Applications Of Chlorothalonil Research Articles

Irish Potato, Control of Colorado Potato Beetle, 1994

Abstract The experiments were randomized complete block designs with six replicates each. The four experiments were planted 23 and 24 May at Presque Isle, ME on land that was in clover in 1993. The 3.0 m space between blocks and the 1.8 m space between the four-row plots were bare soil. All rows were planted with an assisted-feed planter 0.9 m apart and 15.0 m long and the healthy whole seed (ca. 75 g) were 30 cm apart. Fertilization and hilling practices were normal for the area. Early and late blight were controlled by eight foliar applications of chlorothalonil. Foliar insecticide applications were made with a Century boom sprayer, three nozzles per row at 6.3 kg/cm2 pressure and 0.94 k liter/ha. Numbers of larvae and adults were counted weekly on 25 whole plants in the middle rows of each plot. When dates of count and application were the same, beetle counts were made prior to application of insecticides. Analyses of variance were calculated following transformations of data using log10(x + 1). Transformed means of the sum of larvae and adult beetles were compared using Fisher’s LSD Test and then applied to the actual means. The soil was classified as Caribou Loam, pH 5.2. Total monthly rainfall for Jun, Jul, and Aug was respectively 10.9, 9.6, and 3.3 cm. The average temperature for each of the same 3 months was 17.9, 20.3 and 17.7°C.

Early and Late Leaf Spot Resistance and Agronomic Performance of Nineteen Interspecific Derived Peanut Lines1

Abstract Nineteen selected interspecific peanut lines with resistance to leaf spot [Cercospora arachidicola Hori and/or Cercosporidium personatum (Berk, and Curt.) Deighton] were field tested 3 yr for disease reaction and productivity with and without foliar fungicide protection. Measurements included severity ratings of leaf spot every 2 wk based on the Florida leaf spot disease rating scale, and pod yield. Area under disease progress curves (AUDPC) and pod yield losses were calculated. Differences among the interspecific lines in AUDPC values were significant, and one line had values equal to or lower than that of Southern Runner. One-half of the lines were equal in yield (P=0.01) to Southern Runner. Yields among lines averaged 1 to 50% higher with, as compared to without, chlorothalonil application. Yield losses of individual entries varied significantly from 1 yr to another and incongruous with the AUDPC pattern. Correlations between the AUDPC and yield loss were significant (P=0.01) for the 1989 and 1990, but not for the 1988 data. Results of the study indicate that resistance to both C. arachidicola and personatum were incorporated from the wild species parents into productive, runner-type breeding lines, and that the resistance to personatum was equal to or better than that of Southern Runner. Additional effort will be required to transfer levels of leaf spot resistance observed in the wild species parents into successful cultivars.

284 EVALUATION OF THREE DISEASE FORECASTING SYSTEMS FOR CON-l-ROLLING EARLY BLIGHT ON STAKED OR GROUND CULTURE TOMATOES IN NEW JERSEY

Since 1990, FAST - Pennsylvania State University, CUFAST - Cornell University. and TOM-CAST - Ridgetown College, Ontario, three systems for forecasting early blight, have been field tested at The Snyder Research and Extension Farm in northwestern New Jersey for their potential use in fresh market tomato production in that area of the state. In 1993, the number of fungicide applications for tomato early blight control required by the three forecast systems was less than the number required following a weekly schedule. FAST and CUFAST scheduled applications of chlorothalonil, 1.5 lb per acre, reduced disease severity, hut TOM-CAST scheduled applications did not reduce disease severiety compared to the untreated control. Culture did not affect disease control results hut did affect disease incidence and post-harvest losses. Total and marketable yields were not affected by fungicide application schedule. Potential cost savings of $270 or $465 per acre, resulting from reduced numbers of fungicide applications following CUFAST or FAST. were estimated. Chemical name used: tetrachloroisophtalonitrile (chlorothalonil).

RESULTS OF GROUND WATER MONITORING FOLLOWING CHLOROTHALONIL APPLICATION TO A POTATO FIELD IN ATLANTIC CANADA

An experimental field, located in Nova Scotia, Canada, was cropped in potatoes for two consecutive years. During that period, chlorothalonil (tetrachloroisophtalonitrile), a non-systemic, broad-spectrum fungicide used extensively on potato crops in Atlantic Canada, was used according to normal agricultural practices. Ground water samples, collected four times a year from 5 piezometers and 47 lysimeters, were analyzed for chlorothalonil and its degradation products 4-hydroxy-2,5,6-trichloroisophtalonitrile, 3-cyano-2,4,5,6-tetrachlorobenzamide and 3-cyano-2,5,6-trichlorobenzamide. A nearby uncultivated field fitted with 3 piezometers was used as a control site. With the exception of eight questionable results, chlorothalonil and its degradation products were not otherwise detected in any of the 300 piezometer and lysimeter water samples taken from both the experimental and the control field. It was therefore concluded that the application of chlorothalonil, in the form of a commercially available formulati...

