The report will be restricted to the following diseases: i.e. bacterial leaf blight (Xanthomonas campestris pv. oryzae) and blast (Pyricularia oryzae) of rice, scab (Gibberella zeae) and root rot (or leaf spot, Helminthosporium spp. etc.) of wheat and Verticillium wilt (Verticillium dahliae) of cotton. Disease distribution, trend of occurrence and yield losses will be illustrated in general. The pathogenicity of X. campestris pv. oryzae and V. dahliae, the epidemiology of rice blast and wheat scab will be discussed in detail. Defoliating type of V. dahliae and 8 new plants of this pathogen have been first discovered in China. Several different causal organisms of wheat root rot or leaf spot belonging to different species in different genera have been identified. Some of them have been first described in China. Environmental effect on pathogen and disease development is also analyzed. Various control measures for individual diseases are introduced and corresponding emphasis is given in each case. Rice, wheat and cotton are three important crops of great significance in China. Many diseases caused by fungi, bacteria, viruses and other pathogenic organisms frequently affect the production of these three crops. This brief report will be restricted to the following diseases, namely bacterial leaf blight and blast of rice, scab and root rot (or leaf spot) of wheat and Verticillium wilt of cotton

The interactions of many nutritional elements, soil pH, and cultural factors are discussed in the chapters on Fusarium wilt of vegetables, cotton, and ornamentals ; take-all of wheat and other small grains ; Verticillium wilt of cotton, alfalfa and other crops ; Sclerotium rolfsii - incited diseases of various crops especially carrots ; the peanut pot rot disease complex ; aflatoxin contamination of corn and peanuts ; Thielaviopsis root rot of cotton and other crops ; and scab of potato. The special significance of calcium is discussed

The study was conducted to survey and identify soil-borne fungal pathogens causing seedling diseases on cotton. The organisms isolated from the soil samples were Rhizoctonia solani Kuhn, Sclerotium rolfsii Sacc., Pythium sp., Aspergillus sp., Fusarium spp., Penicillium sp., Rhizopus sp., Helminthosporium sp., Colletotrichum sp., Curvularia sp., Thielaviopsis sp., and Cladosporium sp. Of the 13 organisms identified, the most dominant was Aspergillus sp. followed by R. solani, Pythium sp., S. rolfsii and Phytophthora sp. Other species were considered not important because of their scarcity in the soil. Pathogenicity test showed that R. solani, S. rolfsii, Pythium sp., and Phytophthora sp. were the major pathogens causing damping-off diseases on cotton. Plants inoculated with Fusarium spp. were stunted. Poor seed germination and seed rotting were also noted. The two host reactions were also apparent on plants inoculated with Rhizopus and Aspergillus. Thielaviopsis sp. caused shriveled taproots. Species of Colletotrichum, Cladosporium, Penicillium, Helminthosporium and Curvularia were not pathogenic to cotton seedlings.

Manuel destine aux agents de vulgarisation. Description largement illustree des symptomes et des degats pour l'identification des causes, elements de la biologie et de la lutte integree, resistance varietale dans certains cas. Un chapitre est consacre aux insectes utiles. Ce manuel ne traite pas de la lutte chimique en raison des changements constants des donnees et des solutions a appliquer

CTA and Macmillan Publishers have brought out a new book in the series 'The Tropical Agriculturalist', destined to act as practical guides for farmers, extension officers, agricultural students, teachers, and for rural and community development programmes. 'Cotton', originally published in French, covers in detail the characteristics and requirements of this tricky and labour-intensive crop, and methods of cultivation in a variety of African zones and farming systems, with relevance also to other tropical areas. Pest, disease and weed control, harvesting and ginning are also included. The 88 page volume aims to display in a comprehensive but easily assimilated way the main items of technical inforrnation which, if put into practice, will produce good results fron cottongrowing both in individual enterprises and on a national scale. The purpose is to help extension workers in cottongrowing areas, but their endeavours will be fruitless unless farmers themselves learn how to match environment and crop to the demand for increased productivity. Thus the book seeks to oass on to smallholders then~ selves ali the relevant technical knowhow on supply of seed, fertilizer, pesticides, equipment, and collection of the harvested crop. The chapters in 'Cotton' try to answer the following questions: what are the advantages to the smallholder of growing cotton? how does the cotton plant react to this environment? how Is cotton produced? and what place should it have in the tropical cropping system? The thrust of this handbook Is summed up in two rules, for - as the author says - cotton is no exception to the laws governing agricultural production. The first rule is that the various factors of productivity (namely, correct preparation of the soil, early sowing, adequate and regular plant density, early and effective weeding, well-maintained soil fertility, proper protection against pests and diseases, timely pickings) should all be applied together. The second rule is that it is far less arduous and far more remunerative to produce two tonnes of cotton from a single hectare than to obtain the same quantity of crop from an area of two hectares each producing a tonne. So, it is suggested, cotton-arowers should aim to intensify production rather than extend the area under cultivation, and remernber that the increased yield obtained by costly means is not economically viable unless accompanied by adequate intensification. The little book, illustrated with photograps and diagrams, concludes with a alossary of key terms in cotton production, a short bibliography, and a helpful index. Available from: CTA - Postbus 380 - 6700 AJ Waaeninaen THE NETHERLANDS | Cotton in the series 'The Tropical Agriculturalist' CTA and Macmillan Publishers

The organism identified were Rhizoctonia solani Kuhn, Sclerotium rolfsii Sacc, Pythium sp., Phytophthora sp., Aspergillus sp., Fusarium spp., Penicillium sp., Rhizopus sp., Helminthosporium sp., Colletotrichum sp., Curvularia sp., Thielaviopsis sp. and Cladosporium sp. Of the 13 organisms identified, the most dominant was Aspergillus sp. followed by R. solani, Pythium sp., S. rolfsii and Phytophthora sp. Pathogenicity tests showed that R. solani, S. rolfsii, Pythium sp. and Phytophthora sp. were the pathogens that caused damping-off of cotton seedling. Fusarium spp. caused stunting. Poor seed germination and seed rotting were apparent on plants inoculated with Fusarium spp., Rhizopus sp. and Aspergillus sp. while Thielaviopsis sp. caused shriveled toproots. Results suggest that a chemical control program for cotton seedling diseases must be specifically effective against R. solani, S. rolfsii, Pythium sp. and Phytophthora sp. and that seed treatments should be adopted only in areas where these pathogens are present.

Manuel destine aux agents de vulgarisation. Description largement illustree des symptomes et des degats pour l' identification des causes, elements de la biologie et de la lutte integree, resistance varietale dans certains cas. Un chapitre est consacre aux insectes utiles. Ce manuel ne traite pas de la lutte chimique en raison des changements constants des donnees et des solutions a appliquer.

The aim of wide crossing is to transfer useful genes from the wild relatives of crops into cultivars. The wild relative of modern cultivars possess many desirable traits such as resistance to diseases and insects, tolerance to abiotic stresses, high seed protein content, and sources of male sterility. This paper describes achievements in using genes from wild relatives of rice, barley, wheat, and cotton. It shows the success in hybrid rice production in China and how basic sources of male sterility are derived from wild rice. The techniques available for sexual and parasexual gene transfer are also analyzed.