Articles by Author: Johannes A Van Der Linde

Search results for Johannes A Van Der Linde

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  1. Fungi and insects associated with <em>Euphorbia ingens</em> die-off in South Africa

    Fungi and insects associated with <em>Euphorbia ingens</em> die-off in South Africa

    Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science
    Euphorbia ingens, landmark succulent trees in savannas of South Africa, have been dying in large numbers over the last 10–15 years. Initial studies conducted in the Limpopo province of South Africa revealed a diverse group of biotic agents including fungi,...
  2. Diseases of Pines and Eucalypts in South Africa Associated with <em>Pythium</em> and <em>Phytophthora</em> Species

    Item type: Journal Article • Journal: South African Forestry Journal
    This review covers diseases of Pinus and Eucalyptus spp. associated with Pythium and Phytophthora spp. The relative importance of these fungi is discussed and their host range is described. It is shown that the most important species are Phytophthora cinnamomi...
  3. Measurement of exchangeable aluminium in soils and clay minerals by isotopic exchange

    Measurement of exchangeable aluminium in soils and clay minerals by isotopic exchange

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Isotopically exchangeable Al was determined in soils and clay minerals by equilibration with 28Al. Best results were obtained with a weak extractant and an equilibration time of eight min. The calculated amount of isotopically exchangeable Al was independent of the...
  4. Nature and importance of subterranean insect damage to pre-harvest groundnuts

    Nature and importance of subterranean insect damage to pre-harvest groundnuts

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    The nature and importance of insect damage to subterranean pre-harvest groundnuts were determined by regular sampling in commercial groundnut fields. Five categories of damage are described, viz. damage to newly planted seed, pegs, immature pods, mature pods and kernels. Both...
  5. The effect of pod scarification by soil inhabiting insects on the quality of groundnuts (<em>Arachis hypogaea</em> L.)

    The effect of pod scarification by soil inhabiting insects on the quality of groundnuts (<em>Arachis hypogaea</em> L.)

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    The effect of pod scarification by soil insects on the yield and quality of groundnuts was determined at thirty localities in the Highveld Region of South Africa. Subsamples of superficially damaged pods and sound pods were shelled separately, the kernels...
  6. The role of insect damage in the colonization of groundnut (<em>Arachis hypogaea</em> L.) pods by fungi

    The role of insect damage in the colonization of groundnut (<em>Arachis hypogaea</em> L.) pods by fungi

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    The incidence of fungal infection in insect-damaged and healthy pods and the resultant colonization of kernels was determined from commercial fields at four localities over a period of two seasons. Based on number of colonies per 100 plates, the order...
  7. Evaluation of chemical control against the insect complex of groundnuts (<em>Arachis hypogaea</em> L.) in the South African Highveld Region

    Evaluation of chemical control against the insect complex of groundnuts (<em>Arachis hypogaea</em> L.) in the South African Highveld Region

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Chemical compounds representing seed treatments, soil-applied systemic insecticides, contact and systemic corrective sprays were tested on the groundnut pest complex for three seasons in the South African Highveld Region. The efficacy of the compounds was evaluated by determining the effect...
  8. Effect of planting date of maize on damage and yield loss caused by the stalk borer, <em>Busseola fusca</em> (Fuller) (Lepidoptera: Noctuidae) in Lesotho

    Effect of planting date of maize on damage and yield loss caused by the stalk borer, <em>Busseola fusca</em> (Fuller) (Lepidoptera: Noctuidae) in Lesotho

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    The effect of the time of planting of maize on the incidence of infestation and yield loss caused by Busseola fusca (Fuller) was studied using five successive plantings (early November to early January) during the 1995/96 and 1996/97 growing seasons...
  9. Response of local maize varieties and commercial hybrids to natural infestation by <em>Busseola fusca</em> (Fuller) (Lepidoptera: Noctuidae) in Lesotho

    Response of local maize varieties and commercial hybrids to natural infestation by <em>Busseola fusca</em> (Fuller) (Lepidoptera: Noctuidae) in Lesotho

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    The response of farmers' varieties and maize hybrids commonly grown in Lesotho was evaluated in field trials under natural infestations of Busseola fusca (Fuller). Plant response of varieties and hybrids was evaluated in relation to a susceptible and resistant maize...