117 research outputs found
Biocontrol of Tomato Fusarium wilt by Trichoderma species under in vitro and in vivo conditions
Trichoderma spp. have long
been used as biological control agents
against plant fungal diseases, but the
mechanisms by which the fungi confer
protection are not well understood. Our goal
in this study was to isolate species of
Trichoderma, that exhibit high levels of
biocontrol efficacy from natural
environments and to investigate the
mechanisms by which these strains confer
plant protection. In this study, efficacy of
the native isolates of Trichoderma species to
promote the growth and yield parameters of
tomato and to manage Fusarium wilt
disease under in vitro and in vivo conditions
were investigated. The dominant pathogen,
which causes Fusarium wilt of tomato, was
isolated and identified as Fusarium
oxysporum f. sp. lycopersici (FOL). Twenty
eight native Trichoderma antagonists were
isolated from healthy tomato rhizosphere
soil in different geographical regions of
Mazandaran province, Iran. Under in vitro
conditions, the results revealed that
Trichoderma harzianum, isolate N-8, was
found to inhibit effectively the radial
mycelial growth of the pathogen (by
68.22%). Under greenhouse conditions, the
application of T. harzianum (N-8) exhibited
the least disease incidence (by 14.75%).
Also, tomato plants treated with T.
harzianum (N-8) isolate showed a
significant stimulatory effect on plant height
(by 70.13 cm) and the dry weight (by
265.42 g) of tomato plants, in comparison to
untreated control (54.6 cm and 195.5 g).
Therefore, the antagonist T. harzianum
(N-8) is chosen to be the most promising
bio-control agent for F. oxysporum f. sp.
lycopersici. On the base of present study,
the biocontrol agents of plant diseases might
be exploited for sustainable disease
management programs to save
environmental risk
Report of cabbage stem weevil, Ceutorhynchus pallidactylus (Col.: Curculionidae) on oilseed rape from Iran
در بررسی آفات کلزا در منطقهی مرودشت استان فارس، در نیمهی فروردین 1387، ساقههای آفتزده حاوی لارو و تخمهای مشکوک به سرخرطومی مشاهده و جمع آوری گردید. جهت دستیابی به حشرات کامل، لاروهای آفت در آزمایشگاه پرورش داده شد. این سرخرطومی با نام علمی Ceutorhynchus pallidactylus (Marsham) (= C. quadridens Panzer) (Col.: Curculionidae) شناسایی و توسط پروفسور Alziar Gabriel مورد تأیید قرار گرفت. این گونه برای اولین بار از ایران گزارش میشود
Biocontrol of soybean charcoal root rot disease by using Trichoderma Spp.
Macrophomina phaseolina
(Tassi) Goid, causing charcoal rot disease of
soybean, is one of the major factors
threatening soybean production, especially
in dry years. This pathogen remains the
prevailing causal agent of charcoal rot
disease that significantly suppresses the
yield of a variety of oilseed crops. Its wide
host range and ability to survive under arid
conditions, coupled with the ineffective use
of fungicides against it, have spurred
scientific endeavours for alternative avenues
to control this phytopathogen. Hence, the
present study aimed to provide empirical
evidence of the efficacy of fungal isolates
of Trichoderma spp. as biological control
agents against charcoal rot in soybean
(Glycine max L.). In this study Trichoderma
harzianum strains 6, 14, 17, 21, 44,
T. asperellum 26 and T. virens 32 were
evaluated as potential biological agents for
control of this disease. Mycelial growth of
M. phaseolina strain h-7 was reduced by
cell-free and volatile metabolites of
Trichoderma strains by 16.4 to 64.8%.
T. harzianum strain Tj17 significantly
(p≤0.05) reduced the incidence (to 7.3%)
and severity (to 3%) of disease 42 days after
inoculation and increased the 1000 grain
weight (to 178 g) in greenhouse conditions.
