Pests and Diseases
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Browsing Pests and Diseases by Author "AMANI"
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Item A Contribution to the Biology of the Musophagiformes, the So-Called Plantain-Eaters.(1938) Moreau, R.E.; AMANI(1) The various names indicating plantain (banana) eating, by which these birds have been called, have no foundation whatever in their habits in nature. As the English name, " Turacos " is preferred for the Order as a whole. (2) The growth and habits of T. fischeri and T. persa are described from the age of about one month onwards. Young specimens of Crinifer and Corythmola are described. (3) It is a character of the Order that the young are completely clothed with (neossoptile) down; it is probable, but not proved, that they are all born with it. At the age of about four or five weeks this has been replaced as bodycovering by a dense growth of down-feathers (semi-plumes), but on the head and neck it is more or less completely shed (at the age of about two months) before any other covering is ready to take its place. The ear is, however, specially protected at this stage. The coloured contour feathers only begin to appear about the tenth week. The pre-adult wing and tail are complete about the ninth and twelfth week respectively. Evidence (from captive birds) on the date adult plumage is assumed is hopelessly divergent.Item The Internal Anatomy of Corioxenos Antestiae Blair (Strepsiptera)(1938) Cooper, B.; AMANIThe only other species of Strepsiptera of which the internal anatomy has been studied appear to be Xenos rossii and Stylops melittae (Nassonov, 1892-1893). It will be of interest to summarise the principal points in which the internal anatomy of Corioxenos antestiae resembles, or differs from, these species. The alimentary canal is of similar arrangement in all three species. The presence of the large epithelial cells which project into the lumen of the mesenteron and are later absorbed is of interest. The rectal caeca, which are probably homologous with similar organs described by Nassonov, are only slightly different in Corioxenos; they arise separately in two places and each of them branches, whereas in the other species they arise as three in one row, branching and anastomosing, and later being joined to the proctodaeum by a single canal. The nervous system in Corioxenos is more concentrated than in the other species. The abdominal ganglion is not separated from the sub-oesophageal nerve-mass in the female, and it is only separated by a short cord in the male. The circulatory and respiratory systems appear to be similar in all three species.Item Transmission of Plant Viruses by Insects(1939) Storey, H.H.; AMANIInsects, as a general rule, play an essential part in the survival of the viruses that cause plant disease. It is true that a virus will pass from scion to stock, or the reverse, across a graft in those species of plants where organic union is possible. I t is also true that by vegetative reproduction of a diseased plant the virus is perpetuated in its progeny. But every living plant owes its origin ultimately to sexual reproduction; and the real problem, from a theoretical and a practical point of view, is how a virus can become established in a sexually produced plant. In only a few rare instances is it known that a virus can be transferred through the true seed from one or other of the parents (16, 21, 57, 58). Some form of secondary transfer from plant to plant must be possible. Many viruses, but not all, can be experimentally so transferred by mechanical inoculation of juice. It is doubtful, however, whether such a method of transmission can operate generally without human intervention, although the natural spread of one virus has been explained by juice transfer during the rubbing of leaves in the wind (49). A few viruses can be disseminated, in some manner not certainly known, through the air (70) or soil (90). Nevertheless, so far as our present knowledge goes, we believe that the great majority of viruses are transferred in nature from one plant unit, i.e., from the product of a single true seed, to another only by insects; and without the insect the virus would suffer extinction with the death of the plant that had been its host.
