Crop Protection

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    DETERMINATION OF CRITICAL PERIOD OF WEED CONTROL ON GINGER (Zingiber officinale Roscoe) AT SELAM, SOUTH WEST ETHIOPIA
    (Hawassa University College of Agriculture, 2024) MULUKEN ASFAW WOLDE
    Ginger is an important spice and cash crop in Ethiopia. However, its production is constrained by different abiotic and biotic factors; weed is one of the most important biotic factors which reduces yield of ginger. Therefore, this study was conducted in 2023 main cropping season at Yeki, South Western Ethiopia to determine the critical period of weed competition and yield loss. The trial had twenty treatments in two sets, namely weedy set and weed-free set, each sets comprising weed competition durations of 15, 30, 45, 60, 75, 90, 105, 120 and 135 days after crop emergence and weedy control as well as weed-free plot throughout crop life cycle. The trial was laid out as a randomized complete block design with three replications and the treatments were assigned randomly to experimental units within a block. The weed and crop data were collected and subjected to analysis of variance by using SAS software. The most dominant species was Bidens pilosa L. (Asteraceae family) with density and relative density of 73 m -2 and 18.4%, respectively. Weed density, weed dry biomass, yield components and yield of ginger were significantly affected by weed competition durations. Uncontrolled weed growth reduced the yield of ginger by 93%. The beginning of CPWC (Critical period of weed control) based on 10% AYL (acceptable yield loss level) occurred at 180 GDD (Growth degree days), which was corresponded to 26 DAE (Days after emergence). The end of the CPWC at 10% AYL occurred by 1150 GDD or 143 DAE. To prevent more than 10% yield loss, the efficient weed contr ol period for ginger at Selam area could be accomplished by keeping the crop weed free between 26 to 143 DAE. Further research in different physiographic, edaphic and climatic conditions is recommended.
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    CHICKPEA WILT (FUSARIUM OXYSPORUM F. SP. CICERIS) INTENSITY IN NORTH SHOA, ETHIOPIA, AND EVALUATION OF CHICKPEA GENOTYPES AGAINST THE PATHOGEN
    (Hawassa University College of Agriculture, 2024) Kalkidan Wudu
    Chickpea (Cicer arietinum L) is an important pulse crop in Ethiopia. However, chickpea Fusarium wilt (CFW) is the major constraint on its production. Thus, this study was designed with the following objectives: to assess the prevalence, incidence, and association of biophysical factors with CFW in North Shoa Ethiopia and evaluate chickpea genotypes against the pathogen. For this purpose, a field survey was conducted during the 2022 main growing season. Descriptive statistics and logistic regression model were used to analyze association of the disease with different biophysical factors. Fungal isolation was done out by placing small bits of infected root on PDA at Hawassa University Crop Protection Laboratory. Colony characteristic of the fungus were studied on PDA. The spores were obtained by growing the fungal pure culture on SNA. The pathogen was morphologically identified using appropriate identification manual. Sixteen chickpea genotypes were screened for their reaction to CFW under a lath house condition. The survey results revealed that CFW was prevalent in all the surveyed areas, with different levels of incidence. A higher CFW incidence (43.2%) was recorded at Siyadebrna-wayu district, while a lower (34.8%) CFW incidence was recorded at Ensaro district. High mean CFW incidence was recorded on chickpea sown late August (39.2), desi-type chickpea (39.7), fields previously sown with legumes (43.9),lower altitudes (40.3), pod setting stage (41.2) and weedy fields (45.8%). In the model, crop growth stage, district, previous crop, and weeding practice were significantly associated with FOC incidence. The highest (>38%) wilt incidence was highly associated with weedy fields. The fungal mycelia were white in color. The macro conidia were straight to slightly curve with three septa. While the micro conidia were oval and no septation, Based on these, the pathogen was identified as F. oxysporum f. sp. ciceris (FOC). Three chickpea genotypes (DZ-2012-CK-0312 followed by FLIP12-138c and ICCMABCD-21) were moderately resistant, while nine chickpea genotypes were susceptible. The result of the current study confirmed that CFW was highly prevalent in the study areas. Thus, designing effective CFW management options by targeting important biophysical factors that influence disease pressure and using chickpea varieties that have some degree of resistance to the disease is essential. It would be better to repeat the late house experiment for one or two times and further tests under field conditions to come up with sound recommendations.
