scholarly journals Lipid-Based Natural Food Extracts for Effective Control of Botrytis Bunch Rot and Powdery Mildew on Field-Grown Winegrapes in New Zealand

Plants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 423
Author(s):  
Kirstin V. Wurms ◽  
Annette Ah Chee ◽  
Peter N. Wood ◽  
Joseph T. Taylor ◽  
Frank Parry ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Disease Control ◽  
Milk Fat ◽  
Pathogen Resistance ◽  
Effective Control ◽  
Natural Food ◽  
Wine Quality ◽  
Significant Control ◽  
Bunch Rot ◽  
Synthetic Controls

Synthetic controls of crop pathogens are increasingly associated with harm to the environment and human health, and pathogen resistance. Pesticide residues in crops can also act as non-tariff trade barriers. There is therefore a strong imperative to develop biologically based and natural product (NP) biofungicides as more sustainable alternatives for crop pathogen control. We demonstrate the field efficacy, over multiple seasons, of NP biofungicides, NP1 (based on anhydrous milk fat) and NP2 (based on soybean oil), on two major diseases of winegrapes—Botrytis bunch rot (Botrytis) and powdery mildew (PM). The NPs were integrated into a season-long integrated disease management programme that has produced chemical-residue-free wines. Efficacies for Botrytis control on three different varieties were: 63–97% on Chardonnay, 0–96% for Sauvignon Blanc and 46–58% on Riesling; with 65–98% PM control on Chardonnay and Riesling. NP2 exhibited the significant control of Botrytis latent infections, making it a viable alternative to mid-season synthetic fungicides. Disease control was significantly better than the untreated control and usually as efficacious as the synthetic fungicide treatment(s). Yields and wine quality in NP-treated crops were normally equivalent to those in the synthetic fungicide treatments. The results indicate that NP-mediated disease control of Botrytis and powdery mildew can be obtained in the vineyard, without synthetic fungicide input.

scholarly journals Product formulation is crucial to the success of lipid-based bio-fungicides

2018 ◽  
Vol 71 ◽  
pp. 272-284 ◽  
Author(s):  
Kirstin Wurms ◽  
Annette Ah Chee
Keyword(s):  
Powdery Mildew ◽  
Disease Control ◽  
Milk Fat ◽  
Emulsion Stability ◽  
Control Efficacy ◽  
Anhydrous Milk Fat ◽  
Polyglycerol Ester ◽  
Product Formulation ◽  
Fat Globules ◽  
Best Disease

Powdery mildew is a major cause of damage to squash plants. Anhydrous milk fat (AMF) or soybean oil (SBO) may be effective at treating this disease but these active ingredients must be mixed with an emulsifier to enable even distribution and suspension of fat globules, and an antioxidant to prevent rancidity. The overall formulation may affect disease control efficacy, leaf health and product stability. The effect of different emulsifiers and antioxidants on emulsion stability, odour and shelf-life of AMF and SBO bio-fungicides was tested in laboratory assays, and on powdery mildew disease control efficacy and leaf health on glasshouse-grown squash plants. Both AMF and SBO formulations including a polyglycerol ester emulsifier (Grindsted® PGE 20 Veg) resulted in the best emulsion stability, disease control and leaf health. None of the antioxidants tested significantly affected on disease control efficacy in AMF formulations, but SBO formulations containing vitamin E as the antioxidant provided the best disease control efficacy and emulsion stability.

scholarly journals Transgenic Expression of the Functional Fragment Hpa110-42 of the Harpin Protein Hpa1 Imparts Enhanced Resistance to Powdery Mildew in Wheat

Plant Disease ◽  
2014 ◽  
Vol 98 (4) ◽  
pp. 448-455 ◽  
Author(s):  
Defu Wang ◽  
Yajun Wang ◽  
Maoqiang Fu ◽  
Shuyuan Mu ◽  
Bing Han ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Bacterial Blight ◽  
Fungal Species ◽  
Effective Control ◽  
Transgenic Expression ◽  
Rice Bacterial Blight ◽  
Harpin Protein ◽  
Transgenic Lines ◽  
Bacterial Blight Pathogen ◽  
Pathogen Populations

