Browsing by Author "Miller, Sally A."

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    Gibberella xylarioides (anamorph: Fusarium xylarioides), a causative agent of coffee wilt disease in Africa, is a previously unrecognized member of the G. fujikuroi species complex
    (Mycologia, 2005) Geiser, David M.; Ivey, Melanie L. Lewis; Hakiza, Georgina; Juba, Jean H.; Miller, Sally A.
    Tracheomycosis or coffee wilt has emerged as a major disease of robusta coffee in Uganda in the past 10 years. Coffee wilt historically has been associated with Fusarium xylarioides Steyaert (teleomorph Gibberella xylarioides Heim and Sacc.), a species that has been classified as a member of Fusarium section Lateritium. We investigated the molecular phylogenetics of fusarial coffee wilt isolates by generating partial DNA sequences from two protein coding regions, translation elongation factor 1-α and beta-tubulin, in 36 isolates previously identified as F. xylarioides and related fusaria from coffee and other woody hosts, as well as from 12 isolates associated with a current coffee wilt outbreak in Uganda. These isolates fell into two morphologically and phylogenetically distinct groups. The first group was found to represent previously unidentified members of the Gibberella fujikuroi species complex (GFC), a clade that replaces the artificial Fusarium section Liseola. This group of isolates fit the original description of F. xylarioides, thus connecting it to the GFC. The second group, which was diverse in its morphology and DNA sequences, comprised four distinct lineages related to Fusarium lateritium. Our finding of unrelated species associated with coffee wilt disease has important implications regarding its epidemiology, etiology and control.
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    IPM Vegetable Systems in Uganda
    (Springer, Dordrecht., 2016) Karungi, Jeninah; Erbaugh, J. Mark; Ssonko, Robinah N.; Bonabana- Wabbi, Jackline; Miller, Sally A.; Kyamanywa, Samuel
    Smallholder famers in Sub-Saharan Africa (SSA) have been encouraged to produce horticultural crops as an agricultural and rural development strategy to enhance incomes and improve household nutrition. In Uganda, intensifi ed production of marketed vegetable crops has led to changing agricultural practices, including crop and input-intensifi cation, a changing set of pests, and increased use and reliance on synthetic pesticides to manage these pests. Beginning in 2002, the IPM CRSP team in Uganda implemented a participatory IPM program with smallholder farmers to develop and disseminate alternative pest management strategies for managing priority pests and reducing pesticide usage on tomato. The major pest constraints addressed were late blight, bacterial wilt, viruses, bollworm, aphids, thrips and white fl ies. Baseline farmer surveys indicated that farmers were spraying a variety of pesticides 12–24 times per growing season. The component technologies developed into a package and disseminated to farmers included a bacteria wilt resistant tomato variety MT56, mulching, staking, and a minimum spray schedule of 3–4 pesticide sprays per season. Impact assessments indicated that yields were 40 % higher when the package was used and reduced production costs (by reducing the number of sprays) that led to higher net revenues for IPM-practicing tomato farmers. Use of MT56 and mulching led to a 21 % reduction in production costs and led to an internal rate of return of 250 % if adopted. Use of tomato variety MT56 reduced production cost by 21 % with a Benefi t: Cost ratio of 770. Other IPM technologies developed included grafting using bacterial wilt resistant rootstocks; seedling production using low tunnel systems for pest/vector exclusion; and good nursery management practices.