Untreated Control Plots Research Articles

Maintaining an open landscape: Comparison of management methods for semi-natural grasslands: A Swedish multi-site study

Traditional management of semi-natural grasslands by grazing or annual mowing is not always feasible and the current study set out to evaluate alternative management methods. At eleven locations in southern Sweden, block experiments were conducted evaluating seven treatments in 5 m*20 m plots: grazing, annual mowing, annual spring burning, mowing every third year, mechanical removal of woody plants, herbicide control of woody plants, and untreated control. After approximately 13 years, trends for woody plants and species richness, and the occurrence of management-dependent plant species, low-grown species, and pollinator-attracting plant species were analysed. Overall, the annual mowing and grazing treatments resulted in fewer woody plants, the highest species richness, and more management-dependent, low-grown, and pollinator-attracting species. The untreated control plots showed the opposite effect, whereas less intense management (annual burning, mowing every third year, and mechanical and chemical treatments of woody plants) showed mixed and often intermediate effects. Compared to grazing and mowing, less intense management methods do not constitute long-term management alternatives to preserve typical features of species-rich grasslands. However, they may be short-term alternatives at sites where the recruitment of woody species is absent or rare. However, to prevent the encroachment of woody species, less intensive management might be a better long-term alternative at more productive sites with slow or inhibited woody species recruitment.

Glycerin‐based dispensers of fir oil reduce response of Asian citrus psyllid, Diaphorina citri, to citrus odours

AbstractThe Asian citrus psyllid, Diaphorina citri Kuwayama, transmits the bacterial pathogen associated with huanglongbing, a fatal citrus disease. Alternatives to insecticides for D. citri management are being explored, given the development of insecticide resistance and the lack of efficient biological controls. Essential oils as pest repellents have shown some efficacy in laboratory and field evaluations; however, lack of an effective dispenser for field deployment has prevented their application. In this investigation, we evaluated glycerin‐based dispensers releasing fir (Abies spp.) oil as repellents for D. citri. In olfactometer tests, glycerin dispensers loaded with fir oil at 20% w/w repelled psyllids from citrus odours but did not cause repellency at lower loading dosages. Field evaluations were conducted with dispensers at the 20% loading dosage based on laboratory results. In open‐air cage bioassays, fewer psyllids alighted on trees treated with 2 dispensers per tree than on control trees. Similarly, fewer psyllids were found on mature lime trees in homeowner landscapes treated with 4 dispensers per tree compared to paired control trees. In small plot experiments in commercial grapefruit, psyllid infestation of young leaf flush shoots was reduced in plots treated with at least 250 dispensers/ha compared to untreated control plots. Our results indicate that these glycerin‐based fir oil dispensers can reduce infestation of citrus by D. citri. However, the efficacy observed within replicated small plots of citrus grown in monoculture was judged insufficient to manage this vector as a stand‐alone treatment. Larger scale evaluations at higher loading dosages of fir oil and/or in combination with other management tools are warranted based on the outcomes of these initial experiments.

Cultural control methods improve management of leafhopper vector of X-disease

X-disease, caused by the phytoplasma ‘Candidatus Phytoplasma pruni’, is currently threatening Pacific Northwest (USA) stone fruit (Prunus) production, particularly sweet cherry (P. avium). There is no cure, and infected fruit remain unmarketable throughout the tree's life. Management efforts focus on reducing transmission through infected tree removal and frequent chemical applications to control the leafhopper vectors. The increase in chemical inputs has broken down stone fruit integrated pest management techniques and is neither economically nor environmentally sustainable. To investigate sustainable vector management, we assessed the efficacy of two long-lasting cultural management techniques, kaolin clay (Surround WP) and reflective plastic geotextile (Extenday), to deter leafhoppers from trees and prevent population growth within orchards. These methods were tested against untreated control plots in Washington State commercial stone fruit blocks in 2021 and 2022. Colladonus montanus reductus (Van Duzee) was the most abundant leafhopper vector species captured in both years. In cherry blocks, Extenday consistently reduced C. m. reductus densities by 80–90%, while kaolin clay caused a 45–50% reduction in leafhoppers, but only when they were abundant (more than 10 leafhoppers per trap). Sticky cards placed at varying heights revealed that kaolin clay caused C. m. reductus to be proportionally more abundant near the ground cover than in the tree canopy regardless of overall population density. The combination of reducing C. m. reductus density and shifting their distribution into the ground cover demonstrates both plastic geotextiles and kaolin clay provide effective post-harvest strategies for X-disease vector management.