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    EFFECT OF INTERCROPPING MAIZE VARIETIES WITH DIFFERENT CROPS ON FUNGAL CONTAMINATION OF MAIZE GRAIN IN DOREBAFANA WOREDA SIDAMA REGION
    (Hawassa University College of Agriculture, 2023) TESHALE TAFESSE LINTAMO
    Maize (Zea mays) is attacked by many diseases in the field as well as in the storage. Fungi are among the principal causes of deterioration and yield loss on farmers’ maize. The present study was aimed to identify the effect of different crop combinations in the intercropping systems and maize varieties on fungal contamination of maize grain. The experiment was conducted at dorebafana woreda of Sidama region at rukesa suke kebele and the laboratory analysis was conducted at Hawassa University, College of Agriculture, Plant Protection Laboratory. Three maize varieties (Limu, Kurtu and BH 540) and four cropping systems (Maize sole, Maize with haricot bean intercropping, Maize with mung bean intercropping, maize with sweet potato intercropping) were the treatments. The experiment was laid using completely randomized block design (RCBD) with three replications. For each treatment a sample of 100 seeds were tested for fungal contamination using the blotter technique in the laboratory. A total of six fungal genera consisting of nine species of fungi were isolated from maize grains collected from the experimental field. Fusarium sppwere the most frequently isolated ones followed by Aspergillus spp. The fungal contaminations of maize grains were significantly different (p<0.05) between sol cropping and intercropping treatments. The sol cropping had higher fungal contamination level compared to intercropping treatments. On the other hand, i ntercropping maize with haricot bean has resulted in the lowest fungal contamination followed by intercropping maize with mung bean. Fusarium spp had resulted highest contamination level followed by Aspergillus spp, Penicillium spp, Alternaria spp, Trichoderma spp, and Rhizopus sp. Low level of fungal frequency was recorded on limu maize variety. Whereas the variety kurtu had the highest level of fungal contamination. The result of the present study revealed that maize cropping system affects the level of fungal contamination. In the present study it is also seen that maize varieties tested vary in their resistance to fungal contamination. Thus, good agronomic practices like intercropping and variety selection can play determinant role in reduction of fungal contamination in maize grain. Based on the finding of present study, intercropping maize with haricot bean and variety limu can be used to reduce effect of maize contamination with fungi.
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    EVALUATION OF WEED MANAGEMENT PRACTICES ON MUNG BEAN (Vigna radiata L.) YIELD AND YIELD COMPONENTS AT TEPPI, SOUTH WEST ETHIOPIA.
    (Hawassa University College of Agriculture, 2023) MULUKEN ASMAMAW
    Mung bean is characterized by fast growth, low water requirement, and excellent soil fertility enhancement through nitrogen fixation. The productivity of mung beans is decreased by weeds, diseases, and insect pests. Weed competition is among the most important factors responsible for the low yield of mung bean by as much as 87%. Therefore, this study was initiated to evaluate the effect of weed management practices on yield and yield components of mung bean (Vigna radiata L.). Nine control options (One-hand weeding at 4 weeks after sowing, complete weed control, No-weed control, Haloxyfop-R-methyl ester at 0.3, 0.6, and 0.3 kg ai ha⁻¹ + One-Hand weeding at 4 weeks after sowing, pendimethalin at 1, 1.5 and 1 kg ai ha⁻¹ + One-Hand weeding at 4 weeks after sowing) were compared in randomized complete block design in three replications. The application of herbicides and the weeding practices significantly reduced the broadleaf, sedge, and grass weeds. The highest grain yield (0.98 ton ha⁻¹), total dry biomass (2.82-ton ha⁻¹), and plant height (43.76 cm) were obtained in complete weed control followed by application of pendimethalin at 1.5 kg ai ha⁻¹ (0.92 ton ha⁻¹), total dry biomass (2.78 ton ha⁻¹), plant height (50.03 cm). The lowest grain yield (0.36 ton ha⁻¹), total dry biomass (1.59-ton ha⁻¹), and plant height (64.63 cm) were recorded from the No-weed control plot. The highest number of pods per plant, number of seeds per pod, and weight of a hundred seeds were recorded in complete weed control and application of pendimethalin at 1.5 kg ai ha⁻¹. The results indicated that complete weed control and/or control with pendimethalin at 1.5 kg ai ha⁻¹ were the best management practices to maximize economic benefit. Thus, we recommend using the applications of one of the two weed control methods for the management of weeds in mung bean in Teppi, South West Ethiopia, and locations with similar agroecologies of Teppi.
