Reducing the 2, 4 D+MCPA Antagonism from Hard Spray Waters by Ammonium Sulfate

Introduction: Water is the main carrier of herbicides (HC) that its quality plays an important role in herbicide performance hard water has a high concentration of Ca++ and Mg++ and reviews have shown that calcium, manganese and zinc are the main factors reducing the effectiveness of weak acid herbicides. Weak acid herbicides such as glyphosate, paraquat, clethodim and 2, 4 D are compounds that release the H+ ions once dissolved in water, but just slightly. Therefore, herbicides that are weak acids partially dissociate. Herbicides not dissociated (the compound remains whole) are more readily absorbed by plant foliage than those that dissociate. Dissociated herbicide molecules have a negative charge. After being dissociated, herbicides might remain as negatively charged molecules, or they might bind with other positively charged cations. Binding to some cations improves herbicide uptake and absorption, binding to others such as Ca++ and Mg++ antagonizes herbicide activity by decreasing absorption or activity in the cell. To correct such carriers, the use of adjuvants, such as ammonium sulphate (AMS), is recommended, which can reduce the use of herbicides and cause economic savings. The aim of this study was to investigate the simple effects and interactions between different amounts of AMS and carrier hardness (CH) levels on 2, 4 D + MCPA herbicide efficacy in controlling white clover (Trifolium repens L.) in turf grass. Materials and Methods: The experiment was laid out in a RCBD with three replications for each treatment during spring-summer 2013 in 10 years old mixed cold season turf grass (Festuca rubra + Poa pratensis + Poa pratensis) dominated by white clover in Mashhad (Iran). The treatments were the factorial combination of four carrier hardness (CH) rates (Deionized, 45, 90 and 180 ppm of Ca++ +Mg++) and three Ammonium Sulfate (AMS) rates (0, 2, 3 and 4 Kg per100 L of carrier water) were studied. The turf was sprayed with 2, 4 D + MCPA (67.5% SL) at 1.5 L-ha applied once on July. The density and dry matter of clover and turf were recorded. Results and Discussion: Full performance of 2, 4 D + MCPA herbicide to control clover, regardless of the amount of ammonium sulfate used, was obtained in soft water. Adding just 4%, AMS to Carrier water with a hardness of 45 ppm could recover effectiveness of herbicide up to DI water, whereas in 90 ppm of hardness adding only 2 percent ammonium sulfate was enough to increase herbicide efficacy to twice as no ammonium sulfate treatment. The most significant antagonism effect was obtained in 180 ppm hardness level without AMS reducing 84% of 2, 4 D + MCPA performance compared to soft water. The highest antagonism effect of the herbicide carrier went to 180 ppm, 90 ppm and 45 ppm of hardness respectively. Overall, the study revealed that only in 45 ppm of CH the addition of 4% of AMS will help to restore the toxicity of 2, 4 D + MCPA while in 90 ppm and 180 ppm of CH add more than 2% of AMS to 2, 4 D + MCPA carrier water will not benefit the herbicide toxicity. Most reports have considered sufficient two percent of AMS to neutralize the inhibitory effect of CH on the weak acid herbicides. Three weeks after spraying, no phytotoxicity was found in the grass. At the same time interaction between CH and AMS on the lawn dry weight was significant (

Investigting the effects of some physical and cultural methods on the population of bulb mite (Rhizoglyphus robini) and yield of saffron (.Crocus sativus L)

In this research, the effects of solarization by transparent plastics, planting time and the first irrigation after planting on the populations of saffron bulb mite (Rhizoglyphus robini) and yield (Crocus sativus L.) were investigated. A split plot experiment was conducted based on randomized complete block design with three replicates from 2011 to 2015 in Gonabad, Khorasan Razavi province. Solarization and non-solarization factors were placed in the main plots. Seven crop managing packages including 1- planting without irrigation in September, 2- irrigation immediately after planting in September, 3- planting without irrigation in June, 4- irrigation immediately after planting in June, 5- planting in June and irrigation in August, 6- planting without irrigation in September of the next year, and 7- irrigation immediately after planting in September of the next year were placed in sub-plots. The results showed that regardless of management package, solarization suppressed the mite populations and increased saffron yield. Package 4, Irrigation immediately after planting on June, increased the mite populations and decreased saffron yields. However, package 2, irrigation on September, reduces the mite populations and increases saffron yield. Planting Saffron in June (packages 3, 4, and 5) resulted in more yield compared to Planting at September (packages 1, 2, 6, and 7). The lowest reduction in the population of mites (94%) and the highest yield (77%) were achieved through solarization and by implementing package 3, treatment and cultivation in June of the next year with no irrigation after planting

The efficacy of some chemical and botanical pesticides against Tetranychus urticae (Acari: Tetranychidae) on Platanus orientalis (Platanaceae) in urban areas

Fatemi, Masoud, Torabi, Ehssan, Olyaie-Torshiz, Ali, Taherian, Majid (2021): The efficacy of some chemical and botanical pesticides against Tetranychus urticae (Acari: Tetranychidae) on Platanus orientalis (Platanaceae) in urban areas. Persian Journal of Acarology 10 (23): 309-319, DOI: 10.22073/pja.v10i3.6762