Evaluation of variable doses of tachnid fly, <i>Sturmiopsis inferens</i> for the management of <i>Sesamia inferens</i> under field conditions in rice and wheat

Evaluation of variable doses of tachnid fly, Sturmiopsis inferens for the management of pink stem borer, Sesamia inferens under field conditions in basmati rice (var. Pusa Basmati 1121) and wheat (var. HD 2967) was carried out at a farmer’s field in Ludhiana. Two intervals, i.e. one at 10 days and the other at 15 days were followed for releasing different doses (75, 100, 125 and 150 gravid females/ha) of S. inferens during August-October in rice and November-December in wheat. In case of Basmati rice, the minimum incidence of Sesamia inferens was recorded in treatment where a higher dose of 150 gravid females per ha was released (1.05 % DH at 75 DAT, 1.09 % WE), which was significantly at par with the dose of 125 gravid females per ha. The untreated control plot observed the highest incidence of Sesamia inferens (1.81% DH, 2.11% WE). The observations on grain yield revealed that higher doses of 125 and 150 per ha were significantly superior (37.90-38.41 q/ha) while doses of 100 and 75 per ha were at par with each other (36.35 and 36.91 q/ha, respectively) and minimum grain yield was recorded in untreated plots (34.73 q/ha). In the case of wheat, the minimum incidence was recorded in a treatment where a higher dose of 150 gravid females per ha was released (1.49% DH at 45 DAS, 1.28% WE), which was significantly at par with the dose of 125 gravid females per ha (1.66 % DH at 45 DAS, 1.50% WE). The untreated control plot observed the highest incidence (2.48 % DH at 45 DAS, 2.65% WE). The higher doses of 125 and 150 per ha were significantly superior in terms of grain yield (46.68-47.17 q/ha), while doses of 100 and 75 per ha gave a yield of 45.41 and 44.13 q/ha, respectively.

Effect of Acibenzolar-S-Methyl on severity of Fusarium wilt and fruit yield of two tomato cultivars

Tomato wilt caused by Fusarium oxysporum f.sp. lycopersici (Fol) is one of the limiting factors to tomato production in the whole world because of its negative effect on the fruit yield of tomato. The study investigated the application of Acibenzolar-S-Methyl (ASM), a plant activator that stimulates plants’ defence mechanisms, at different concentrations (0, 25, 35 and 45 mg/L) on two tomato genotypes (Delila and Kerewa) using drenching method. Factorial experiments were laid out in a randomized complete block design and completely randomized design in both field and the screenhouse, respectively. Results showed that the application of ASM significantly reduced (p≤0.05) disease severity. At 9 weeks after transplanting Delila recorded severity scores of 3.00 and 3.33(screenhouse) and 0.33 (field) while Kerewa had severity scores of 1.33 and 1.50 (screenhouse) and 0.33 (field) when ASM was apllied at 35 and 45 mg/L concentrations, respectively. These values were significantly lower (p≤0.05) than those recorded in untreated plots. Delila yielded 151.23 and 151.73 kg/ha (screenhouse), and 754.70 and 795.8 kg/ha (field) while Kerewa yielded 109.60 and 124.03 kg/ha (screenhouse) and 601.10 and 279.8 kg/ha (field) when ASM was apllied at 35 and 45 mg/l concentrations, respectively. Yields in both screenhouse and the field were significantly higher (p≤0.05) than yields in the untreated control plots. The study concluded that application of ASM at 35 and 45 mg/L to tomato could enhance its resistance which would translate to fruit yield increase.

