摘要:

Different methods of dealing with sorghum stalks after harvest are surveyed. The recommended practices of burning stalks completely after the grain has been harvested or spreading them thinly in the field throughout the dry season to kill diapausing larvae ofBusseola fuscaare not followed by farmers. Over 95% of farmers keep their stalks in stacks, sometimes in the shade. This allows the survival of diapausing larvae inside the stalks. Partial burning of stalks (to cure them for use as firewood) immediately after grain harvest kills 95% of the larvae with no damage to the stalks. It is suggested that partial burning is an ideal compromise, because it has proved impossible over the years to make farmers completely burn stalks which they use for building, fencing and fuel.

ISSN:0143-6147    

DOI:10.1080/09670878009414383

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Barbados once grew large amounts of Sea Island cotton but the accidental introduction of pink bollworm(Pectinophora gossypiella)in the 1920s, falling prices and rising costs led to the collapse of the industry. Falling sugar prices subsequently led to a revival of interest in the crop but pink bollworm still presented a problem and warranted investigation.

ISSN:0143-6147    

DOI:10.1080/09670878009414384

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The incidence, economic importance, ecology, biology and control measures are described in brief for common pests of sorghum and millets in India. At present, shoot flies, stem borers, earhead midges, birds and rats are considered major pests. However formerly occasional or minor pests are becoming a menace in some states due to changes in cultural practices. For most of the recently recorded pests, information on factors responsible for their outbreak, bionomics, yield losses etc. is needed before planning the control operations. As an immediate remedy, chemicals have been used extensively, mainly on high yielding varieties and hybrids of sorghums. It is emphasized that studies should be intensified on varietal resistance, mass rearing techniques, predators and parasites and manipulation of population by cultural practices leading to the possibility of using all available methods on an integrated basis for future pest management programmes for sorghum and millets.

ISSN:0143-6147    

DOI:10.1080/09670878009414385

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Eldana saccharinais a serious pest of maize in Ghana on the second rains crop grown in the south of the country. The question is raised whether it is worth growing a second maize crop under present conditions.E. saccharinais also a serious pest of sugarcane, causing severe losses to a valuable cash crop, and more work is needed to find suitable means of control, preferably combining the use of resistant varieties, cultural practices and natural enemies.

ISSN:0143-6147    

DOI:10.1080/09670878009414386

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

A bioassay method which makes use of dewinged flies to evaluate residue of insecticides is described. It was used to evaluate nine insecticides, five on cattle and four on three types of surface, againstStomoxys nigra, an important pest of cattle in some parts of the Ethiopian region.

ISSN:0143-6147    

DOI:10.1080/09670878009414387

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Laboratory feeding tests were conducted to determine the efficacy of 0.025% warfarin against two separate populations ofRattus argentiventer(Robinson and Kloss) in Peninsular Malaysia. No-choice feeding periods of 2, 4, 6, 8, 10 and 12 days gave mortalities of 27.5, 57.5, 82.5, 87.5, 97.5 and 100% respectively for the pooled data. No significant heterogeneity was found between the sexes of the populations but there was marked individual variation in susceptibility to warfarin. A base-line for the susceptibility ofR. argentiventerto warfarin was established; the upper 95% confidence limit calculated for the LFP (Lethal Feeding Period) 98 indicated that survival following an 18-day feeding period on 0.025% warfarin bait is a suitable test for the detection of warfarin resistance. It is concluded that warfarin is appropriate for use againstR. argentiventerinfesting rice fields and that poisoned bait would be best applied when alternative foods are most limited.

ISSN:0143-6147    

DOI:10.1080/09670878009414388

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The extent of damage caused by elephant (Loxodonta africanaBlumenbach) in exotic pine plantations in Zambia was determined by survey. Elephants damaged pine trees by stripping the bark. In commercial plantations the number of injured trees was small, but in seed orchards and seed stands the damage was extensive, and is associated with wide espacement. In 1979, some 1000 pine seed trees were dead or dying following elephant damage which occurred during the last two or three years.Pinus kesiyawas worst affected, butP. oocarpaandP. caribaeaalso proved vulnerable, andP. merkusiiseems least susceptible.

ISSN:0143-6147    

DOI:10.1080/09670878009414389

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Apical meristem tips excised from vines ofDioscorea alatacv. White Lisbon produced normal plantlets when culturedin vitroon Murashige and Skoog basal medium supplemented with a range of auxins and cytokinins. Highest yields were obtained on basal medium supplemented with either 1.0 or 0.5 mg/l2-naphthaleneacetic acid, in combination with either 0.2 or 0.1 mg/l6-benzyladenine, respectively. Eradication of flexous rod virus infections was possible only when meristems were excised from mother plants which had been growing at 36 + 1°C for at least 14 days; progeny of plantlets obtained from such meristems remained free of detectable virus infection as judged from symptomless growth for 16 months and electron microscopic examination of both sap and ultrathin sections of leaf tissue.

ISSN:0143-6147    

DOI:10.1080/09670878009414390

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The influence of ecosystems on cassava (Manihot escutentaCrantz) cultivars and the possible reasons for this are discussed, as well as the effect of distinct negative production factors, i.e., edaphic and climatic constraints, and disease and pest stresses, on regional and introduced varieties. Decentralised improvement programmes in different ecosystems based on 10 years research are suggested, and are selected according to socioagro-economic studies related to actual and/or potential production of cassava.

ISSN:0143-6147    

DOI:10.1080/09670878009414391

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The Yemen Arab Republic is divided into four main areas according to the climatic conditions. These areas are the coastal plains, the foothills and midlands, the central highlands and the eastern areas. A range of crops are grown in these areas using traditional agricultural methods. Yields are low and disease is one of the factors affecting them. Surveys of economically important diseases have previously been undertaken and the results of these together with a survey carried out by the authors during the period June 1976 – June 1978 are presented. A revised list of plant diseases for several crops is given and includes new, previously unpublished records.

ISSN:0143-6147    

DOI:10.1080/09670878009414392

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor