Effectiveness Of Foliar Fungicides Research Articles

Modeling the relationship between estimated fungicide use and disease-associated yield losses of soybean in the United States I: Foliar fungicides vs foliar diseases.

Fungicide use in the United States to manage soybean diseases has increased in recent years. The ability of fungicides to reduce disease-associated yield losses varies greatly depending on multiple factors. Nonetheless, historical data are useful to understand the broad sense and long-term trends related to fungicide use practices. In the current study, the relationship between estimated soybean yield losses due to selected foliar diseases and foliar fungicide use was investigated using annual data from 28 soybean growing states over the period of 2005 to 2015. For national and regional (southern and northern United States) scale data, mixed effects modeling was performed considering fungicide use as a fixed and state and year as random factors to generate generalized R2 values for marginal (R2GLMM(m); contains only fixed effects) and conditional (R2GLMM(c); contains fixed and random effects) models. Similar analyses were performed considering soybean production data to see how fungicide use affected production. Analyses at both national and regional scales showed that R2GLMM(m) values were significantly smaller compared to R2GLMM(c) values. The large difference between R2 values for conditional and marginal models indicated that the variation of yield loss as well as production were predominantly explained by the state and year rather than the fungicide use, revealing the general lack of fit between fungicide use and yield loss/production at national and regional scales. Therefore, regression models were fitted across states and years to examine their importance in combination with fungicide use on yield loss or yield. In the majority of cases, the relationship was nonsignificant. However, the relationship between soybean yield and fungicide use was significant and positive for majority of the years in the study. Results suggest that foliar fungicides conferred yield benefits in most of the years in the study. Furthermore, the year-dependent usefulness of foliar fungicides in mitigating soybean yield losses suggested the possible influence of temporally fluctuating abiotic factors on the effectiveness of foliar fungicides and/or target disease occurrence and associated loss magnitudes.

Effect of Foliar Fungicides on Hail-damaged Corn

To test if fungicide applied to hail-injured corn improves yield and reduces disease, we simulated hail at VT and R2 growth stages for three years at three Iowa locations for a total of five site years. Hail damage was simulated using a string trimmer or an ice-propelling machine and non-hail controls were included. Estimated defoliation ranged from 5 to 51%, along with ear and stalk injury. After hail events, Headline AMP fungicide (pyraclostrobin + metconazole) was applied at an “immediate” or “deferred” timing (averaging 3 and 8 days afterwards, respectively). A non-fungicide treated control was included in hailed and non-hail control plots. Hail injury reduced fungal foliar disease compared to plants without hail injury, although overall disease severity was low during this study. Hail events at VT or R2 decreased yield compared to control plots (P = 0.1). Fungicide application did not provide yield-increasing plant health benefits after VT and R2 hail, at either “immediate” or “deferred” timing. While yield differences were not statistically significant, a cost/benefit analysis showed deferred fungicide application after VT hail, and immediate and deferred applications after VT for non-hail plots did provide positive economic returns. Results will help inform decisions about fungicide use in hail-damaged corn when foliar diseases are not present at high levels. Accepted for publication 7 January 2016. Published 13 January 2016.

The effect of foliar fungicides on the mycoflora of seeds of Triticum aestivum

The effect of three foliar fungicides. i.e., Bayloton 25 WP, Dithane M-45, and Funaben K. on the mycoflora associated with the seeds of spring <i>Triticum aestivum</i> cv. Kolibri cultivated in the field was investigated. The fungicide which highly reduced the number of both fungal colonies and species was Funaben K. Of the fungi most frequently occurring. Only Funaben K applied on the seeds reduced the proportion of seeds with <i>Alternaria alternata, Cladosporium</i> spp.. and <i>Septoria nodorum</i>. In contrast. seeds from plants traeted with Funaben K harboured significantly more colonies of non-sporulating fungi.

Effect of Foliar Fungicides on Late-season Anthracnose Stem Blight on Soybean

Anthracnose stem blight, caused by Colletotrichum truncatum, is responsible for soybean (Glycine max) yield losses in subtropical and tropical growing regions. There are inadequate data regarding the effect of anthracnose stem blight on yield in Iowa, and it is unknown if fungicide application can manage this disease. Field studies were conducted from 2008 to 2010 to determine the effect of fungicide application timing on late-season development of this disease. We also investigated the effect of anthracnose stem blight on yield and specific yield components. Fungicides reduced late-season symptom development when compared to the untreated control; however, there were no differences in yield and yield components. While foliar fungicides can reduce late-season disease development, anthracnose stem blight typically should not affect crop management decisions involving use of foliar fungicides on soybean in Iowa. Accepted 7 July 2014. Publication 14 August 2014.

Effect of Foliar Fungicides on Corn with Simulated Hail Damage.

Quinone outside inhibitor (QoI) foliar fungicides can be effective at reducing foliar diseases in corn (Zea mays), and they have been shown to provide physiological benefits experimentally in other crops in the absence of disease. A new supplemental label for pyraclostrobin that was approved in January 2009 by the United States Environmental Protection Agency (EPA) states that corn plants applied with pyraclostrobin may have better tolerance to damage caused by hail. To determine the effects of QoI foliar fungicides on hail-damaged corn, field research trials were conducted near Champaign, IL in 2007 and 2008. Hail damage was simulated with a gasoline-powered string-mower at the V12 growth stage, which caused injury to leaves and defoliation. At VT, the foliar fungicides azoxystrobin and pyraclostrobin were applied to corn. Control treatments included a nontreated control and a nondamaged control. The simulated hail damage significantly (P ≤ 0.05) increased gray leaf spot severity (caused by Cercospora zeae-maydis) in 2007 but not in 2008. Simulated hail damage also significantly reduced yield compared with the nondamaged control in both 2007 and 2008. Foliar fungicides significantly reduced disease severity compared with the nontreated control in 2007 but not in 2008; however, foliar fungicides did not significantly improve yield in either the damaged or nondamaged plots compared with the nontreated controls. Results from our research trials indicated that foliar fungicides provided very little benefit to corn injured by simulated hail; thus, growers should consider factors other than hail damage when making fungicide application decisions for corn.

