Application Of Mancozeb Research Articles

Movement and degradation of mancozeb fungicide and its metabolites, ethylenethiourea and ethyleneurea in silty clay loam soil

Abstract The persistence and movement of mancozeb and its metabolites, ethylenethiourea and ethyleneurea, in silty clay loam soil under Philippine field conditions were investigated using soil columns and radiotracer techniques. The degradation of mancozeb, ethylenethiourea (ETU) and ethyleneurea (EU) in soil showed a half‐life of 2.9, 2.5 and 4.8 days, respectively. Mancozeb remained in the first 2.5 cm of the topsoil fraction for 12 days only. The maximum depth of permeability for ETU was 8 cm up to 14 days after application, which was the same for EU up to 21 days. ETU degraded rapidly, with a 78% reduction at 3 days after application. It is concluded that the recommended agricultural practices for mancozeb application, under lowland conditions, should not lead to groundwater contamination by ETU.

Stemphyliumdisease of asparagus (Asparagus officinalisL.) in New Zealand

Abstract In New Zealand purple spot of asparagus spears and leaf spot of asparagus fern are caused by Stemphylium vesicarium (Wallroth) Simmons (teleomorph Pleospora sp.). Ascospores and conidia were both trapped above asparagus crops during the spear and fern growing season, September–May. Numbers of ascospores and the frequency with which they were trapped were low during February–April. In experimental fields of ‘Mary Washington 500W’ annual losses in weight of harvested spears as a result of leaf spot were estimated as ranging from 18 to 51% over a 5-year period. Leaf spot was reduced and yield of spears increased by spraying fern with four applications of chlorothalonil or mancozeb during January–March. In 1986–87 three sprays of captafol applied to fern during January–March were as effective as weekly sprays from December to May in reducing leaf spot and increasing spear yield for three cultivars—‘Rutgers Beacon’, ‘Cito’, and ‘Mary Washington 500W’.

Fungicide and cultivar control of Septoria diseases of wheat

Single applications of triazole fungicides propiconazole (125 g ha −1), tebuconazole (125 g ha −1) and cyproconazole (120 g ha −1) were equally effective in reducing Septoria nodorum and increasing yield on the spring wheat cultivar Aroona, which is moderately susceptible to the pathogen. A single application of propiconazole (125 g ha −1) at head emergence (GS 55) was as effective or more effective at increasing yield than application at full flag-leaf emergence (GS 39) or three applications of propiconazole (125 g ha −1) or mancozeb (1.6 kg ha −1) starting at stem elongation (GS 31). Application of propiconazole in either 154–2001 water ha −1 or 301 water ha −1 with 1% spray oil had similar effects. The response of two cultivars differing in resistance to S. nodorum and S. tritici varied, at least partly owing to the differing occurrence of the diseases at two locations. Resistance to only one Septoria species reduced, but did not prevent, yield losses because of occurrence of the other species. In the absence of combined resistance, fungicide sprays may offer a cost-effective means of reducing losses to S. tritici and S. nodorum in southern Western Australia when yield potentials are high and disease levels are moderate.

High-Performance Liquid Chromatographic Determination of Ethylenethiourea in Food

Abstract An HPLC procedure was developed for the determination of ethylenethiourea (ETU) in peels of potatoes, tomatoes and apples after application of mancozeb suspension (ethyl-enebisdithiocarbamate fungicide). The analytical procedure consisted of a single extraction step with methanol and ETU was eluated from SEPARON CN column. Mobile phase was 4 % methanol in chloroform cyclohexane (1:1). The level of ethylenthiourea after application of mancozeb decreased slowly, with a half time six days in each case.

