Applications Of Carbendazim Research Articles

Functional Roles of Two β-Tubulin Isotypes in Regulation of Sensitivity of Colletotrichum fructicola to Carbendazim.

Colletotrichum fructicola is the major pathogen of anthracnose in tea-oil trees in China. Control of anthracnose in tea-oil trees mainly depends on the application of chemical fungicides such as carbendazim. However, the current sensitivity of C. fructicola isolates in tea-oil trees to carbendazim has not been reported. Here, we tested the sensitivity of 121 C. fructicola isolates collected from Guangdong, Guangxi, Guizhou, Hainan, Hunan, Jiangsu, and Jiangxi provinces in China to carbendazim. One hundred and ten isolates were sensitive to carbendazim, and 11 isolates were highly resistant to carbendazim. The growth rates, morphology, and pathogenicity of three resistant isolates were identical to those of three sensitive isolates, which indicates that these resistant isolates could form a resistant population under carbendazim application. These results suggest that carbendazim should not be the sole fungicide in control of anthracnose in tea-oil trees; other fungicides with different mechanisms of action or mixtures of fungicides could be considered. In addition, bioinformatics analysis identified two β-tubulin isotypes in C. fructicola: Cfβ1tub and Cfβ2tub. E198A mutation was discovered in the Cfβ2tub of three carbendazim-resistant isolates. We also investigated the functional roles of two β-tubulin isotypes. CfΔβ1tub exhibited slightly increased sensitivity to carbendazim and normal phenotypes. Surprisingly, CfΔβ2tub was highly resistant to carbendazim and showed a seriously decreased growth rate, conidial production, pathogenicity, and abnormal hyphae morphology. Promoter replacement mutant CfΔβ2-2×β1 showed partly restored phenotypes, but it was still highly resistant to carbendazim, which suggests that Cfβ1tub and Cfβ2tub are functionally interchangeable to a certain degree.

The win-win effects of nitrification inhibitors on soil-crop systems: Decreasing carbendazim residues but promoting soil bacterial community diversities and stabilities and crop yields

Applying nitrogen (N)-cycling inhibitors is an effective measure to improve N fertilizer utilization efficiency, but the effects of N-cycling inhibitors on fungicide residues in soil-crop systems are unclear. In this study, nitrification inhibitors dicyandiamide (DCD) and 3, 4-dimethylpyrazole phosphate (DMPP) and urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) were applied into agricultural soils with fungicide carbendazim applications. The soil abiotic properties, carrot yields, carbendazim residues, bacterial communities and their comprehensive relationships were also quantified. Compared to the control treatment, the DCD and DMPP significantly decreased soil carbendazim residues by 96.2% and 96.0%, and the DMPP and NBPT significantly reduced carrot carbendazim residues by 74.3% and 60.3%, respectively. The nitrification inhibitor applications also generated significant and positive effects on carrot yields and soil bacterial community diversities. The DCD application significantly stimulated soil Bacteroidota and endophytic Myxococcota and modified soil and endophytic bacterial communities. Meanwhile, the DCD and DMPP applications also positively stimulated the co-occurrence network edges of soil bacterial communities by 32.6% and 35.2%, respectively. The linear correlation coefficients between soil carbendazim residues and pH, ETSA and NH4+-N contents were − 0.84, − 0.57 and − 0.80, respectively. The nitrification inhibitor applications generated win-win effects on the soil-crop systems by decreasing carbendazim residues but promoting soil bacterial community diversities and stabilities and crop yields.