Effect of banana spray oil on banana yield in the absence of Sigatoka ( Mycosphaerella sp.)

A possible phytotoxic effect of banana spray oil (BSO) was studied on banana cultivar ‘Grand Nain’ (Musa spp., AAA subgroup) in Israel where no yellow or black Sigatoka was present. Texaco Spraytex® CT774, at rates of 2.6, 5.2 and 7.8 l ha −1, was applied using simulated aerial application during two consecutive production cycles. Twelve and ten spray cycles were applied during the first and second production cycles, respectively. BSO treatments were compared with the chlorothalonil treatment (BRAVO® 720 2 l ha −1), and an untreated control. No visual phytotoxicity or very subtle symptoms resulted from BSO application even at the highest rate. However, the highest rate of BSO reduced growth rate, delayed flowering by 4 days, and reduced bunch weight by 5.6% ( P < 0.05) during the first production cycle when compared with the untreated control. A decrease of 8.4% in bunch weight ( P < 0.05) was observed in the second production cycle when the highest BSO rate was compared with the untreated control. Bunch weight losses were directly related to BSO application rates. The number of green leaves at harvest and number of hands per bunch were also significantly reduced during the second production cycle. Chlorothalonil application did not significantly affect any of the parameters measured in this test when compared with the untreated control. This study indicates BSO usage causes a reduction in banana yield.

Forage Yield Losses in Hybrid Pearl Millet Due to Leaf Blight Caused Primarily byPyricularia grisea

The effects of leaf blight, caused primarily by Pyricularia grisea, on forage yield and digestibility of pearl millet hybrids were evaluated in 1990, 1991, and 1992. A range of disease severities on Pyricularia-susceptible hybrid Tifleaf 1 and on the resistant, near-isogenic hybrid Tifleaf 2 were established by inoculation with P. grisea or by application of chlorothalonil. Even with irrigation, no appreciable leaf blight developed in the dry 1990 season. In 1991 and 1992, disease severities (percentage of foliage with chlorosis and necrosis) in individual plots ranged from 3 to 35%. Leaf blight severity in 1991 and 1992 was negatively correlated (P<0.01) with green plot yield, dry matter yield, and digestible dry matter yield [...]

Evaluation of Chlorothalonil, Fenarimol, and Flusilazole for Control of Eastern Filbert Blight

In a greenhouse experiment, treatment of 3-wk-old hazelnut (Corylus avellana) seedlings with suspensions of chlorothalonil (1.8 g a.i./L), fenarimol (0.038 g a.i./L), or flusilazole (0.030 g a.i./L) prior to inoculation with ascospores of Anisogramma anomala resulted in 4, 5, and 7% incidence of eastern filbert blight, respectively, compared to 53% in the inoculated control. In field experiments, exposure of 1- or 2-yr-old potted trees to natural releases of A. anomala ascospores demonstrated that hazelnut is susceptible to infection after vegetative budbreak, and that one to five applications of chlorothalonil, fenarimol, or flusilazole onto vegetative tissues that develop after budbreak significantly (P≤0.05) reduced disease development

Chemigation and Ground-Spray Applications of Cyproconazole for Control of Late Leaf Spot of Peanut

In field experiments conducted during 1990 and 1991, chemigation applications of biosynthesis inhibiting fungicide cyproconazole (0.112 kg a.i./ha) were equal to or bether than ground-spray applications of cyproconazole or chlorothalonil (1.26 kg a.i./ha) late leaf spot, caused by Cercosporidium personatum, on peanut (Arachis hypogae) cultivars Florunner and Southern Runner. Late-season leaf spot epidemics and resulting defoliation were severe in nontreated plots in both years. All fungicide treatments provided similar levels of control in 1990 (.)

Effect of Foliar Fungicide Treatment on Early Blight and Yield of Fresh Market Tomato in Ontario

A 2-yr field study investigated the effects of a FAST-based fungicide application regime (TOMCAST) employing chlorothalonil on early blight severity and yield of 13 fresh market tomato cultivars commercially grown in Ontario. During both years, applications of chlorothalonil decreased early blight severity, measured either as area under the disease progress curve (AUPDC) or as the last disease rating (LDR) made in late August. However, applications did not affect the yield of any cultivar, nor were fungicide-cultivar interactions detected (.)

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’.