For confirmation of the greenhouse tests,
the selected antagonists were re-examined
in field trials, where this isolate reduced the
disease incidence (to 10%) and severity (to
3%). The overall results of this study show
high capability of used antagonists in
reduction of disease severity and incidence,
and resulting in increased weight of the
product. Hence, the findings reported in the
present study supported the applicability of
Tj17 isolate as possible alternative to
fungicides for the control of charcoal rot in
soybean
Higher-order approximation of cubic–quintic duffing model
We apply an Artificial Parameter Lindstedt-Poincaré Method (APL-PM) to find improved approximate solutions for strongly nonlinear Duffing oscillators with cubic–quintic nonlinear restoring force. This approach yields simple linear algebraic equations instead of nonlinear algebraic equations without analytical solution which makes it a unique solution. It is demonstrated that this method works very well for the whole range of parameters in the case of the cubic-quintic oscillator, and excellent agreement of the approximate frequencies with the exact one has been observed and discussed. Moreover, it is not limited to the small parameter such as in the classical perturbation method. Interestingly, This study revealed that the relative error percentage in the second-order approximate analytical period is less than 0.042% for the whole parameter values. In addition, we compared this analytical solution with the Newton– Harmonic Balancing Approach. Results indicate that this technique is very effective and convenient for solving conservative truly nonlinear oscillatory systems. Utter simplicity of the solution procedure confirms that this method can be easily extended to other kinds of nonlinear evolution equations
Analytical solutions to nonlinear mechanical oscillation problems
In this paper the Max-Min Method is utilized for solving the nonlinear oscillation problems. The proposed approach is applied to three systems with complex nonlinear terms in their motion equations. By means of this method the dynamic behavior of oscillation systems can be easily approximated using He Chengtian’s interpolation. The comparison of the obtained results from Max-Min method with time marching solution and the results achieved from literature verifies its convenience and effectiveness. It is predictable that He's Max-Min Method will find wide application in various engineering problems as indicated in the following cases
First record of 3 species of Parasitoid wasps on Coccoidea from Iran
During faun survey on parasitoids wasps of Coccoidea in Mazandaran province (north of Iran) collected two species of the family Encyrtidae and one species of Aphelinidae family (2010-2013). One species collected from Chionaspis salicis on Salix acmophylla from Amool in April 2012. This parasitoid was later identified as Adelencyrtus brachycaudae Xu& Shi, 1999. The other species was collected from Planococcus citri on Citrus aurantum from Jouybar in April 2013. This parasitoid identified as Clausenia purpurea Ishii, 1933.Theses parasitoid wasps belonging to Encyrtidae. Also Coccophagus yoshidae Nakayama, 1921 collected from Coccus hesperidum on Euonymus fortune from Sari in September 2013. This parasitoid wasp belonging to Aphelinidae. All of these parasitoid wasps identified by Dr. Zhi Hong Xu from China. These parasitoid wasps are new for Iranian fauna
Effect of Application of Plant Growth Promoting Bacteria and Amino Acids Foliar Application on Growth Characteristics, Yield, and Nutritional Value of Rice (Oryza sativa L.)
Introduction Rice (Oryza sativa L.), as one of the most important cereals, is the main food of more than 50% of the world's population. Excessive use of chemical fertilizers in paddy fields has caused many environmental problems. Therefore, the application of biological fertilizers instead of chemical fertilizers to increase the yield of crops and produce more food is one of the important goals of sustainable agriculture, which is necessary for human life. Bacteria is an example of biological fertilizer used in agriculture, which plays an important role in improving soil structure, improving plant growth, and increasing the quantitative and qualitative yield of crops. Another biological stimulant of plants is amino acids, which can increase plant growth, improve nutrients uptake, and increase grain yield and grain quality of crops. Methionine is the precursor of growth regulators such as auxin, cytokinin, and brassinosteroids and is known as the most important growth-limiting amino acid in plants. Lysine is an essential amino acid that is involved in the germination of pollen grains, chlorophyll synthesis, and crop production. Therefore, the present study aimed to evaluate the effects of different strains of plant growth-promoting bacteria and amino acids on growth, yield, and concentration of nutrients in rice.Materials and Methods The field experiment was arranged as a split-plot in a randomized complete block design with three replications at the farmer's field located in Mazandaran province, Amol during 2019-2020 cropping seasons. In the present research, the plant growth-promoting bacteria at five levels (control or without bacteria [B0], P. agglomerans strain O4 [B1], P. putida strain P13 + P. agglomerans strain P5 [B2], P. koreensis strain S14 + P. vancouverensis strain S19 [B3] and combination of different strains [B4]) as the main factor and amino acids foliar application in four levels (control or without amino acids [A0], methionine [A1], lysine [A2] and methionine + lysine [A3]) as the sub-factor were considered. The plant growth-promoting bacteria at the rate of 100 g.ha-1 and amino acids at a concentration of 2.5 per thousand were applied in this study. At physiological maturity, the growth, yield components, grain yield, and nutrients uptake (NPK) in grain were measured. A combined analysis of