Combined effects of spent mushroom substrate and dicyandiamide on carbendazim dissipation in soils: Double-edged sword effects and potential risk controls

Repeated and high-dose carbendazim applications have caused serious soil carbendazim contamination, and eco-friendly and economical approaches have been suggested to promote carbendazim removal in agricultural soil. Spent mushroom substrate (SMS) is a special recycled resource after harvesting mushrooms and can be utilized in contaminated soil amendment. The SMS application into agricultural soil might increase antibiotic resistance gene abundances, and the health risks of SMS application might be reduced with reasonable management to adjust the related electron transport of soil nitrification or denitrification. In this study, the SMS and nitrification inhibitor dicyandiamide were used to remediate agricultural soil contaminated with the carbendazim, and the carbendazim contents, soil microbial biomass, activities and community and human disease genes were determined. Compared to the control treatment, the combined applications of SMS and dicyandiamide significantly decreased soil carbendazim content by 38.14% but significantly enhanced soil β-glucosidase, chitinase, arylsulfatase, urease and electron transfer system activities. The relative abundances of Proteobacteria and Actinobacteria were increased by 11.0% and 8.2% with the SMS application, respectively. The carbendazim residues were negatively correlated with the soil pH, electron transfer system activities and relative abundances of Proteobacteria and Actinobacteria. The relative abundances of human disease genes were also dramatically increased with the SMS application, but compared to the SMS alone, extra dicyandiamide application significantly reduced the relative abundances of human disease genes in soils. The SMS applications into fungicide-contaminated soils could generate double-edged sword effects of facilitating fungicide dissipation but leading to potential health risk increase, while applying the dicyandiamide with SMS might be an effective strategy to decrease the negative effect of health risk.

Effects of Thiram and Carbendazim Application Rates on Growth and Grain Yield of Chickpea ( Cicer arietinum ) in Kenya

Fusarium wilt caused by Fusarium oxysporum f. sp. ciceris is a soil and seed borne disease affecting chickpea (Cicer arietinum). It is widely distributed where chickpea is grown and it causes variable yield losses depending on the level of resistance of the genotype and suitability of environmental conditions for disease development. Thiram and carbendazim fungicides are used in most crops as seed dress fungicides against a wide variety of pathogens. The impact of the 0%, 50%, 100% and 150% of the recommended 1.5g fungicide/kg seed rates of these two fungicides on plant height, periodic dry matter and number of pods and grain yield of chickpea was evaluated in the field in a split plot design. Two varieties, Chania 1 which is moderately resistant and Chania 2 which is highly susceptible were grown. Plant height, dry matter and pods per plant were significantly higher in Chania 1 moderately resistant variety and when grown under increasing rates of fungicide application. Increasing fungicide application rates significantly increased grain yield of chickpea. The highest Grain yield of 1.4 t/ha was obtained from 150% (2.25g/kg seed) application of either thiram or carbendazim for MR Chania 1 was grown and treated with either thiram or carbendazim at 150% rate of application. Farmers should grow Chania 1 chickpea variety to minimize use of fungicide application rates to range within 1.5 to 2.25 g fungicide/kg seed and obtain high chickpea growth; yield attributes and grain yields ranging between 1.32 to 1.4 t/ha, respectively.

English

Experiments were conducted to know the effect of recommended dose of fungicides (Propiconazole, Carbendazim and Hexaconazole), bio-agents and botanicals on incidence and severity of spot blotch disease and seed yield of wheat. Two sprays of Carbendazim at 0.1% at tillering and boot leaf stage resulted in the maximum reduction in spot blotch incidence and severity followed by two applications of Propiconazole at tillering and boot leaf stage. Propiconazole was also found to be quite effective in reducing the level of disease and enhancing crop yield followed by Carbendazim and Hexaconazole. However, Carbendazim, Propiconazole and Hexaconazole were almost equally effective against spot blotch of wheat and may be used as an alternative to each other for management of disease. Two applications of Carbendazim at tillering and boot leaf stages resulted in highest grain yield. Out of the two bio-agents tested against spot blotch of wheat under field conditions, Pseudomonas fluorescence followed by Trichoderma harzianum resulted in the highest reduction in disease incidence. However, both of these bio-agents were comparatively less effective in minimizing the disease as compared to chemical fungicides. Out of four plant extracts two applications of aqueous Eucalyptus leaf extract at tillering and boot leaf stage resulted in the highest wheat yield as compared to other botanical extracts. Key words: Fungicides, bio-agents, Pseudomonas fluorescence, botanicals, Bipolaris sorokiniana, spot blotch, Triticum aestivum.

