Tank Mix Research Articles

Comparing rates of mineral oil, sulfur, and phosphorous acid on Microdochium patch suppression and turfgrass quality

AbstractMicrodochium patch is a turfgrass disease caused by the fungal pathogen Microdochium nivale (Fr.) Samuels and I.C. Hallett that occurs in climates similar to the cool, humid regions of North America's Pacific Northwest. Mineral oil, S, and phosphorous acid (H3PO3) have been shown to suppress Microdochium patch on annual bluegrass (Poa annua L.) putting greens in western Oregon. Previous research using rates of 19.9 kg mineral oil ha–1 applied every 2 wk alone or as a tank mixture with 12.2 kg S ha–1, 3.7 kg H3PO3 ha–1, or both resulted in unacceptable turfgrass thinning. The objective of this field experiment was to evaluate whether tank mixes of these products would suppress Microdochium patch and yield acceptable turfgrass quality when rates of mineral oil were reduced from 19.9 to 10.0 kg ha–1, S from 12.2 to 6.1 kg ha–1, or H3PO3 from 3.7 to 1.8 kg ha–1. In both years of the experiment, all treatments suppressed Microdochium patch to <2% disease compared to more than 40% disease in the non‐treated control. Mineral oil applied with S resulted in a larger loss of green cover compared to mineral oil applied with H3PO3 regardless of rate. These results suggest that tank mixing mineral oil and S should be avoided in the winter months. Further research studying the mitigation of green cover loss associated with these treatments is warranted.

Assessing the United States Grape Industry’s Understanding of Fungicide Resistance Mitigation Practices

In 2019, a national survey of 252 members of the United States grape industry from 20 states assessed knowledge perception of fungicide resistance management, application of that knowledge to vineyard practices, and knowledge acquisition sources. Overall, respondents demonstrated clear understanding of resistance management practices. The specific distribution of responses was influenced by the respondent’s job role, duration of industry experience, and their farming operation size. Nationally, respondents were moderately familiar with the acronym FRAC (Fungicide Resistance Action Committee), with nearly 75% indicating they could identify the FRAC code of a fungicide. They felt moderately competent they could design a fungicide program that adhered to resistance management principles. Respondents identified fungicide resistance as a serious problem nationally, and as a moderate problem in their own vineyards. They ranked practices that include rotating fungicides of different FRAC codes, avoiding multiple sequential applications of the same trade name or FRAC code, tank mixing with different FRAC codes, using multisite products in a spray program, routine sprayer maintenance and calibration, and good canopy management as very-to-extremely important in managing fungicide resistance; whereas practices such as rotating between trade names and tank mixing different trade names ranked slightly important. Respondents identified university-based extension programs as the primary information resource for fungicide efficacy and fungicide stewardship (resistance management). To maximize potential effect, these results suggest that future educational efforts should be aimed at improving practices for fungicide resistance stewardship and should align with the knowledge-base and demographic factors of the target audience—particularly their job role, experience, and size of operation.

Management of Onion Thrips (Thrips tabaci) in Organic Onion Production Using Multiple IPM Tactics.

Simple SummaryOnion thrips (Thrips tabaci) is a major pest in organic onion production and effective integrated pest management strategies are lacking. Our objective was to evaluate pest management programs consisting of several different tactics: (1) two onion plant cultivars with semi-glossy leaves (“Rossa di Milano” and B5336AxB5351C) and one with waxy leaves (“Bradley”), (2) silver reflective and white plastic mulches, and (3) with or without an application of a biopesticide (spinosad + neem oil tank mix). Thrips densities were counted weekly and bulbs weighed at harvest. The application of the biopesticide had the most significant reduction in thrips densities and increase in yield. The cultivar “Rossa di Milano” had lower thrips densities compared with “Bradley” and B5336AxB5351C, but also had the lowest yield. Reflective mulch had lower thrips densities than white mulch but had no effect on yield. None of the other tactics provided any significant additional benefits to thrips management. While biopesticides will still be a key component to onion thrips management programs, their application frequency should be further optimized.Onion thrips (Thrips tabaci Lindeman) is a major pest in organic onion production and effective integrated pest management strategies are lacking. Our objective was to evaluate combinations of semi-glossy (“Rossa di Milano” and B5336AxB5351C) and waxy (“Bradley”) onion cultivars with reflective mulch, with or without biopesticides (spinosad + neem oil tank mix), to manage T. tabaci in organic onion production. Thrips densities were assessed weekly and bulbs graded and weighed at harvest. Onions sprayed with spinosad + neem oil had fewer T. tabaci (adults: 74% (2019); larvae: 40% (2018), 84% (2019) and produced higher yields (13% (2018), 23% (2019)) than onions that were unsprayed, regardless of mulch type or onion cultivar. “Rossa di Milano” had relatively fewer adult and larval thrips populations compared with “Bradley” (21% (2018), 32% (2019)) and B5336AxB5351C. However, “Rossa di Milano” had the lowest marketable yield in both years. Reflective mulch reduced densities on certain dates in both years compared to white mulch, but the largest and most consistent reduction only occurred in 2019. Reflective mulch had no impact on bulb yield. While spinosad + neem oil reduced thrips numbers and increased yield alone, none of the treatment combinations were effective at suppressing populations of thrips. Future T. tabaci management in organic onions will require optimization of the available effective biopesticides.

