Chemical control of crown rot in Queensland bananas

1991 ◽  
Vol 31 (5) ◽  
pp. 693 ◽  
Author(s):  
DR Jones
Keyword(s):  
Chemical Control ◽  
Good Control ◽  
Crown Rot ◽  
Postharvest Disease ◽  
Adequate Control ◽  
Fusarium Pallidoroseum ◽  
Banana Plantations

The efficacy of benomyl, prochloraz, flusilazole and other fungicides in controlling crown rot, a postharvest disease of bananas, was studied. In experiments with harvested fruit, prochloraz and flusilazole were the most effective fungicides. Benomyl was less effective than prochloraz. In 1 experiment, Fusarium pallidoroseum and a Verticillium sp. were frequently isolated from diseased crowns of untreated fruit. Both fungi were pathogenic and sensitive to prochloraz in vitro, but only F. pallidoroseum was sensitive to benomyl. The Verticillium sp. was consistently isolated from diseased crowns of benomyl-treated fruit. The failure of benomyl to control crown rot adequately in Queensland may be related to the presence of benomyl-tolerant crown rot fungi in the flora of banana plantations. In 2 experiments, prochloraz gave good control of crown rot in fruit stored for extended periods before ripening; however, it failed to give adequate control in a third.

Improving the toolbox to manage Phytophthora diseases of strawberry: searching for chemical alternatives

2021 ◽  
Author(s):  
Marcus Vinicius Marin ◽  
Natalia Peres
Keyword(s):  
Fungicide Resistance ◽  
Chemical Control ◽  
Mycelial Growth ◽  
Crown Rot ◽  
Resistance Risk ◽  
In Vivo Assays ◽  
Modes Of Action ◽  
Phytophthora Spp

Florida strawberry production is affected by two economically important Phytophthora diseases, Phytophthora crown rot (PhCR) and leather rot (LR), caused primarily by P. cactorum and P. nicotianae. Although products are available, chemical control is limited to mefenoxam, phosphites, and azoxystrobin and resistance to mefenoxam and azoxystrobin has been reported. Both in vitro and in vivo assays were conducted to evaluate the effectiveness of eight different chemical classes on controlling PhCR and LR of strawberry. The fungicides mandipropamid, fluopicolide, oxathiapiprolin, and cymoxanil completely inhibited mycelial growth of both species at 1µg/ml. The same fungicides controlled LR and PhCR caused by P. cactorum, in detached fruit and greenhouse trials, respectively, including mefenoxam-resistant isolates. However, for PhCR caused by P. nicotianae only oxathiapiprolin and cymoxanil were effective in controlling the disease. Cyazofamid, fluazinam, propamocarb, and tebuconazole did not control PhCR caused by either Phytophthora spp. Except for tebuconazole, all fungicides tested reduced incidence of LR caused by P. cactorum in the detached fruit assay; in contrast, fluazinam, cyazofamid, and propamocarb had no effect on P. nicotianae. This study identifies four fungicides that could potentially be registered to manage both PhCR and LR of strawberry. The registration of additional fungicides with different modes of action would allow fruit and nursery growers to alternate products to reduce fungicide resistance risk.

Phytophthora crown rot of Florida Strawberry: Inoculum Sources and Thermotherapy of Transplants for Disease Management

Plant Disease ◽  
2021 ◽  
Author(s):  
Juliana Silveira Baggio ◽  
Marcus Vinicius Marin ◽  
Natalia A. Peres
Keyword(s):  
Heat Treatment ◽  
Chemical Control ◽  
Pathogen Resistance ◽  
Crown Rot ◽  
Phytophthora Cactorum ◽  
Inoculum Sources ◽  
Phytophthora Spp ◽  
Commercial Farms ◽  
Important Disease

Phytophthora crown rot, caused mainly by Phytophthora cactorum, and also by the recently reported P. nicotianae, is an important disease in the Florida strawberry annual production system. Mefenoxam is the most effective and widely used fungicide to manage this disease. However, due to pathogen resistance, alternatives to chemical control are needed. Phytophthora spp. were rarely recovered during the summer from soil of commercial farms where the disease was observed during the season. In a more detailed survey on research plots, neither of the two species was recovered one month after the crop was terminated and water was shut off. Therefore, Phytophthora spp. does not seem to survive in the soil over summer in Florida. In a field trial, asymptomatic nursery transplants harboring quiescent infections were confirmed as the major source of inoculum for these pathogens in Florida. Heat treatment of P. cactorum zoospores at 44oC for as little as 5 min was effective in inhibiting germination and colony formation; however, oospore germination was not inhibited by any of the tested temperatures in vitro. In the field, thermotherapy treatment of inoculated plants was shown to have great potential to serve as a non-chemical approach for managing Phytophthora crown rot in production fields and reducing mefenoxam-resistant populations in nursery transplants.