Deleterious effect of soil‐applied metalaxyl and mancozeb on the mycoparasitePythium oligandrum

Pythium oligandrum was recovered, identified and quantified from air‐dried soil plated on 1.5% water agar containing 0.1% glucose. Isolations of P. oligandrum over 2 years from soils treated with single applications of metalaxyl plus mancozeb were consistently lower than those from untreated soil from the same fields. In three fields in the first year P. oligandrum was reduced from a range of 43.3–115.0 to 17.0–43.2 isolates g‐1 soil. In the second year, results from 11 fields showed reductions from 27.8–141.8 to 2.8–44.5 isolates g‐1 soil. P. oligandrum was sensitive to both metalaxyl and mancozeb, with median effective dose (ED50) values of 0.13 ± 0.02 μg m‐1 and 3.33 ± 0.12 μg ml‐1, respectively. In a pot test with three soils treated with metalaxyl, mancozeb or the combination of fungicides, levels of P. oligandrum declined over 3 months, with effects first recorded 2 weeks after treatment. Levels of P. oligandrum were reducd by differing degrees in the three soils. Isolate counts from untreated soils...

Status of ornithine decarboxylase activity and DNA synthesis in mancozeb-exposed mouse skin

The effect of mancozeb, a fungicide, on mouse skin ornithine decarboxylase (ODC) activity and DNA synthesis was studied. ODC activity was induced after topical application of mancozeb and exhibited a peak level at 5 h. This ODC induction was dependent on the dose of mancozeb applied. Cycloheximide, an inhibitor of protein synthesis, inhibited the mancozeb-caused ODC induction, indicating the effect on enzyme protein synthesis. The rate of DNA synthesis was also increased by mancozeb, as indicated by increased [3H]thymidine incorporation into skin DNA. Induction of ODC activity and DNA synthesis are among the events probably involved in the tumorigenic action of mancozeb on mouse skin.

Carcinogenic activity of a carbamate fungicide, mancozeb on mouse skin

Mancozeb, a polymeric complex of ethylene bis (dithiocarbamate) maganese with zinc salt is a protective fungicide. In the present study complete carcinogenic activity of mancozeb, has been observed following topical application on dorsal mouse skin. Female Swiss albino mice were exposed to mancozeb at a dose of 100 mg/kg body weight dissolved in 100 μl dimethyl sulfoxide 3 times per week. Development of tumours was observed after 31 weeks (217 days) of mancozeb application. A high rate of mortality was observed after 54 weeks (378 days) of mancozeb application due to its toxicity and the study was terminated after 60 weeks. On histological examination, these tumours were found mostly to be benign in nature, e.g., squamous cell papillomas and keratoacanthomas.

Comparison of Chemical and Cultural Controls for Cercospora Blight on Asparagus and Correlations Between Disease Levels and Yield

The relationship between disease levels of Cercospora blight on ferns of four cultivars of asparagus during the summer and yield of asparagus during the following spring was investigated for a 3-yr period (1986-1989). The area under the disease progress curve (AUPDC) was used to describe overall disesa levels. Five treatments: residue management before spear production in the spring either through tillage or burning, application of mancozeb or chlorothalonil fungicides to ferns during summer, and an untreated contol were followed to attain different disease levels (...)

Time of Infection and Control of Phomopsis Fruit Rot of Grape

Inoculations of Vitis labrusca «Concord» clusters at or shortly after bloom using 1×10 7 alpha spores per milliliter resulted in 16-30% fruit rot at harvest. Inoculations at earlier or later growth stages did not result in fruit rot significantly higher than that in nontreated controls. Berries inoculated in the laboratory were progressively less susceptible bto infection and colonization as they aged from pea-size to ripe stages of growth. Two applications of mancozeb during bloom significantly reduced fruit rot and rachis lesions on cv. Delaware during the 1987 growing season

Tumour-promoting ability of mancozeb, a carbamate fungicide, on mouse skin

In this study the tumour-promoting activity of a carbamate fungicide, mancozeb, has been observed following topical application on mouse skin in a two-stage initiation--promotion protocol for carcinogenesis. Female Swiss albino mice were initiated with a single subcarcinogenic dose (52 micrograms) of 7,12-dimethylbenz[a]anthracene painted on the interscapular region. Seven days after initiation the mice underwent topical application of mancozeb (100 mg/kg body wt) three times per week as promoter. Development of tumours was observed after 12 weeks of mancozeb application in 1/14 animals and 100% tumorigenesis was recorded after 17 weeks of mancozeb application. On histological examination, these tumours were found mostly to be benign in nature, e.g. squamous cell papillomas and keratocanthomas.