Development of a QuEChERS-LCMS/MS method for simultaneous estimation of tebuconazole and chlormequat chloride in wheat crop

Tebuconazole (TBZ) and Chlormequat chloride (CCC) combination has been established as highly effective in reducing plant height of lodging prone wheat varieties. In this work, a novel analytical method employing the quick, easy, cheap, effective, rugged and safe (QuEChERS) cleanup technique and LC-MS/MS (liquid chromatography-tandem mass spectroscopy) was developed for simultaneous estimation of TBZ and CCC in wheat grains and harvest stage plant leaves. A total of 10 mL of acetonitrile and 50 mg of primary secondary amine (PSA) sorbent was consumed in the optimized QuEChERS process for leaves and grain samples. The LC-MS/MS analysis was performed using a C-18 column operating under electrospray ionization in positive mode. The QuEChERS approach achieved extraction recoveries in the acceptable range of 70%–120%, for both the compounds and was validated in terms of accuracy, precision, sensitivity and linearity. Persistence study was conducted using Lihocin (CCC 50% SL), Folicur (TBZ 25.9% EC) and their combination tank mix (Lihocin + Folicur-50% SL + 25.9% EC) applied as foliar spray twice in wheat crop (tester tall variety C-306). The results demonstrated that the developed QuEChERS-LCMS/MS is rapid and confirmatory for simultaneous quantification of both the test analytes in wheat crop.

Effect of Herbicides on the Management of the Invasive Weed Solanum rostratum Dunal (Solanaceae).

Solanum rostratum Dunal is an invasive weed species that invaded Israel in the 1950s. The weed appears in several germination flashes, from early spring until late summer. Recently, an increase in its distribution range was observed, alongside the identification of new populations in the northern part of Israel. This study aimed to investigate the efficacy of herbicide application for the control of S. rostratum using two field populations originated from the Golan Heights and the Jezreel Valley. While minor differences in herbicide efficacy were recorded between populations, plant growth stage had a significant effect on herbicide response. Carfentrazone-ethyl was found to be highly effective in controlling plants at both early and late growth stages. Metribuzin, oxadiazon, oxyfluorfen and tembutrione showed reduced efficacy when applied at later growth stage (8–9 cm height), as compared to the application at an early growth stage (4–5 cm height). Tank mixes of oxadiazon and oxyfluorfen with different concentrations of surfactant improved later growth stage plant control. Taken together, our study highlights several herbicides that can improve weed control and may be used as chemical solutions alongside diversified crop rotation options. Thus, they may aid in preventing the spread and further buildup of S. rostratum field populations.

A New Approach in Agronomic Biofortification for Improving Zinc and Iron Content in Chickpea (Cicer arietinum L.) Grain with Simultaneous Foliar Application of Zinc Sulphate, Ferrous Sulphate and Urea