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    ASSESSMENT OF MANGO YIELD LOSS AND FRUIT FLY (DIPTERA, TEPHRITIDAE) MANAGEMENT PRACTICES OF MANGO PRODUCING FARMERS IN ARBAMINCH ZURIA WOREDA, ETHIOPIA
    (Hawassa University College of Agriculture, 2023) ESSEYNESH ALEMAYEHU FENTAHUN
    Mango (Mangifera indica L.) is a valuable food and cash crop that contributes to agricultural development agents. This study was conducted to assess mango fruit yield loss due to fruit flies (Diptera, Tephritidae) and management approaches by farmers in Arbaminch, Zuria Woreda. Three administrative kebeles, viz., "Chano mile," "Lante," and "Kolla shele," were purposively selected from the Arbaminch Zuria Woreda. Both survey and assessments were collected. Sixty respondents were interviewed using semi-structured questionnaires. Mango variety, mango pests and their economic importance, abundance, infestation, yield loss estimation, management practices applied for fruit flies and farmers’ willingness to pay for the best management options were assessed. The results were analyzed using SPSS software and presented using descriptive statistics; and the variables were tested by chi-square test. Farmers in Arbaminch Zuria produced five types of mango varieties, with local mango varieties being the most common. All the respondent farmers (100%) had the local mango variety. Common mango fruit pests like fruit flies, white mango scales, mealybug, grivet monkeys, speckled birds, and weaver ants as an indirect pest which may interfere with natural enemies were recognized. The fruit fly species Bactrocera invadens was trapped in the field with the abundance of 43 flies per trap per day (FTD). Fruit flies caused 94.28±10.21 Kg and 29.84% of loss in fruit yield per tree. The mean monetary loss value was estimated to 471,412.3±51010.9 birr/ha/year. The highest infestation was recorded in the peak harvest time (February) which was 40.78%. To overcome the fruit fly damage, mango producers applied different management methods. Of these methods, Methyl Eugenol trapping, field sanitation, burying infested fruits, and smoking the field were the most common. It was concluded that mango fruit flies are the most economically important insect pests of mango in the Arbaminch Zuria Woreda. The study recommends the evaluation and release of less susceptible mango varieties to fruit fly infestation, white mango scale, and other pests and diseases, evaluate the farmers’ practices. And new methods of management to develop a holistic integrated pest management system
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    SURVEY ON FUNGAL AND AFLATOXIN CONTAMINATION OF STORED MAIZE (Zea mays) GRAINS IN SOUTHERN ETHIOPIA
    (Hawassa University College of Agriculture, 2022) MEMHIRU MEKISO MADEBO
    Maize (Zea mays L.) is attacked by more than sixty diseases and a number of species of insect pests and microorganisms in the field as well as in the storage. Fungi are among the principal causes of deterioration and yield loss on farmers’ maize during the storage period. Among the storage fungal pathogens Fusarium, Aspergillus, and Penicillium are the most predominant species attacked maize grain and resulting in production of harmful products of Mycotoxins. The study was conducted at the Hawassa University College of Agriculture in plant pathology laboratory. The study was aimed to study effect of storage duration and storage type on fungal contamination and assessments of aflatoxin contamination of maize grains in southern Ethiopia . A total of 165 Maize grains samples were collected from different storage type and storage duration in southern Ethiopia, in 2019/2020. A total of seven fungal genera consisting of twenty one species of fungi were isolated from maize grain by using morphological characterstics; Fusarium spp. were most frequently isolated, followed by Aspergillus spp.The fungal contaminations of maize grains were significantly different (p<0.05) increased with storage periods. At the last six months of storage, the contamination of the