Getnet Yitayih Alemu* and Yehizbalem Azmeraw Tadele
Department of Plant Sciences, Debre Tabor University, Ethiopia
Received date: January 17, 2017; Accepted date: January 30, 2017; Published date: February 06, 2017
Citation: Alemu GY, Tadele YA (2017) Management of Faba Bean Gall Disease through the use of Host Resistance and Fungicide Foliar Spray in Northwestern Ethiopia. Adv Crop Sci Tech 5:254. doi: 10.4172/2329-8863.1000254
Copyright: © 2017 Alemu GY, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Most developing countries are hesitated in maximizing tissue culture technology due to the overhead costs involved. Therefore, this research was initiated to evaluate alternative cheap carbon sources and energy in culture media in order to reduce production input costs of sugarcane in vitro propagation. The experiment was carried out in completely randomized design (CRD) with 2 × 6 factorial treatment arrangements of genotypes and carbon source in combination. The interaction analysis of genotypes and table sugar concentration significantly influenced in vitro sugarcane multiplication. On MS medium with 50 gl-1 table sugar, B4906 gave the highest (13.42 ± 0.29) shoots, whereas Pr1013 produced a maximum of 7.78 ± 0.19 shoots at 60 gl-1 table sugar. However, 40 gl-1 table sugar was optimum to produce usable and separable shoots for further subculture of multiplication. Accordingly results showed that table sugar not only enhanced multiplication but also significantly reduced the production input costs by 94.89% when compared with the analytical grade sucrose.
Faba bean gall; Bayleton; Severity; Incidence
Faba bean (Vicia faba L.) also referred to as broad bean, horse bean and sometimes field bean occupies nearly 3.2 million hectare worldwide . It is believed that the crop was introduced to Ethiopia from the Middle East via Egypt around 5000 B.C., immediately after domestication . In 2003, China leads the world in faba bean production in both area coverage and production followed by Ethiopia, Egypt and Australia . Ethiopia is considered as the secondary center of diversity and also one of the nine major agro-geographical production regions of faba bean [1,2,4,5].
Among pulse crops, faba bean is majorly grown in Ethiopia and leading protein source for the rural people and used to make various traditional dishes. Faba bean is well known by farmers in improving soil fertility by fixing atmospheric nitrogen, and widely use them in rotation with cereals . The crop can be grown for green manure and silage . The majority of the seed produced would be consumed domestically and only a smaller percentage of the crop is delivered to the export market . However, still this small portion of export volume put Ethiopia among the top broad bean exporting countries of the world . Amhara and Oromia are the two major faba bean producing regions. The Amhara region contributes to the highest production (47%) in the country followed by Oromiya region that contributes 39% to national production .
Faba bean is an important legume crop and pre-dominantly grown by every individual farmers in Ethiopia. However, there are different faba bean biotic (diseases, insect pests, and weeds) and abiotic production constraints that limit the production and productivity of the crop [6,11]. Among which diseases are the most important biotic factors causing faba bean yield reduction. More than 17 pathogens have been reported so far on faba bean from different parts of the country. Diseases that are economically most important in the major faba bean growing regions including chocolate spot, faba bean rust, and Aschochyta blight [12-14]. In recent years, in additional to the previous common diseases, the crop is threatening by new gall forming disease with typical symptoms of green and sunken on the upper side of the leaf and bulged to the back side of the leaf, and finally develops light brownish color lesion, chlorotic galls, and progressively broaden to become circular or elliptical uneven spots [8,15]. The faba bean gall caused yield loss up to 30-100% . These data showed that faba bean gall is the most destructive disease that causes total yield loss. The disease affects leaves and stems and it affects large areas in the country where faba bean is cultivated and cause considerable losses in quality and quantity of the products . The disease was highly expanding and distributing violently in the country from year to year.
Even though the disease is disseminated at violent rate, there is no management options under took to control the disease. Hence, this needs more attention to find solution for farmers to manage the disease and sustain their life with producing faba bean crops. Therefore, this study was conducted to manage faba bean gall disease through the integrated use of host resistance and fungicide foliar spray.