scholarly journals Biological control of strawberry crown rot, root rot and grey mould by the beneficial fungus Aureobasidium pullulans

BioControl ◽  
2021 ◽  
Author(s):  
Mudassir Iqbal ◽  
Maha Jamshaid ◽  
Muhammad Awais Zahid ◽  
Erik Andreasson ◽  
Ramesh R. Vetukuri ◽  
...  
Keyword(s):  
Root Rot ◽  
Fungal Pathogens ◽  
Aureobasidium Pullulans ◽  
Grey Mould ◽  
Lesion Size ◽  
Plant Diseases ◽  
Crown Rot ◽  
Whole Plants

AbstractUtilization of biocontrol agents is a sustainable approach to reduce plant diseases caused by fungal pathogens. In the present study, we tested the effect of the candidate biocontrol fungus Aureobasidium pullulans (De Bary) G. Armaud on strawberry under in vitro and in vivo conditions to control crown rot, root rot and grey mould caused by Phytophthora cactorum (Lebert and Cohn) and Botrytis cinerea Pers, respectively. A dual plate confrontation assay showed that mycelial growth of P. cactorum and B. cinerea was reduced by 33–48% when challenged by A. pullulans as compared with control treatments. Likewise, detached leaf and fruit assays showed that A. pullulans significantly reduced necrotic lesion size on leaves and disease severity on fruits caused by P. cactorum and B. cinerea. In addition, greenhouse experiments with whole plants revealed enhanced biocontrol efficacy against root rot and grey mould when treated with A. pullulans either in combination with the pathogen or pre-treated with A. pullulans followed by inoculation of the pathogens. Our results demonstrate that A. pullulans is an effective biocontrol agent to control strawberry diseases caused by fungal pathogens and can be an effective alternative to chemical-based fungicides.

scholarly journals Trichoderma asperellum T76-14 Released Volatile Organic Compounds against Postharvest Fruit Rot in Muskmelons (Cucumis melo) Caused by Fusarium incarnatum

2021 ◽  
Vol 7 (1) ◽  
pp. 46
Author(s):  
Warin Intana ◽  
Suchawadee Kheawleng ◽  
Anurag Sunpapao
Keyword(s):  
Volatile Organic Compounds ◽  
Organic Compounds ◽  
Cucumis Melo ◽  
Fungal Growth ◽  
Fruit Rot ◽  
Postharvest Disease ◽  
Dual Culture ◽  
Trichoderma Asperellum ◽  
Volatile Organic

Postharvest fruit rot caused by Fusarium incarnatum is a destructive postharvest disease of muskmelon (Cucumis melo). Biocontrol by antagonistic microorganisms is considered an alternative to synthetic fungicide application. The aim of this study was to investigate the mechanisms of action involved in the biocontrol of postharvest fruit rot in muskmelons by Trichoderma species. Seven Trichoderma spp. isolates were selected for in vitro testing against F. incarnatum in potato dextrose agar (PDA) by dual culture assay. In other relevant works, Trichoderma asperellum T76-14 showed a significantly higher percentage of inhibition (81%) than other isolates. Through the sealed plate method, volatile organic compounds (VOCs) emitted from T. asperellum T76-14 proved effective at inhibiting the fungal growth of F. incarnatum by 62.5%. Solid-phase microextraction GC/MS analysis revealed several VOCs emitted from T. asperellum T76-14, whereas the dominant compound was tentatively identified as phenylethyl alcohol (PEA). We have tested commercial volatile (PEA) against in vitro growth of F. incarnatum; the result showed PEA at a concentration of 1.5 mg mL−1 suppressed fungal growth with 56% inhibition. Both VOCs and PEA caused abnormal changes in the fungal mycelia. In vivo testing showed that the lesion size of muskmelons exposed to VOCs from T. asperellum T76-14 was significantly smaller than that of the control. Muskmelons exposed to VOCs from T. asperellum T76-14 showed no fruit rot after incubation at seven days compared to fruit rot in the control. This study demonstrated the ability of T. asperellum T76-14 to produce volatile antifungal compounds, showing that it can be a major mechanism involved in and responsible for the successful inhibition of F. incarnatum and control of postharvest fruit rot in muskmelons.