Fungal isolates revealed that Fusarium spp had the highest contamination of 43.6% followed by Aspergillus spp, 28.6%, then Penicillium spp 5.27%, Alternaria spp 4.12%, Rhizopus spp 3.08%,Tricoderma spp 1.65% while the least contamination of 1.22%, was Cladosporium spp. The highest contamination of Fusarium spp (44.79%) and Aspergillus spp (24.98) were recorded in storage basket whereas the minimum contamination of Fusarium spp (35 %) and Aspergillus spp (15.5%) were obtained from plastic storage. As a result of this research, the Plastic container storage was determined to be more appropriate for protecting the stored maize grains from fungal attack during the storage periods and the stored grains have low fungal contamination until initial t o six months. Therefore, storage Basket, storage Crips, storage Sacks and Gombisa storages were inadequate for protecting stored maize from fungal attacks. Total aflatoxins has quantified from the maize samples collected from different maize growing areas in southern Ethiopia by using Enzyme Linked Immune Assay (ELISA) Kit. The result reveal that the mean 32(66.7%) of 48 maize grain sample were positive for aflatoxin contamination with levels of aflatoxin concentration ranging from 0.21-18.06µg/kg. The average aflatoxin concentrations detected in the present study were below the US Food and Drug Administration (FDA), the World Health Organization (WHO) maximum limit of total aflatoxin 20μg/kg. The EU has maximum limit of 4 μg kg−1 total aflatoxin in cereal for direct human consumption. Thus, most of the samples contaminated with aflatoxins in this study are not suitable for human consumption by the EU standards.
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    INVESTIGATION OF ANTI MICROBIAL ACTIVITY OF TRADITIONAL BOTANICAL PESTICIDES COLLECTED FROM SIDAMA AREA, SOUTHERN ETHIOPIA
    (Hawassa University College of Agriculture, 2022) Getachew Binchamo Anno
    Indigenous knowledge and systems of crop protection are at risk of extinction today because of the rapidly changing natural environments and cultural shifts at global scale. Many traditional pest control practices are disappearing because of introduction of foreign technologies like synthetic pesticides that assure short-term solutions to the problems. The aim of the present study was therefore, to identify the potential of botanical used by farmers in Sidama region, and investigate their antimicrobial activities against some plant pathogens. Information on traditional botanicals pesticides used for crop pests control was collected through observation, key informant interview, questionnaire, and group discussions. The antimicrobial activities of the common botanicals in the study area were investigated using filter paper disc and agar well diffusion method following standard procedure. The bioactive compounds from leaves of 16 botanicals were extracted with 95% ethanol, and the phytochemical tests were conducted. The result revealed that farmers in the study area have different ethnobotanical experience in their neighbourhood. Various plants belonging to different families were valued for pesticide activities. The botanically-derived pesticides were perceived to be affordable, effective, available, safe and dependable. However, estimating the proportion/ concentration of botanicals to be used for pest control where mentioned as a critical challenge. The ethanolic extract of Cordia africana (18.30mm) showed the maximum inhibition zone against Fusarium vertecelloides while the minimum antibacterial activity was observed by Eucalyptus globules extract (9.43mm) against Ralstonia solanacearum as compared with other botanicals included in the current work. Our investigation showed that the botanicals contain phenols, tannins, glycosides, flavonoids, saponins and steroids. The present work revealed that botanicals in the study area have potential to be used for crop pest control. In order to exploit this potential; standardized techniques of preparation, bio-safety and environmental guidelines are required.