The experiment was conducted at Farta and Tach gaynt in farmers’ field during 2014 main cropping season. Farta and Tach gaynt are found an altitude of 2500 and 2880 above sea level in Amhara region, South Gondar Zone, respectively. The average annual rainfall of Farta is about 1750 mm and Tach gaynt is 925 mm. The average annual temperatures of Farta and Tach gaynt are 17°C and 18.5°C, respectively. The major soil type of Farta and Tach gaynt are clay loam and clay loam, loamy sand, respectively.
Experimental design and procedures
The field experiment was conducted within two sites at Farta and Tach gaynt in farmers, fields during 2014 main cropping season. The treatments to be evaluated were 14 faba bean varieties, released (CS20DK, NC58, Kasa, Bulga70, Mesay, Tesfa, Degaga, Adet-Hana., Moti, Gebelecho, Obse, Dosha, Tumsa), and local check. The varieties to be evaluated were collected from Holeta and Adet Agricultural Research Centers. The treatments were arranged in split plot design with three replications. The experiment has 14 main plots and two subplots i.e protected with fungicide and unprotected. The size of main plot was 4 m length × 3.8 m width with having 0.8 m spacing between main plots and the sub-plot size was 4 m length × 1.4 m with having 4 seedling rows (with 2 net rows) and spacing between blocks, was 1 m and spacing between plots, rows and plants was 0.6 m and 0.4 m, 10 cm respectively. The protected plots were sprayed using triadimefon (Bayleton(R) WP 25) systemic fungicide at the rate of 0.125 kg a.i/ha for all varieties starting from 3 weeks after sowing in 15 days interval. 15 g of Bayleton was diluted within 5 liter of water to spray the experimental plots. All necessary agronomic practices were done as required.
Crop data: The grain yield of faba bean was measured at maturity, from the central rows of each plot by harvesting the plants manually. Seed yield per plot was measured using a sensitive balance and then adjusted to 9% moisture content, and yield per plot was converted into kg/ ha.
Disease assessment: Faba bean gall incidence and severity assessments were started as soon as the first disease symptoms occurred in every 10 days interval at both locations. Using 10 randomly pretagged faba bean plants in the two central rows, severity was rated using standard disease scales of 0-9 [17,18]. The following infection levels on the scale were used: 0, no visible infection on leaves; 1, a few dot-like accounting for less than 5% of total leaf area; 3-4, discrete galls less than 2 mm in diameter, accounting for 6-25% of leaf area; 5, numerous scattered galls with a few linkages, diameter 3-5 mm, on 26-50% of leaf area with a little defoliation; 6, confluent galls formation accounting for 51-75% of leaf/stem area, mild gall formation, half the leaves dead or defoliated; 7, complete destruction of the larger leaves, galls covering more than 76% of leaf area, abundant gall formation; 8, 80% of the defoliated and plants darkened and dead; 9, disease covering more than 80% of the foliar tissue heavy defoliation and plants darkened and dead. Diseases incidence was calculated using the following formula.
Disease development data were rated using 1-9 rating scale and then converted in to percentage severity index using the formula.
The area under the disease progress curve (AUDPC) was calculated from percentage severity index using the following formula
Where: Xi = the cumulative disease severity expressed as a proportion at the ith observation ti=time of the ith assessment , n=the total number of observation
The collected data from the two experimental sites were subjected to ANOVA to determine the treatment effects. AUDPC for each treatment were evaluated from disease severity values. The severity grades were converted into percentage severity index using the formula stated above. Least significant difference (LSD) value was used to separate the treatment means. All diseased and agronomic data were analyzed by using SAS version 9.1.3 statistical software .