variance was performed using SAS software version 9.2. Mean values were compared using least significant difference (LSD) test at 5% probability level.Results and DiscussionThe outcomes established that the bacteria treatment exerted a notable impact on all examined traits, excluding the count of fertile tillers per hill. Equally noteworthy, the amino acid intervention displayed significance in terms of 1000-grain weight, grain yield, and nitrogen concentration in rice grains. However, the interaction between bacteria and amino acids exhibited no significance across the quantitative and qualitative characteristics of rice. The concurrent utilization of bacteria strains, specifically B4, yielded substantial enhancements in panicle length (24.22 cm), the count of filled grains per panicle (60.30 filled grains), 1000-grain weight (28.52 g), grain yield (5097.50 kg.ha-1), and the amelioration of nutrients concentrations. Notably, nutrients like nitrogen (1.61%), phosphorus (7.04%), and potassium (1.53%) exhibited improvements in rice grains, in comparison to instances involving separate strain applications and the control group. Simultaneous foliar application of methionine and lysine amino acids resulted in maximum 1000-grain weight (26.90 g), highest grain yield (4844.73 kg.ha-1), and production of the greatest nitrogen content in grain (1.40%). In the present research, the increase in grain yield by combined application of different bacteria strains might be due to enhancing growth, improving yield components such as 1000-grain weight and filled grains number per panicle, and increasing nutrients concentration (NPK) in rice. Also, the simultaneous foliar application of methionine and lysine led to an increase in rice grain yield through increasing 1000-grain weight and improving nitrogen uptake in rice grains.ConclusionAccording to the results of this experiment, the combined application of the bacteria strains (P. agglomerans strain O4 + P. putida strain P13 + P. agglomerans strain P5 + P. koreensis strain S14 + P. vancouverensis strain S19) and simultaneous foliar application of methionine and lysine can play an important role in improving growth, yield and nutrients uptake in rice grains
Compatibility of the entomopathogenic fungus Beauveria bassiana with the insecticides fipronil, pyriproxyfen and hexaflumuron
The compatibility of Beauveria bassiana isolate DEBI 002 (Atashgah) with fipronil, pyriproxyfenand hexaflumuron insecticides was assayed. To determine the impact of the insecticides on thegermination of the fungal spore, different concentrations of the compounds were added to the culturemedium (malt agar). In order to calculate the mycelial growth in different treatments, each colonydiameter was measured and the spores were counted in the surface area to assess its sporulation. Theresults showed that pyriproxyfen at 1500 ppm and hexaflumuron at 80 ppm completely inhibited mycelialgrowth, while the inhibitory effect of fipronil at 1600 ppm remained at 76.6%. The inhibitory effect oflower concentrations of all three insecticides was between 10 and 20%. All tested insecticides inhibitedthe spore production between 80 to 100% at the highest concentrations without any significantdifferences. Pyriproxyfen at 400 ppm and hexaflumuron at all concentrations completely inhibited sporegermination, with significant difference, comparing with the rest of treatments. The results indicate thathexaflumuron has the highest inhibitory effect on the spore germination and is not recommended to beused simultaneously with B. bassiana against the insect pests
Higher-order approximation of cubic–quintic duffing model
We apply an Artificial Parameter Lindstedt-Poincaré Method (APL-PM) to find improved approximate solutions for strongly nonlinear Duffing oscillators with cubic–quintic nonlinear restoring force. This approach yields simple linear algebraic equations instead of nonlinear algebraic equations without analytical solution which makes it a unique solution. It is demonstrated that this method works very well for the whole range of parameters in the case of the cubic-quintic oscillator, and excellent agreement of the approximate frequencies with the exact one has been observed and discussed. Moreover, it is not limited to the small parameter such as in the classical perturbation method. Interestingly, This study revealed that the relative error percentage in the second-order approximate analytical period is less than 0.042% for the whole parameter values. In addition, we compared this analytical solution with the Newton– Harmonic Balancing Approach. Results indicate that this technique is very effective and convenient for solving conservative truly nonlinear oscillatory systems. Utter simplicity of the solution procedure confirms that this method can be easily extended to other kinds of nonlinear evolution equations
Effect of shade materials on rectal temperature, respiration rate and body surface temperature of crossbred calves during rainy season
An attempt was made to study the effect of different shade materials on body surface temperature, rectal and respiration rate in Vrindavani calves during the rainy season. Crossbred calves (18) were divided into 3 group, viz. thatch shading roof with plastic covering (T1), agro-net shading roof- 60% light diffusion (T2), and asbestos with canvas shading roof (T3). The recording of macro and microclimate as well as the entire physiological parameters, viz. rectal temperature, respiration rate and body surface temperature were recorded at 9:00 and 2:00 PM for 2 consecutive days at every fortnight interval. The microclimate, viz. maximum and minimum, RH, THI and surface temperature of roof was lower in T2 group. The physiological parameters values were significantly lower in T2 group. It can be concluded that in rainy season agro-net helped to protect calves from the hot and humid condition
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