The investigation was undertaken with the aim of studying the effect of individual and tank mix applications of zinc sulphate (ZnSO4), ferrous sulphate (FeSO4) and urea on zinc (Zn) and iron (Fe) biofortification of chickpea. A field experiment was conducted in 2015–2016 and 2016–2017 with treatments comprising individual and tank mix applications of ZnSO4 (0.5%), FeSO4 (0.5%) and urea (2%) at flowering and pod formation stages along with control (no nutrient application). Tank mix foliar application of ZnSO4 (0.5%) + FeSO4 (0.5%) + urea (2%) resulted in similar Zn (44.01 and 43.01 mg Zn kg−1 grain in the first and second year of study) and Fe (71.08 and 73.91 mg Fe kg−1 grain) content as in case of individual application of these nutrients (45.08 and 45.00 mg Zn kg−1 and 71.41 and 74.16 mg Fe kg−1 grain) thus showing a positive impact over unsprayed control (25.08 and 25.53 mg Zn kg−1 and 47.58 and 48.66 mg Fe kg−1 grain). Addition of urea (2%) helped in further improvement of Zn and Fe contents over ZnSO4 (0.5%) + FeSO4 (0.5%) spray only. Both tank mix application and individual application of these nutrients recorded significantly higher grain yield and protein content over sole application and control. Tank mix application of ZnSO4 (0.5%), FeSO4 (0.5%) and urea (2%) at flowering and pod formation stages of chickpea is a new method of biofortification which improves Zn and Fe contents and needs a special attention for improving malnutrition in humans.

Effect of Fertiactyl® on the absorption and translocation of 14C-glyphosate in young eucalyptus plants

Fertiactyl® is a foliar fertilizer with the potential to minimize the phytotoxicity effects caused by glyphosate drift in eucalyptus plants. As the interactions of the glyphosate and Fertiactyl® in tank mix on the plant behavior are not yet known, the objective was to evaluate the absorption and translocation of 14C-glyphosate, applied isolated and mixed in tank with Fertiactyl®, in young eucalyptus plants (clone I-144, Eucalyptus urophylla x E. grandis). The addition of Fertiactyl® to the mixture of 14C-glyphosate reduced the absorption by 94.3% in relation to the total absorbed at the end of the evaluation compared to plants treated only with 14C-glyphosate, i.e., Fertiactyl® protected the eucalyptus plants of the glyphosate intoxication by drift. The translocation rates from the treated leaves to the rest of the shoots and roots were low (<2% of the total recovered) in both treatments, suggest that restricted translocation is a mechanism of natural tolerance to glyphosate in plants of clone I-144. It is concluded that Fertiactyl®, mixed in the solution with glyphosate, protects young eucalyptus plants against glyphosate drift by reducing the amount of herbicide absorbed.

Effect of alone and tank mix application of herbicides on weed infestation and productivity of kharif Maize (Zea mays L.)

A field trial was conducted during the kharif season at agricultural research farm of Trihut college of Agriculture (TCA) Dholi under the RPCAU Pusa, Samastipur (Bihar) to find out the efficiency of sole and sequential application of herbicides on weeds and productivity of the maize crop. A total of eleven treatments viz : Weedy check, Topramezone @ 25.2 g ha -1 , Tembotrione @ 120 g ha -1 , Atrazine @ 1 kg ha -1 fb hand weeding at 25 DAS, Atrazine @ 0.75 kg ha -1 fb topramezone @ 25.2 g ha -1 , Atrazine 0.75 kg fb tembotrione 120 g ha -1 , Atrazine 1.0 kg ha -1 fb topramezone 25.2 g ha -1 , Atrazine 1.0 kg ha -1 fb tembotrione 120 g ha -1 , Topramezone 25.2 g ha -1 + atrazine @ 0.75 kg ha -1 , Tembotrione @ 120 g ha -1 + atrazine @ 0.75 kg ha -1 , Weed free were tested in randomized block design with three replication. A total of twelve weed species comprised of four grasses, seven broad leaved weeds and one sedge were recorded in experiment field. The application of atrazine @ 1.0 kg ha -1 fb tembotrione @ 0.120 kg ha -1 significantly reduced the weed density of grass weeds, broad leaved weeds and total weeds and its dry weight compared to all other weed control treatments. This treatment had weed control efficiency (WCE) of 78 % and weed index 2.7%. Thereby, recorded higher yield attributes and grain yield (6.24 t ha -1 ) which was at par with weed free (6.42 tha -1 ). Therefore, it may be concluded that application of atrazine @ 1.0 kg ha -1 fb tembotrione @ 0.120 kg ha -1 as effective weed control practice for kharif maize

Impact of tank mixing plant hormones with bentazon and mesotrione on sweetpotato injury and weed control