Insecticidal activity of <i>Ricinus communis L.</i> seed extract against <i>Spodoptera frugiperd</i>a J.E. Smith under laboratory and field conditions

Insecticidal activity of the aqueous extract of the castor seed (Ricinus communis L.) against the Fall Armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae), one of the worst pests of maize crop, was assessed under laboratory and field conditions. In laboratory, the larvicidal activity of three concentrations of the extract that are 150 g/l, 200 g/l and 250 g/l and their effects on the development of FAW were evaluated through direct exposure and ingestion tests. The field experiment consisted of a randomized block design with two extract concentrations – 200 g/l and 250 g/l – and negative control consisted of untreated plots and positive control plots were treated with Emacot (Emamectin benzoate). Results of the laboratory experiments revealed considerable larvicidal activity of the extract through the ingestion test, inducing the larvae mortality of 75.8%, 60.3% and 46.5% for the extract concentrations of 250 g/l, 200 g/l and 150 g/l respectively, whereas positive (Emacot) and negative controls (emulsified water) recorded 100% and 3.3% of the larvae mortality, respectively. The field results showed 10% and 11% of infested plants in plots treated with 200 and 250 g/l, respectively, whereas Emacot-treated plots recorded 9.5% of infested plants. Untreated plots recorded the highest infested plants of 22.5%. The two- castor seed extract concentrations 200 g/l and 250 g/l reduced about 50% of maize plant infestation by FAW, thus could be a good candidate as alternative to chemical pesticides in controlling the pest.

Efficacy and Economics of Selected Insecticides against Pod Borer [Helicoverpa armigera (Hubner)] on Cowpea [Vigna unguiculata (L.)Walp.

A field trail was conducted at CRF, SHUATS, Naini, Prayagraj during Kharif season 2022. Eight treatments were evaluated against Helicoverpa armigera i.e. of Chlorantraniliprole 18.5 SC, Emamectin benzoate 5 SG, Flubendiamide 480 SC, Spinosad 45 SC, Thiamethoxam 25 WG, Lambda cyhalothrin5 EC, Indoxacarb 14.5 SC and untreated Control. Results revealed that, among the different treatments lowest larval population of cowpea pod borer was recorded in Chlorantraniliprole 18.5 SC (1.323). Lambda cyhalothrin5 EC (1.478) was found tobe the next best treatment followed by Emamectin benzoate 5 SG (1.589), Indoxacarb 14.5 SC (1.734) and Flubendiamide 480 SC (1.922).The least effective treatments were Spinosad 45 SC (2.089) where as Thiamethoxam 25 WG (2.200) was found to be least effective. The plot treated with Chlorantraniliprole 18.5 SC show highest yield (19.46 q/ha) followed Lambda cyhalothrin5 EC (17.82 q/ha) the best and most economical treatment was Chlorantraniliprole 18.5 SC (1: 3.89). Among the treatments studied, the best and most economical treatment was Chlorantraniliprole 18.5 SC (1: 3.89) followed by Lambda cyhalothrin 5 EC (1:3.67), Emamectin benzoate 5 SG (1:3.41), Indoxacarb 14.5 SC (1:2.95), Flubendiamide 480 SC (1:2.56), Spinosad 45 SC (1:2.27) and Thiamethoxam 25 WG (1:2.17) as compared to untreated control plot (1:1.60).

Study on financial assessment of rice production causing false smut disease of different varieties at farm level in Kushtia district

The present study was conducted to evaluate the false smut incidence and its effect on yield in different varieties, and to determine the financial cost, return and profitability of rice production during the year 2018–2019 in Kushtia district. The highest average farmers (65%) lost their yield 0.85 t/ha in 5 severity scale of BRRI dhan49, while Dhani Gold as hybrid variety exerted the lowest yield losses of 0.20 t/ha in 7% affected farmers. Spraying of Nativo (75 WG) 0.40 kg/ha increased the yield 34.87% over control, and Amister Top 325 SC was applied in the field that produced lower yield compared to Nativo. Tilt (250 EC) 0.45 l/ha and Folicur 0.90 l/ha also showed significant increase of yield over untreated control plot. The highest gross return of BRRI dhan39 was determined at Tk. 114753/ha with higher price and its fine quality. The lowest gross return and net return were estimated at Tk. 106958/ha and (−) Tk. 1215/ha, respectively, in Shorna cultivar due to higher incidence of false smut disease.

