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Use of resistant genotype is considered to be the most feasible means to mitigate sorghum grain damage by grain mold in a climate favourable for fungal invasion and subsequent mycotoxin contamination. Field-based experiments were conducted at Babile and Haramaya for two consecutive cropping seasons to evaluate 20 sorghum genotypes for their reaction to grain molds as well as aflatoxin and fumonisin contamination. Aspergillus flavus and Fusarium verticillioides with spore concentrations of 106 ml-1 were inoculated by spraying into the inflorescence, when the anther emerged from approximately 50–70% of the spikelets. Mycotoxin analysis was done using enzyme-linked immunosorbent assay (ELISA). The results revealed that the sorghum genotypes evaluated for their reactions to A. flavus and F. verticillioides inoculation had significantly different responses. Variety Melkam was identified as a susceptible genotype to F. verticillioides and variety Birhan was found resistant to both fungal species. Variety Long Muyera was the most susceptible to both toxigenic fungi. Long Muyera was contaminated with aflatoxin B1 and total fumonisin above the maximum tolerable limit of 10 µg kg-1 and 2000 µg kg-1, respectively. Though the sorghum genotype Birhan was resistant to A. flavus, its aflatoxin B1 contamination was relatively high. In this study, it was recognized that none of the tested sorghum genotypes exhibited possession of multiple resistance to the inoculated toxigenic fungi. Therefore, it is commendable to select and use genotypes, which are resistant to specific toxigenic fungi for a particular location, where the problem exists.

Sugarcane is one of the most important sugar crops grown commercially and by small-scale farmers in Ethiopia. However, production of this crop is adversely affected by biotic constraints among which sugarcane smut, caused by Sporisorium scitamineum, is one of the most important diseases. Field surveys were conducted once in eight sugar estates (Arjo, Beles, Fincha, Kesem, Kuraz, Metehara, Tendaho, and Wonji) of Ethiopia from 2017 to 2019 to determine the smut distribution, incidence, severity, and association of biophysical factors with smut incidence and severity. A total of 311 fields were assessed in eight sugar estates. Logistic regression was used to analyze the association of independent factors with smut incidence and severity. The results revealed that sugarcane smut prevailed in 62.7% of the fields. Moreover, mean smut incidence and severity varied significantly among the surveyed fields and sugar estates. High smut incidence (>5%) and severity (>25%) were highly associated with Kesem, Kuraz, Metehara, and Tendaho sugar estates; NCo 334, Natal, Mexican, and Guyana sugarcane varieties; altitude of ≤1000 m above sea level (m.a.s.l.); ratoon crop; heavy and intermediate-textured soils; and tillering growth stage. On the other hand, low smut incidence (≤5%) and severity (≤25%) had high probability of association with Cuba and Barbados sugarcane varieties; furrow irrigation; altitude of 1001–1500 m.a.s.l.; and weed-free and fertilizer applied fields. In conclusion, the presence of high intensity of sugarcane smut in most surveyed areas implies a stringent need for the development of integrated smut management that incorporates resistant varieties, fungicide and biofungicide seedcane treatment at planting, threshold information for ratooning, ecological-based varietal allocation and recommended crop husbandry for effective and efficient management of smut, and sustainable sugarcane production and productivity in the study areas. Therefore, research should give attention to the development of viable and economically feasible integrated smut management programs.

Garlic rust is the most destructive and production limiting disease in all garlic growing areas of Ethiopia. Thus, a field survey was conducted to assess the distribution, importance and association of agro-ecological factors with garlic rust epidemics in eastern Amhara, Ethiopia, during the 2018/19 cropping season. A survey of garlic rust was held in four major garlic producing districts in the main rainy and irrigation seasons. A total of 137 farms (78 farms in irrigation and 59 farms in main rainy season) were assessed in the study. The results confirmed 100% prevalence of garlic rust though incidence and severity varied among districts. High disease incidence varied from 87.50% at Lasta to 96.60% at Gidan district. Conversely, garlic planting at Meket reduced disease severity by 79.84, 77.85 and 73.98% compared with Gidan, Lalibella Zuria and Lasta district, respectively. The associations between disease parameters and agro-ecological factors were assessed using a logistic regression model. High disease incidence (> 80%) and severity (> 40%) had a high probability of association with districts Gidan, Lalibella Zuria and Lasta, irrigation season, maturity growth stage, medium altitude range, poor management practices, sole cropping and in some preceding crops in the reduced regression model. Moreover, high (> 80%) disease pressure was strongly associated with dense plant and weed populations in the model. Thus, the field survey has confirmed that garlic rust was highly distributed and was a major constraint in the study areas. This could imply the need for developing effective and feasible disease management options in the study areas and related agro-ecological environments.

