Crop Protection

Permanent URI for this collectionhttps://etd.hu.edu.et/handle/123456789/50

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Start date: 2020Has files: Yes

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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.
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    EFFECT OF VARIETY AND FUNGICIDE FREQUENCY ON THE MANAGEMENT OF TOMATO LATE BLIGHT (Phytophthora infestans (MONT) DE BARY) IN BOMBE WOREDA, WOLAITA ZONE, SNNPR, ETHIOPIA
    (Hawassa University College of Agriculture, 2020) DINKINESH DESTA ANSHEBO
    Diseases are the major constraints that limit production of tomato in Ethiopia. Late blight is a very severe disease in most tomato growing regions, including in Wolaita zone, where information on disease management options through integration of varieties and fungicide applications are poor. Aim of the present study was therefore, to determine frequency of fungicide spray with respect to host resistance level on the management of late blight of tomato. A field experiment was conducted at Frwocha kebele in Boloso Bombe Woreda during 2019 cropping season. The experiment was laid using RCBD in factorial arrangements with three replications. The treatments consisted of four foliar spray frequencies, and three tomato varieties (Melkasalsa, Metadel and ARPTd2). Important parameters collected were incidence and severity of late blight, and growth and yield related traits of tomato. Significant variations were observed among varieties in reducing late blight of tomato and increasing the fruit yield. The highest late blight severity and AUDPC (43.2 and 629.81, respectively) were recorded from variety Melkaslsa, and the lowest (32.59 and 441.61, respectively) were recorded from variety ARPTd2. Interaction of varieties and fungicide spray frequencies did not show significant difference on most components of late blight epidemics, crop growth and yield related parameters. However, significance differences were observed on marketable and total fruit yield. The maximum marketable (61.70) and total fruit yield (67.30) were recorded from plots treated with three and two time sprayed on ARPD2 tomato variety, respectively, while the lowest marketable (24.06) and total fruit yield (35.43) were recorded from unsprayed plots of Melkasalsa and Metadel varieties, respectively. Correspondingly, the highest disease progress rate of (0.09) was obtained in unsprayed plot of the variety Melkasalsa; however the lowest disease progress rate of (0.04) was recorded from the plots of ARPTd2 and Metadel variety treated with Ridomil four times at 7 days interval. Fruit yield loss of up to 47.04% was calculated on unsprayed plots as compared to highly treated plots. On the other hand, marginal analysis indicates that the highest 87.94% marginal rate of return in comparison with unsprayed plots was obtained where ridomil sprayed two times on ARPTd2 variety as compared to other spray frequencies. In conclusion, integrations of varieties and two times foliar spray of ridomil on ARPTd2 variety were found to be an effective treatment in reducing tomato late blight epidemics and increasing fruit yield. Moreover, ARPTd2 variety appears to have comparative resistance to late blight and is a promising tomato variety. However, further investigation should be carried out for developing concrete recommendation for late blight management options through integration of varieties and fungicide spray frequency that may contribute to sustainability by stabilizing tomato production in the country.
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    SURVEY OF CHICKPEA WILT IN NORTH SHEWA ZONE, NORTH EASTERN ETHIOPIA AND EVALUATION OF CHICKPEA VARIETIES AGAINST FUSARIUM WILT (Fusarium oxysporum f. sp. ciceris) ATSIYA DEBRNA WAYU WOREDA
    (Hawassa University College of Agriculture, 2020) BASAZIN DEMISS
    Chickpea is an important source of human food and animal feed and is grown in many parts of the world including Ethiopia. Chickpea production is constrained by several biotic and abiotic factors. Chickpea wilt disease is among the major constrains of chickpea in Ethiopia. Presently the information on the status of Chickpea wilts disease and reaction of chickpea varieties to the disease in the study area is lacking. Therefore the present study was conducted with the main objective of determining the status of Chickpea wilt disease at selected woredas of North Shewa Zone, North Eastern Ethiopia and to evaluate chickpea varieties for their reaction against the disease. The survey was conducted at chickpea potential production woredas (Moretna Jiru, Ensaro, Mojana Wedera and Siyadebrna Wayu) during 2018/2019 cropping season. The field data (disease incidence and prevalence)were collected by using simple random sampling technique from farmers’ and research fields. The pathogen was isolated from chickpea plants showing typical wilting symptoms. Pathogenicityof Fusarium oxysporum f.sp.ciceris was confirmed by root dipping inoculation technique in pots under plastic greenhouse condition by using susceptible variety kassech. Seven chickpea varieties were evaluated against Fusarium wilt reaction at Siyadebrna Wayu woredas naturally infested field. The design used for this experiment was randomized complete block design (RCBD) under field condition with three replications. Both incidence and severity data was taken from the field experiment. Chickpea Fusarium wilt incidence was recorded three weeks after sowing while severity data was taken for four consecutive weeks starting from three weeks after sowing. Disease prevalence of 100, 95, 90 and 85% were recorded in Siyadebrna Wayu, Ensaro, Mojana Wedera and Moretna Jiru woredas, respectively. While the percent disease incidence of four selected Woredaswere Ensaro (30.4%), Moretna Jiru (32.25%), Siyadebrna Wayu (36.55%) and Mojana Wedera (27.8%). The fungal mycelia of the isolates were smooth, white in color and, abundant on PDA. The macro conidia were falcate shaped i.e. straight to slightly curved with 3 septation, While the micro conidia was oval shaped. Based on these the pathogen was identified as F. oxysporum f. sp. ciceris. The re-isolated fungus was confirmed to be Fusarium oxysporium f.sp. ciceris in order to full filling the requirement for Koch’s postulates by pathogenicity test. From the tested varieties Minijar, Yelbe and Kassech were relatively susceptible, the check variety Kutaye was relatively moderately resistant (tolerant) and Natoli, Mastewal and Areriti were relatively resistant. Based on the findings of the present study, the chickpea varieties, Natoli, Mastewal and Areriti are relatively resistance and can be recommended for the farmers in the study area since they perform better than the control.it is essential to do further research on molecular identification of the fungus associated with chickpea wilt.