AbstractDue to excessive crop damage, currently, there are no selective postemergent (POST) herbicides registered for sweetpotato [Ipomoea batatas (L.) Lam] to control broadleaves and nutsedge species. Expansion of bentazon and mesotrione herbicide labels to include sweetpotato would be beneficial for growers. Two experiments were conducted. The first evaluated the dose response of sweetpotato cultivars Beauregard and Covington to bentazon (514, 1,028, and 1,542, g a.i. ha–1) and mesotrione (105, 210, and 315 g a.i. ha–1) when melatonin, 24‐epibrassinolide, or ascorbic acid (AsA) were included in the tank mix. The second experiment evaluated the efficiency of bentazon and mesotrione for control of yellow nutsedge (Cyperus esculentus L.) and Palmer amaranth (Amaranthus palmeri S. Wats.), when different doses of melatonin, 24‐epibrassinolide, or AsA were added to each herbicide. In the first experiment, when treated with herbicide alone, Beauregard exhibited injury levels lower than Covington for both herbicides. No injury was observed when plants were treated with plant hormones or AsA alone. At the lowest dose of bentazon and mesotrione, the addition of AsA or plant hormones in the tank mix significantly reduced percentage injury and increased plant tolerance, requiring higher doses of herbicide to cause 10, 20, and 30% injury. In the second experiment, the addition of plant hormones and AsA in the tank mix had no antagonistic effect on herbicide effectiveness, exhibiting similar levels of injuries as herbicides application alone. These results suggest that the use of plant hormones and AsA could improve sweetpotato tolerance to POST applications of bentazon and mesotrione without reducing herbicide effectiveness.

ВЛИЯНИЕ ЭЛЕМЕНТОВ ТЕХНОЛОГИИ ВОЗДЕЛЫВАНИЯ НА УРОЖАЙНОСТЬ И КАЧЕСТВЕННЫЕ ПОКАЗАТЕЛИ КЛУБНЕЙ КАРТОФЕЛЯ СРЕДНЕСПЕЛОГО СОРТА «БАРНА» В ЛЕСОСТЕПНОЙ ЗОНЕ РСО-АЛАНИЯ

The results of studying the effect of microfertilizer "Ultramag Combi" and growth regulator "Regoplant" on productivity and the developed system of their combined use for the production of environmentally friendly potatoes are presented. Field experiments were carried out in 2018-2020. on leached heavy loamy chernozem underlain by pebbles of the forest-steppe zone of North Ossetia-Alania. For all variants of treatment with the growth regulator "Regoplant" and the microfertilizer "Ultramag Combi", an increase in the yield of tubers was obtained. The maximum potato yield was obtained when treated with a tank mix - 22.8 t/ha. The quality indicators of potato tubers (dry matter content, starch, vitamin C) improved markedly in all variants of the experiment compared to the control. The highest content of dry matter (22.6%) and starch (12.7%) was noted when using the tank mixture: Regoplant (25 ml/ha) + Ultramag Combi (0.75 l/ha). The calculation of economic efficiency showed that the costs are paid off in all variants of the experiment, however, the most profitable option turned out to be the treatment with a tank mixture: "Regoplant" (25 ml/ha) + "Ultramag Combi" (0.75 l/ha), where the profitability was 54.4% or 19% more than the control variant, and compared with II and III experimental variants - by 10.2; 7.8% more respectively.

Evaluation of Rice (Oryza sativa L.) under integrated nitrogen management practices and succeeding maize (Zea mays L.) under residual nutrient and weed management practices

A field experiment was conducted at Central Research Station of the College of Agriculture, OUAT, Bhubaneswar, during two consecutive kharif and rabi seasons of 2017-18 and 2018-19 to study the influence of integrated nitrogen management practices on rice and its residual effects on growth, yield attributes and yield of maize with different weed management practices. The field experiment was laid out in a RBD design for rice with four treatments and 15 replications and split-plot design for maize with three replications. The four Integrated nitrogen management (INM) treatments for rice were D1=100% STBN (Soil test based nitrogen) D2=50%STBN+50%FYM, D3=50%STBN+50%VC and D4=50%STBN+50%PM. Maize is taken as the succeeding crop grown with RDF (120-60-60Kg/ha, N-P-K respectively). There were altogether 20 treatment combinations for maize with Main Plot (Nutrient management, i.e. residual nutrients of rice crop) and Sub-Plot (Weed management): W1= Topramezone@25g a.i./ha, W2=Tembotrione@105g a.i./ha,W3=Topramezone@25g a.i. + Atrazine@ 250g a.i./ha as tank mix, W4=Tembotrione@105g a.i./ha + Atrazine@ 250g a.i./ha and W5=Weedy check. Rice yield was found to be maximum under 50% STBN+ 50% VC followed by 50% STBN+ 50% PM. The residual effects of these nutrients practices have found to be influence the growth and yield of succeeding maize crops. Among the nutrient management practices, 50% STBF+ 50% VC gives the highest kernel yield (6.36t/ha) and among the weed management practices combined application of Topramezone@25g a.i. +Atrazine@ 250g a.i./ha as tank mix resulted the maximum kernel yield (7.18t/ha) over both the years. Highest kernel yield of maize, 7.59t/ha was recorded in the treatment combination, comprising 50%STBN+50%VC with Topramezone@25g a.i. +Atrazine@ 250g a.i./ha as tank mix application in maize at 15 DAS.

