Pest Managment Journal of Ethiopia

Eco-Biological Studies on Wild Sunflower (Verbesina encelioides) in the Central Rift Valley of Ethiopia

Amare Fufa, Taye Tessema, Zelalem Bekeko, Tewodros Mesfin — Wed, 05 May 2021 00:00:00 -0400

Wild sunflower threatens crop production, animal husbandry, and biodiversity in areas where it has spread. Even though the weed has already concurred huge areas of different land use systems of the Central Rift Valley, there is no available information on its eco-biology. Thus, this study was conducted to generate eco-biological information on wild sunflower by investigating the effects of different seasons of the year, soil ploughing, seed storage time, and burial depth on seed germination and seedling emergence. Wild sunflower matured in about 128 to 141 days, during which it attained a height of up to 82 cm. The weed could produce up to 22 branches and 32 flower heads per plant. The weed attained a biomass yield of about 26 and 34 g plant^-1 at Adamitulu and 35 and 44 g plant^-1 at Melkassa at flowering and maturity, respectively. Wild sunflower produced 813 to 1124 seeds per plant. Seedling emergence m^-2 averaged 42.6 at Melkassa and 34.4 at Adamitulu under unploughed soil but declined to 23.8 and 20.6, respectively, when the plot was ploughed. During the summer, the highest seedling densities of 38.3 and 54.7 plant m^-2 emerged at Adamitulu and Melkassa, respectively. The proportion of germinating seeds was highest in seeds stored for 24 weeks (97%), and emergence increased with increasing storage time until germination stabilized while only 2% germinated from freshly harvested seeds. The required storage time for 50% germination was only 2.8 weeks. The percentage of seedling emergence was highest for seeds placed on the soil surface (94%), and decreased with the burial depth; no seedlings emerged from a depth of 6 cm. It was observed that a burial depth of only 2.7 cm reduced seedling emergence by 50%. Overall, the information generated on the biology and ecology of wild sunflower in this study will assist in the development of its management strategies.

Complex Viral Diseases Threatening Lentil and Chickpea Production in Ethiopia

Wed, 05 May 2021 00:00:00 -0400

In Ethiopia, lentil and chickpea have many of uses as sources of income and in the preparation of various dishes and nutritional security of millions of Ethiopians. Farmers have well recognized the importance of lentil and chickpea as rotation crops in improving soil fertility. However, several biotic agents of viral origin are threatening the production and productivity of chickpea and lentil. The current study was carried out to assess the relative distribution and importance of viruses infecting lentil and chickpea in major production areas to prioritize and design focused and action-oriented research to develop effective management. Two consecutive surveys were carried out in 2018 and 2019 main cropping seasons, and a total of 635 (chickpea, lentil, grasspea and fenugreek) and 676 (lentil and chickpea) samples were collected, respectively, from 57 and 81 fields in central, north, and northwest regions. The study revealed that Pea seed-borne mosaic virus (PSbMV, genus Potyvirus, family Potyviridae) and Chickpea chlorotic stunt virus (CpCSV, genus Polerovirus, family Solemoviridae) are the most-wide spread and frequently recovered viruses from lentil samples, while CpCSV had the highest incidences and was a more prevalent viruse in chickpea fields assessed. Based on this result, integrated management options can be developed targeting factors aggravating the epidemics of the dominant viruses along with continuous disease and vector monitoring.