Molecular characterization of the Fusarium graminearum species complex in Eastern China

Members of the Fusarium graminearum species complex (FGSC) cause Fusarium head blight in small cereal grains all over the world. To determine the species and trichothecene chemotype composition and population structure of FGSC in Jiangsu and Anhui provinces, an area where epidemics occur regularly, 891 isolates were collected in two consecutive years (2011 and 2012) and characterized with species- and chemotype-specific polymerase chain reaction. Of the 891 isolates typed, 83 were F. graminearum sensu stricto (s. str.) and 808 were F. asiaticum. All 83 F. graminearum s. str. isolates were of a 3ADON (26.51 %) or 15ADON (73.49 %) type, while F. asiaticum isolates included 696 3ADON producers, 46 15ADON producers, and 66 NIV producers. Eight variable number tandem repeat (VNTR) markers were tested on a representative 384 F. asiaticum isolates from 55 sampling sites. VNTR analysis showed high gene diversity and genotypic diversity but low linkage disequilibrium in both populations Fg2011 and Fg2012 grouped based on the year of collection. Low genetic differentiation (F ST = 0.026) and high gene flow (N m = 15.13) was observed between the two populations and among subpopulations within the same population (N m = 3.53 to 48.37), indicating that few influence of temporal and spatial variations on population differentiation in this area. Similar result was obtained from 3ADON, 15ADON and NIV populations or carbendazim resistant and sensitive populations, indicating that chemotype of Fusarium isolates and carbendazim application had minor influence on population subdivision.

Efficacy and timing of application of fungicides for control of citrus postbloom fruit drop

Citrus postbloom fruit drop (PFD) caused by Colletotrichum spp. occurs in several countries in the Americas reducing yields by as much as 80%. Fungicide application is the main strategy for PFD control. Two field trials were performed to assess the timing of applications and another two were set up to investigate the efficacy of fungicides for PFD control in São Paulo State, Brazil. The percentage of symptomatic flowers per branch, the number of persistent calyces per branch, the number of fruit per branch and yield were evaluated. Four sprays of trifloxystrobin + tebuconazole, carbendazim, difenoconazole or cyprodinil + fludioxonil were effective in reducing yield losses due to PFD, however the trifloxystrobin + tebuconazole mixture was significantly more effective than all other treatments. The conventional PFD control programme, with one spray of difenoconazole followed by up to three carbendazim applications at different intervals, showed variable results, probably due to rainfall. The trifloxystrobin + tebuconazole mixture was effective at controlling PFD under favourable conditions for infection and can be recommended in PFD control programmes.

Efecto de Pyraclostrobin+Epoxiconazole en la producción de fresa (Fragaria sp.)

<p>Cundinamarca ha sido un gran productor de fresa(Fragaria sp),en comparación con los demás departamentos de Colombia; pero uno de sus mayores limitantes es la pérdida de fruta causada por el moho gris, enfermedad desarrollada por el agente Botritis cinerea; por esta razón, se aplicó Pyraclostrobin+Epoxiconazole® a los cultivos, en tres dosis, y se compararon con un testigo regional, Carbendazim®, teniendo como variables de estudio: producción, calidad, grados Brix, pH, acidez titulable y la incidencia de la enfermedad sobre el cultivo. Los resultados obtenidos y analizados por medio del software SAS y aplicando las pruebas de comparación de Tukey demostraron que la dosis de Pyraclostrobin+Epoxiconazole® de 80cc/200L presentó la mayor producción de fruta de segunda, tercera y total, y la menor cantidad de fruta dañada, junto con la dosis de 120cc/200L. La menor producción total y por calidad se obtuvo con la dosis de Carbendazim® (250cc/200L). En cuanto a los grados Brix, no se encontraron diferencias significativas, pero sí un aumento durante las cuatro semanas de cosecha. Los valores más altos de pH y ATT se obtuvieron con las dosis de Pyraclostrobin+Epoxiconazole®, y los menores valores, con las aplicaciones de Carbendazim® (250cc/200L).Se recomienda hacer aplicaciones de estos ingredientes en el manejo de la enfermedad moho gris.</p>