Powdery mildew, one of devastating diseases of wheat worldwide, is caused by Erysiphe graminis f. sp. tritici, a fungal species with constant population changes, which often poses challenges in disease management with host resistance. Transgenic approaches that utilize broad-spectrum resistance may limit changes of pathogen populations and contribute to effective control of the disease. The harpin protein Hpa1, produced by the rice bacterial blight pathogen, can induce resistance to bacterial blight and blast in rice. The fragment comprising residues 10 through 42 of Hpa1, Hpa110-42, is reportedly three- to eightfold more effective than the full-length protein. This study evaluated the transgenic expression of the Hpa110-42 gene for resistance to powdery mildew in wheat caused by E. graminis f. sp. tritici. Nine Hpa110-42 transgenic wheat lines were generated. The genomic integration of Hpa110-42 was confirmed, and expression of the transgene was detected at different levels in the individual transgenic lines. Following inoculation with the E. graminis f. sp. tritici isolate Egt15 in the greenhouse, five transgenic lines had significantly higher levels of resistance to powdery mildew compared with nontransformed plants. Thus, transgenic expression of Hpa110-42 conferred resistance to one isolate of E. graminis f. sp. tritici in wheat in the greenhouse.

Managing Powdery Mildew of Cherry in Washington Orchards and Nurseries with Spray Oils

2000 ◽  
Vol 1 (1) ◽  
pp. 2 ◽  
Author(s):  
G. G. Grove ◽  
R. J. Boal ◽  
L. H. Bennett
Keyword(s):  
Powdery Mildew ◽  
Disease Control ◽  
Sweet Cherry ◽  
Primary Concern ◽  
Disease Forecasting ◽  
Development Of Resistance ◽  
Dmi Fungicides ◽  
Forecasting System ◽  
Serious Disease ◽  
Eastern Washington

Powdery mildew of sweet cherry is the most serious disease in irrigated orchards and nurseries of Washington. The fungus infects foliage and fruit, but fruit infections are of primary concern due to the potential for rejection of entire crops. Development of resistance to demethylation inhibiting (DMI) fungicides in the mid-1990s increased the difficulty in controlling this disease. Orchard mildew management programs that utilize oils, DMI and strobilurin fungicides have been developed for use in eastern Washington. A growth stage (phenology)/calendar-based program provides excellent disease control, utilizes three fungicidal modes of action, and minimizes oil-induced fruit and foliar phytotoxicity by limiting oil use to no later than the pit hardening stage. A second approach that utilizes oils in a temperature-based disease forecasting system provides excellent disease control with fewer fungicide applications. Accepted for publication 19 July 2000. Published 28 July 2000.

scholarly journals Ontogenic Resistance and Plant Disease Management: A Case Study of Grape Powdery Mildew

2002 ◽  
Vol 92 (6) ◽  
pp. 671-675 ◽  
Author(s):  
Andrea Ficke ◽  
David M. Gadoury ◽  
Robert C. Seem
Keyword(s):  
Powdery Mildew ◽  
Host Defense ◽  
Secondary Growth ◽  
Resistance Mechanism ◽  
Infection Process ◽  
Host Susceptibility ◽  
Wine Quality ◽  
Age Related ◽  
Ontogenic Resistance ◽  
Plant Disease Management

A fundamental principle of integrated pest management is that actions taken to manage disease should be commensurate with the risk of infection and loss. One of the less-studied factors that determines this risk is ontogenic, or age-related resistance of the host. Ontogenic resistance may operate at the whole plant level or in specific organs or tissues. Until recently, grape berries were thought to remain susceptible to powdery mildew (Uncinula necator) until late in their development. However, the development of ontogenic resistance is actually quite rapid in berries, and fruit become nearly immune to infection within 4 weeks after fruit set. Our objective was to determine how and at what stage the pathogen was halted in the infection process on ontogenically resistant berries. Adhesion of conidia, germination, and appressorium formation were not impeded on older berries. However, once berries were approximately 3 weeks old and older, few germlings were able to form secondary hyphae. Ontogenically resistant berries responded rapidly to infection by synthesis of a germin-like protein that had been previously shown to play a role in host defense against barley powdery mildew. On susceptible berries, cell discoloration around penetration sites indicated the oxidation of phenolic compounds; a process that was followed by localized cell death. However, the pathogen was still able to infect such cells prior to their death, continue secondary growth, and thereby colonize young berries. Formation of papillae was not involved in the differential resistance mechanism of older berries. In susceptible berries, papillae formed frequently at infection sites but did not always contain the pathogen, whereas in resistant berries, the pathogen was always halted prior to the formation of papillae. The host defense, which conditions ontogenic resistance, operates in the earliest stages of the infection process, in the absence of gross anatomical barriers, prior to the formation of a functional haustorium and prior to the development of a conspicuous penetration pore. We also found that diffuse powdery mildew colonies that were not visible in the field predisposed berries to bunch rot by Botrytis cinerea, increased the levels of infestation by spoilage microorganisms, and substantially degraded wine quality. Our improved understanding of the nature, causes, and stability of ontogenic resistance in the grapevine/ powdery mildew system has supported substantial changes in how fungicides are used to control the disease. Present applications are more focused on the period of maximum fruit susceptibility instead of following a calendar-based schedule. This has improved control, reduced losses, and in many cases reduced the number of fungicide applications required to suppress the disease. Particularly where fungicides are deployed in a programmatic fashion and ontogenic resistance is dynamic, there may be equivalent improvements to be made in other hostpathogen systems through studies of how host susceptibility changes through time.

