Articles by Keyword: Disease Severity

Search results for Disease Severity

We found 137 results for you
  1. Predicting <em>Mycosphaerella</em> leaf disease severity in a <em>Eucalyptus globulus</em> plantation using digital multi-spectral imagery

    Item type: Journal Article • Journal: Southern Hemisphere Forestry Journal
    Digital remote sensing is rapidly developing into an operational tool for forest health assessment at a range of scales. A key aspect of this development is the derivation of models relating spectral data contained in the images to the extent...
  2. An assessment of cassava African mosaic disease in South Africa and Swaziland

    An assessment of cassava African mosaic disease in South Africa and Swaziland

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    A preliminary assessment of the distribution of African mosaic disease (AMD) in cassava in Natal, Transvaal and Swaziland suggests that at present the threat to commercial plantings in Natal has been contained through (i) commercial establishment of cassava in an...
  3. Field reactions of lucerne genotypes to anthracnose and crown rot caused by <em>Colletotrichum trifolii</em>

    Field reactions of lucerne genotypes to anthracnose and crown rot caused by <em>Colletotrichum trifolii</em>

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Nineteen different cultivars and experimental lines of lucerne (Medicago sativa L.) were inoculated with sand-bran cultures of Colletotrichum trifolii Bain & Essary and evaluated for resistance to anthracnose and crown rot under local conditions. The various genotypes differed significantly in...
  4. Registration of cotton (<em>Gossypium hirsutum</em> L.) cultivars Letaba, NIK2 and OR19

    Registration of cotton (<em>Gossypium hirsutum</em> L.) cultivars Letaba, NIK2 and OR19

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Letaba, NIK2 and OR19 were released for commercial cultivation in the R.S.A. in 1989. Letaba has potential as a dryland cultivar in the Springbok Flats and northern Natal. NIK2 is intended for cultivation under irrigation in the same areas and...
  5. Resistance in wheat to maize streak virus

    Resistance in wheat to maize streak virus

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Sixteen spring wheat cultivars were screened for resistance to maize streak virus (MSV) in the eastern Transvaal where the disease often attains epidemic proportions in wheat and maize. In this area four cultivars were resistant, two were susceptible and ten...
  6. Influence of crop production practices on <em>Pythium</em> infections and yield of winter wheat in fumigated and non-fumigated soil

    Influence of crop production practices on <em>Pythium</em> infections and yield of winter wheat in fumigated and non-fumigated soil

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Field trials consisting of different tillage and soil fertility treatments were conducted to study possible causes of yield decline of monoculture winter wheat in the eastern Orange Free State. Soil fumigation with methyl bromide enhanced plant growth, reduced Pythium infections...
  7. Effect of sugary disease exudates on germination, seedling development and predisposition to seedling diseases of sorghum (<em>Sorghum bicolor</em>)

    Effect of sugary disease exudates on germination, seedling development and predisposition to seedling diseases of sorghum (<em>Sorghum bicolor</em>)

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Sorghum harvested for seed from Claviceps africana-infected fields becomes coated with sugary disease exudates in which the fungal spores are borne. The role of exudates in the inhibition of seed germination, seedling growth and predisposition to seedling diseases was investigated...
  8. Implications of <em>Chalara elegans</em> resistance in groundnut breeding

    Implications of <em>Chalara elegans</em> resistance in groundnut breeding

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Genetic advances in six important traits in the groundnut, including resistance to C. elegans, were determined in field trials conducted at the Vaalharts Research Station during 1988/89 using a randomized block design. Results indicated that significant genetic advances for the...
  9. Efficacy of systemic fungicides and timing of preventative sprays in the control of sugary disease of grain sorghum (<em>Sorghum bicolor</em>)

    Efficacy of systemic fungicides and timing of preventative sprays in the control of sugary disease of grain sorghum (<em>Sorghum bicolor</em>)

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    Eight systemic fungicides, benomyl, bitertanol, carbendazim/flusilazol, CG169374, procymidone, propiconazole, terbuconazole and triadimenol, were evaluated in two separate field trials during the 1989/90 and 1990/91 seasons to determine their efficacy against the control of sugary disease of sorghum with a single...
  10. Field evaluation of leaf rust severity, yield loss and quality characteristics in near-isogenic wheat lines with <em>Lr29, Lr35</em> or <em>Lr37</em>

    Field evaluation of leaf rust severity, yield loss and quality characteristics in near-isogenic wheat lines with <em>Lr29, Lr35</em> or <em>Lr37</em>

    Item type: Journal Article • Journal: South African Journal of Plant and Soil
    The potential of three Lr genes in the wheat lines RL6080 (Thatcher*6/Lr29), RL6081 (Thatcher*8/Lr37) and RL6082 (Thatcher*6/Lr35) was evaluated in field experiments. Leaf rust reaction types on flag leaves of lines with Lr29, Lr35 or Lr37 varied between resistance and...