1,720,999 research outputs found
Biology of barley shoot fly Delia flavibasis Stein (Diptera: Anthomyiidae) on resistant and susceptible barley cultivars
Full text linkThe biology of barley shoot fly Delia flavibasis was studied using resistant (Dinsho and Harbu) and susceptible (Holker) barley cultivars at Sinana Agricultural Research Center, Ethiopia. A higher number of eggs was laid on Holker (17 eggs/female) than on Dinsho (11 eggs/female) or Harbu (12 eggs/female). However, there were no differences between cultivars in preoviposition and total reproductive periods. The shortest time required to complete larval, pupal and total developmental stages from egg to adult emergence occurred when the insect was reared on the cultivar Holker. Pupal weight, adult emergence and adult longevity did not differ between cultivars. The female to male sex ratio was 1:1. This study enabled us to understand the duration of each of the life stages of D. flavibasis, which will undoubtedly aid researchers and growers to design a sustainable management strategy against barley shoot fly
WOOLLY WHITEFLY ALEUROTHRIXUS FLOCCOSUS (MASKELL) (HeMOPTERA: ~LEYRODIDAE): A NEW INV ASIVE ALIEN INSECT PEST OF CITRUS FRUITS IN ETHIOPIA
Full text linkThe woolly whitefly, Aleurothrixus floccosus (Maskell) (Homoptera: Aleyrodidae), is anew invasive alien insect pest of citrus fruits recorded in Ethiopia in 2001 in Nazareth toWn. Woollywhitplly was recorded in Ethiopia on all citrus fruits. The pest sucks phloem sap, causing leaves to wiltand drop when populations are large. Honeydew droplets t:ollect dust and support the growth of sootymold. Heavy infestations where copious amounts of honeydew -are produced can result in theblacJsening of the entire tree. Honeydew' and sooty .mold can also contaminate the fruit. The pest hasinvaded Central Rift Valley starting from Dukem to Shashemene. In Western Ethiopia, the pest invadedAmbo and &ko tQWnB. Pupal parasitoid, Cales noacki Howard (Hymenoptera: Aphelinidae) wasrecorded on woolly whitefly. The description of woolly whitefly aided by pi~tures, its current status inEthiopia and some experiences in the managen .ent of the pest elsewhere are discussed in this paper.More over, future research direction to solve the problem is indicated
Review articleBiology, ecology and management of cereal stemborers in Africa, with particular reference to Ethiopia
No full textGrains of gramineous crops are of paramount importance in the world for feeding humans and livestock, and generating income. Moreover, the stalks of thick stemmed gramineous crops such as maize and sorghum are used for fuel, construction and livestock feed. The contribution of cereals like maize and sorghum towards food requirements of Ethiopian population is tremendous and these cereals rank first and second, respectively, in terms of yield per hectare and total production. However, their yields are affected by a large number of lepidopteran stemborers found in the families Pyralidae, Crambidae and Noctuidae and two species of Coleoptera in the family of Rhynchophoridae. Of the stemborer species attacking cereals, the spotted stemborer, Chilo partellus (Swinhoe) is an exotic species which has no co-evolved natural enemies to keep its population low. This species is very problematic in the dry lowland of eastern and southern African countries including Ethiopia. The other problematic species which is indigenous to Africa is maize stemborer, Busseola fusca (Fuller). This species can cause complete crop failure in most African countries in the wet-higher elevation. Other than these two species, the stemborers recorded in Africa are either minor or sporadic or pests of pocket areas. The yield losses due to these stemborers to cereals have been reported to vary from country to country and ranges from 20-80% depending on the pest density, type and variety of crops, species of stemborers involved in the infestation and phenological stage of the crop during infestation. To combat the complex species of stemborers involved in the infestation of important cereal crops, quite a large number of basic and applied researches have been conducted in Africa which include species composition, economic importance, distribution, biology, ecology and management. Hence, in this paper, critical review of stemborers’ research outputs is presented. From the review, conclusions and recommendations are made to help cereal growers to make use of research results for the effective management of cereal stemborers which ultimately boost production and productivity. Keywords/phrases: Applied research; Basic research; Cereal stemborers; Cereal stemborers management; ReviewEthiop. J. Biol. Sci., 9(1): 79-116, 201
Efficacy of plant derived and synthetic insecticides against cabbage aphid, Brevicoryne brassicae (L.) (Homoptera: Aphididae) and their effect on coccinellid predators
Full text linkCabbage aphid, Brevicoryne brassicae (L.) is one of the major insect pests of brassica crops worldwide. Mainly insecticides are being used for its management which poses hazardous effects on the environment and the applicator. Low efficacy and non-target effect of the available insecticide are the main challenge in the management of the pest in Ethiopia. The use of bio-rational and neonicotinoid pesticides is a promising alternative as they are less vulnerable to resistance development and relatively safe to the environment and the applicator. This study was carried out in 2018/19 cropping season to evaluate the efficacy of plant derived and synthetic insecticides for the management of cabbage aphid and their effect on coccinellid predators on Ethiopian kale. Ten treatments including six synthetic and two botanical insecticides were tested in comparison with the standard check dimethoate 40% EC and the untreated control in Randomized Complete Block Design with three replications. Significant (P<0.05) differences were observed among the treatments in terms of cabbage aphid population reduction and their