprotected plots), 18 months after setting up herbivores exclosures. Soil and grass 13C and 15N were used as integrative indicators of carbon and nitrogen cycles. The results revealed no significant effect of livestock on soil total carbon and nitrogen and on soil δ13C and δ15N values. Moreover, grazing had no significant effect on grass carbon and δ13C, while it significantly increased grass total nitrogen and δ15N. Therefore, our hypothesis that grazing would increase soil 13C and 15N values and plant biomass was only verified for grass 15N. Grass δ15N results suggest that grazing improves the immediate availability of nitrogen but could also increase nitrogen losses.

Wild Herbivore Forage Preferences in Semi-Natural Mountain Hay-Meadows

In the context of increasing grassland abandonment we observed wild herbivore impact on the vegetation in order to understand their influence. To quantify semi-natural grassland usage by wild herbivores, we determined grazing intake in semi-natural hay-meadows surrounded by forest vegetation. Grazing exclusion cages were placed at three locations in the Valea Mare village area situated in Bistriţa-Năsăud County, Romania, from 1 April 2014 – 5 October 2014. Sampling took place at two times during this period, first shortly before the hay meadows were mowed and second at the end of the vegetation growing season. Herbage air dry matter yield was measured using two types of observation plots (cage protected plots and unprotected plots). Plant composition on the studied hay-meadows was analyzed using PC-ORD (in order to explain the preference of herbivores for each location. Although herbage production did not vary significantly between locations, the herbage intake of total dry matter production did vary between locations. Wild animals grazed through the entire growing season and based upon the floristic composition analyses we explained differences in herbage intake based on plant species preference. The management of these meadows maintains an offer of good quality forage throughout summer, and the forest surrounding grasslands provides cover when needed. In order to inhibit woody vegetation and to conserve species-rich open landscape further observation need to be made about the optimal deer species densities.