Systemicity and persistence of cymoxanil in mixture with oxadixyl and mancozeb against Phytophthora infestans and Plasmopara viticola

Uptake and translocation of the fungicide cymoxanil was studied using tomato and potato plants infected with Phytophthora infestans and grape plants infected with Plasmopara viticola. Translocation of cymoxanil was mainly translaminar and acropetal from roots and stems to leaves to an extent similar to that of the phenylamide fungicide oxadixyl. Basipetal translocation from upper to lower leaves, as well as lateral movement, was also observed but to a lesser extent. Plant parts that grew after application were protected against P. infestans and P. viticola because of systemic activity up to 7 days by cymoxanil alone and up to 14 days when cymoxanil was used as part of a three-way mixture with oxadixyl and mancozeb. Drench application of cymoxanil and a simultaneous spray application of mancozeb against P. infestans and P. viticola resulted in a significant synergistic interaction. The spray application of the three-way mixture oxadixyl/mancozeb/cymoxanil was more effective against both sensitive and phenylamide-resistant strains of P. infestans and P. viticola than the individual components alone, representing significant levels of synergistic interactions. Synergy ratios were higher for resistant than for sensitive strains of both pathogens.

Possible explanations of synergism in fungicide mixtures against Phytophthom infestans

SUMMARYSingle foliar sprays of oxadixyl, mancozeb or cymoxanil alone or the mixtures oxadixyl/mancozeb and oxadixyl/cymoxanil were applied to tomato plants (cv. Baby) one day before inoculating with a sensitive or a phenylamide‐resistant strain of Phytophthora infestans. Fungicide mixtures were far more effective in controlling both sensitive and resistant strains compared to the individual components alone, representing significant levels of synergistic interactions. When analysed by the Abbott method, synergy ratios continuously decreased with increasing amounts of fungicides in the mixture. All fungicide mixtures showed higher synergy ratios against resistant strains when using the Abbott method, whereas only mixtures containing cymoxanil showed this phenomenon when using the Wadley method for interpretation of interactions. Synergism significantly decreased when the components were used as foliar split applications with intervals of 48 and 72 h. A combination of a drench application of oxadixyl and a single spray application of mancozeb or cymoxanil resulted in a high level of synergism. The explanation of synergism may be that the exposure of sporangia to sublethal concentrations of one fungicide affects them to an extent that sublethal doses of the other fungicide becomes detrimental.

Determination of Mancozeb in air. Occupational exposure during its use in control of potato late blight

A simple method for the determination of occupational exposure to Mancozeb (an ethylenebisdithio-carbamate) was evaluated. This method is based on filter sampling and determination of the manganese content in the samples by means of atomic absorption spectroscopy. The method shows good linearity and accuracy for determinations in the range 0.05 to 2 mg/m 3. Exposure during field application of Mancozeb in potato cultivations was studied and was found, during preparation and filling of the spraying liquid, to be 0.22 mg/m 3 on average (n=18). The highest individual eight-hour time-weighted average exposure was 0.05 mg/m 3.

Título en español

Los fungicidas chlorothalonil, mancozeb y benomyl, protegieron eficazmente el follaje de los cultivares de habichuela Bonita y Naranjito contra el ataque de los hongos Isariopsis griseola y Ascochyta phaseolorum. El cv. Bonita mostró un incremento significativo en rendimiento como resultado de los tratamientos. Tanto mancozeb como chlorothalonil indujeron el aumento en rendimiento de Bonita cuando ésta fue atacada por ambos patógenos. Sin embargo, solamente la dosis más alta de benomyl (1.12 kg/ha) aumentó el rendimiento de la Bonita afectada por la mancha angular.

Fungicidal control of groundnut leafspots and rust by ultra‐low volume spray

Abstract Four systemic fungicides, a formulation of tridemorph + maneb (0.39 and 1.26 kg a.i./ha respectively), carbendazim (0.125 kg a.i./ha), benomyl (0.30 kg a.i./ha), tridemorph (0.45 kg a.i./ha) and a non‐systemic fungicide, mancozeb (2.00 kg a.i./ha) were evaluated for the control of groundnut leafspots caused by Mycosphaerella arachidis Deighton (Cercospora arachidicola Hori) and M. berkeleyii Jenkins (Cercosporidium personatum (Berk. & Curt.) Deighton) and rust, caused by Puccinia arachidis Speg., using ultra‐low volume application. Mancozeb application resulted in significantly higher pod and haulm (shoot) yields than the application of the systemic fungicides, except tridemorph + maneb. Mancozeb and tridemorph + maneb controlled both the leafspots and rust, consequently, their application resulted in higher yields than the other fungicides which controlled either the leafspots or the rust. The pod and haulm yields from the mancozeb treated plots were approximately 200 and 286%, respectively, of ...