effect on coccinellid beetles. The botanical mix (Garlic+onion+pepper) and imidacloprid were at par with each other and found to be the best treatment with 93.79% and 91.04% efficacy, respectively. The maximum leaf yield was obtained from imidacloprid (14.18 t/ha) followed by botanical mix (13.45 t/ha) and lufenuron (12.42 t/ha). The highest yield increment over control was obtained from imidacloprid (3.1 t/ha), followed by botanical mix (2.37 t/ha). The botanical mix, imidacloprid and neem seed extract were highly effective in aphid control as well as less hazardous to ladybird beetle (Coccinella septempunctata L.). The highest cost benefit ratio was recorded with profenofos (1:1.14) followed by lufenuron (1:0.2), spinosad and nimbecidine (1:0.18). Results of the current study demonstrated that imidacloprid and plant-based insecticides can reduce aphid populations equally to conventional insecticides and could be used as an alternative component for the integrated pest management (IPM) of cabbage aphid, Brevicoryne brassicae (L.) on kale crop under field condition of smallholder farming system
Evaluation of shallot cultivars against onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae) in Bishoftu, Ethiopia
Full text linkOnion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), is a worldwide pest of allium crops that can reduce shallot yield by more than 50% and even more problematic when it transmits iris yellow spot virus (Family Bunyaviridae, Genus Tospovirus, iysv). Because of its cryptic nature, it is difficult to control thrips merely with insecticides. Thus, a field experiment was conducted to investigate the effect of shallot cultivars against T. tabaci. The study was conducted between June 2017 and March, 2018 in two locations at Debre Zeit Agricultural Research Center (dzarc), Ethiopia. Ten shallot cultivars were evaluated in a complete randomized design with three replications, by counting the number of thrips larvae at weekly interval and recording leaf damage percentage. Most of the cultivars had shown a significant difference (P<0.05) for all recorded evaluation parameters. Five out of the 10 tested cultivars scored low thrips population had very little leaf damage and were considered resistant to T. tabaci. Visual assessment to shallot plant canopy indicated that all the cultivars has shown low damage symptom. Moreover, the result revealed that the registered shallot varieties namely Huruta and Minjar were superior in bulb yield and resistant level to thrips damage. Our findings indicate that the presence of thrips resistant/tolerant shallot cultivars in the germplasm collections at dzarc and the potential for developing T. tabaci resistance shallot cultivars as part of an overall integrated pest management strategy. Therefore, these cultivars could be used by complementing them with insecticides and cultural practices to manage onion thrips populations
Moth Species Diversity, Composition and Abundance in Different Land Use Types of Chebera Churchura National Park and Its Surroundings, Southwestern Ethiopia
Get PDFLand use change and habitat fragmentation affect biodiversity through an increasing level of disturbance and destruction of natural habitats. The present study is the first report on species diversity, species composition, and abundance of moth fauna in and around Chebera Churchura national park. During the survey from January to June 2021, 6206 specimens were collected from 105 species and 11 families from the 3 land use types. Based on the number of species, the family Erbidae is the most abundant with 41 species, and the family Pyraldae was the least abundant with one species. Based on the number of individuals, the family Crambidae was the most abundant, with 2,474 individuals, and the least was the family Pyraldae with 10 individuals. The most abundant species was Cyligramma latona, and Cyana abyssinica was the least. Compared to the three land use types, riverine forest had the highest diversity, with 94 species and 3592 individuals, and mosaic habitat had the lowest, with 30 species and 971 individuals. Across the survey diversity indices, riverine forest had the highest Shannon value of 4, Simpson value of 0.98, and evenness value of 0.89, while mosaic habitat had the lowest Shannon value of 3, Simpson value of 0.94, and evenness value of 0.87. The Chi-square test results showed that the diversity of moths differed significantly between the three habitats. A month-wise comparison of moth abundance showed that January was the most abundant and the least was recorded in June. The highest similarity was found between riverine forest and wooded grassland; the least was between riverine forest and mosaic habitat. Generally, the habitat was good for moth and butterfly diversity
Efficacy of plant derived and synthetic insecticides against cabbage aphid, Brevicoryne brassicae (L.) (Homoptera: Aphididae) and their effect on coccinellid predators
No full textCabbage aphid, Brevicoryne brassicae (L.) is one of the major insect pests of brassica crops worldwide. Mainly insecticides are being used for its management which poses hazardous effects on the environment and the applicator. Low efficacy and non-target effect of the available insecticide are the main challenge in the management of the pest in Ethiopia. The use of bio-rational and neonicotinoid pesticides is a promising alternative as they are less vulnerable to resistance development and relatively safe to the environment and the applicator. This study was carried out in 2018/19 cropping season to evaluate the efficacy of plant derived and synthetic insecticides for the management of cabbage aphid and their effect on coccinellid predators on Ethiopian kale. Ten treatments including six synthetic and two botanical insecticides were tested in comparison with the standard check dimethoate 40% EC and the untreated control in Randomized Complete Block Design with three replications. Significant (P<0.05) differences were observed among the treatments