A Novel Biopesticide Formulation for Organic Management of Aphis gossypii in Cucumber Greenhouses

Intensive chemical pesticide usage in crop protection for pest control causes major pollution of the environment. Replacing chemical pesticides with biopesticide is an essential agro-ecological principle that should be considered in agro-ecosystems. In this study, a novel biopesticide formulation based on plant extract was prepared, and then aphid mortality in cucumber greenhouses was evaluated in comparison to common chemical insecticide. Our eco-friendly insecticide consists of methanolic extract of Rosmarinus officinalis (4.38 g in 1 L water) and succinic acid (0.5 g in 1 L water) in combination with Triton® X-100 (10 mL in 1 L water), canola seeds oil (10 mL in 1 L water), and potassium nitrate (5 g in 1 L water). Additionally, the common insecticide against Aphis gossypii in cucumber greenhouses is dichlorvos (Dichlorvos® 48% EC) which was applied at the recommended dose (0.6 g a.i./L). Twenty-four hours after sprayings, aphids that survived through each treatment were recorded, and mortality percentages were calculated. Results showed that in biopesticide treatment, mortality (65.6 ± 2.8%) has no significant difference compared to dichlorvos (71.1 ± 2.9%) (p = 0.0629). Finally, plant performance including numbers of leaves (p = 0.0951), flowers (p = 0.0842), fruits (p = 0.0730), and branches (p = 0.0698) were not influenced by the biopesticide application. Our results propose that the mentioned biopesticide can be used in cucumber greenhouses for aphid control with no adverse effect on plant growth and development, leading to zero-pollution tactics in crop protection, which is necessary for sustainable agriculture

Dissipation of S-metolachlor and butachlor in agricultural soils and responses of bacterial communities: Insights from compound-specific isotope and biomolecular analyses

International audienceThe soil dissipation of the widely used herbicides S-metolachlor (SM) and butachlor (BUT) was evaluated in laboratory microcosms at two environmentally relevant doses (15 and 150 mg/g) and for two agricultural soils (crop and paddy). Over 80% of SM and BUT were dissipated within 60 and 30 days, respectively, except in experiments with crop soil at 150 mg/g. Based on compound-specific isotope analysis (CSIA) and observed dissipation, biodegradation was the main process responsible for the observed decrease of SM and BUT in the paddy soil. For SM, biodegradation dominated over other dissipation processes, with changes of carbon isotope ratios (Dd 13 C) of up to 6.5‰ after 60 days, and concomitant production of ethane sulfonic acid (ESA) and oxanilic acid (OXA) transformation products. In crop soil experiments, biodegradation of SM occurred to a lesser extent than in paddy soil, and sorption was the main driver of apparent BUT dissipation. Sequencing of the 16S rRNA gene showed that soil type and duration of herbicide exposure were the main determinants of bacterial community variation. In contrast, herbicide identity and spiking dose had no significant effect. In paddy soil experiments, a high (4:1, V/V) ESA to OXA ratio for SM was observed, and phylotypes assigned to anaerobic Clostridiales and sulfur re-ducers such as Desulfuromonadales and Syntrophobacterales were dominant for both herbicides. Crop soil microcosms, in contrast, were associated with a reverse, low (1:3, V/V) ratio of ESA to OXA for SM, and Alphaproteobacteria, Actinobacteria, and Bacillales dominated regardless of the herbicide. Our results emphasize the variability in the extent and modes of SM and BUT dissipation in agricultural soils, and in associated changes in bacterial communities

Micronutrient Fertilization Amplified the Antioxidant Capacity in Tomato Plants with Improved Growth and Yield

Micronutrients play a critical role in plant growth and development, and their deficiency can have adverse effects on plant performance. These elements can also influence plant physiological processes as they are incorporated into the molecular structure of enzymes as cofactors. In this study, the impact of a micronutrient solution containing manganese (125 ppm), iron (200 ppm), zinc (60 ppm), and copper (20 ppm) was investigated on the growth parameters, yield, and antioxidant enzyme activity of tomato (Solanum lycopersicum) plants. Greenhouse tomatoes (cultivar Jet Star F1) were irrigated with the above-mentioned concentrations of elements in a completely randomized design, with five independent biological replicates. The micronutrient treatment increased the specific activities of superoxide dismutase, ascorbate peroxidase, glutathione reductase, guaiacol peroxidase, catalase, and phenylalanine ammonia-lyase, as well as the phenol and salicylic acid contents in tomato leaves. However, the malondialdehyde level and electrolyte leakage index were unaffected. Analysis of the plant growth parameters revealed that the micronutrients increased the stem diameter, root length, number of leaves, stem height, and fruit’s fresh weight in the treated plants. Overall, our results indicated that micronutrients positively affected the growth and development of tomato plants without adverse effects on the health indices. Moreover, the application of micronutrients can magnify the antioxidant capacity of tomato plants through increasing enzyme activity, as well as the phenol and salicylic acid levels. These changes would benefit those plants under abiotic/biotic stress conditions, where elevated levels of antioxidant activities are crucial