2 results
Search Results
Now showing 1 - 2 of 2
Item Evaluation of Bacterial Perpetuation Assays and Plant Biomolecules Antimicrobial Activity against Cotton Blight Bacterium Xanthomonas citri subsp. malvacearumAutores: Naqvi, Syed Atif Hasan; Iqbal, Shehzad; Hafeez-Ur-Rehman; Farooq, Umar; Hassan, Muhammad Zeeshan; Shahid, Muhammad Nadeem; Shah, Adnan Noor; Abbas, Aqleem; Mubeen, Iqra; Farooq, Ammara; Ghareeb, Rehab Y.; Kalaji, Hazem M.; Alrefaei, Abdulwahed Fahad; Ahmed, Mohamed A. A.Cotton (Gossypium hirsutum) is a global cash crop which has gained importance in earning foreign exchange for each country. Bacterial blight caused by Xanthomonascitri subsp. malvacearum (Xcm) has been a seriousdisease in Pakistan’s cotton belt on multiple occasions. Bacterium was isolated and identified through various biochemical and diagnostic tests wherehypersensitivity reaction, Gram staining, KOH (potassium hydroxide), catalase, starch hydrolysis, lecithinase and Tween 80 hydrolysis tests confirmed bacterium as Gram-negative and plant pathogenic. Xcm perpetuation assays wereevaluated on various cotton varieties under glasshouse conditions in completely randomized design by three different methods, wherein the scratch method proved to be the best upon CIM-496 and showed 83.33% disease incidence as compared with the other two methods, where Bt-3701 responded with 53.33% incidence via the spray gun method, and 50% with the water splash method on CIM-616, as compared with the control. Similarly, for disease severity percentage, Bt-3701 was pragmatic with 47.21% through scratch method, whereas, in the spray gun method, 45.51% disease severity was noted upon Bt-802, and 31.27% was calculated on Cyto-179 through the water splash method. Owing to the unique antibacterial properties of aqueous plant extracts, the poison food technique showed Aloe vera, Mentha piperita, Syzygiumcumini and Azadirachta indica with 17.77, 29.33, 18.33 and 20.22 bacterial colonies counted on nutrient agarmedium petri plate, respectively, as compared with the control. Measurement of the inhibition zone by disk diffusion technique showed Mentha piperita, Syzygiumcumini, Citrus limon, Moringa oleifera and Syzygium aromaticum to present the most promising results by calculating the maximum diameter of the inhibition zone, viz., 8.58, 8.55, 8.52, 8.49 and 8.41 (mm), respectively, at the highest tested concentration (75 ppm, parts per million) compared with the control. It is probable that the decoction’s interaction with the pathogen population on the host plant will need to be considered in future experiments. However, at this moment, more research into the effective management of cotton bacterial blight by plant extracts in terms of concentration determination and development of biopesticides will provide future avenues to avoid environmental pollution.Item Sensibilidad y control de Botryosphaeriaceae causantes de muerte regresiva en manzanosAutores: Galdames Vilches, Matías IgnacioAutor Institucional: Universidad de TalcaProfesor Guía: Díaz Ulloa, GonzaloProfesor Informante: Lolas Caneo, MauricioLa variedad de manzanos Fuji, Gala y Cripps Pink, son importantes en la Región del Maule. La muerte regresiva de árboles de manzanos es uno de los principales problemas que presenta la producción a nivel de campo. Esta enfermedad es causada por especies de Botryosphaeriaceae, que provocan síntomas de muerte de ramillas, brazos y plantas, disminuyendo la productividad de los huertos comerciales. Sin embargo, a nivel nacional no se ha estudiado la eficacia de fungicidas. Por esta razón, la investigación se centró en estudiar la sensibilidad in vitro de fungicidas (grupos SDHI, MBC, QoI y DMI) contra Botryosphaeriaceae y determinar la eficacia como protectores de heridas de poda contra Diplodia seriata. Los resultados de la sensibilidad in vitro en medio APD (2%), mostraron que los aislados de D. seriata, Lasiodiplodia theobromae y Neofusicoccum arbuti fueron sensibles a los fungicidas benomil (MBC) con valores de EC50 entre 0,07 a 0,422 μg/ml y para tebuconazol (DMI) valores entre 0,12 y 046 μg/ml (EC50). Para los fungicidas piraclostrobin (Qol) y boscalid (SDHI) los valores de EC50 variaron entre 0,58 a 39,6 μg/ml y 10,03 a 1383,8 μg/ml, respectivamente. Los productos fungicidas obtuvieron una eficacia entre un 40% para el producto en base a Trichoderma sp. (Utalca) y 78% para el producto benomil aplicados en forma líquida. Interesantemente, los productos biológicos comerciales basados en consorcios biológicos proporcionaron una eficacia de 55% para su versión liquida (Mamull) y 62% para su versión en pintura (Coraza).