Evaluation of the Dynamic Tube Method for Measuring Ammonia Emissions after Liquid Manure Application

Easy and inexpensive methods for measuring ammonia emissions in multi-plot field trials allow the comparison of several treatments with liquid manure application. One approach that might be suitable under these conditions is the dynamic tube method (DTM). Applying the DTM, a mobile chamber system is placed on the soil surface, and the air volume within is exchanged at a constant rate for approx. 90 s. with an automated pump. This procedure is assumed to achieve an equilibrium ammonia concentration within the system. Subsequently, a measurement is performed using an ammonia-sensitive detector tube. Ammonia fluxes are calculated based on an empirical model that also takes into account the background ammonia concentration measured on unfertilized control plots. Between measurements on different plots, the chamber system is flushed with ambient air and cleaned with paper towels to minimize contamination with ammonia. The aim of this study was to determine important prerequisites and boundary conditions for the application of the DTM. We conducted a laboratory experiment to test if the ammonia concentration remains stable while performing a measurement. Furthermore, we investigated the cleaning procedure and the effect of potential ammonia carryover on cumulated emissions under field conditions following liquid manure application. The laboratory experiment indicated that the premeasurement phase to ensure a constant ammonia concentration is not sufficient. The concentration only stabilized after performing more than 100 pump strokes, with 20 pump strokes (lasting approximately 90 s) being the recommendation. However, the duration of performing a measurement can vary substantially, and linear conversion accounts for those differences, so a stable concentration is mandatory. Further experiments showed that the cleaning procedure is not sufficient under field conditions. Thirty minutes after performing measurements on high emitting plots, which resulted in an ammonia concentration of approx. 10 ppm in the chamber, we detected a residual concentration of 2 ppm. This contamination may affect measurements on plots with liquid manure application as well as on untreated control plots. In a field experiment with trailing hose application of liquid manure, we subsequently demonstrated that the calculation of cumulative ammonia emissions can vary by a factor of three, depending on the degree of chamber system contamination when measuring control plots. When the ammonia background values were determined by an uncontaminated chamber system that was used to measure only control plots, cumulative ammonia emissions were approximately 9 kg NH3-N ha−1. However, when ammonia background values were determined using the contaminated chamber system that was also used to measure on plots with liquid manure application, the calculation of cumulative ammonia losses indicated approximately 3 kg NH3-N ha−1. Based on these results, it can be concluded that a new empirical DTM calibration is needed for multi-plot field experiments with high-emitting treatments.

MANAGEMENT OF RED PUMPKIN BEETLE AND FRUIT FLY IN ASH GOURD USING BIORATIONAL INSECTICIDES

Ash gourd Benincasa hispida Thumb., a cucurbit vegetable, faces frequent infestation of red pumpkin beetle and cucurbit fruit fly. Farmers in Bangladesh mainly apply conventional synthetic insecticides to protect crops from the attack of these pests. The current study was conducted in the experimental field of the Department of Entomology, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur during March 2021 to July 2021 to know the effects of five biorational insecticides, namely Biotrin (matrine), Proclaim (emamectin benzoate), Sunmectin (abamectin), Mahogany oil and Neem oil on the abundance and infestation of red pumpkin beetle and fruit fly infesting ash gourd. The insecticides were applied 3 times maintaining 7 days interval. Results showed significant reduction of the insect population compared to untreated control. Sunmectin (1.55±0.34) treated plot showed the lowest abundance of red pumpkin beetle after the 3rd spray with 65% reduction of population compared to untreated control plot. Biotrin (8.59±1.00%) treated plot showed the lowest leaf and flower infestation by red pumpkin beetle after 3rd spray, with the reduction (69% in both) over control. The lowest fruit infestation was found in Sunmectin treated plot (23.01±8.05%). The highest yield of ash gourd (17.9 T/ha) was recorded from Sunmectin treated plot which showed statistical similarity to Proclaim (16.01 T/ha) and Biotrin (15.90 T/ha) treated plots with 3.5, 2.5 and 2.6 benefit cost ratio, respectively. Therefore, it could be concluded that Sunmectin, Proclaim and Biotrin were more effective to control the infestation of red pumpkin beetle and fruit fly of ash gourd than the other tested insecticides.