Carbendazim dissipation in the biomixture of on-farm biopurification systems and its effect on microbial communities

The impact of repeated carbendazim (CARB) applications on the extent of CARB dissipation, the microbial diversity, the community level physiological profile (CLPP), and the enzymatic activity within the biomixture of an on-farm biopurification system was evaluated. After three successive CARB applications, the CARB dissipation efficiency was high; the efficiency of dissipation was 87%, 94% and 96% after each application, respectively. Although microbial enzymatic activity was affected significantly by CARB application, it could recover after each CARB pulse. Likewise, the numbers of cultivable bacteria, fungi and actinomycetes (as measured in CFUs) were slightly affected by the addition of CARB, but the inhibitory effect of the pesticide application was temporary. Denaturing gradient gel electrophoresis (DGGE) and Biolog Ecoplate assays demonstrated that the microbial populations remained relatively stable over time when compared to the control. The results obtained herein therefore demonstrate the high dissipation capacity of this biomixture and highlight the microbiological robustness of this biological system.

Response of soil bacterial community to repeated applications of carbendazim

The effect of repeated carbendazim applications on functional diversity of culturable microorganisms and bacterial community composition was studied under field conditions. The functional diversity of soil culturable microbial community (Shannon index, H′) reduced significantly ( P<0.05) after the first introduction of carbendazim at levels of 0.94, 1.88 and 4.70 kg active ingredient (a.i.) ha −1 and then recovered to that in the control with subsequent applications. An evident ( P<0.01) difference in the bacterial community composition was observed after the second carbendazim application by Temperature Gradient Gel Electrophoresis (TGGE) analysis of 16 S rRNA genes amplified from treated and control soils, which remained after the third and fourth treatments. Our results indicated that repeated carbendazim applications have a transient harmful effect on functional diversity of soil culturable microbial community and result in an alteration in bacterial community composition largely due to one species within the γ- proteobacterium.

Characterization of soybean genotypes for Asian soybean rust reaction

Our objective was to characterize soybean experimental lines for Asian soybean rust reaction. In the 2004/2005 growing season, three experiments were conducted with middle-cycle and three with late-cycle genotypes, designed in randomized blocks with four replications. Twelve experimental lines and two cultivars of each cycle were used. In each experiment the plant management differs as follows: three applications of carbendazim or three of flutriafol or without applications. The experimental lines with high yield, low notes to the symptoms and resistance to lodging, were selected and tested again in the 2005/2006 growing season. Genotypes with high severity and yield were considered tolerant to rust and the low severity and high yield ones as moderately resistant. Among the medium-cycle genotypes, there was moderate resistance to rust in one line and tolerance in five. Among the late-cycle genotypes, the six lines showed moderate resistance. The line USP 97-08135 is more tolerant to rust.

Determining the influence of rainfall patterns and carbendazim on the surface activity of the earthwormLumbricus terrestris

Carbendazim is highly toxic to earthworms and is used as a standard control substance when running field-based trials of pesticides, but results using carbendazim are highly variable. In the present study, impacts of timing of rainfall events following carbendazim application on earthworms were investigated. Lumbricus terrestris were maintained in soil columns to which carbendazim and then deionized water (a rainfall substitute) were applied. Carbendazim was applied at 4 kg/ha, the rate recommended in pesticide field trials. Three rainfall regimes were investigated: initial and delayed heavy rainfall 24 h and 6 d after carbendazim application, and frequent rainfall every 48 h. Earthworm mortality and movement of carbendazim through the soil was assessed 14 d after carbendazim application. No detectable movement of carbendazim occurred through the soil in any of the treatments or controls. Mortality in the initial heavy and frequent rainfall was significantly higher (approximately 55%) than in the delayed rainfall treatment (approximately 25%). This was due to reduced bioavailability of carbendazim in the latter treatment due to a prolonged period of sorption of carbendazim to soil particles before rainfall events. The impact of carbendazim application on earthworm surface activity was assessed using video cameras. Carbendazim applications significantly reduced surface activity due to avoidance behavior of the earthworms. Surface activity reductions were least in the delayed rainfall treatment due to the reduced bioavailability of the carbendazim. The nature of rainfall events' impacts on the response of earthworms to carbendazim applications, and details of rainfall events preceding and following applications during field trials should be made at a higher level of resolution than is currently practiced according to standard International Organization for Standardization protocols.