Cytochrome P450 enzymes inhibitor in the control of Digitaria insularis

ABSTRACT Herbicide interactions can be synergic, additive, or antagonist when mixed in the spray tank. A good example is an association between 2,4-D and graminicides. One hypothesis is that 2,4-D contributes to increasing the Cytochrome P450 activity, which may be one of the causes of antagonism. This study aimed to investigate the use of CYP450 enzymes inhibitor associated with the herbicide mixtures 2,4-D and ACCase inhibitors in vivo on the control of Digitaria insularis. The experiment was performed using a randomized block design in a factorial scheme of 6x2 with four replications. Factor A consisted of untreated check, 2,4-D (1005 g a.e ha-1), clethodim (192 g a.i ha-1) and haloxyfop (62.4 g a.i ha-1), 2,4-D + clethodim (1005 g a.e ha-1+192 g a.i ha-1), and 2,4-D + haloxyfop (1005 g a.e ha-1 +62.4 g a.i ha-1). Factor B represented the presence or absence of malathion (1000 g ha-1) applied two hours before applying the herbicides. A physicochemical test was performed to verify the compatibility of the herbicides in the tank. Malathion application performed two hours before applying the herbicide mixtures (2,4-D and clethodim/haloxyfop) did not provide adequate control of sourgrass, suggesting that CYP450 enzymes inhibited by malathion are not involved in the antagonistic effect between 2,4-D and both graminicides in the management of sourgrass. The 2,4-D + haloxyfop in tank mix demonstrated less efficacy in controlling sourgrass than 2,4-D + clethodim, but both mixtures were incompatible in the tank mix, which may be associated with reduced efficacy in sourgrass management.

Weed management efficacy of tank mix herbicides in wet-seeded rice

Weed management efficacy of tank mix herbicides in wet-seeded rice

ASSOCIAÇÃO DE HERBICIDAS PARA O MANEJO DE PLANTAS DANINHAS EM MILHO

O uso de herbicidas para o controle de plantas daninhas na cultura do milho tem sido uma prática muito comum pelos produtores, sendo aplicados de modo isolado ou em mistura em tanque. Diante disso, o objetivo do trabalho foi avaliar a eficiência, a fitotoxicidade, o efeito em características fisiológicas e produtivas do milho após a aplicação de herbicidas de modo isolado ou em mistura em tanque. O experimento foi instalado a campo, no delineamento de blocos casualizados, com quatro repetições. Como tratamentos foram utilizados de forma isolada ou em mistura em tanque o glyphosate, [atrazine+simazine], nicosulfuron, mesotrione, tembotrione, mais uma testemunha capinada. Avaliou-se a fitotoxicidade dos herbicidas ao híbrido de milho AG 9025 PRO3, a eficiência no controle de papuã (Urochloa plantaginea) e milhã (Digitaria ciliaris) aos 7, 14, 21 e 28 dias após a aplicação dos tratamentos (DAT). Aos 50 DAT aferiu-se ainda as variáveis referentes às características fisiológicas do milho e na colheita determinou-se a produtividade de grãos. A fitotoxicidade ocasionada pelos herbicidas não foi perceptível ao híbrido de milho AG 9025 PRO3. O controle foi eficiente nos tratamentos que apresentaram a mistura em tanque de glyphosate com nicosulfuron e tembotrione. A taxa fotossintética aumentou com a aplicação de nicosulfuron e mesotrione ao se comparar com os demais tratamentos. A concentração interna de CO2, taxa de transpiração, condutância estomática de vapores de água, eficiência de carboxilação e uso eficiente da água não foram alteradas ao se usar os herbicidas isolados ou em mistura. A aplicação dos herbicidas não interferiu na produtividade de grãos de milho. A associação de glyphosate com outros herbicidas demonstra ser prática favorável para melhorar a eficácia de controle.