Root-knot nematode, Meloidogyne incognita, is the major limiting factor in tomato production in many regions of the world, including Ethiopia. Hence, there is a need for development of root-knot nematode management methods that are cheap and environmentally friendly. A greenhouse experiment was conducted with an objective to evaluate the integrated effect of botanicals and intercropping against M. incognita on tomato. The experiment was laid out in a 2×3×3 factorial completely randomized design (CRD) with four replications. About 30 ml of lantana leaf extract (at 5% v/v concentration) was applied one week before transplanting of convert to days tomato cv Moneymaker seedlings into 20 cm diameter size pot containing 2 kg sterilized soil. Seeds of mustard and garlic were sown directly into the plastic pots on either side of the tomato seedlings. M. incognita was inoculated at the rate of 1000 and 2000 second-stage juveniles (J2) per pot one week after transplanting. A control without any nematode treatment was also maintained. The results revealed that combination of lantana leaf extract and tomato-mustard intercropping at both nematode inoculum levels proved to be the most effective treatment that reduced the soil and root population of the nematode. Application of lantana leaf extract alone and in combination at both inoculation levels showed superiority on tomato growth characteristics. Hence, this ecofriendly approach could be incorporated into integrated nematode management in tomato. However, further research is needed to evaluate their efficacies under field conditions. Key words: Egg-mass, gall, garlic, juvenile, Lantana camara, mustard, management.

Leaf rust caused by the pathogen Puccinia triticina is one of the important diseases of wheat in Ethiopia; and yield loss due to this disease has reached up to 75%. A study was carried out to detect physiologic races of the pathogen from some parts of Bale, Gondar and Shewa and to identify seedling resistance of Ethiopian durum cultivars. Twenty-four mono pustule isolates were made, and out of those, only three P. triticina races namely; BBBB, BBBN and BBBQ were identified. Race BBBN was detected for the first time in Ethiopia and was less virulent to commercial durum wheat cultivars than BBBQ and BBBB, while phenotype BBBB was relatively highly virulent to Ethiopian durum wheat and it infect 42.5% of the tested cultivars and is not virulent to Thatcher and Thatcher isoline leaf rust differential cultivars. Thirty six commercial durum wheat cultivars and three land race cultivars were evaluated against those three leaf rust pathogen races at seedling stage in the green house at Debre-Zeit Agricultural Research Center. Varieties Utuba, Lelisa, Worer, Bekelcha, Tate, Filakit, Foka, Alem tena, Hitosa, Kilinto, Denbi, Ude, LD-357, Boohai, Mukuye, Robe, Mangudo and Assasa exhibited resistance reaction (; to 2) to all the three leaf rust races, while the rest showed susceptible at least to one of the race. All the three land race cultivars (Mcd4-12, Mcd4-32 and Mcd7-42) were susceptible to all pathogen races. Key words: Durum wheat, leaf rust, Puccinia triticina, race, seedling resistance.

Groundnut (Arachis hypogaea L.) is the 13 and 4th most important food and oil seed crops in the world. Groundnut is a source of vitamin E. However, due to low soil fertility, drought stress, fungal diseases and lack of appropriate management, production has been constrained qualitatively and quantitatively in the study area. Trichoderma harzianum and wheat straw mulch could increase the growth performance of groundnut and soil moisture content at maturity and near harvest to overcome terminal drought stress. Therefore, a field experiment was conducted in Rama, Central Zone of Tigray, Northern Ethiopia, to evaluate the effects of wheat straw mulch and T. harzianum on yield and yield components of groundnut genotypes (ICGV00308, ICIAR19BT, Werer-961 and Rama local). The treatments were arranged in factorial randomized complete block design (RCBD) with three replications. Results showed that groundnut genotypes, T. harzianum and wheat straw mulch highly significantly (p