The soil-dwelling earthworm Allolobophora chlorotica modifies its burrowing behaviour in response to carbendazim applications

Carbendazim-amended soil was placed above or below unamended soil. Control tests comprised two layers of unamended soil. Allolobophora chlorotica earthworms were added to either the upper or the unamended soil. After 72h vertical distributions of earthworms were compared between control and carbendazim-amended experiments. Earthworm distributions in the carbendazim-amended test containers differed significantly from the ‘normal’ distribution observed in the control tests. In the majority of the experiments, earthworms significantly altered their burrowing behaviour to avoid carbendazim. However, when earthworms were added to an upper layer of carbendazim-amended soil they remained in this layer. This non-avoidance is attributed to (1) the earthworms’ inability to sense the lower layer of unamended soil and (2) the toxic effect of carbendazim inhibiting burrowing. Earthworms modified their burrowing behaviour in response to carbendazim in the soil. This may explain anomalous results observed in pesticide field trials when carbendazim is used as a control substance.

Carbendazim, at concentrations used on pasture for facial eczema control, reduces development of Trichostrongylus colubriformis when sprayed onto infected sheep faeces

AIM: To determine whether the fungicide, carbendazim, as applied to pastures for controlling facial eczema (FE), would inhibit development of the free-living stages of the gastrointestinal nematode parasite Trichostrongylus colubriformis. METHODS: Two studies were conducted, using sheep faeces containing eggs of T. colubriformis. In the first, the faeces were either exposed or not to an application of carbendazim sprayed at the recommended rate for FE control. After spraying, dishes containing the faeces were incubated at 20°C for 14 days, and the resulting third-stage infective larvae (L3) extracted by baermannisation and counted. In addition, naturally infested pasture was also sprayed, and the number of L3 present 7 days later was assessed by cutting herbage samples and extracting larvae by soaking in water and baermannisation. In the second, the faeces were incubated at 20°C for 0, 3 or 7 days before being exposed to no, one or two applications of carbendazim. After further incubation for 14, 11 or 7 days, L3 were similarly extracted by baermannisation and counted. RESULTS: In the first study, there was a 74% reduction in the number of T. colubriformis larvae recovered from faeces exposed to carbendazim compared with faeces not exposed, but there was no reduction in the number of L3 recovered from herbage. In the second study, faeces incubated for 0 or 3 days prior to exposure to a single application of carbendazim yielded 98% or 89% fewer larvae, respectively, than faeces not exposed. Faeces incubated for 7 days prior to exposure yielded similar numbers of larvae to faeces not exposed. CONCLUSION: Treatment of pastures with carbendazim for FE control is likely to result in reduced development of the larvae of T. colubriformis, and by inference those of other species, where the application coincides with the presence of freshly deposited faeces containing eggs and developing larvae. However, no effect of treatment on L3 was indicated. The significance of this for on-farm nematode parasite control remains to be determined, as does any potential for strategic applications of carbendazim to pasture aimed at reducing numbers of parasite larvae on pasture. The latter should not be contemplated without due consideration of the implications for the development of anthelmintic resistance.