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    EFFECTS OF FORAGE LEGUME INTERCROPPING AND FERTILIZER APPLICATION ON FUNGAL CONTAMINATION OF MAIZE (Zea mays) GRAIN IN DORA BAFANO WOREDA SIDAMA REGION
    (Hawassa University College of Agriculture, 2022) ASMAMAW SISAY ASCHENAKI
    Maize (Zea mays) is one of the most important cereal crops grown throughout the world. It serves as staple food for millions of people and a source of feed for animals. The crop gives 365 Kcal of energy per 100 g of grain. However, maize is reported as the most susceptible crop to fungi contamination. Hence, management of grain contaminating fungi is vital to ensure sustainable and safe food and feed production. In the present study, a field experiment was conducted to evaluate the effects of forage legume intercropping and fertilizer application on fungi contamination of maize grains. The experiment was done using a randomized complete block Design with 10 treatments replicate trice. The experiment employed factorial combinations of five cropping systems and two fertilizer (with ad without) application. Isolation and identification of fungi from the maize grain and soil was done. A total of 6 fungal genera consisting of 12 species were isolated and identified by their morphological characteristics. Fusarium species were the most frequently isolate, followed by Aspergillus and Pencilium spp. Both forage legume intercropping and fertilizer application significantly reduced the frequency of grain contaminating fungi. The frequency of fungi contamination observed to reduce from 17.66 to 8.66 % in case of Fusarium verticillioides when intercropped with cowpea in double rows. Similarly, when fertilizer is applied, the frequency of Fusarium verticillioides was reduced from 14.6 to 9.0 %. The population density (CFUg -1 ) of Aspergillus, Fusarium, Penicilliu, Mucor and Trichoderama species in the soil were significantly reduced when maize was intercropped with forage legume. The finding revealed that intercropping of maize with forage legume and application of fertilizer highly reduce maize grain contaminating fungi.
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    Evaluation of Selected Bio-rational and Synthetic Insecticides Against Onion Thrips (Thrips tabaci L.) (Thysanoptera: Thripidae) on Onion (Allium cepa L.) in the Central Rift Valley of Ethiopia
    (Hawassa University College of Agriculture, 2021) TAMENE GETAHUN BARISO
    Onion thrips, Thrips tabaci (Thysanoptera: Thripidae) is a key insect pest of onion. Onion growers at Meki and Batu locations rely on synthetic insecticides to control onion thrips. This practice encourages the development of insecticide resistance. Therefore, the search for alternative measures has become increasingly important. The present study was designed to evaluate the efficacy of selected bio-rational insecticides and the efficacy of selected synthetic and bio-rational insecticides in rotation against onion thrips. Field experiments were conducted in two locations at Meki and Batu, Eastern Shewa of Oromiya Regional state of Ethiopia during the dry season of 2019/2020. Two experiments were laid out in a randomized complete block design (RCBD) with four replications. Experiment one evaluated the efficacy of bio-rational insecticides (nimbecidine, spinosad, spinetoram, mixture of natural plant extracts and phytoenzyme, Sophora flavescens plant extract 25% + emamectin benzoate 1% SL, Milletia ferrugienea, profenofos (as a standard check) and untreated plots). Experiment two evaluated efficacy of selected bio-rational and synthetic insecticides in rotation (nimbecidine + profenofos, nimbecidine + imidacloprid, mixture of natural plant extracts and phytoenzyme + profenofos, mixture of natural plant extracts and phytoenzyme + imidacloprid, imidacloprid, profenofos (as a standard check) and untreated plots). The study showed that all the biorational insecticides reduced thrips population when compared with the untreated plots. Spinosad, nimbecidine and mixture of natural plant extracts and phytoenzyme effectively controlled thrips on onion and