Integrated approach using insecticides in combination with reflective plastic mulch for the management of pepper weevil, Anthonomus eugenii (Coleoptera: Curculionidae).

Pepper weevil, Anthonomus eugenii Cano, is a serious pest of peppers (Capsicum annuum) in the United States and worldwide. This study evaluated the combined effect of insecticides (thiamethoxam and oxamyl) and reflective mulches (reflective silver on white and reflective silver on black) on pepper weevil suppression and yield increase. This study was conducted under field conditions in Homestead, FL, during the fall 2020, spring 2021, and 2022 growing seasons. The study consists of 2 mulch treatments as the main plots (reflective "silver on white," "white on black") and a bare ground with "no mulch" treatment in fall 2020 and spring 2021, and in spring 2022 with an additional treatment of reflective "silver on black" mulch. We hypothesized that jalapeño pepper grown on either reflective "silver on black" or "silver on white" plastic mulches would have fewer pepper weevil adults, fewer pepper weevil infested fruits, and higher yield than those grown on "white on black" plastic mulch or bare soil. Overall, the number of pepper weevil adults on plants and infested fruits was lower in the fall season compared to the spring season. In the fall 2020 season, the number of adults was not significantly different regardless of insecticide treatment and mulch type. However, infested fruits were higher on the untreated control plots than the treated plots in Fall 2020. Marketable yield was not significantly different among insecticide treatment on the "white on black" and reflective "silver on white" mulches. However, thiamethoxam treated plots had significantly higher yield than on the rest of the treatment on the bare soil with "no mulch." The number of adults was higher in the untreated control plot than the treated plots in spring 2021. The number of infested fallen fruits was not significantly different. However, marketable yield was significantly different among treatments on the "white on black" and reflective "silver on white" mulches in 2021. The treated plots on the reflective "silver on white" mulch produced significantly higher yield than the untreated control plots in 2022. The result of this study suggests that growing jalapeño peppers on reflective plastic mulch ("silver on white") in integration with thiamethoxam or oxamyl has the potential in reducing pepper weevil adult population and increasing yield of jalapeño pepper.

Effect of Fertilization Level on the Yield, Carotenoids, and Phenolic Content of Orange- and Purple-Fleshed Sweet Potato

Maintaining a diverse diet is essential for the preservation of one’s health and may contribute to the fight against significant civilization diseases such as obesity or diabetes. Sweet potato can be fitted into a diverse diet and serve as a functional food with its antioxidant content. Therefore, it is important to know how the production technology alters the content and composition of these antioxidant compounds. The objective of this study was to collect information on how the increased potassium dominant fertilizer levels and also the additional high-dose fertigation can affect the phytonutrient contents and yields in an orange- and a purple-fleshed sweet potato cultivar. Field experiments were conducted in the Hungarian county of Heves in two consecutive growing seasons in 2021–2022. Different doses of potassium-predominant fertilizer were applied to an orange flesh (Beauregard) and a purple flesh (Stokes Purple) varieties of sweet potatoes. Different application techniques were used in the form of base and top dressing at different rates. The effect on yield and polyphenol content of the different fertilizer rates was investigated. Analytical studies were carried out by high-performance liquid chromatography (HPLC). In the case of the Beauregard variety, in addition to identifying the carotenoids, we also performed their quantitative determination. We found that 87% of the carotenoid content was ß-carotene. The total anthocyanin content was investigated for the purple variety—Stokes Purple, for which a new extraction method was developed. In our study, the split dosages, when the pre-planting fertilizer was supplemented with additional liquid fertilization, resulted in 36 and 30.5% higher yields in the Beauregard in Experiment I and Experiment II, respectively, compared to the untreated control plots over the two years. The additional liquid fertilizer increased the yield to a lesser extent when compared to treatments received only pre-planting fertilizer. As for Experiment III, the split dosages resulted in 34.4% higher yields in the Stokes Purple compared to the control plots. However, the additional liquid fertilizer was not effective at all when the plants received a double dose of pre-planting fertilizer in the case of Stokes Purple. Total carotenoid (Experiment I–II) was higher and anthocyanin yield per plant (Experiment III) was significantly higher in the split-dosage treatment than in the untreated control plots.