Effects of repeated applications of fungicide carbendazim on its persistence and microbial community in soil

Carbendazim, a systemic benzimidazole fungicide, is applied repeatedly to control plant diseases including soilborne diseases, over a growing season. Studies were carried out under laboratory conditions to assess the effects of repeated carbendazim applications on its persistence and microbial community in soil. The results indicate that dissipation of carbendazim in soil was accelerated with its application frequency. The degradation rate constant of carbendazim was increased significantly from 0.074 d(-1) to 0.79 d(-1). The corresponding half-life was shorten markedly from 9.3 d to 0.9 d after four repeated applications. No significant inhibitory effect of carbendazim on soil microbial utilization of the carbon sources was observed after first treatment, but a slight increase in average well color development (AWCD) was shown after second, third, and fourth applications. It suggested that soil microorganisms become adapted to carbendazim after repeated application. Simpson and Shannon indexes of soil microbial community from carbendazim treated soil were also similar to those from the control soil, indicating that the richness and dominant character of soil microorganisms remain unchangeable after repeated application. However, after first, second, and third addition of carbendazim, McIntosh indexes on day 21 were significantly higher compared with the control, suggesting that balance of soil microorganisms was altered due to the enrichment of the specific carbendazim-adapting strains in soil.

Carbendazim induces a temporary change in soil bacterial community structure

The effect of carbendazim applications on the diversity and structure of a soil bacterial community was studied under field conditions using temperature gradient gel electrophoresis (TGGE) and partial sequence analysis of PCR-amplified 16S rRNA gene. After four successive introductions of carbendazim at a level of 0.94 kg active ingredient (a.i.)/ha, the genetic diversity (expressed as Shannon index, H') decreased from 1.43 in the control to 1.29 in treated soil. This harmful effect seems to increase with the concentration of carbendazim. The value of H' in the soil treated with carbendazim at 4.70 kg a.i./ha was reduced to 1.05 (P < or = 0.05). The structure of soil bacterial community was also affected after four repeated applications of carbendazim at levels of 0.94, 1.88 and 4.70 kg a.i./ha, as seen in the relative intensities of the individual band. However, the bacterial community in carbendazim-treated soil recovered to that in the control 360 d after the first treatment. The results indicated that repeated applications of carbendazim could reduce soil microbial diversity and alter the bacterial community structure temporarily.

Relating plant and pathogen development to optimise fungicide control of phoma stem canker (Leptosphaeria maculans) on winter oilseed rape (Brassica napus)

In winter oilseed rape experiments at Rothamsted in 2000/01 to 2002/03 growing seasons, the severity of phoma stem canker epidemics in summer depended on the timing of phoma leaf spot epidemics in the previous autumn, and hence on the timing of Leptosphaeria maculans ascospore release. The first major release of L. maculans ascospores was earlier in 2000 (26 September) and 2001 (18 September) than in 2002 (21 October). Consequently, the autumn phoma leaf spot epidemic was also earlier in 2000 and 2001 than in 2002. The resulting stem canker epidemics were severe by harvest (July) in 2001 and 2002 but not in 2003. No correlation was found between the severity or duration of phoma leaf spotting (lesion days or lesion °C-days) and the subsequent severity of phoma stem canker epidemics. Rates of leaf production and loss were similar in the three growing seasons. Out of ca. 25 leaves produced on plants during each season, leaf numbers 10–14 generally remained on plants for the longest. Treatment with flusilazole + carbendazim in autumn decreased the severity of phoma leaf spotting for several weeks after treatment, decreased the severity of stem canker the following summer and increased yield significantly in 2001 and 2002 but not in 2003. The most effective timings for flusilazole + carbendazim application were when leaves 7–11 were present on most plants and at least 10% of plants were affected by phoma leaf spot. Two half-dose applications of fungicide reduced phoma stem canker and increased yield more than a single full dose application when phoma leaf spot epidemics were early (<800 °C-days after sowing).