scholarly journals Geostatistical Analysis of the Spatiotemporal Dynamics of Powdery Mildew and Leaf Rust in Wheat

2009 ◽  
Vol 99 (8) ◽  
pp. 974-984 ◽  
Author(s):  
Jonas Franke ◽  
Steffen Gebhardt ◽  
Gunter Menz ◽  
Hans-Peter Helfrich
Keyword(s):  
Spatial Analysis ◽  
Powdery Mildew ◽  
Disease Control ◽  
Leaf Rust ◽  
Temporal Dynamics ◽  
Growth Parameters ◽  
Spatiotemporal Dynamics ◽  
High Variability ◽  
Plant Diseases ◽  
Disease Spread

Plant diseases are dynamic systems that progress or regress in spatial and temporal dimensions. Site-specific or temporally optimized disease control requires profound knowledge about the development of each stressor. The spatiotemporal dynamics of leaf rust (Puccinia recondite f. sp. tritici) and powdery mildew (Blumeria graminis f. sp. tritici) in wheat was analyzed in order to evaluate typical species-dependent characteristics of disease spread. During two growing seasons, severity data and other relevant plant growth parameters were collected in wheat fields. Spatial characteristics of both diseases were assessed by cluster analyses using spatial analysis by distance indices, whereas the temporal epidemic trends were assessed using statistical parameters. Multivariate statistics were used to identify parameters suitable for characterizing disease trends into four classes of temporal dynamics. The results of the spatial analysis showed that both diseases generally occurred in patches but a differentiation between the diseases by their spatial patterns and spread was not possible. In contrast, temporal characteristics allowed for a differentiation of the diseases, due to the fact that a typical trend was found for leaf rust which differed from the trend of powdery mildew. Therefore, these trends suggested a high potential for temporally optimized disease control. Precise powdery mildew control would be more complicated due to the observed high variability in spatial and temporal dynamics. The general results suggest that, in spite of the high variability in spatiotemporal dynamics, disease control that is optimized in space and time is generally possible but requires consideration of disease- and case-dependent characteristics.

scholarly journals INFLUENCE OF GIBBERELLIC ACID AND FUNGICIDE EXPERIMENTS ON YIELD, QUALITY AND DISEASE CONTROL OF `CHENIN BLANC' GRAPES IN -SOUTHEAST TEXAS.

HortScience ◽  
1990 ◽  
Vol 25 (8) ◽  
pp. 852f-852
Author(s):  
Iva Suzanne Wilson ◽  
George Ray McEachern ◽  
J Dan Hanna
Keyword(s):  
Gibberellic Acid ◽  
Disease Control ◽  
Southeast Texas ◽  
Yield Quality ◽  
Bunch Rot ◽  
Effect On Yield ◽  
And Control ◽  
Chenin Blanc

Gibberellic acid and fungicide experiments were conducted in 1988 and 1989 to examine their effect on yield, quality and disease control of 'Chenin Blanc' grapes in Southeast Texas. Gibberellic acid applied 7 and 14 days prior to bloom at 2.5 and 5.0 ppm reduced the number of berries per cluster in 1988 and 1989. The 2.5 ppm rate reduced berries and increased yield. The GA treatments also reduced bunch rot at harvest. Benomyl + Manzate fungicide treatments were superior to Nova and control in reducing bunch rot.

scholarly journals Powdery mildew and wine quality

2003 ◽  
Vol 24 (3) ◽  
pp. 20 ◽  
Author(s):  
Belinda E Stummer ◽  
I Leigh Francis ◽  
Andrew J Markides ◽  
Eileen S Scott
Keyword(s):  
Disease Management ◽  
Powdery Mildew ◽  
Wine Industry ◽  
Uncinula Necator ◽  
Wine Quality ◽  
Important Disease

Powdery mildew, caused by the fungus Uncinula necator, is a widespread and economically important disease of grapevines. The fungus grows superficially on green tissues of grapevines and other members of the Vitaceae. Powdery mildew costs the Australian grape and wine industry approximately A$30 million per year in terms of lost yield, reduced quality and disease management.

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