scholarly journals Biological control of Golovinomyces cichoracearum, the causal pathogen of sunflower powdery mildew

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Adel Ateyh Esawy ◽  
Mohsen Mohamed Elsharkawy ◽  
Reda Ibrahim Omara ◽  
Mamdouh Abdel Fattah Khalifa ◽  
Fawzya Mohamed Fadel ◽  
...  
Keyword(s):  
Biological Control ◽  
Powdery Mildew ◽  
Foliar Application ◽  
Biological Control Agent ◽  
Control Agent ◽  
Fungal Mycelium ◽  
Pooled Data ◽  
Progress Curve ◽  
Powdery Mildew Disease ◽  
Disease Parameters

Abstract Background Powdery mildew was found in most of the sunflower fields in Egypt, causing severe yellowing of the blade, petiole, stem and calyx, as well as a considerable defoliation during the summer season of 2018. Out of the fungal mycelium from infected leaves, collected from sunflower fields in the four Egyptian Governorates (Kafr El-Sheikh, Gharbia, Giza and El-Beheira), five isolates of powdery mildew pathogen were obtained and identified using morphological and molecular identification methods. Results In 2019 and 2020 seasons, five biocontrol agents (Bacillus subtilis, B. pumilus, Trichoderma harzianum, T. viride and T. koningii) were used to control powdery mildew disease on sunflower plants under field conditions compared with the fungicide (Vectra 10% SC). Treatments were significantly effective for controlling the powdery mildew disease relative to the control. The best treatment for reducing disease parameters (final disease severity (FDS%), area under disease progress curve (AUDPC) and efficacy) than the control was T. koningii. Foliar application of all the tested treatments improved plant height, head and stem diameters and seed yield in relation to untreated plants (control). The components (FDS%, AUDPC and efficacy) were extracted and described approximately 95.251% of the pooled data of seasons 2019 and 2020. In such pooled data, the principal components (PC1, PC2 and PC3) of all disease parameters, plant development parameters and yield components were recorded 76.305, 86.635 and 96.265% of the total variance, respectively. Conclusion A biological control agent, such as T. koningii, can be suggested for disease control based on the experimental findings.

scholarly journals Biological Control of Rose Powdery Mildew with the Antagonist Yeast Tilletiopsis pallescens

HortScience ◽  
1997 ◽  
Vol 32 (2) ◽  
pp. 262-266 ◽  
Author(s):  
Ken K. Ng ◽  
Leslie MacDonald ◽  
Zamir K. Punja
Keyword(s):  
Biological Control ◽  
Powdery Mildew ◽  
Culture Filtrate ◽  
Biological Control Agent ◽  
Control Agent ◽  
Spore Suspension ◽  
Distilled Water ◽  
Significant Difference ◽  
Growing Conditions ◽  
Sphaerotheca Pannosa

The efficacy of Tilletiopsis pallescens Gokhale, a naturally occurring ballistosporeforming yeast isolated from mildew-infected leaves, was evaluated as a biological control agent against rose powdery mildew [Sphaerotheca pannosa (Wallr.:Fr.) Lév. var. rosae Woronichin]. Two trials were conducted on potted rose (Rosa sp.) plants (1-year-old cv. Cardinal Pink) under commercial greenhouse-growing conditions during the summer (June to September) when mildew was most severe. Mildew-infected plants were subjected to one of four treatments: a T. pallescens spore suspension applied three times (3–4 d apart), distilled water (applied three times), one application of T. pallescens spore suspension, or one application of culture filtrate without spores. Two weeks after treatment began, mildew development was evaluated by enumerating conidial density on sampled leaflets. Sporulation was significantly reduced (by 97%–98%) on plants treated with three applications of T. pallescens spore suspension, compared to a 47%–57% reduction on plants treated with three applications of distilled water. There was no significant difference in conidial density between plants treated with one application of T. pallescens spore suspension and plants treated with one application of its culture filtrate, with a 78%–94% reduction in conidia, which was significantly higher than for the water treatment. The mode(s) of action of T. pallescens appears to be eradicant and associated with enzymes or metabolites produced in the culture filtrate. The results from this study demonstrate the potential for biological control of rose powdery mildew under commercial growing conditions in British Columbia.