Two decades of fumigation data from the Soybean Free Air Concentration Enrichment facility

The Soybean Free Air Concentration Enrichment (SoyFACE) facility is the longest running open-air carbon dioxide and ozone enrichment facility in the world. For over two decades, soybean, maize, and other crops have been exposed to the elevated carbon dioxide and ozone concentrations anticipated for late this century. The facility, located in East Central Illinois, USA, exposes crops to different atmospheric concentrations in replicated octagonal ~280 m2 Free Air Concentration Enrichment (FACE) treatment plots. Each FACE plot is paired with an untreated control (ambient) plot. The experiment provides important ground truth data for predicting future crop productivity. Fumigation data from SoyFACE were collected every four seconds throughout each growing season for over two decades. Here, we organize, quality control, and collate 20 years of data to facilitate trend analysis and crop modeling efforts. This paper provides the rationale for and a description of the SoyFACE experiments, along with a summary of the fumigation data and collation process, weather and ambient data collection procedures, and explanations of air pollution metrics and calculations.

Assessment of the influence of soil inoculation on changes in the adaptability of maize hybrids

The aim of this paper is to present the results of the field trial carried out to collect and assess data on the interaction of maize (Zea mays L) genotypes and beneficial microorganisms. The small plot field trial consisting of untreated control plots and plots treated with biostimulants was conducted in three consecutive years (2019, 2020 and 2021). Yield is a particularly important trait from the aspect of maize breeding as well as maize production; therefore, the present study focused more closely on how it was influenced by the biostimulant treatments. The level of grain yield, grain moisture content at harvest and grain dry-matter content were observed and recorded as the components of yield. The nutritional value of kernels was also tested, and protein, oil and starch contents were analysed as the most important components of this trait. The results reflected that the treatment with biostimulants constituted from beneficial microorganisms can be listed among the factors influencing the grain yield, in addition to the seasonal effect, the genotype and the nutrient supply of the soil. The treatment with biostimulants, even on its own among the factors, had an impact on the quantity and components of yield, and on the characteristics determining the kernel nutritional value. The interaction between the genotypes and the interacting microorganisms is of specific importance. The most spectacular result was attained with the application of one of the biostimulants leading to elevated grain yield in 75% of the maize genotypes in the study, along with a kernel nutritive value equal to the control group over all of the three years of the trial.

A Paradigm Shift towards Beneficial Microbes Enhancing the Efficiency of Organic and Inorganic Nitrogen Sources for a Sustainable Environment

The use of beneficial microbes as biofertilizer has become fundamental in the agricultural sector for their potential role in food safety and sustainable crop production. A field trial was conducted to study the influence of beneficial microbes on the efficiency of organic and inorganic sources. The experiment was conducted in two consecutive years (2008–2009 and 2009–2010) in a farmer’s field at Dargai Malakand Division. A randomized complete block design was used with four replications. The results revealed a significantly higher straw and grain nitrogen concentrations for the treatments receiving 50% N from urea + 50% N from FYM + BM, followed by the treatments receiving 50% N from urea + 50% N from (FYM + PM) + BM and 120 kg N ha−1 from urea fertilizer, respectively. Comparing the relevant treatments with and without BM, an increasing trend in N concentrations in straw and grain was observed with BM. The results revealed the highest grain total nitrogen, straw total nitrogen and total nitrogen uptake by wheat crop for the treatments receiving 120 kg N ha−1 from urea, followed by the treatments receiving 50% N from urea + 50% N from PM + BM and 50% N from urea + 50% N from (FYM + PM) + BM. Moreover, after comparing the relevant treatments with and without BM, for the parameters mentioned, an increasing trend in nitrogen uptake was observed. Significantly higher total soil nitrogen was obtained for treatment with 50% N from urea + 50% N from FYM + BM, followed by the treatment with 50% N from urea + 50% N from (FYM + PM) + BM or 50% N from urea + 50% N from PM + BM, respectively, as compared to the control treatment plot. Markedly higher soil mineral nitrogen was obtained for the 50% N from urea + 50% N from (FYM + PM) + BM treatment, followed by the treatment with 50% N from urea + 50% N from FYM + BM and 50% N treatment from urea + 50% N from PM + BM, compared to the control treatment. Comparing the relevant treatments with and without BM, an increasing trend in total soil N (g kg−1 soil) and soil mineral N (mg kg−1 soil) was noted with BM application. From the results, a significant increase in soil organic matter status (g kg−1 soil) due to application of organic and inorganic fertilization was summarized. Significantly higher soil organic matter (g kg−1 soil) was recorded for the treatment receiving 50% N from urea + 50% N from FYM + BM compared to untreated control plots. Our study further revealed an increasing trend in soil organic matter status (g kg−1 soil) when comparing the relevant treatments with and without BM.