Reduction of Onion Yields by Chlorothalonil1

Abstract Ten weekly applications of mancozeb, chlorothalonil, or alternate applications of mancozeb and chlorothalonil were made on ‘Granex 33’ and ‘Texas Early Grano 502’ onions (Allium cepa L.). Disease incidence was nil in all treatments, including the unsprayed control. There was no significant difference between the untreated check and mancozeb treatment for all measured yield components. Alternating chlorothalonil with mancozeb significantly decreased marketable yield and size of bulbs. Chlorothalonil alone reduced weight and size of marketable bulbs by 44 and 34%, respectively. Alternate applications of chlorothalonil and mancozeb reduced these values by 27 and 23%, respectively. Response of bulb size to fungicides was affected by both cultivar and harvest date. Chlorothalonil had no influence on the rate of maturation, but it did contribute to yield reduction.

Effect of septoria leaf spot in spring wheat

Abstract A natural infection of Septoria tritici first appeared in an ‘Aotea’ wheat trial at tillering (G.S.3), when the disease occupied 10% of the third-leaf area. Fungicide sprays applied at tillering reduced the severity of the disease for up to 6 weeks. Application of mancozeb or benomyl at ear emergence (G.S.10.1) reduced infection on the flag leaf and leaf 2 by 10-20%, and increased the persistence of green leaf tissue. A yield increase of 14% and 17% over that of the unsprayed plots was achieved, but this increase was not significant under the experimental conditions. The increased yields were due to a significant increase in 1000-grain weight.

Fehlermöglichkeiten bei Rückstandsuntersuchungen von Gemüse und Obst- bedingt durch die Probenahme

Mistakes in the results of residue analysis in vegetables and fruits based on samples Mistakes in the results of residue analysis can be separated into mistakes of “sample-taking” and those of “analysing”. The mistakes of “sample-taking” can be avoided when the sample represents the contents of the whole material which is to be analysed in percent. But this is an ideal case. In two examples, lettuce and leek, it is demonstrated that the pesticides are not in the same amount distributed at the different zones of the plant, the differences in the amounts can be, in the case of lettuce after application of quintozene, more than a fourtyfold amount or, in the case of leek after application of mancozeb, a twentyfold amount. Furthermore, the residues can be different from one plant individual to another demonstrated at cherries and radishes. The differences may be caused either by different application techniques or, for example, by different weight of individuals of the same species. Also, different habitus and growth can lead to different residues from one plant individual to another. When the plants take up the pesticides from the soil, a different pesticide distribution in the areas of the soil can also give rise to different residue values. Therefore, the man (engineer or analyst) who takes the samples, must take care for: 1. taking the samples symmetrically from the field or from bottom to top of the trees 2. chosing those plant individuals to give the „labour sample” which represent the average weight and the average habitus of the individuals. If plant individuals are analysed which take up the pesticides from the soil, the area from which the sample is derived, must be given. From all points shown, there is clear that “a range of disseminating values” which can be more than 100% must accounted in the values of residue analysis.

Research and Development of High and Ultra-low volume Sprays to Control Tomato Leaf Diseases at Samaru, Nigeria

Abstract Fungicide spray trials showed that high volume applications (1121 lha) of mancozeb, captafol and vondozeb reduced foliage and stem disease and substantially increased marketable yields of rain-fed tomatoes in northern Nigeria. The results suggest that captafol had a more persistent fungicidal action as there was no yield difference between the 7 and 14 day frequencies of application. U.I.v. methods (<12 l/ha) using three fungicides were compared with high volume treatments. The u.I.v. captafol treatment was particularly effective. An assessment was made of droplet distribution in relation to atomiser disc rotation speed and the height of carriage of the sprayer.