Various biotic, abiotic and socio-economic factors negatively affect the productivity of the crop. Among these, a new disease known as Faba bean galls (Olpidium viciae) has become a serious threat to faba bean production and productivity in highland areas of central and northern Ethiopia. Thus, field experiment was conducted in Lay Gorebela and Mush to assess the efficacies of fungicides for the management of faba bean gall under natural infection. Six fungicides were evaluated alongside control in randomized complete block design in three replications. Fungicides showed different levels of efficiency at both locations in both seasons. In 2014/15, the highest percent severity index and area under disease progress curve were calculated from control plots at both locations. At Lay Gorebela, higher grain yields were recorded from Metalaxyl 8% + Mancozeb 64% WP and Triadimefon 250 g/L sprayed plots whereas plots sprayed with Metalaxyl 8% + Mancozeb 64% WP gave higher yield at Mush. Similar trends in percent severity index and grain yield were observed with control treatment in 2015/16. Percent severity index and area under disease progress curve were negatively correlated with grain yield and positively correlated with each other at both locations and seasons. Partial budget analysis indicated as Triadimefon 250 g/L and Metalaxyl 8% + Mancozeb 64% WP were cost-effective. The chemical treatment could be used as a short-term control strategy, and a component in integrated management of faba bean galls.

Biological control of sugarcane smut (Ustilago scitaminea Syd.) using Trichoderma isolates is one of the untapped potentials in Ethiopian sugarcane plantations. To this end, this study was carried out with the objective to identify potential native Trichoderma isolates for the management of sugarcane smut. A total of 120 soil samples were collected from Kesem, Metehara, and Wonji sugarcane plantation fields. Consequently, 21 Trichoderma isolates were recovered from the samples, and in-vitro antagonist study of Trichoderma isolates against U. scitaminea was done using dual culture technique on fresh PDA. Among the native isolates, 12 of them revealed a pathogen suppression potential of >90% at 7 days after inoculation and most of them had higher pathogen suppression than the commercial isolate. However, five of the isolates were selected as potential candidates based on distinct suppression features, growth rate, and antagonistic performance. Identification of the five effective Trichoderma isolates (WI4-27, MKI2-k17, MI3-m33, WI12-25, and MKI3) was done based on macroscopic and microscopic characteristics. Thus, the isolates were identified as T. harzianum, T. asperellum, T. viride, T. viride, and T. harzianum, respectively. Accordingly, these isolates could be used as one component of integrated smut management practices once a study on compatibility with fungicides, in-vivo efficacy test against smut, and substrate selection for mass production of the isolates were commenced.

Groundnut (Arachis hypogaea L.) is an important cash crop in the lowland areas of Ethiopia. However, prevalence of Aspergillus invasions and subsequent aflatoxin contamination compromises the quality of groundnut kernels. This study was conducted to evaluate the effect of farm yard manure (FYM) and seed treatments against Aspergillus species pod colonization and aflatoxin accumulation under field conditions. The inhibitory efficacy of Trichoderma species as biocontrol agents was also assessed. A total of 20 treatment combinations including pre-planting applications of FYM at 0, 2.5, 5, and 7.5 tons/ha and seed treatments with carbendazim at 2 g/kg and mancozeb at 3 g kg-1, and Trichoderma harzianum and Trichoderma viride each at 5 g/kg as well as untreated seed as control were used. Treatments were laid out in a randomized complete block design (RCBD) in three replications. The experiment was conducted in two consecutive seasons (2014 and 2015) at Babile Haramaya University sub-Research Station. The highest pod and seed yields (1901.5 and 1281.5 kg/ha, respectively) were recovered from plots treated with T. harzianum at 5 g/kg seed. A. flavus was abundantly recorded in control plots, which could be responsible for the high aflatoxin B1 (5704.4 µg/kg) and B2 (2219.0 µg/kg) contamination. However, plots treated with T. harzianum at 5 g/kg seed and FYM at 5 tons/ha + T. harzianum at 5 g/kg were free from aflatoxin. Integrations of T. harzianum as biocontrol seed treatment and soil amendment with FYM were effective in the pre-harvest management of Aspergillus spp. and aflatoxins contamination. Key words: Aflatoxin, Aspergillus, carbendazim, farm yard manure, groundnut, mancozeb, Trichoderma species.