Increase in longevity and amelioration of pesticide toxicity by natural levels of dietary phytochemicals in the honey bee, Apis mellifera.

For the past decade, migratory beekeepers who provide honey bees for pollination services have experienced substantial colony losses on a recurring basis that have been attributed in part to exposure to insecticides, fungicides, or their combinations applied to crops. The phytochemicals p-coumaric acid and quercetin, which occur naturally in a wide variety of bee foods, including beebread and many types of honey, can enhance adult bee longevity and reduce the toxicity of certain pesticides. How variation in concentrations of natural dietary constituents affects interactions with xenobiotics, including synthetic pesticides, encountered in agroecosystems remains an open question. We tested the effects of these two phytochemicals at a range of natural concentrations on impacts of consuming propiconazole and chlorantraniliprole, a triazole fungicide and an insecticide frequently applied as a tank mix to almond trees during bloom in California’s Central Valley. Propiconazole, even at low field concentrations, significantly reduced survival and longevity when consumed by adult bees in a sugar-based diet. The effects of propiconazole in combination with chlorantraniliprole enhanced mortality risk. The detrimental effects of the two pesticides were for the most part reduced when either or both of the phytochemicals were present in the diet. These findings suggest that honey bees may depend on non-nutritive but physiologically active phytochemical components of their natural foods for ameliorating xenobiotic stress, although only over a certain range of concentrations; particularly at the high end of the natural range, certain combinations can incur additive toxicity. Thus, efforts to develop nectar or pollen substitutes with phytochemicals to boost insecticide tolerance or immunity or to evaluate toxicity of pesticides to pollinators should take concentration-dependent effects of phytochemicals into consideration.

Surfactants in plant disease management: A brief review and case studies

AbstractIn plant disease management, surfactants are generally used in combination with pesticides to facilitate delivery of the pesticide chemicals to the target sites in plants, vectors, or pathogens. Their intended use is rarely for direct effect on plant pathogens. However, trends in recent studies have revealed an appreciable increase in their use for direct management of plant diseases. In this paper, we briefly review the progress made in the use of surfactants for disease management, as adjuvants and when applied for direct effect. We carried out experiments to evaluate the effect of selected synthetic surfactants (Cohere, Kinetic, Silwet‐77, and Induce) on powdery mildew in squash and bacterial spot in tomato. Results from this study showed that the effect of surfactants on these pathogens is dependent on the type of plant pathogen or disease. All tested surfactants exhibited in vitro bactericidal activity against Xanthomonas perforans, a causal pathogen of bacterial spot of tomato. In the greenhouse, Cohere significantly reduced disease severity of powdery mildew in squash compared to the untreated control. Cohere also showed promise in field trials against bacterial spot of tomato, but the other surfactants tested promoted this disease. Our studies demonstrate the importance of evaluating surfactants for their use in management of plant diseases both for direct effect and as adjuvants in tank mix.

Choline-based ionic liquids as adjuvants in pesticide formulation

Current research focusing on using compounds of natural origin has led to the synthesis of new biobased ionic liquids (ILs) with surface-activity containing a dodecyl(2-hydroxyethyl)dimethylammonium cation and anions of natural (d-gluconate, α-ketoglutarate, l-pyroglutamate, cholate or glycolate) or synthetic origin (dioctyl sulfosuccinate or bis(2-ethylhexyl)phosphate). The influence of the anion on the physicochemical properties (thermal stability, phase transitions, solubility, surface-activity, refractive index) was examined. Subsequently, the obtained ILs' impacts as herbicide additives were assessed on a common windgrass (Apera spica-venti L. Beauv) using the greenhouse test, and the toxicity of the compounds toward bacteria, fungi, and plants was evaluated. We established that the surface wettability of tank mixes and their biological activity were correlated. This discovery may greatly facilitate the design of new, biocompatible adjuvants of low toxicity, which can be particularly useful as additives to plant protection products in organic farming.