Integrated pest management of Hypsipyla robusta shoot-tip borer (Lepidoptera: Pyralidae) in Chukrasia tabularis (Sapindales: Meliaceae).

Chukrasia tabularis A. Juss produces a valuable timber but plantations are susceptible to attack by the shoot-tip borer Hypsipyla robusta Moore. An integrated pest management (IPM) approach is desirable to limit the extent of damage. Therefore, this study was undertaken to evaluate the deployment of IPM measures in plantations in Vietnam. Data on tree damage and the biology of H. robusta were gathered in 4 provinces over one year and used to build an investigation schedule. Two preliminary IPM trials were then established in which Bacillus thuringiensis and Metarhizium anisopliae were applied to the foliage when the damage incidence (P%) was in the range 5-10%; and insecticides (Carbaryl, Carbosulfan) were applied when the P% exceeded 10%. In addition, larvae and pupae were removed manually over time. In the first trial, the combination of manual and biological control methods reduced the damage index (DI) of trees from 4 tolerant families by 82% compared to the untreated control plots. In the second trial using standard planting stock, application of insecticides was required to reduce the DI by 83%. Six extended IPM trials were undertaken using the same IPM protocols and these reduced the DI to the same extent as in the preliminary trials. Over an 18-month period, the deployment of IPM increased height growth by 19-22% and diameter growth by 38-41% compared to the controls. These findings highlight the value of planting improved seed and the benefit of adopting an IPM approach to manage the shoot-tip borer.

Plant and mule deer responses to pinyon‐juniper removal by three mechanical methods

AbstractLand managers in western North America often reverse succession by removing pinyon (Pinus spp.) and juniper (Juniperus spp.) trees to reduce fire risk and increase forage for wildlife and livestock. Because prescribed fire carries inherent risks, mechanical methods such as chaining, roller‐chopping, and mastication are often used. Mechanical methods differ in cost and the size of woody debris produced, and may differentially impact plant and animal responses. We implemented a randomized, complete‐block, split‐plot experiment in December 2011 in the Piceance Basin, northwestern Colorado, USA, to compare mechanical methods and to explore seeding (subplot) interactions. We assessed vegetation 1‐, 2‐, 5‐, and 6‐years post‐treatment, and mule deer (Odocoileus hemionus) response via GPS locations 3–8 years post‐treatment. By 2016, treated plots had 3–5 times higher perennial grass cover and ~10 times higher cheatgrass (Bromus tectorum) cover than untreated control plots. Roller‐chopped plots had both the highest non‐native annual forb cover, and when seeded, the highest density of bitterbrush (Purshia tridentata), a nutritious shrub used by mule deer. Masticated plots had higher bitterbrush use during summer and fall, leaving less forage available for winter. Days of winter mule deer use from GPS point locations in chained and roller‐chopped plots was ~70% higher than in control plots, while winter use in masticated plots was similar to control plots. Mule deer use appears related to a combination of hiding cover, resulting from residual woody debris, and winter forage availability. Roller‐chopped plots provide the best combination of hiding cover and winter forage, but mastication or chaining, applied leaving dispersed security cover, may be better options at large scales or when invasive species concerns exist.

