Integration of host resistance, fungicides, and spray frequencies for managing Fusarium head blight of bread wheat under field conditions in southern Ethiopia

Abstract

A field experiment was carried out in Adiyo, Bonke, Chencha, Sodo zuriya, and North Ari districts, they are found in Southern Ethiopia, during the 2019 main production season. The objective of the experiment was to evaluate the effectiveness of the integrations of host resistance and application of fungicides with designated spray frequency on Fusarium head blight under natural epiphytotic conditions and to determine the management effects on yield and yield components of wheat. The treatments consisted of wheat cultivars (Shorima and Hidase) and fungicides (Propiconazole and Tebuconazole) with four spray frequencies, including an unsprayed one. The experiment was arranged in a split-split plot design with three replications. Wheat cultivars were assigned to the main plots and fungicides allotted to the sub-plots, while the spray frequencies were appointed to sub-sub plots. Results exhibited that integration of wheat cultivars and fungicides with spray frequencies significantly (p < 0.001) reduced disease pressure and increased grain yields across the locations. The highest disease severity (36.46%) and area under disease progress curve (AUDPC) (404.78%-day) and lowest grain yield (2.42 t ha À1 ) were recorded at North Ari. The lowest severity (7.70%), and AUDPC (130.26%-day), and the highest grain yield (6.68 t ha À1 ) were recorded in Bonke. The lowest severity (4.78 and 5.74%) and AUDPC (52.86 and 59.78%-day) were recorded from Shorima due to integrated use of Tebuconazole with three and two times spray frequencies, respectively. The highest grain yield of 5.30 t ha À1 was recorded on Shorima in combination with Tebuconazole with three times spray frequencies. The grain yield loss of 46.49% was computed on unsprayed plots of Hidase cultivar. Overall, the results exhibited a combination of moderately resistance wheat cultivars supplemented by fungicide with appropriate spray frequencies right at disease onset reduced disease pressure and increased grain yield. Planting of Shorima combined with Tebuconazole with three times spray frequencies was found effective in reducing FHB epidemics and increasing grain yield with the highest monetary advantage. Therefore, this could be recommended to growers in the study areas and similar agro-ecologies to manage F. graminearum causing FHB in wheat.

Genotype by environment interaction analysis for Fusarium head blight response and yield performance of bread wheat (Triticum aestivum L.) in southern Ethiopia

“…During the study, FHB symptoms were first observed on Hidase, Kakaba, Danda'a, Kingbird, and Ogolcho genotypes at the Zadok's growth stage (ZGS) of 59 at Adiyo, Gedeb, North Ari, Sodo Zuriya, Hubareg, Chencha, and Bonke. FHB symptoms observed on the test wheat genotypes were in agreement with its typical symptoms reported by other scholars in different parts of the world (Gilbert and Tekauz 2000;Murray et al 2009; Dill-Macky Ghimire et al 2020;Mengesha et al 2021Mengesha et al , 2022. On the other hand, the identified Fusarium species such as F. graminearum, F. culmorum, F. avenaceum, F. poae, F. ussurianum, F. semitectum, F. lateritium, F. sambucinum, and F. heterosporum were in line with the reports of Earecho et al (2020), Getachew et al (2022), and Mengesha et al (2021 in Ethiopia.…”

“…This could be due to the variation in environmental conditions and the existence of various Fusarium species, which affect the interaction between FHB and wheat genotype for epidemic development. Variation in genotypic response to FHB has been known to result from variations in climate conditions and Fusarium species (Buerstmayr et al 2008;Beres et al 2018;Earecho et al 2020;Mengesha et al 2021).…”

“…The disease is caused by a number of Fusarium species, of which Fusarium graminearum Schwabe [teleomorph Gibberella zeae (Schwein.) Petch] is a well-known causal agent worldwide (Gilbert and Tekauz 2000;Dean et al 2012;Gilbert and Haber 2013;Earecho et al 2020;Shude et al 2020;Mengesha et al 2021). The disease has not been as well studied as other wheat diseases in Ethiopia (Earecho et al 2020;Mengesha et al 2021).…”

“…Petch] is a well-known causal agent worldwide (Gilbert and Tekauz 2000;Dean et al 2012;Gilbert and Haber 2013;Earecho et al 2020;Shude et al 2020;Mengesha et al 2021). The disease has not been as well studied as other wheat diseases in Ethiopia (Earecho et al 2020;Mengesha et al 2021). The harvested grains infected with the pathogen are small, light, pre-mature, shriveled, shrunken, and sometimes covered with white or pink fungal mass and contaminated with mycotoxins (deoxynivalenol, DON) (Langseth et al 1995;Andersen et al 2014;Karasi et al 2016).…”

Characterization and Fungicide Screening of a New Pathogen That Causes Leaf Spot on Rehmannia glutinosa

“…Flusilazole and tebuconazole selected in this study have high antifungal activities against F. equiseti and F. acuminatum, which is consistent with the results of a previous study [48]. In addition, Mengesha et al [50] reported that tebuconazole is effective for controlling wheat scab; thus, triazole fungicides such as flusilazole and tebuconazole could be used to control leaf spot of R. glutinosa caused by Fusarium spp. In our study, prochloraz showed high antifungal activity against F. equiseti and F. acuminatum.…”