Chemical control of potato tuber moth, Phthorimaea operculella (Zell.), in Rhodesia

1967 ◽  
Vol 57 (2) ◽  
pp. 271-278 ◽  
Author(s):  
Margaret E. Richardson ◽  
D. J. W. Rose
Keyword(s):  
Chemical Control ◽  
Good Control ◽  
Field Trials ◽  
Phthorimaea Operculella ◽  
Macrosiphum Euphorbiae ◽  
Control Field ◽  
Azinphos Methyl ◽  
History Of ◽  
New Compounds ◽  
Made In

An account is given of the history of chemical control Phthorimaea operculella (Zell.) in potato fields in Rhodesia since the introduction of DDt prior to 1952. The failure of DDT and endrin, in routine spraying, to control field infestations is reproted, and some evidence that this is due to insecticide resistance is given. The results of critical field trials made in 1961, 1964 and 1965 to evaluate a range of insecticides for control of P. operculella and for their effects on populations of Macrosiphum euphorbiae (Thos.) are presented, together with the results of some laboratory tests. Good control of P. operculella in the field was obtained with sprays of azinphos-methyl at the rate of 0.5 lb active ingredient in 20 gal. water per acre, and two new compounds, methidathion and chlorfenvinphos, showed promise for the future.

scholarly journals Antagonistic effectiveness of some bacteria against Fusarium graminearum causing crown rot disease on wheat (Triticum aestivum)

2021 ◽  
Vol 13 (1) ◽  
pp. 69-80
Author(s):  
Majida Hadi Mahdi Alsaady ◽  
Hussein Ali Salim ◽  
Rakib A. Al-ani ◽  
Hadi M. Aboud ◽  
Jamal Talib M Al Roubaie
Keyword(s):  
Fusarium Graminearum ◽  
Culture Method ◽  
Dry Weight ◽  
Antagonistic Effect ◽  
Crown Rot ◽  
Control Treatment ◽  
Enzyme Analysis ◽  
Dual Culture ◽  
Rot Disease

In this study, the antagonistic effect of five bacteria genera namely Bacillus, Pseudomonas, Azotobacter, Azospirillum, and Streptomyces isolated from rhizosphere of wheat were evaluated against Fusarium graminearum as potential biocontrol agents in vitro. F. graminearum was molecularly diagnosed using the Polymerase chain reaction (PCR) technique. Each bacteria were tested for the production of catalase enzyme, oxidase enzyme, analysis of starch, analyze of gelatin, and the motility, where Azotobacter, Azospirillum, and Bacillus subtilis were positive for all tested. Fungal inhibition tests were performed by using the dual culture method and agar well diffusion technique. Among them, Streptomyces and Azospirillum exhibited potent inhibition to the growth of F. graminearum (72.14% and 66.42%) respectively, followed by B.pumillus, P.fluorescens, B. subtilis and Azotobacter ( 58.28%, 43.23%, 39.71% and 35.71%) respectively as compared with the control treatment (0.0%).The dry weight of the fungus biomass was decreased with bacteria P. fluorescens, Streptomyces sp, Azotobacter sp, Azospirillum sp, B. subtilis, and B. pumillus which reached (0.114, 0.103, 0.147, 0.101, 0.143, and 0.107 g) respectively compared to the control treatment that was 0. 665 g.

scholarly journals Plant Defensin Peptides have Antifungal and Antibacterial Activity Against Human and Plant Pathogens

2019 ◽  
Vol 109 (3) ◽  
pp. 402-408 ◽  
Author(s):  
Andrew E. Sathoff ◽  
Siva Velivelli ◽  
Dilip M. Shah ◽  
Deborah A. Samac
Keyword(s):  
Antibacterial Activity ◽  
Plant Pathogens ◽  
Crown Rot ◽  
Plant Defensin ◽  
Core Motif ◽  
Potential Control ◽  
Fungal Plant Pathogens ◽  
Plant Defensins ◽  
Animal Pathogens