Turcicum leaf blight (TLB) (Exserohilum turcicum) is a major disease affecting maize production in western Ethiopia. The objectives of this study were to determine the effect of maize varieties integrated with fungicides on epidemics of turcicum leaf blight; to determine the effect of turcicum leaf blight severity on yield and yield components of maize; and to assess the cost and benefit of using fungicides. The field experiment was conducted at Bako Agricultural Research Center in 2014 main cropping season using six maize varieties (BH-540, BH-543, BH-546, BH-660, BH-661 and AMHQ-760) integrated with foliar sprays of the systemic fungicide propiconazole (Tilt) at the rate of 350 ml ha-1and the contact fungicide mancozeb (Dithane M-45) at 2.6 kg ha-1. The experiment was arranged in 3 × 6 factorial combinations in split plot design with three replications. A pinch of ground maize leaf infected by E. turcicum was inoculated at third-fifth leaves. Unsprayed plots were left as control or check for each variety. Disease severity was scored using 1 to 5 scale on 12 randomly-tagged plants in the central rows. Integration effects of varieties with fungicides significantly affected the grain yield and thousand kernel weight (TKW) of maize varieties. The highest (11383 kg ha-1) grain yield was obtained from propiconazole-treated hybrid maize variety BH-546. Turcicum leaf blight resulted in grain yield losses of up to 40.7% on the unsprayed plots of the susceptible variety BH-543. Percent severity index, AUDPC, incidence and disease progress rates were negatively correlated with yield components regardless of grain yield loss. The highest marginal benefit (ETB 48,801.28 ha-1) and marginal rate of return (ETB 6.33) were obtained from propiconazole-treated varieties BH-543 and BH-546, respectively. This study contributes to integrated TLB management options, and to make a valid recommendation for TLB management strategy, the study should be repeated over years and locations where TLB of maize is of major economic importance. Key words: Exserohilum turcicum, fungicides, percent severity indices, maize-varieties, yield.

Barley (Hordeum vulgare) is an economically, nutritionally and industrially important cereal crop worldwide. Ethiopia is believed to be the center of origin and diversity of the cultivated barley crop. The crop has been cultivated in the country since time immemorial. The midlands and highlands of Ethiopia are suitable for barley cultivation. However, there are many biotic and abiotic factors that reduce production and productivity of the crop in Ethiopia and elsewhere. Of the various fungal plant diseases limiting barley productivity, loose smut (Ustilago nuda) is one of the major cosmopolitan and destructive seedborne pathogen in many barley-producing countries in the world. This piece of work was undertaken to: 1) review the economic importance and ecological requirements of barley and extent of grain loss due to barley loose smut; 2) review the biology and ecological requirements of the pathogen leading to epidemics; and 3) compile the management options for sustainable barley production and productivity. To achieve these objectives, data and information were gleaned from scientific journal publications, PhD dissertations, Master’s theses, research reports, books and book chapters, proceedings and symposia papers, relevant compendia, internet resources, personal communications, and similar other resources. From the reviews made, it could be deduced that barley loose smut on average causes estimated grain yield losses that range from 25 to 30% in the world. The systemic pathogen is embedded in the scutellum part of the embryo and easily transmitted to the next cropping season. The pathogen sori commonly replace the spike during anthesis and healthy ears are infected at flowering through the teliospores blown by wind. Warm soil when seedlings emerge is more conducive to loose smut than cold soil; however, moderate temperature (15 to 22 oC) and damp cloudy weather or heavy rainfall at flowering time are the preconditions required by the pathogen for heavy infection because of elongated or extended period of open flowers. Barley loose smut can be better managed through the use of proper cultural practices in integration with hot water and solar heat seed treatment, use of resistant varieties, and effective systemic fungicides, like Azoxystrobin, Carboxin, Difenoconazole, Mancozeb, Propiconazole, Tebuconazole, Triadimenol, and Triticonazole. It could, thus, be concluded that barley loose smut is a very important disease that seriously affects barley production and productivity worldwide, but can be reasonably managed through the use of smut-free seed, certified seed, host resistance, and hot water/solar heat or systemic fungicidal seed treatment or their integration., East African Journal of Sciences, Vol. 13 No. 1 (2019): East African Journal of Sciences

The reaction of eighteen hot pepper genotypes to Meloidogyne incognita and M. javanica populations from Ethiopia was evaluated under glasshouse condition. In addition, a laboratory experiment was conducted to examine the effect of root exudates on hatching of the nematode populations. None of the pepper genotypes were found immune. However, ‘Acc.003’ and ‘Melka Awaze’ were found resistant, while ‘Oda Haro’ was susceptible to all populations tested. The hatching assay indicated that the root exudates had no significant effect on cumulative hatching. However, the time in which half of the population hatched varied significantly among the genotypes. After validation under field condition, the genotypes that were found resistant to both M. incognita and M. javanica could be used in areas infested with species complex in the country to enhance hot pepper productivity.