Epiphytic growth and survival of Tilletiopsis pallescens, a potential biological control agent of Sphaerotheca fuliginea, on cucumber leawes

1997 ◽  
Vol 75 (6) ◽  
pp. 892-901 ◽  
Author(s):  
E. J. Urquhart ◽  
Z. K. Punja
Keyword(s):  
Biological Control ◽  
Relative Humidity ◽  
Powdery Mildew ◽  
Canola Oil ◽  
Leaf Surface ◽  
Biological Control Agent ◽  
Liquid Paraffin ◽  
Control Agent ◽  
Sphaerotheca Fuliginea ◽  
Growth And Survival

The influence of low (70%) and high (90%) relative humidity on epiphytic growth, development, and survival of Tilletiopsis pallescens, a ballistospore-forming yeast-like fungus, on cucumber leaves was investigated. In addition, survival of the fungus in the presence or absence of powdery mildew (Sphaerotheca fuliginea) colonies was determined. Growth and development were visualized by scanning electron microscopy of the leaf surface, and survival was quantified as colony-forming units recovered on a semiselective medium. Development of T. pallescens from blastospores that were applied to healthy leaves at 70% relative humidity was limited to small colonies that grew adjacent to leaf veins 7 days after application. At 90% relative humidity, extensive hyphal networks had developed within 3 days of blastospore germination, and ballistospores were produced within 7 days. Growth and sporulation of T. pallescens were most extensive at the base and on the surface of leaf trichomas. In the presence of S. fuliginea, T. pallescens mycelium developed adjacent to hyphae and conidiophores of the pathogen within 3 days at both 70 and 90% relative humidity. However, at 90% relative humidity, growth of T. pallescens was more extensive and ballistospores were produced within 5 days, and there was visible collapse of mildew hyphae. There was no evidence of penetration of the leaf or mildew hyphae by T. pallescens. Survival of T. pallescens was significantly (P = 0.05) increased at 1 and 5 days postapplication at 70% relative humidity when blastospores were amended with 1% (v/v) canola oil – lecithin. Survival at 90% relative humidity was also significantly increased with canola oil – lecithin and by the presence of S. fuliginea. The addition of liquid paraffin – lecithin or liquid paraffin – Tween had no effect on survival when compared to the control. The results from this study indicate that growth and survival of T. pallescens are enhanced by high relative humidity and by the presence of powdery mildew, and canola oil – lecithin amendment improved survival on the leaf surface at reduced ambient humidity. Key words: antagonism, biological control, powdery mildew, yeast.

The potential of Mecysolobus erro (Curculionidae) as a biological control agent for Buddleia

2002 ◽  
Vol 55 ◽  
pp. 433-433
Author(s):  
B.A. Gresham ◽  
M.K. Kay ◽  
W. Faulds ◽  
T.M. Withers
Keyword(s):  
Biological Control ◽  
Biological Control Agent ◽  
Control Agent

scholarly journals Limited host range in the idiobiont parasitoid Phymasticus coffea, a prospective biological control agent of the coffee pest Hypothenemus hampei in Hawaii

2021 ◽  
Author(s):  
Fazila Yousuf ◽  
Peter A. Follett ◽  
Conrad P. D. T. Gillett ◽  
David Honsberger ◽  
Lourdes Chamorro ◽  
...  
Keyword(s):  
Biological Control ◽  
Native Species ◽  
Biological Control Agent ◽  
Classical Biological Control ◽  
Environmental Safety ◽  
Control Agent ◽  
Hypothenemus Hampei ◽  
Parasitism Rate ◽  
Limited Host Range ◽  
Parasitoid Development

AbstractPhymastichus coffea LaSalle (Hymenoptera:Eulophidae) is an adult endoparasitoid of the coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera:Curculionidae:Scolytinae), which has been introduced in many coffee producing countries as a biological control agent. To determine the effectiveness of P. coffea against H. hampei and environmental safety for release in Hawaii, we investigated the host selection and parasitism response of adult females to 43 different species of Coleoptera, including 23 Scolytinae (six Hypothenemus species and 17 others), and four additional Curculionidae. Non-target testing included Hawaiian endemic, exotic and beneficial coleopteran species. Using a no-choice laboratory bioassay, we demonstrated that P. coffea was only able to parasitize the target host H. hampei and four other adventive species of Hypothenemus: H. obscurus, H. seriatus, H. birmanus and H. crudiae. Hypothenemus hampei had the highest parasitism rate and shortest parasitoid development time of the five parasitized Hypothenemus spp. Parasitism and parasitoid emergence decreased with decreasing phylogenetic relatedness of the Hypothenemus spp. to H. hampei, and the most distantly related species, H. eruditus, was not parasitized. These results suggest that the risk of harmful non-target impacts is low because there are no native species of Hypothenemus in Hawaii, and P. coffea could be safely introduced for classical biological control of H. hampei in Hawaii.

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