Effect of Hermetic Storage Bags and Storage Duration on Occurrence of Storage Insect Pests in Seeds of Cereals and Legumes

Tebkew Damte, Aderaw Tiruaynet — Wed, 05 May 2021 00:00:00 -0400

Hermetic storage has been introduced and disseminated in some parts of Ethiopia; although their efficacy in protecting seeds has not been studied. Thus, a study was conducted to determine whether different hermetic storage protect or not tef, durum wheat, lentil, and chickpea seeds from damage by storage insect pests over various storage periods. The hermetic storage tested were GrainPro super bag, Purdue Improved Crop Storage (PICS) bag, and fertilizer bag, while polypropylene bag was used as control. In each bag 10 kg of insecticide untreated seeds of tef, durum wheat and chickpea and 4 kg of lentil seed was put and stored for 6, 12, 18 and 24 months. The treatments were arranged in two factor nested design and treatments were replicated three times. Only lentil and chickpea seeds were infested by Adzuki bean beetle (Callosobruchus chinensis). It was found that throughout the tested storage periods, lentil seeds stored in PICS bag and GrainPro super bag had the lowest proportion of seeds with egg or hole; the lowest average number of eggs per seed; and holes per seed than seeds stored either in polypropylene bag or fertilizer bag. Relatively high level of infestation was found on chickpea seeds stored in a single inner layer GrainPro super bag and polypropylene bag. There were no insect infestations in both tef and durum wheat seeds stored in all packaging materials. Therefore, PICS and GrainPro super bags (as double layer) are effective in protecting both cereals and pulses from insect pests in storage.

Effect of Integrated Weed Management Practice on Weeds and Yield of Cotton

Workishet Taye, Zemedkun Alemu, Bedane Gudeta — Wed, 05 May 2021 00:00:00 -0400

Weeds are one of the causes of underproduction which leads to severe losses in cotton yield due to competition and increased production costs. This study was aimed at determining the effect of different weed management practices on weeds and cotton yield in the Middle Awash, Ethiopia. The experiment was conducted during the 2017 and 2018 cropping seasons at Werer Agricultural Research Center and Gewane cotton commercial farm. The experiment was laid out in a Randomized Complete Block Design (RCBD) with three replications. Treatments consisted of various combinations of mechanical, cultural, and chemical control methods. These were: hand weeding + inter-culturing, pre-irrigation + hand weeding, pendimethalin + hand weeding, pre-irrigation + inter-culturing, pendimethalin + inter-culturing, pre-irrigation + pendimethalin, pre-irrigation, and control. Data on weed density and cotton yield and yield components were recorded. Weed density, cotton boll number per plant, boll weight, and seed cotton yield were significantly affected by weed management practices. Hand weeding + inter-culturing and pendimethalin + inter-culturing resulted in seed cotton yield of 60.74 and 64% higher than the weedy check. However, the maximum net benefit was obtained from pendimethalin + inter-culturing followed by hand weeding + inter-culturing. Based on the results observed, the use of pendimethalin + hand-weeding or hand-weeding + inter-culturing can be used to economically and effectively control weeds in cotton fields of Middle Awash areas.

Distribution of Fusarium Wilt of Chickpea and its Association with Biophysical Factors in East Shewa Zone, Central Ethiopia

Edeo Negash — Wed, 05 May 2021 00:00:00 -0400

Chickpea fusarium wilt (CFW) caused by Fusarium oxysporum f.sp. ciceris has become a great threat to chickpea production in Ethiopia. A field survey was conducted to determine the distribution and association of CFW with biophysical factors in the Central Rift Valley of Ethiopia in the 2019/20 main cropping season. The associations of CFW incidence with independent variables were analyzed using a logistic regression model. A total of 68 fields were assessed in four districts and results revealed that all the surveyed fields were infected with CFW. However, substantial variations were observed in CFW incidence across the surveyed districts. The mean incidence varied from 31.79% in Lume to 55.81% in the Gumbichu district. Variables like district, crop growth stage, variety, previous crop history, seed source, crop density, and weed density had a very highly significant (P<0.0001) association with disease incidence in reduced multiple variable models. Associations between disease parameters and chickpea variety were also observed to be significant in the reduced model. Results from this study showed a 100% prevalence of CFW in the study area, implying the need for proper intervention. Emphasis on proper agronomic practices such as the use of improved seeds, appropriate sowing date, cropping pattern, and weed management should be given in the integrated management of CFW in the study area and other related agroecologies.