Incidence of faba bean gall disease
Percentage of disease incidence was showed significant difference (P<0.05) among faba bean varieties at both locations at all dates of assessment. Highly significant difference (P<0.01) was observed on incidence of faba bean gall disease between sprayed and unsprayed plot at both locations at all dates of assessment. Higher disease incidence was recorded from variety Adet-Hana at both initial and final dates of assessment at Farta. Lower disease incidence was scored from variety Tumsa at initial and Degaga and Nc58 at final date of assessment at Farta (Table 1). At Tach gaynt, the disease incidence was higher on variety Bulga70 and Adet-Hana at both initial and final dates of assessment. While lower mean disease incidence was scored from variety Tumsa at both initial and final dates of assessment (Table 1).
|Incidence (%)DAS||PSI (%) DAS||Incidence (%) DAS||PSI (%) DAS|
|Initial (26)||Final (66)||Initial (26)||Final (66)||Initial (28)||Final (68)||Initial (28)||Final (68)|
PSI=percentage of severity index, DAS=days after sowing, means with in a column followed by the same letter were not significantly different, CV=Coefficient of variation, LSD=Least Significant Difference.
Table 1: Effect of faba bean varieties on percentage severity index and incidence of faba bean gall disease at Farta and Tachgaynt under field condition in 2014 cropping season.
The combined use of varieties and Bayleton foliar spray was showed highly significant difference (P<0.01) at Farta and significant difference (P<0.05) at Tach gaynt on disease incidence at the initial and final dates of assessment (Table 2). Higher disease incidence was scored from unsprayed plots of variety Bulga70, Adet-Hana, Dosha, CS20DK and Gebelecho at the final date (66 days after sowing) of disease assessment at Farta. However, lower disease incidence was recorded from unsprayed plots of variety Nc58 and Degaga. At Tach gaynt, the disease incidence was lower on unsprayed plots of variety Tumsa and Moti at final date of assessment. While the disease incidence was higher on unsprayed plots of variety Bulga70, Kasa, Local check, Adet-Hana, Degaga and Mesay at the final assessment. The disease incidence was completely zero in sprayed plots of all faba bean varieties except Adet-Hana, Dosha, Moti and Tesfa at Farta and Adet-Hana, Bulga70, Gebelecho at Tach gaynt at final date of assessment (Table 2). The interaction of variety with Bayleton foliar spray reduced the percentage of disease incidence by 90% and 83.3% on sprayed plot of variety Adet-Hana over unsprayed plot of this variety at Farta and Tach gaynt, respectively, at the final date of assessment. Similarly, Bayleton foliar spray lowers the disease incidence by 80% and 100% on sprayed plot of variety Bulga70 over unsprayed plot of this variety at Farta and Tach gaynt, in that order, at the final date of assessment. The disease incidence was reached 100% on variety Bulga70, Kasa and Local check on unsprayed plots at Tach gaynt at the final date of assessment. This result showed that all the assessed plants of these varieties were infected by the faba bean gall disease. From three surveyed regions by the maximum mean incidence of 43.4% was recorded in South Gondar in Amhara region . The study by Teklay et al.  in Tigray showed that the incidence range of the disease varied from 5-100%. In unsprayed plot, mean faba bean gall incidence ranged from 50-93.3% and 56.7-100% at Farta and Tach gaynt, respectively at final date of assessment. At both locations all faba bean varieties were infected by the newly emerged faba bean gall disease. This agreement with the study by Teklay et al.  and Hailu et al.  who are reported that all improved and local faba bean varieties affected by the diseases indifferently. The prevalence of the new gall disease was in the range of 0 and 100% [8,16].
|Variety X Foliar spray||Disease incidence at FartaDAS (%)||Disease incidence at Tachgaynt DAS (%)|
|Initial (26)||Final (66)||Initial (28)||Final (68)|
PSI=percentage of severity index, DAS=days after sowing, CV=Coefficient of variation, LSD=Least Significant Difference.
Table 2: Effect of faba bean varieties with fungicide foliar spray on incidence of faba bean gall disease at Farta and Tach gaynt under field condition in 2014 cropping season.