Validation of BLEVE events using the hybrid code exploCFD

AbstractA hybrid (analytical‐numerical) method for the modeling of BLEVE events seems the most realistic approach given the complex coupled physical models required for a purely numerical approach. The code exploCFD employs just such a method for the calculation of events involving multiple types of explosions including BLEVEs whereby the results from an analytical model are fed into a CFD code to model the wider domain. The CFD code is configured as a 2D solver hence the methodology carries some uncertainty. So how do the results from a hybrid method compare with those obtained from experiments? Here we look at the BLEVE experiments of Birk and Vandersteen. We show that despite simplifications inherent in the methodology, which include the combining separate discrete events such as initial tank rupture, catastrophic failure and mixing and subsequent ignition into one equivalent event, exploCFD produces results which are in good agreement with the experimental peak pressures and impulses. The peak pressure is captured at locations 10, 20, 30, and 40 m from tank side and the impulse values also show good agreement. Surprisingly, the time histories also show better than expected agreement.

Reducing Chlorothalonil Use in Fungicide Spray Programs for Powdery Mildew, Anthracnose, and Gummy Stem Blight in Melons.

Fungicides are applied to nearly 80% of U.S. melon acreage to manage the numerous foliar and fruit diseases that threaten yield. Chlorothalonil is the most widely used fungicide but has been associated with negative effects on human and bee health. We designed alternative fungicide programs to examine the impact of reducing chlorothalonil use (Bravo Weather Stik) on watermelon, cantaloupe, and honeydew melon in 2016, 2017, and 2018 in Maryland. Chlorothalonil was replaced in the tank mix of weekly sprays of targeted fungicides with either polyoxin D zinc salt (Oso) or an extract of Reynoutria sachalinensis (Regalia). Powdery mildew (PM; Podosphaera xanthii), gummy stem blight (GSB; Stagonosporopsis spp.), and anthracnose (Colletotrichum orbiculare) were the most prevalent diseases to occur in the 3 years. Replacing chlorothalonil with the biopesticides as the tank-mix component of the fungicide spray program was successful in reducing GSB and PM severity in cantaloupe, honeydew melon, and watermelon compared with the untreated control, with the exception of GSB in 2017 in cantaloupe, and similar to the program including chlorothalonil in all cases, except anthracnose in watermelon. Anthracnose disease severity was not significantly reduced compared with the untreated control when chlorothalonil was replaced with the biopesticides and yields were not improved over the chlorothalonil-alone treatment in any of the trials. Therefore, replacement of chlorothalonil may not fully address its loss as a fungicide resistance management tool but efficacy can be maintained when polyoxin D is alternated with R. sachalinensis as a tank mix with targeted fungicides to manage PM and GSB.

Weed density and productivity of dry direct seeded rice in relation to weed management practices and seedbed preparation methods

Effective weed management practice is important for successful dry direct seeded rice (DDSR) cultivation. Field experiments were conducted during rainy seasons of 2016 and 2017 to assess the effect of herbicides, or herbicides mixture, and seedbeds preparation methods on weed density and grain yield of DDSR. The experiments were done by using two factors factorial strip plot design with four replications. The treatments consisted of nine weed management practices (weed free; weedy check; spraying Pendimethalin; Bispyribac sodium; Ethoxysulfuron; Pendimethalin followed by Bispyribac sodium; Pendimethalin followed by Ethoxysulfuron; Bispyribac sodium tank mix with Ethoxysulfuron, and Pendimethalin followed by Bispyribac sodium tank mix with Ethoxysulfuron) as horizontal factor whereas two seedbed preparation methods (stale, and normal seedbed) were considered as the vertical factor. The data were collected and analyzed using MSTAT-C statistical software. Total density and dry matter of weeds were significantly (p&lt;0.05) lower in weed free treatment followed by Pendimethalin spray and Bispyribac sodium tank mix with Ethoxysulfuron spray at all the growth stages of rice in both the years. Similarly, rice grain yield was significantly higher (p&lt;0.05) in weed free treatment followed by Pendimethalin spray and Bispyribac sodium tank mix with Ethoxysulfuron spray in both the years. Effect of seedbed preparation methods on weed density and dry matter, yield attributes and yield of rice were non-significant. Therefore, Pendimethalin spray followed by Bispyribac sodium tank mix with Ethoxysulfuron spray seems better option for managing weeds in DDSR.