Using Some Promising Insecticides as A Management Tool Against The Major Sucking Pests of Country Bean

An experiment has been conducted to know the efficiency of some promising pyrethroids and bio-rational insecticides for controlling the major sucking pests of country beans under field conditions during the winter season September 2020 – March 2021. The different treatments were Cypermethrin 10 EC (T1), Lambda-Cyhalothrin 2.5 EC (T2), Emamectin benzoate 5 SG (T3), Abamectin 1.8 EC (T4), Spinosad 45 SC (T5), and untreated control (T6). The rate of leaf infestation at the lower, middle, and top stages of country bean ranged from 8.82–17.78, 13.89–36.39, and 13.72–33.33% in T5treated and untreated control plots, respectively. The rate of shoot infestation at the middle and top stages of country bean ranged from 18.67–34.33 and 17.00–39.27% in T5 treated and untreated control plots, individually. The lowest and highest inflorescence infestation of 29.15% and 46.67% was recorded in T5 treated and untreated control plots, separately.The lowest fruit infestation of 8.84% by number and 8.32% by weight was recorded in the treated plot T5. The rate of reduction of pod infestation over control was 48.58, 24.02, 23.39, 21.81, and 19.92% by number and 73.53, 61.76, 58.82, 52.94, and 41.18% by weight in the treated plot T5, T4, T1, T3, and T2, respectively. The yield in different treatments ranged from 1.35-2.50 t ha-1. The highest adjusted net return and BCR of Tk. 52220.00 and 2.42, respectively were obtained from T2 treated plots. The second highest BCR of 2.16 was calculated from T4 treated plot. The lowest BCR of 1.05 was found in T2 treated plot. The treatments T5, T4, and T3 were effective to suppress the major sucking pests of the country bean.

FIELD EVALUATION OF FUNGICIDES FOR THE MANAGEMENT OF CERCOSPORA LEAF SPOT IN BLACKGRAM

The aim of this study was to investigate the effects of different fungicides on the management of Cercospora leaf spot in black gram. The investigation was carried out for two years at experimental field of College of Agriculture, A.A.U., Jabugam, Gujarat. The experiment was laid out in randomized block design (RBD ) with three replications. Fungicides were applied two times at 15 days interval after initiation of disease and results showed that among the tested treatments including control, Hexaconazole @ 0.1 % recorded a much lower per cent disease index (17.85%) which was at par with Azoxystrobin 23 SC @ 0.023% (17.93%) and they were significantly superior over control. The maximum mean grain yield was recorded from plots treated with Azoxystrobin 23 SC @ 0.023% (1817 kg/ha) followed by Hexaconazole 5 EC @ 0.1% (1698 kg/ha), while lowest mean grain yield (1256 kg/ha) was obtained from untreated control plots.

EFFECT OF VERMICOMPOST-TEA AND PLANT EXTRACTS ON GROWTH, PHYSIOLOGICAL, AND BIOCHEMICAL TRAITS OF LETTUCE (LACTUCA SATIVA L.)

The vermicompost and exogenous plant extracts as a foliar application can provide as an alternative means to enhance the growth and yield of leafy vegetable crops under low-fertility soil conditions. The objectives of the recent study sought to characterize the effect of vermicompost tea in combining some natural plant extracts to enhance the growth and yield of the lettuce plant. A study on lettuce (Lactuca sativa L.) took place during two successive seasons, in 2018–2019 and 2019–2020, using foliar spray— vermicompost-tea rates in combination with rosemary leaf extract (RLE) and eucalyptus buds extract (EBE). It sought to determine the effects on growth, yield, and some physiological and biochemical traits of lettuce (cv. ‘Dark Green’) grown on sandy soil with drip irrigation. The experiment employed the split-plot design, with four rates of vermicompost tea (0%, 5%, 10%, and 20%) as main plots and three plant extract levels (without, RLE, and EBE) as subplots. The vermicompost tea and plant extracts increased the growth characteristics, photochemical activity, photosynthetic pigments, relative water content, membrane stability index, excised leaf water retention, vitamins C and E, and total soluble solids in lettuce plants compared with the untreated control plots. The interaction and combined application of vermicompost tea (20%) and RLE proved most effective in enhancing the growth and yield traits and physio-biochemical properties in lettuce. Therefore, the integrative application of vermicompost tea (20%) with RLE comes highly recommended for growing lettuce in sandy soil conditions.