Severity of faba bean gall disease
Percentage severity index (PSI) calculated from disease severity assessed five times at both locations. Percent severity index was higher in unsprayed plot as compared to sprayed plot at both locations (Table 3). Percentage severity index was showed significant difference (P<0.05) among faba bean varieties at both locations at all dates of assessment. There was also a significant variation (P<0.05) between sprayed and unsprayed plot on percentage severity index of the disease at both locations at all dates of assessment except at initial (26 and 28 days after sowing).
|Variety X Foliar spray||Location|
|PSI DAS (%)||AUDPC
( % days)
|PSI DAS (%)||AUDPC ( % days)|
|Initial (26 )||Final (66)||Initial (28)||Final ( 68)|
PSI=percentage of severity index, DAS=days after sowing, AUDPC=area under disease progress curve, CV=Coefficient of variation, LSD=Least Significant Difference.
Table 3: Effect of faba bean varieties with fungicide foliar spray on percentage severity index and AUDPC at Farta and Tach gaynt under field condition in 2014 cropping season.
Higher mean severity of faba bean gall was recorded from variety Adet-Hana at both initial and final dates of assessment at Farta. Whereas the mean severity was lower on variety Kasa at both initial and final date of assessment (Table 1). At Tach gaynt, lower mean severity was scored from variety Tumsa at both initial and final dates of assessment. Faba bean gall disease severity was higher on variety Kasa at 28 days after sowing (DAS) and Bulga 70 at 68 DAS disease assessment (Table 1).
The integration of varieties with fungicide spray by Bayleton was showed a significant difference (P<0.05) on percentage severity index (PSI) of faba bean gall all dates of assessment at both sites. The PSI of faba bean gall was reached zero on sprayed plot of variety Degaga, NC58, Obse, Tumsa and Local check at 46 and 48 DAS at Farta and Tach gaynt, respectively. Whereas the mean value of unsprayed plot of these varieties was showed increasing PSI of faba bean gall from the initial to the final date of disease assessment. The percentage severity index of faba bean gall was significantly reduced on sprayed plot than unsprayed at both locations. From unsprayed plot, PSI of faba bean gall was higher on variety Adet -Hana and Bulga70 while lower value of PSI was scored from variety Kasa and Local check at Farta at final date of assessment (Table 3). The use of Bayleton foliar spray reduced PSI of faba bean gall by 60.7%, 55.9% and 46.7% on sprayed Adet Hana, Bulga70 and CS20DK varieties in their order over unsprayed plot of these varieties. Similarly, Bayleton foliar spray in combination with variety Moti, Tesfa and Gebelecho decreased PSI of faba bean gall by 38.5%, 33.3% and 30.0% in that order over unsprayed plot of these varieties at final date of severity assessment at Farta. At Tach gaynt, Bayleton foliar spray with variety was lower the PSI of faba bean gall on sprayed variety of Bulga70, Nc58, and Kasa by 55.6%, 50.4% and 45.2%, respectively over unsprayed plot of these varieties at final date of assessment. In addition to these, foliar application of Bayleton on Mesay, Adet Hana and CS20DK varieties was reduced the PSI of faba bean gall by 44.8%, 44.8% and 41.1%, in that order over the unsprayed plot of these varieties at the final date of severity record. The maximum mean severity of 57.5% was observed in Awi zone followed by the study area with mean severity of 40.7% . Lower mean value of PSI of faba bean gall was scored from unsprayed plot of Tumsa and Obse at the final date of assessment at Tach gaynt. The disease was more severe in study area as compared to other regions . The plot subjected to foliar spray was reduced the faba bean gall diseases severity in all varieties including local check at all dates of assessment as compare to unsprayed plot at both sites. All faba bean varieties were significantly affected by the disease. This result coincides with Dereje et al., Teklay et al., Hailu et al. [8,15,16]. Generally, Bayleton foliar spray on faba bean varieties has significant effect in reduction of PSI of faba bean gall disease at both locations.