Combining Center Pivot Irrigation Applications of Chlorothalonil with a Moderately Resistant Cultivar for Control of Late Leaf Spot in Peanut

The efficacy of center pivot irrigation applications (chemigation) of chlorothalonil at recommended rates (1.25 kg a.i/ha) was less than with conventional, ground spray applications for control of late leaf spot (Cercosporidium personatum) in Florunner (susceptible) and Southern Runner (moderately resistant) peanut (Arachis hypogaea) cultivars in 1989 and 1990. Final leaf spot ratings in chemigated plots of Florunner were lower (P≤0.05) than those in untreated plots in both years and in 1989 were higher (P≤0.05) than ratings of unsprayed plots of Southern Runner (...)

A SCREENING SURVEY FOR CHLOROTHALONIL RESIDUES IN WATERS PROXIMAL TO AREAS OF INTENSIVE AGRICULTURE

Waters in four components of the hydrologic cycle were sampled from study sites in New Brunswick, Nova Scotia and Prince Edward Island, and analyzed for chlorothalonil (TCIN) residues. Four out of 66 tile drainage samples, collected from replicated plots, indicated TCIN residues at detection limit concentrations of 0.005 to 0.008 μg∙L−1 in the spring of 1990, 7 months after application. No TCIN residues were reported in duplicate samples from 19 private wells sampled during the fall even though these wells were influenced by agriculture as measured by Nitrate-N. TCIN was detected at 2 of 11 surface water stations at concentrations ranging from 0.006 to 0.011 μg∙L−1. Concentrations in precipitation from two monitoring sites ranged from not detected to 0.034 μg∙L−1 with maxima occurring in April and August. Agricultural land use as well as rate and timing of chlorothalonil application was best quantified for the crop rootzone study sites and was least quantified for the precipitation collection sites.

Quantitative Comparison of Stem Lesions Caused by Cercosporidium personatum in Florunner and Southern Runner Peanut Cultivars

Abstract Fewer stem lesions caused by Cercosporidium personatum (Berk. &amp; Curt.) Deighton developed on peanut (Arachis hypogaea L.) cultivar Southern Runner than on cultivar Florunner in field tests conducted near Tifton, GA, in 1989 and 1990 and near Marianna, FL in 1990. Numbers of lesions per stem and lesions per dm of stem length ranged from 3.1 to 9.5 times higher on Florunner than on Southern Runner in tests where severe leafspot epidemics developed and no foliar fungicides were applied. Seven applications of chlorothalonil at 0.5, 0.63 or 1.26 kg ai/ha via ground sprays and 1.26 kg ai/ha via an underslung boom (Pivot Agricultural Spray System = PASS) allowed few stem lesions to develop on either cultivar compared to non-sprayed plants. Delayed harvest required for Southern Runner resulted in an increase in incidence of stem lesions, but incidence of stem lesions at harvest on Southern Runner still was significantly lower (P ≤ 0.01) than incidence on Florunner at harvest. Differences in number of stem lesions between the two cultivars and among fungicide treatments were reflected in yields. Healthier stem tissue due to fewer stem lesions may be partially responsible for higher yields in Southern Runner than in Florunner grown during severe leafspot epidemics. Incidence of stem lesions caused by C. personatum may be useful as a new parameter to be considered in evaluation and selection for resistance and/or tolerance to C. personatum in peanut.

STUDIES ON THE EPIDEMIOLOGY AND CONTROL OF MANGO ANTHRACNOSE ON THE VARIETY 'CARABAO' IN THE PHILIPPINES

A field trial was conducted in the Cavite region of Luzon Province, the Philippines, from October 1988 to March 1989 with 40–50 year-old trees of the mango variety Carabao to study the epidemiology of anthracnose disease of mango caused by Colletotrichum gloeosporioides. The effects of pre-harvest applications of benomyl, chlorothalonil and prochloraz, each at 250ppm, on post-harvest development of anthracnose was also assessed. Five pre-harvest applications of benomyl, from flowering to fruit set, and one application a month later gave excellent control of post-harvest development of anthracnose on fruit harvested 112 days after floral induction and incubated at ambient temperatures for 16 days. Chlorothalonil and prochloraz were intermediate in effectiveness between benomyl and the control where no fungicide was applied. Data from spore-trapping showed that benomyl applications had significantly reduced the number of conidia disseminated by rainfall compared with those recovered from control trees, one week before harvest. Dipping mangoes from all four treatments in hot benomyl (850ppm at 52–54°C for 10 minutes) on the same day as harvest gave 100% control of the disease post-harvest. A technique devised to assess the development of quiescent infections on mango fruit during maturation detected few colonies of C. gloeosporioides in any of the treatments. This indicates that either the technique is insensitive to quiescent infections of this pathogen/host combination or that few quiescent infections occurred during this drier than average season. Preliminary work with a polyclonal antibody raised against an isolate of Colletotrichum gloeosporioides, was successful in labelling conidia of C. gloeosporioides from the Philippines and other countries using an immunofluorescence marker.

