Diseases of captive marine mammals.     

D O Cordes  P J O'Hara 《New Zealand veterinary journal》1979,27(7):147-150

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Improving cost‐effectiveness of brown rot control: the value of bio‐economic modelling*     

A. Breukers  W. Van Der Werf  M. Mourits  A. O. Lansink 《EPPO Bulletin》2007,37(2):391-394

Since 1995, the Dutch potato production chain has been hit by several outbreaks of brown rot, a quarantine disease caused by Ralstonia solanacearum race 3, biovar 2. To avoid establishment of brown rot in the potato production chain and avert the consequences on potato export, the Dutch government has implemented an intensive and costly control policy. It is unknown whether this policy is cost‐effective. A bio‐economic model was developed that can be used to simulate the effect of a control policy on the epidemiology and economic consequences of brown rot in the Dutch potato production chain. Two applications of this model are presented, based on which the potential contribution of the model to cost‐effective control of brown rot is discussed.  相似文献   

A NEW TECHNIQUE FOR THE ACCURATE AERIAL APPLICATION OF HERBICIDES TO DRAINAGE CHANNELS WITH NEGLIGIBLE SPRAY DRIFT     

T. O. ROBSON  E. C. S. LITTLE  D. R. JOHNSTONE  R. F. HILL 《Weed Research》1966,6(3):254-266

Summary. Difficulties of access met with in Britain when applying dalapon to emergent water weeds in drainage channels led to work starting in 1964 on the development of a method of accurate aerial application of aqueous solutions of herbicide. The narrow, sinuous nature of the targets and the proximity of susceptible crops made it necessary to minimize spray drift and maintain a constant height and a slow speed. Nozzles designed to give large droplets were tested for droplet size and distribution. Selected nozzles were then tested from a helicopter in the field and the effect of their spray characteristics on the biological performance of dalapon was assessed. No daman occurred as a result of spray drift and satisfactory control of Phragmites communis, Typha angustifolia and T. latifolia was achieved with a lower dose of dalapon in a lower volume of spray than previously considered necessary for ground applications.
Une nouvelle technique pour l'application précise d'herbicides par voie aérienne sur les canaux de drainage, avec des risques négligeables d'entrainement  相似文献   

Utilization of Thiobacillus to reclaim alkali soils     

O.P. Rupela  P. Tauro 《Soil biology & biochemistry》1973,5(6):899-901

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Diseases of the Oil Palm     

F. O. Aderungboye 《国际虫害防治杂志》2013,59(3):305-326

Abstract

Thirty two diseases and disorders affecting the oil palm in Africa, Southeast Asia and South America are described with their distribution, economic importance, etiology and control. Of these, nine diseases are considered to be of major economic importance, 19 are of minor importance, and four are due to nutrient deficiencies. The major diseases causing serious economic losses are freckle (Cercospora elaeidis), blast (Pythium splendens and Rhizoctonia lamellifera), vascular wilt (Fusarium oxysporum f. sp. elaeidis). Ganoderma trunk rot (Ganoderma spp.) and Armillaria trunk rot (Armillariella mellea) in Africa; Ganoderma trunk rot, Corticium leaf rot (Corticium solani). Marasmius bunch rot (Marasmius palmivora) in S.E. Asia; sudden wilt and spear rot in S. America. Some of the diseases and disorders of minor economic importance recorded in these areas are anthracnose (Botryodiplodia palmarum, Melanconium sp. and Clomerella cingulata), dry basal rot (Ceratocystis paradoxic), patch yellows (Fusarium oxysporum), crown disease, Cylindrocladium leaf spot (Cylindrocladium macrosporum), algal spot (Cephaleuros virescens), bronze streak, ring spot and little leaf in Africa; Curvularia leaf blight (Curvularia eragrostidis), Leptosphaeria leaf spot (Pestalotiopsis spp.) infectious chlorosis, upper stem rot (Phellinus noxius), stem wet rot, charcoal base rot in S.E. Asia and Leptosphaeria leaf spot and coconut wilt disease in S. America. Little is known, however, about the disease problems in the smaller but rapidly expanding oil palm growing areas of Thailand, Papua New Guinea, India and Sri Lanka. Infectious chlorosis, bronze streak and ring spot have a suspected virus etiology; little leaf, spear rot and stem wet rot are attributed to bacteria and leaf chlorosis, mid-crown yellowing, orange frond and hook leaf to nutrient deficiencies. The etiology of some minor disorders including brown germ, crown disease and several miscellaneous abnormalities is unknown.

