Abstract: In agricultural ecosystems, insect pests, pathogens, weather patterns, and reduced soil fertility pose major challenges to crop productivity and are responsible for significant yield losses worldwide. Iris yellow spot virus (IYSV) vectored by Thrips tabaci Lindeman,is a major hindrance to onion production in eastern Africa. Control measures often rely on insecticides with deleterious effects. Endophytes are one key alternative as they can play important roles in mediating induced s...
Abstract: Citrus greening is a serious disease of Citrus sp. and has been associated with the collapse of several citrus industries in Asia and America (Bové 2006). The disease is associated with the presence of a phloem-limited bacterium, of the ‘Candidatus Liberibacter’ genus. ‘Candidatus Liberibacter africanus’, the principal agent of African citrus greening disease (ACG) has been reported in South, East, and Central Africa (Aubert et al. 1988; Garnier and Bové 1996), but its pr...
Abstract: Endophytic fungi live within plant tissues without causing any harm to the host, promote its growth, and induce systemic resistance against pests and diseases. To mitigate the challenging concealed feeding behavior of immature stages of Tuta absoluta in both tomato (Solanum lycopersicum) and nightshade (Solanum scabrum) host plants, 15 fungal isolates were assessed for their endophytic and insecticidal properties. Twelve isolates were endophytic to both host plants with varied colo...
Abstract: The Asian citrus psyllid (Diaphorina citri) is a key pest of Citrus spp. worldwide, as it acts as a vector for “Candidatus Liberibacter asiaticus (Las)”, the bacterial pathogen associated with the destructive Huanglongbing (HLB) disease. Recent detection of D. citri in Africa and reports of Las-associated HLB in Ethiopia suggest that the citrus industry on the continent is under imminent threat. Endosymbionts and gut bacteria play key roles in the biology of arthropods, especia...
Abstract: Entomopathogenic fungi are commonly applied as inundative sprays to protect plants against insect pests. Their artificial establishment as fungal endophytes to provide other benefits to the host plants aside mere protection against the primary pests has also been widely demonstrated. In the present study, two fungal strains of Beauveria bassiana and one strain of Isaria fumosorosea were assessed in a pathogenicity test against adults of Asian citrus psyllid (Diaphorina citri) and f...
Abstract: African citrus greening is a destructive disease of citrus that has been reported in South Africa since the 1920s. The disease is associated with ‘Candidatus Liberibacter africanus’ (Laf) and is transmitted by Trioza erytreae (Cook et al. 2014; McClean 1974). The related bacteria ‘Candidatus Liberibacter asiaticus’ (Las), which is associated with the much more severe Huanglongbing disease and is transmitted by Diaphorina citri, was recently reported in Ethiopia (Saponari et...
Abstract: Aphids vector many plant viruses in a non-persistent manner i.e., virus particles bind loosely to the insect mouthparts (stylet). This means that acquisition of virus particles from infected plants, and inoculation of un infected plants by viruliferous aphids, are rapid processes that require only brief probes of the plant’s epidermal cells. Virus infection alters plant biochemistry, which causes changes in emission of volatile organic compounds and altered accumulation of nutrie...
Abstract: Endophytic fungi are important in diverse plant functions but knowledge of the factors that shape assemblages of these symbionts is lacking. Here, using a culture-dependent approach, we report 4,178 endophytic fungal isolates representing 16 orders isolated from stems, roots and leaves of three cruciferous plant species, Chinese cabbage (Brassica rapa L.), radish (Raphanus sativus L.) and white cabbage (B. olerocea L.), collected from 21 focal fields with different landscape contex...
Abstract: Potato cyst nematodes (PCN), such as Globodera rostochiensis and Globodera pallida, are quarantine restricted pests of potato causing major yield and financial losses to farmers. G. rostochiensis was first reported from Kenya’s key potato growing area in 2015. We sought to determine the diversity, prevalence and distribution of PCN species across the country by conducting a country-wide survey between 2016 and 2018, which included a more focused, follow-up assessment in three key...
Abstract: Pratylenchus goodeyi appears to be the most prevalent nematode pest of enset in Ethiopia, where it can occur in extremely high densities. However, the damage to yield or how different enset cultivars react to the nematode has yet to be determined. The current study therefore sought to establish a first assessment of these reactions by enset to P. goodeyi infection. Determining pest-resistant cultivars is an important task in developing management strategies. Our study evaluated nin...
Abstract: Spatiotemporal information on crops and cropping systems can provide useful insights into disease outbreak mechanisms in croplands. In September 2011, a severe outbreak of Maize Lethal Necrosis (MLN) disease was reported in Bomet County, Kenya. We aimed to detect severely MLN-infected fields and discriminate mono, inter, and continuous maize cropping systems. We collected in-situ MLN severity observations and acquired multi-date and multi-sensor data viz., RapidEye (RE), Sentinel-1...
Abstract: The banana weevil (Cosmopolites sordidus) and the burrowing nematode Radopholus similis represent two of the most important pests of bananas. Previously, colonization of banana plants by the non-pathogenic Fusarium oxysporum (isolate V5w2) and the entomopathogenic Beauveria bassiana (isolate WA) have been shown to increase host resistance to various banana pests and diseases. However, there is limited data on how the combined inoculation of these isolates would affect field perform...
Abstract: We have assessed the distribution and mating type of chickpea blight (Didymella rabiei (Kov.) v. Arx) from a total of 350 and 272 fields in major chickpea (Cicer arietinum L.) growing areas of Ethiopia for two consecutive cropping seasons 2017 and 2018, respectively. The prevalence of D. rabiei was 20 % for the year 2017 and 7% for 2018. Severity range of 2 9 and incidence of 10–100 % were recorded for both seasons in only 7–20 % of the assed fields. Field prevalence of 2017 an...
Abstract: The African citrus triozid (ACT), Trioza erytreae Del Guercio (Hemiptera: Triozidae), is the major vector of the ‘Candidatus Liberibacter africanus’, associated with the African citrus greening disease [huanglongbing (HLB)]. Although T. er y treae is a very destructive pest in citrus production with yield losses up to 100%, there is limited information on its thermal biology, which is a prerequisite for developing an envi-ronmentally friendly management strategy. This study inv...
Abstract: Mother-in-law’s tongue, Dracaena (Sansevieria) trifasciata S. is an ornamental houseplant of Asparagaceae family and native to tropical western Africa and southern Asia. Following a yellow withered spot symptom observed on up to one third of D. trifasciata plants at the field, a new bacterium pathogen was discovered for the first time in South of China. This pathogen was isolated from the early irregular yellow spot and its pathogenicity to the host plant was confirmed through ar...