Plant Disease (Collins New Naturalist Library, Volume 85)
David Ingram, Noel Robertson
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Plant Disease covers all aspects of diseases of plants growing in the wild or likely to be encountered on cultivated plants in farm, forest and garden. This edition is exclusive to newnaturalists.com This book covers all aspects of diseases of plants growing in the wild or likely to be encountered on cultivated plants in farm, forest and garden. Between 1845 and 1851 one and a half million Irish men, women and children died in misery from starvation and disease; the result of potato blight, a fungal disease that destroyed their potato crops. A million more people, driven to despair by the succession of appalling harvests, emigrated, mostly to America. So it was that a plant disease changed the course of history, its economic effects causing not only social but also major political upheaval. Many plant diseases have had surprisingly far reaching social and economic effects, so the study of these diseases is of great interest and importance to scientists, horticulturists, agriculturalists and foresters. In Plant Disease: A Natural History, Ingram and Robertson draw on personal observations in the field and laboratory to discuss all types of diseases caused by fungi, from rots and mildews to rusts, smuts and tumours. The symptoms encountered in the wild are described, together with their causes. A final chapter discusses the diseases caused by viruses, bacteria and flowering plants.
climatic requirements. An interesting example of adaptation is shown by P. recondita, brown rust of wheat, barley and rye, which has adapted to different aecial hosts: in Portugal it has been found in geographically separate areas producing aecia on Thalictrum spp. in the family Ranunculaceae; in other areas it is reputed to produce aecia on Anchusa spp. and other members of the family Boraginaceae; while in Siberia it has been found on Isopyrum fumarioides, another member of the Ranunculaceae.
symptoms in potatoes, was a cause of crop failure at the time of the potato blight epidemics in the nineteenth century, and in 1869 the variegation of Abutilon striatum (Fig. 12.1), a decorative plant used extensively in Victorian conservatories, was found to be infectious when variegated scions were grafted on to green stocks in the course of propagation. This was all circumstantial evidence for the existence of a ‘new’ infective agent until Mayer, in 1886, transmitted tobacco mosaic disease to
experiments have shown that hrp genes are not active when the bacteria are grown in culture on media rich in nutrients. They are activated immediately, however, when the bacteria are transferred to a starvation medium. This suggests that in nature it is the nutrient-deficient state of the region between the cells of the host, which a pathogenic bacterium encounters as soon as it has passed through a stomatal pore or other opening, that activates hrp genes. Specific compounds such as sulphur-rich
The ectomycorrhizal fungi are associated with trees growing on soils that are nutrient-deficient. These depleted soils not only present a challenge for the extraction of minerals by the trees, but also favour the accumulation of leaf litter, which breaks down less quickly than on mineral and base-rich soils. The active mycorrhizal roots grow particularly in the layer between the disintegrated litter and the litter composed of whole leaves. Such situations are found in coniferous and broadleaved
were made to eradicate it, and it is still an offence to plant barberries in certain states. Nevertheless, the fungus also attacks other wild Berberis spp. in the United States, and in Europe it occasionally infects the young berries of Mahonia aquifolium, a related species of American origin; the berries, unlike the leaves, have not normally developed a thick cuticle when spores are available for infection. Chinese and Chilean barberries are generally not attacked. Several other species of