Plant defensins are small, cysteine-rich antimicrobial peptides. These peptides have previously been shown to primarily inhibit the growth of fungal plant pathogens. Plant defensins have a γ-core motif, defined as GXCX3-9C, which is required for their antifungal activity. To evaluate plant defensins as a potential control for a problematic agricultural disease (alfalfa crown rot), short, chemically synthesized peptides containing γ-core motif sequences were screened for activity against numerous crown rot pathogens. These peptides showed both antifungal and, surprisingly, antibacterial activity. Core motif peptides from Medicago truncatula defensins (MtDef4 and MtDef5) displayed high activity against both plant and human bacterial pathogens in vitro. Full-length defensins had higher antimicrobial activity compared with the peptides containing their predictive γ-core motifs. These results show the future promise for controlling a wide array of economically important fungal and bacterial plant pathogens through the transgenic expression of a plant defensin. They also suggest that plant defensins may be an untapped reservoir for development of therapeutic compounds for combating human and animal pathogens.

scholarly journals New Case of False-Star-Grass (Chloris distichophylla) Population Evolving Glyphosate Resistance

Agronomy ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 377 ◽  
Author(s):  
José G. Vázquez-García ◽  
Sajedeh Golmohammadzadeh ◽  
Candelario Palma-Bautista ◽  
Antonia M. Rojano-Delgado ◽  
José A. Domínguez-Valenzuela ◽  
...  
Keyword(s):  
Weed Management ◽  
Chemical Control ◽  
Shikimic Acid ◽  
Dry Weight ◽  
Glyphosate Resistance ◽  
Integrated Weed Management ◽  
Resistance Level ◽  
Susceptible Population ◽  
First Case

Chloris distichophylla, suspected of glyphosate resistance (GR), was collected from areas of soybean cultivation in Rio Grande do Sul, Brazil. A comparison was made with a susceptible population (GS) to evaluate the resistance level, mechanisms involved, and control alternatives. Glyphosate doses required to reduce the dry weight (GR50) or cause a mortality rate of 50% (LD50) were around 5.1–3 times greater in the GR population than in the GS population. The shikimic acid accumulation was around 6.2-fold greater in GS plants than in GR plants. No metabolized glyphosate was found in either GR or GS plants. Both populations did not differ in the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) basal activity or in vitro inhibition of EPSPS activity by glyphosate (I50). The maximum glyphosate absorption was observed at 96 hours after treatment (HAT), which was twofold higher in the GS plants than in the GR plants. This confirms the first case of glyphosate resistance in C. distichophylla. In addition, at 96 HAT, the GS plants translocated more 14C-glyphosate than the GR ones. The best options for the chemical control of both C. distichophylla populations were clethodim, quizalofop, paraquat, glufosinate, tembotrione, diuron, and atrazine. The first case of glyphosate resistance in C. distichophylla was due to impaired uptake and translocation. Chemical control using multiple herbicides with different modes of action (MOA) could be a tool used for integrated weed management (IWM) programs.

scholarly journals The effect of biological and chemical control agents on the health status of the very early potato cultivar Rosara

2015 ◽  
Vol 55 (4) ◽  
pp. 389-395
Author(s):  
Bożena Cwalina-Ambroziak ◽  
Marta Maria Damszel ◽  
Małgorzata Głosek-Sobieraj
Keyword(s):  
Biological Control ◽  
Health Status ◽  
Chemical Control ◽  
Potato Cultivar ◽  
Growing Season ◽  
Control Treatment ◽  
In Vitro Test ◽  
Ne Poland ◽  
Vitro Test

Abstract The external appearance and quality of table potatoes are determined, among other factors, by the health status of the plants during the growing season. Chemical control methods are often combined with biocontrol agents to effectively fight potato pathogens. Potatoes of the very early cultivar Rosara were grown in experimental plots. The plots were located in Tomaszkowo (NE Poland, 2007-2009). The experiment involved the following treatments: 1) biological control − mycorrhizal Glomus spp. inoculum was applied to the roots, − tubers were dressed and plants were sprayed with Polyversum three times during the growing season, 2) chemical control - at two-week intervals, plants were sprayed with the following fungicides: Infinito 687.5 SC and Tanos 50 WG, Valbon 72 WG and Tanos 50 WG. In the control treatment, potato plants were not protected against pathogens. During the growing season, the severity of late blight and early blight was evaluated on a nine-point scale. The composition of fungal communities colonising potato stems was analysed. The fungistatic properties of the fungicides used in the field experiment were evaluated in an in vitro test. The symptoms of infections caused by Phytophthora infestans and Alternaria spp. were significantly reduced in the treatment which used the integrated chemical and biological control. The least diverse fungal community was isolated from fungicide-treated plants. In the in vitro test, fungicides at all analysed concentrations inhibited the linear mycelial growth of selected pathogens.

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