AUDPC (Area under disease progress curve)
The integration of varieties with fungicide spray by Bayleton was showed significant difference (P<0.05) on AUDPC of faba bean gall disease at both sites. The maximum mean AUDPC of the disease was scored on variety Adet-Hana and Bulga 70 on unsprayed plot at Farta and Tach gaynt in their order. Lower value of AUDPC was recorded from variety Local check and Tumsa on unsprayed plot at Farta and Tach gaynt respectively. Higher mean AUDPC faba bean gall was scored from unsprayed plots than sprayed plots (Table 3). The area under disease progress curve (AUDPC) is a very convenient summary of plant disease epidemics that incorporates into initial intensity, the rate parameter, and the duration of the epidemic which determines final disease intensity . The AUDPC was used to summarize the epidemics of the disease in the different varieties evaluated during this experiment.
Seed yield of faba bean
Faba bean varieties with foliar spray were showed significant variation (P<0.05) on seed yield at both locations. At Farta, higher yield was obtained from sprayed plot of variety Adet-Hana and CS20DK while lower yield was scored from sprayed plot of variety Mesay and Obse. From unsprayed plot, higher yield per hectare was scored from variety CS20DK and lower value was obtained from variety Moti at Farta (Table 4). At Tach gaynt, the highest yield was scored from sprayed plot of variety Kasa (1441.7 kg/ha) and Nc58 (1333.3 kg/ha) where as lower yield per hectare was obtained from sprayed plot of variety of Tesfa (558.3 kg/ha). From unsprayed plot, lower yield was recorded from variety Gebelecho, Tumsa, Moti and Dosha at Tach gaynt. Maximum mean yield was gained from unsprayed plot of variety Local check. The epidemic conditions of the disease have significant implication on the production of faba bean and on the country’s Economy . The disease reduced the yield by 1116.7 kg/ha, 700 kg/ha, 541.6 kg/ha on variety Adet-Hana, Degaga and Gebelecho in their order at Farta. The faba bean gall caused yield loss up to 30-100% . At Tach gaynt, it reduced the yield by 123.4 kg/ha, 291.7 kg/ha, 166.6 kg/ha on the above varieties in their previous order. In this study, the yield of all varieties reduced on unsprayed plots at both locations. Past surveyed study explained that faba bean production in Ethiopia is highly challenged by new faba bean gall forming disease .
|Variety X Foliar spray||Yield(kg/ha) at Farta||Yield(kg/ha)
CV=Coefficient of variation, LSD=Least Significant Difference.
Table 4: : Effect of faba bean varieties with fungicide foliar spary on yield of faba bean at Farta and Tach gaynt under field condition in 2014 cropping season.
Faba bean gall disease is the newly emerging and aggressively spread disease in the country and cause 100% yield loss in susceptible faba bean varieties. The combined use of Bayleton foliar spray with variety significantly reduced PSI of faba bean gall by 60.74% and 55.93% on sprayed Adet Hana and Bulga70 varieties in their order over unsprayed plot of these varieties at Farta. At Tach gaynt, the interaction effect was lower the PSI of faba bean gall on sprayed variety of Bulga70, Nc58, and Kasa by 55.56% and 50.37%, respectively over unsprayed plot of these varieties at final date of assessment. The disease reduced the yield by 1116.7 kg/ha and 123.4 kg/ha on unsprayed plot of variety Adet-Hana at Farta and Tach gaynt in their order. It also decreased the yield by 700 kg/ha and 291.7 kg/ha on unsprayed plot of variety Degaga respectively at Farta and Tach gaynt.
The investigation showed that all faba bean varieties were infected by the newly emerged faba bean gall disease at both locations. The plot subjected to foliar spray was reduced the faba bean gall diseases severity in all varieties including local check at all dates of assessment as compare to unsprayed plot at both sites. In general, Bayleton foliar spray on faba bean varieties has a significant effect in reduction of the severity of faba bean gall disease at both locations. Therefore, foliar spray using Bayleton at rate of 1.5 a.i/ha with variety Adet-Hana, Bulga70 and CS20DK, Nc58 and Kasa provided better yield and the fungicide could be recommended as the best management option for control of faba bean gall disease in south Gondar zone, Northwestern Ethiopia.
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