Anatomy of Russeting Induced in Concord Grape Berries by the Fungicide Chlorothalonil

The fungicide chlorothalonil produced russeting on the skin of <i>Vitis labruscana</i> Bailey cv. Concord berries growing in full sun, when applied at 3.37 kg/ha in a season-long spray program. Prebloom and full bloom application of chlorothalonil did not result in russeting. Application of single sprays showed russeting resulted from the 10-day post-bloom (p.b.) application. Visible spray residues remained on the fruit for the whole growing season. The first anatomical evidence of russeting occurred at three weeks p.b., when epidermal cells died beneath regions covered by residue and exposed to the sun. The hypodermis then developed thickened cell walls and appeared to contain mucilaginous or gummy materials. As the season progressed, fruit growth stretched the dead epidermal cells, while epidermal breaks and disruptions occurred. The innermost living cells of the hypodermis or outermost flesh cells became meristematic. This resulted in the production of either an organized periderm beneath non-broken skin regions or a less layered "filling tissue" of cell progenies, or "packets," beneath broken regions of the skin. Substantive increase in russeting did not occur after mid-August (8 weeks p.b.), and the injury, even to mature fruit sprayed six times during the season, was confined to the fruit skin. Russeted berries virtually stopped enlarging after five weeks p.b. Chlorothalonil-sprayed fruits that remained in the shade, and unsprayed fruit in sun or shade, did not russet.

The fate of chlorothalonil in ground water in commercial cranberry culture in the New Jersey pine barrens

Abstract Concern over the possibility of groundwater contamination by agricultural pesticide (Chlorothalonil) applications stimulated this study in the sensitive Pine Barrens overlying the Cohansey aquifer. Wells of three depths were emplaced in an experimental cranberry bog and weekly surface and groundwater samples were taken as well as soil cores and mature cranberries for extraction and analysis of residues of the Chlorothalonil. It was concluded that there is little risk of chlorothalonil contamination.

Fungicide Effects on Acremonium Endophyte, Plant-Parasitic Nematodes, and Thatch in Kentucky Bluegrass and Perennial Ryegrass

Foliar applications of benomyl, chlorothalonil, iprodione, thiram, and triadimefon were assessed for possible nontarget effects on Acremonium loliae, plant-parasitic nematodes, thatch accumulation, and soil pH. Fungicides were applied monthly from April to September during 1983-1987 to field plots of Regal and Fiesta perennial ryegrass (Lolium perenne) and South Dakota, Merion, Sydsport, and Vantage Kentucky bluegrass (Poa pratensis). None of the fungicides significantly affected soil pH and only thiram enhanced thatch significantly when compared with untreated plots. Fungicides did not significantly affect population densities of plant-parasitic nematodes (...)

Effect of chlorothalonil application frequency on quality factors of peanuts (Arachis hypogaea)

AbstractYield, disease rating, seed quality and seed size parameters were determined from four peanut (Arachis hypogaea L)genotypes with different levels of resistance to leafspot to evaluate the effects of controlling peanut leafspot with chlorothalonil. In 1981 and 1983, main plot treatments were (i) no fungicide applications, (ii) applications of chlorothalonil (1242 g ai ha−1) at 14‐day intervals, and (iii) applications of chlorothalonil (1242 g ai ha−1) at 20‐day intervals. After shelling, a narrow seed size range (&lt;8.33 mm ≤7.14 mm width) was used to reduce maturity effects in analyses of free fatty acids, total carbonyls, carbohydrates, oil content, and fatty acid profile. Oil content increased significantly with spray frequency in both years only in Southern Runner, and treatment differences in all genotypes were no more than 1.7%. Oleic and linoleic acid decreased and increased, respectively., with increased spray frequency in Florunner (susceptible) and the resistant genotype with the highest unsprayed disease rating. Florunner median seed size for the unsprayed treatment (8.07 mm) was significantly smaller than the median sizes for the 20‐day interval (8.15 mm) and 14‐day interval (8.16 mm) treatments.

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.

Disease management implications of age-related changes in susceptibility of potato foliage toPhytophthora infestans

Epidemics of potato late blight progressed more slowly in plots of intermediate-aged plants than in plots of older plants. The suppression of epidemics achieved by intermediate-aged plants relative to old ones was equivalent to the suppression achieved by weekly applications of chlorothalonil of as much as 0.30 kg a.i./ha. The age effect on epidemic development was most noticeable for late-season cultivars and least noticeable for early-season cultivars.