Fusarium species are the most toxigenic fungal pathogens responsible for various diseases in maize and other food grains. Fusarium infection in maize contaminates harvested grain with mycotoxins such as Fumonisins. Fumonisins contamination in maize can cause yield loss and health problems in humans and animals. The study aims to assess Fusarium species and fumonisin contamination in fresh harvested and three-month stored maize samples collected from five major maize growing districts of eastern Ethiopia, during the 2017/18 cropping season. Fusarium species were isolated and identified using direct plating technique, while Fumonisin concentration was analyzed by ELISA protocols. Higher numbers of Fusarium isolates were recorded in fresh harvested (2376 isolates) than in three-month stored maize samples (1897 isolates). The isolates were recorded in 97 and 90% of fresh harvested and three-month stored maize samples, with an average kernel contamination of 62 and 50%, respectively. A total of seven Fusarium species were identified from the samples. The most prevalent species was F. verticillioides in both samples, followed by F. proliferatum and F. subgulitnans in fresh harvested and three-month stored samples, respectively. All fresh harvested and 92% of three-month stored maize samples were found fumonisin-positive (ranging from 105 to 5,460 )ig kg '). In all districts fumonisin concentration recorded in fresh harvested samples (2,509 j.ig kg-1) was higher than that of three-month stored maize samples (1,668 Hg kg-1). Prevalence of different Fusarium species could indicate the possibility of maize contamination by other mycotoxins. Therefore, further studies are needed considering different factors over different cropping years. Findings of the study could serve as foundation for any other study on Fusarium species and fumonisin contamination in maize in Ethiopia to design appropriate management strategies.

This study was conducted to assess major Aspergillus species and aflatoxins associated with groundnut seeds and cake in Eastern Ethiopia and evaluate growers’ management practices. A total of 160 groundnut seed samples from farmers’ stores and 50 groundnut cake samples from cafe and restaurants were collected. Fungal isolation was done from groundnut seed samples. Aspergillus flavus was the dominant species followed by Aspergillus parasiticus. Aflatoxin analyses of groundnut seed samples were performed using ultra performance liquid chromatography; 22.5% and 41.3% of samples were positive, with total aflatoxin concentrations of 786 and 3135 ng g−1 from 2013/2014 and 2014/2015 samples, respectively. The level of specific aflatoxin concentration varied between 0.1 and 2526 ng g−1 for B2 and B1, respectively. Among contaminated samples of groundnut cake, 68% exhibited aflatoxin concentration below 20 ng g−1, while as high as 158 ng g−1 aflatoxin B1 was recorded. The study confirms high contamination ...

Natural contamination of sorghum grains by aflatoxin B1 and total fumonisin and their producing toxigenic fungi has been studied. A total of 90 sorghum grain samples were collected from small-scale farmers' threshing floors and 5-6 months later from underground pits during 2013 harvest from three districts of East Hararghe, Ethiopia. Mycotoxin analysis was done using enzyme-linked immunosorbent assay (ELISA). The limits of detection were in the range 0.01-0.03 μg kg-1. The results revealed that all sorghum grain samples were contaminated with both Aspergillus and Fusarium species. Aflatoxin B1 was detected at levels ranging from

Coffee berry disease (CBD) caused by Colletotrichum kahawae causes yield loss of more than 50% if not controlled with the appropriate fungicides or/and resistant cultivars. This study was aimed to screen indigenous coffeeassociated microorganisms for their inherent antagonistic potential. From a total of 4323 microorganisms isolates tested, over 3% exhibited remarkable inhibition against C. kahawae. 13 bacterial isolate showed maximum inhibition of mycelial growth against the fungal pathogen tested. Among the yeast and fungal isolate 11 and 9 islates were most antagonistic to C. kahawae respectively. Twenty four isolates produced antibiosis, 5 isolates showed micoparacitic activity and 4 islates produced enzyme. The result indicated the species richness of indigenous coffee in Ethiopia which can be explored for their beneficial application as biological control. The in vitro results provide the first evidence of an antagonistic effect of coffee associated microorganisms against the CBD and potential of all bacterial, yeast and fungal groups for biological control of CBD.