Effects of foliar fungicides on kernel black point of wheat in southern Saskatchewan

This study was undertaken to determine the effect of fungicides on the incidence of black point in wheat (Triticum spp.) in southern Saskatchewan, Canada. Experiment 1 was conducted at Swift Current and Indian Head for 3 years. Folicur 3.6F (tebuconazole) and Bravo 500 (chlorothalonil) were applied at different growth stages from stem elongation to head emergence. Three spring common wheat (Triticum aestivum) and three durum wheat (Triticum turgidum var. durum) genotypes were used in this study. Experiment 2 was conducted at Indian Head for 3 years. Folicur 3.6F was applied from stem elongation to early milk stage for a durum cultivar. The incidence of black point was very low at Swift Current. Severe black point incidence occurred at Indian Head in 1999, which could be related to low temperature and high rainfall during the grain filling stage. Durum wheat cultivars had higher black point incidence than the common wheat cultivars. Fungicide applications from stem elongation to flag emergence could increase black point infection and it was, in many cases, associated with an increase in kernel mass. Fungicide applications at or after head emergence could reduce the incidence of black point, although this was not consistent.

Effect of foliar fungicides on disease control, yield and test weight of soft red winter wheat

Several fungicide treatments are available for control of leaf rust and Septoria leaf blotch of wheat. The objectives of this study were to compare fungicide treatments across environments (location-years) for effects on leaf rust and leaf blotch control, yield and test weight, and to partition the total variability into components associated with environment, environment × treatment interaction and experimental error. Eight treatments were evaluated on three wheat cultivars across four environments. Tebuconazole applied at flag leaf emergence and propiconazole applied at flag leaf emergence followed by triadimefon plus mancozeb at heading were consistently among the treatments with the lowest disease severities and highest yields and test weights. Efficacy of full or half rates of propiconazole applied at flag leaf emergence or triadimefon plus mancozeb applied at heading were not significantly different. Most of the variability for yield was due to environment, and little was due to environment × treatment interaction, indicating that the ranking of treatments did not differ across environments. The proportion of variability due to environment × treatment interaction was higher for test weight and disease severity than for yield. Because of economic considerations, only one fungicide application is feasible. Extending the application time for propiconazole beyond flag leaf emergence or registering tebuconazole for use on wheat probably would be a benefit to growers.

Disease resistance in winter wheat cultivars and effects of foliar fungicides on yield

Disease resistance in winter wheat cultivars and effects of foliar fungicides on yield

Effect of foliar fungicides on foliar diseases and pod, haulm and plant crude protein yields of groundnut

Abstract The efficacy of three rates each of tridemorphcarbendazim‐maneb and tridemorph‐maneb and one rate each of carbendazim and tridemorph fungicide formulations on groundnut foliar disease control was studied. The application of 1.06 kg a.i./ha of tridemorph‐carbendazim‐maneb resulted in the most effective disease control and the highest pod yield of 2258–3368 kg/ha. Though spraying carbendazim formulation resulted in the highest haulm yield (4835–5581 kg/ha), plot receiving the former had the highest plant protein content of 16.3% and overall crude protein production of 831 kg/ha. Comparatively, the un‐sprayed plots were severely affected by the diseases and had significantly lower yields of 1275 kg to 1886 kg and 1790 kg to 2543 kg/ha of pod and haulm respectively; with 11.8% protein content and 218 kg/ha crude protein production.

The effects of foliar fungicides on beneficial arthropods in wheat fields

Large scale replicated field trials were carried out over a 2 year period to quantify the insecticidal properties of 3 foliar fungicides commonly used in wheat fields. Pyrazophos significantly reduced the numbers of many groups of the natural enemies of cereal aphids and the insects known to be vital in the diet of gamebird chicks for up to 4 weeks after spraying. No such reductions were found after the use of either triadimefon or propiconazole. Aphid numbers on plots sprayed with pyrazophos were twice the numbers found on unsprayed plots either 6 weeks after spraying in 1985 or on unsprayed plots and plots sprayed with the other fungicides 20 days after treatment in 1984. In 1985, this necessitated the additional use of an aphicide only on those plots previously sprayed with pyrazophos. The removal of chick food insects following the use of pyrazophos was considered to be sufficient to reduce survival rates of wild gamebird chicks.

Effect of foliar fungicides on aflatoxin, oil and protein content and maturing rate of peanut kernels.

AbstractArachis hypogaea L. ‘Tifspan’ and ‘Florunner’ peanuts (groundnuts) were treated with selected foliar fungicides for control of Cercospora leafspot. Peanut fruits were harvested on three different dates and analysed for aflatoxin, oil and protein content and degree of maturity. No significant differences (P = <0.05) in aflatoxin incidence were associated with either fungicide treatments or harvest dates. Significant differences were observed, however, in the percentage protein and oil content of the peanut kernels, depending upon the fungicide treatment. Delayed maturity was caused by specific fungicide treatments.