were comparable to the standard check insecticide (profenofos) and gave significantly higher yield than the untreated. Nimbecidine + profenofos and mixture of natural plant extracts and phytoenzyme + profenofos in rotation treatments effectively controlled thrips on onion and were comparable with the standard insecticide (profenofos). The highest yield (29.75, 31.22 ton/ha) was obtained from nimbecidine + profenofos in rotation treatment and the lowest (13.93, 14.36 ton/ha) from the untreated. Thus, spinosad, nimbecidine and mixture of natural plant extracts and phytoenzyme as a sole application or nimbecidine + profenofos and mixture of natural plant extracts and phytoenzyme + profenofos in rotation can be used to control onion thrips on onion
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    Evaluation of Selected Bio-rational and Synthetic Ins ecticides against Cabbage Aphid (Brevicoryne brassicae) (Homoptera: Aphididae) on Cabbage in the Central Rift Valley of Ethiopia
    (Hawassa University College of Agriculture, 2021) ETENESH ADNEW ALOTO
    Cabbage (Brassica oleracea L. var. capita) is one of the most popular food crops and grows well in many parts of Ethiopia. One of the constraints for the production and use of head cabbage is cabbage aphid (Brevicoryne brassicae (L.)) which damages cabbage from seedling to final growth (head formation) stage. This study aimed to evaluate the efficacy of selected bio rationales and to investigate the use of effective bio -rationales in rotation with synthetic insecticides against cabbage aphids under field conditions. Field experiments were conducted in two locations at Batu, Eastern Shewa of Oromia Regional state, and Hawassa, Sidama Regional state during the dry season of 2019/2020. Two separate expe riments were laid out in a randomized complete block design (RCBD) with four replications. The first experiment was an efficacy test of bio-rational insecticides (mixture of natural plant extracts and phytoenzyme, Spinosad, Millettia ferruginea, Nimbecidine, Sophora flavescens plant extract 25% + emamectin benzoate 1% SL, dimethoate 40% EC (as a standard check), and untreated plots). The second experiment was an efficacy test of selected bio-rational and synthetic insecticides in rotation (Nimbecidine + dim ethoate 40% EC, Sophora flavescens plant extract 25% + emamectin benzoate 1% SL+ dimethoate 40% EC, mixture of natural plant extracts and phytoenzyme + dimethoate 40% EC, Spinosad+ dimethoate 40% EC, Milletia ferruginea+ dimethoate 40% EC, dimethoate 40% EC (as a standard check) and untreated plots). The results showed that all biorational insecticides reduced aphid population when compared with the untreated plots. Spinosad, Nimbecidine, and a mixture of natural plant extracts and phytoenzyme effectively controlled aphids on cabbage and were comparable to the standard check (dimethoate 40% EC) and gave higher yield. The maximum total yield of head cabbage was obtained from dimethoate 40% EC treated plots, 57.6 tons/ha and 58.4 tons/ha, followed by Spinosad 55.4 and 56.4 tons/ ha at Hawassa and Batu, respectively; Nimbecidine 51.4 tons/ ha at Hawassa which were not significantly (P<0.05) different from dimethoate 40% EC treatment. In rotation applications of Spinosad, Nimbecidine, and a mixture of natural plant extracts and phytoenzyme with dimethoate 40% EC effectively controlled aphids on cabbage and were comparable with the sole application of standard insecticide (dimethoate 40% EC). The highest total yield of head cabbage was obtained from dimethoate 40% EC treated plots, 60.6 tons/ ha at Hawassa and 61.2 tons/ ha at Batu, and was not significantly different from Spinosad + dimethoate 40% EC treatment in both locations and Nimbecidine+ dimethoate 40% EC at Hawassa. The lowest yield (12.8, 12.4 ton/ha) was obtained from the untreated plots. Thus, Spinosad, Nimbecidine, and mixture of natural plant extracts and phytoenzyme as a sole application or Spinosad, Nimbecidine, and mixture of natural plant extracts, and phytoenzyme in rotation with dimethoate 40% EC can be used to control cabbage aphids on cabbage.