in terms of cabbage aphid population reduction and their effect on coccinellid beetles. The botanical mix (Garlic+onion+pepper) and imidacloprid were at par with each other and found to be the best treatment with 93.79% and 91.04% efficacy, respectively. The maximum leaf yield was obtained from imidacloprid (14.18 t/ha) followed by botanical mix (13.45 t/ha) and lufenuron (12.42 t/ha). The highest yield increment over control was obtained from imidacloprid (3.1 t/ha), followed by botanical mix (2.37 t/ha). The botanical mix, imidacloprid and neem seed extract were highly effective in aphid control as well as less hazardous to ladybird beetle (Coccinella septempunctata L.). The highest cost benefit ratio was recorded with profenofos (1:1.14) followed by lufenuron (1:0.2), spinosad and nimbecidine (1:0.18). Results of the current study demonstrated that imidacloprid and plant-based insecticides can reduce aphid populations equally to conventional insecticides and could be used as an alternative component for the integrated pest management (IPM) of cabbage aphid, Brevicoryne brassicae (L.) on kale crop under field condition of smallholder farming system
Efficacy of botanical extracts against termites on maize (Zea mays (L.)) under field condition in western Ethiopia
Full text linkMaize (Zea mays L.) is grown popularly in the world. It is severely attacked by termites. Insecticides are widely used to control, but could not minimize termites’ damage mainly because of resistance development and easily break down of the active ingredients. Hence, field experiment was conducted with the aim of evaluating different botanical crude extracts from leaves of Croton macrostachys (Hochst), Jatropha curcas L. and Phytolacca dodecandra L. for the management of termites. The experiment was conducted at Wollega University (wu) under irrigation and rain fed conditions. Leaves of the botanicals were collected from experimental sites in western Ethiopia and dried under shade. The dried leaves were grounded to a fine powder using a small hand-operated manual grinder and the powder was further sliced with analytical mill and sieved through a 0.25 mm pore size mesh to make uniform fine dust particle. The treatments were C. macrostachys, P. dodecandra, J. curcas, C. macrostachys + P. dodecandra, C. macrostachys +J. curcas, P. dodecandra + J. curcas, C. macrostachys + P. dodecandra + J. curcas. Untreated check was used for comparison. For treatment preparation, 300 g. of each botanical leaf powder was soaked in 1000 ml distilled water for 72 hrs. The mixtures were filtered with clean cheese cloth and stored in a beaker of 250 ml capacity. The experiment was laid-out in a Randomized Complete Block Design (rcbd) in four replications. Shallow holes for maize seed planting were prepared well ahead of planting on the experimental plots. From the stock solution of each botanical, 20 ml was drenched to each planting hole 10 days before planting and continued at all maize growth stages. Treatments were applied using 30 ml capacity Syringe. Data on termite damage symptoms were collected two days before planting and two days after treatment application at every growth stage. The results revealed that mixed botanicals treatments were significantly (p<0.05) superior to non-mixed botanical treatments in the management of termites. The highest number of foraging termites, galleries and mounds were recorded in the untreated check plot, while the lowest was recorded in the mixed botanical treatments. Moreover, the highest number of maize stand count, maize cobs and maize yield were recorded from plots that received mixed botanicals and the lowest were recorded from the untreated plot. In conclusion, mixtures of C. macrostachys, J. curcas and P. dodecandra can be used as part of an integrated termites’ management
Biology of Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) under different temperature and relative humidity
No full textGeographical and population diversity of African honeybees, Apismellifera L. (Hymenoptera: Apidae): A review
Full text linkThis review was prepared to summarize the information on geographic and genetic diversity of Apismellifera L. of African honeybees and the progresses made through time and applications of various advanced tools in their taxonomy at subspecies level. African honeybees have developed distinct morphology, behavior and physiology as they evolved in tropical favorable climate. The variations among the African honeybee populations have helped to produce geographic subspecies based on the morphological characteristics. However, the introduction of molecular taxonomic tools has come up with discrepancies in the number of subspecies and lineages, and subspecies composition of evolutionary lineages in Africa and other parts of the world. It has also brought up controversies in the evolutionary history of A. mellifera reporting different location as the center of origin of the species at different times: Asia, Africa and Europe. It is not only the tools that are used, but also the genetic variations within subspecies, within colonies in an apiary site and within individuals of the same colony temporally are the factors for continually appearing discrepancies. Natural hybridization between populations of adjacent subspecies along the geographic transition zones and introgression of genes through introduction of colonies that is mainly driven by human demand for desirable traits of honeybees have been among the challenges for discrimination of honeybee subspecies. Therefore, in future genetic diversity and taxonomic investigations, considering these natural variations at subspecies level and developing standardized and integrated procedures from sampling to analysis methods would help to produce generally recognized data base that is critically important to resolve the problem of inconsistencies in taxonomy and nomenclature of honeybee subspecies of Arica and elsewhere.
 
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