Biofertilizer for control of Guignardia citricarpa, the causal agent of citrus black spot

Biofertilizers generated from the anaerobic and aerobic digestion of cattle manure, known as Bio1 and Bio2, respectively, were studied with regard to their microbial composition and effect on the mycelial growth of Phyllosticta citricarpa, the causal agent of citrus black spot (CBS). Two field experiments were conducted to determine the biofertilizer's potential (Bio1) in controlling CBS (2001/2002 and 2002/2003 crops). It was observed that the greatest number of microorganisms was found in the aerobically produced biofertilizer. Bio2 did not inhibit the mycelial growth of P. citricarpa. Mycelial growth of P. citricarpa was inversely proportional to the Bio1 biofertilizer concentration. In the 2001/2002 cropping season, the Bio1 effect in controlling CBS was directly proportional to its concentration, at the rate of 0 (healthy fruit), with R 2 = 0.88 . Bio1 had a significant effect in controlling CBS, at a concentration of 10%, during the 2001/2002 cropping season, with DI values of 0.246 and 0.229 for the 10 and 20% doses, respectively, compared to DI of 0.329 for the control. A directly proportional effect of the biofertilizer concentration on the percentage of fruits with a rating of zero was also observed in the 2002/2003 cropping season, with R 2 = 0.48 . However, even at doses higher than in the preceding cropping season, the biofertilizer was less effective, possibly due to a higher occurrence of the disease. Copper oxychloride and combined applications of copper oxychloride and carbendazim plus mancozeb controlled the disease. The possibility of using the biofertilizer as a protective biofungicide to replace copper oxychloride, especially in organic agriculture, should be explored.

Storage behaviour of onion (Allium cepa L.) varieties under the influence of preharvest and postharvest treatment of maleic hydrazide and carbendazim

Influence of MH and carbendazim application in preventing loss of onion bulbs during storage was assessed in two varieties. Individual treatment of 2,000 ppm MH reduced the percentage of rotting, fungal infection and sprouting to a greater extent in variety 'N-53'. The preharvest treatment appeared more effective than the postharvest in this variety. In case of 'Local White' also a similar trend was observed but the response obtained in general was not promising. Preharvest treatment with carbendazim significantly reduced the rotting and fungal infection in both the varieties during storage. However a combined application of carbendazim and MH (1,000 ppm and 2,000 ppm, respectively) exhibited better results as compared to the individual treatments in both the varieties.

Fungicide application and phosphorus uptake by hyphae of arbuscular mycorrhizal fungi into field-grown peas

The effect of two commercial fungicide formulations on phosphorus (P) uptake into peas via hyphae of a native arbuscular mycorrhizal (AM) fungal community was examined in the field. The fungicides contained carbendazim or a mixture of propiconazole and fenpropimorph as their active ingredients and were applied at 1× and 100× the rate recommended for field use. Hyphal compartments (HCs; soil cylinders completely surrounded by nylon mesh of 25 μm mesh size) were buried between two rows of peas. The soil inside these HCs was labelled with 32P to distinguish hyphal P uptake from inside the HCs from overall P uptake. Fungicides were added to the soil inside the HCs at concentrations assumed to reflect their concentration in the surrounding soil. At two harvests, plant growth, total P and 32P uptake as well as root length density and AM root colonisation were measured. Length of hyphae inside the HCs was measured at the final harvest. Both carbendazim and the propiconazole/fenpropimorph-mixture stimulated hyphal P uptake from inside HCs when applied at rates recommended for normal field use. This increase in hyphal P uptake was significant only in the case of carbendazim. A negative effect of the fungicides on other components of the soil microbial community with which AM fungi interact is considered the most likely explanation for the observed stimulation in hyphal P uptake. Hyphal P uptake was completely inhibited by application of carbendazim at 100× the recommended rate. Plant growth and overall P uptake were not affected by fungicide applications apart from application of the propiconazole/fenpropimorph mixture at 100× the recommended rate. This rate completely inhibited plant growth. AM root colonisation was reduced by the high rate of carbendazim application only. This reduction had no effect on plant growth which may be due to the fertile soil conditions at the field site. It is concluded that the testing for side effects of pesticides on non-target organisms should include functional parameters such as P uptake by AM fungi. Such measures may be more sensitive to harmful effects than measures of plant growth or biomass.