Samples of saved barley (Hordeum vulgare) seed were collected at sowing and threshing time from mid-altitudes and highlands of southern Ethiopia in 2009, and were examined in the laboratory and field condition to determine the status of seed quality. The seed samples included farmers’ cultivar ‘Horsiso’ (two-rowed), ‘Nuro’ and ‘Melo’ (six-rowed). This study revealed that saved barley seeds were not vulnerable to insect pests. However, Alternaria, Aspergillus, Cladosporium. Epicoccum, Fusarium, Helminthosporium, Penicillium, Trichoderma, Trichothecium spp. and Ustilago hordei were detected. The seed samples collected at sowing showed lower standard germination (SG) and higher electrical conductivity (EC). All cultivars had SG above 80%, nevertheless field emergence index (FEI) showed 15.22 up to 37.35%, which is less than the ideal plant population. This indicates differences among cultivars in seed quality deterioration during storage. SG was positively correlated (r = 0.678) with field emergence (FE); EC showed a negative correlation with FE (r = -0.347) and SG (r = -0.233). In conclusion, farmers’ saved seed was found to be low in quality. Therefore, farmers’ seed management practices need to be improved to retain the seed quality and enhance productivity. Key words: Field emergence index, fungi, germination, seed health.

Natural contamination of sorghum grains by aflatoxin B

Sorghum grain stored in traditional underground pits was sampled from seven districts of Hararghe, eastern Ethiopia, representing lowland, intermediate and highland zones, from February to August 2001, and was analysed at the International Livestock Research Institute (ILRI) for changes in chemical composition over time. Samples were also taken from a replicated aboveground bin and pit storage experiment at Alemaya University campus at 2-month intervals from March 2000 to August 2001 and analysed in a similar manner. The effect of geographic location on chemical composition was significant, but there were differences in the sorghum varieties grown. The organic matter (OM) content of grain samples from pits in the lowlands was lower than those from the highlands. The crude protein (CP) and OM contents of samples from the seven districts did not change in 7–9 storage months. The OM content decreased and the CP slightly increased over time in samples from soil pits without any lining material on Alemaya University campus. The OM content decreased from 97.8 to 91.6%; and CP increased from 10.1 to 11.2% in these samples over a 17-month period. Soluble carbohydrate (SCHO) content significantly decreased over time in samples from the districts (from 2.4 to 1.2% by 7 months) and in samples from soil pits on campus (from 2.4 to 1.9% after 7 months and to 0.97% after 17 months). There was no significant change in the organic matter, CP and SCHO contents in samples taken from the cemented aboveground bin, cement- and dung-lined pits at the Alemaya campus, all of which were lined with polythene sheeting. From these data, we conclude that the combination of storage methods, storage period, geographic location and/or sorghum variety affected grain quality. Grain storage in traditional underground pits for long periods does lead to grain deterioration. The use of improved grain storage structures maintains the grain quality and nutritional value of sorghum for a reasonably long period.

Garlic (Allium sativum L.) is one of the most important crops grown in Bale highlands. Garlic rust caused by Puccinia allii is the major disease of garlic in almost all garlic producing regions of Ethiopia. To determine the effects of this disease on yield and yield components of garlic, field experiment was conducted using two garlic varieties, namely the improved variety MM-98 and a local variety at Sinana Agricultural Research Center (SARC), Ethiopia. Five different spray intervals of a systemic fungicide, Tebuconazole (Folicur), were used to create different levels of rust severity. The plots were arranged in Randomized Complete Block Design (RCBD) in factorial arrangement with three replications. There was severe garlic rust development on the plots. The spray intervals created significantly different rust severity levels. The disease inflicted total yield losses as high as 58.75. The results from this study confirmed that garlic rust can cause considerable losses on the crop in areas where it is prevalent. Hence, application of control measures to minimize the loss is justifiable. Fungicide can be used to effective control of the disease. Its application should be started at very low level of severity and frequent application should be used if the prevailing weather condition seems very conducive for development of the disease. But, the frequency of application should be based on economic analysis with consideration of the costs of fungicide application and return from yield recovery.