Effective control measures, based on the application of various chemicals, have been devised for the leaf diseases but other than precautionary cultural operations, there are no such effective and practical control measures for the root and stem diseases. For this latter group of diseases field transplanting or resistant or tolerant varieties seems to be the best method of control. Seeds selected for tolerance to vascular wilt are being produced on a commercial scale at the Nigerian Institute for Oil Palm Research, Institut de Recherches pour les Huiles et Oleagineux in Ivory Coast and the Unilever Plantations in Cameroun Republic. These efforts need to be supplemented by breeding for resistance to the other major diseases.  相似文献   

Larger bioavailability of soil phosphorus for irrigated rice compared with rainfed rice in Madagascar: results from a soil and plant survey     

L. Rabeharisoa  O. R. Razanakoto  M.‐P. Razafimanantsoa  T. Rakotoson  F. Amery  E. Smolders 《Soil Use and Management》2012,28(4):448-456

Irrigated rice is less prone generally to phosphorus (P) deficiency than rainfed rice because redox reactions release P upon soil flooding. It is not known whether that is also true in highly weathered soils of Madagascar where the combination of high soil Fe and low P input may impede significant release of P. Soils and flag leaf samples were collected in 2010 in 38 irrigated rice and 46 rainfed rice fields belonging to private farmers. A critical flag leaf P content was derived from a P‐dosed pot trial study with three soils, and the results suggested 2.4 g P/kg as the critical value. Average flag leaf P was significantly larger in irrigated than in rainfed rice (2.2 compared with 1.7 g P/kg), and flag leaf P was below the critical value in 76% of irrigated rice fields while this fraction was 100% in rainfed rice. Nitrogen and K deficiencies were less prevalent. Flag leaf P increased with increasing soil pH and soil pH explained partially differences in leaf P between irrigated and rainfed rice. Flag leaf P was unrelated to soil organic matter, but increased with oxalate‐extractable soil P (P_o). Multiple regression analysis revealed greater leaf P at equal soil P_o and equal pH in irrigated compared with rainfed rice. Grain yield estimates (1‐m² squares) increased with flag leaf P but not with leaf N and K. In a regression model, about 42 % of the yield variance was explained with soil P_o and a rice‐growing system. The survey suggests that P is the main limiting nutrient for rice, and that soil P bioavailability is larger for irrigated than for rainfed rice in weathered soils of Madagascar.  相似文献   

HONEY ANTS     

H LO 《Science (New York, N.Y.)》1896,3(78):923-924

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THE SPHERE OF BACTERIOLOGY     

Jordan EO 《Science (New York, N.Y.)》1904,20(516):657-666

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The Cell Characteristics of Apple Chat Fruit     

R. O. Sharples 《The Journal of Horticultural Science and Biotechnology》2013,88(3):383-384

In two successive seasons, fruit from Lord Lambourne apple trees infected with chat-fruit virus contained fewer cells at harvest. The volume of the cortical cells of such fruit also tended to be smaller and it is suggested that this virus exerts a general retarding effect on fruit growth rather than affecting either cell division or enlargement only.  相似文献   

The Effect of a Growth Retardant Compound (B4) on Phaseolus Beans     

E. O. Lucas  G. M. Melbourn  H. F. Taylor 《The Journal of Horticultural Science and Biotechnology》2013,88(2):239-244

When the growth retardant B₄ was applied to Phaseolus beans at the primary leaf stage or at one week before flowering, a temporary dwarfing effect occurred and less total vegetative growth was produced. Although these pre-flowering treatments delayed the production of peak pod numbers, no effect on final seed yield occurred. In contrast, an application of B₄ during the early pod-fill stage gave a less marked reduction in vegetative tissue, but increased seed yield by 16%. It is suggested that this extra yield may have resulted from a reduction in pod shading by leaves which enabled a greater direct contribution to seed yield from pod photosynthesis. Alternatively, a restriction in growth of new leaves may have given a greater transfer of assimilate to the pods from older leaves.  相似文献