摘要:

Schistosoma mansoniwas first recorded in Brazil in 1908, currently official estimates are that schistosomiasis is endemic in 1,000 municipalities and possibly ten million individuals are infected. Infection foci are rural communities and irrigated areas without sewage disposal facilities. In the past The Servicio Especial de Saúde Publica: The Servico Nacional de Malaria and later the Department of Rural Endemic Diseases (DNERu) attempted with some success to control the intermediate hosts,Biomphalarlaspp., and improve sanitation and water supplies. Following examination of past policies DNERu in 1965 authorised the organisation of pilot projects for the control of schistosomiasis in 4 states: Pernambuco, Bahia, Minas Gerais, and Gaunabara. In 1970 the results of the pilot projects were evaluated and recommendations made regarding drug treatment and snail control for immediate use by the Superintendencia de Campanhas of the Federal Ministry of Health, involving the use of the drug Hycanthone, the molluscicide niclosamide (Bayluscide) and complimentary measures such as drainage and education in basic sanitation. In the future with the greater urbanisation of Brazil and increasing number of irrigation projects the incidence of the disease could increase. Improvements in sanitation, education and nutritional state will counteract this.

ISSN:0030-7793    

DOI:10.1080/09670877409411850

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

In all cases assessed yield loss from rat damage in coconut plantations has been based on counts of immature damaged nuts, it being assumed that yield loss was directly proportional to the number of nuts attacked. Insect attack on coconuts and other crops has indicated that compensation for pest damage can occur, hence counts of immature damaged coconuts were unlikely to be directly related to yield loss. A trial involving artificial rat damage at four intensities was therefore established to investigate the relationship between damage and yield. Several possible compensatory modes were investigated and two responses were noteable: 1. The number of female flowers increased in response to the loss of immature coconuts but this compensatory response could not influence the number of harvestable nuts until 23-24 months after damage started, since this represents the time lapse from flower formation to nut maturity. 2. There was no apparent decrease in the number of harvestable nuts produced by the highest levels of artificial damage and it was postulated that there could be a decrease in late immature nutfall caused by factors other than rat attack, since the flower responses were ineffective within the two years.

ISSN:0030-7793    

DOI:10.1080/09670877409411851

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Rattus norvegicusoccurs in Singapore, with several other commensal rodent species. This preliminary study examined populations and a possible control method in urban and semi-urban areas. Commensal rats are generally undesirable, and a possible role forR. norvegicusin spreading any introduced plague is a particular worry. Populations were examined by catch, mark, release (CMR) and by removal (regression) methods. Species and numbers indicated by removal were—R. norvegicus(57.4, 31.9 and 48.5/ha in different trials),R. exulans(37.2/ha) andMus musculus(8.3/ha). There were indications that these figures were very considerable underestimates; a Lincoln Index, using recovered dead rats (after poisoning in a CMR Plot) as the second sample, estimatedR. norvegicusat 985/ha (i.e. in a ca 0.6 ha plot—618 ± 694); the recovery of only three out of 32 marked rats, and the presence of many dead but uncollected rats, even though more than the number estimated by removal was picked up in the plot (58) Banana, coconut and dried fish cage baits all trapped rats. Maize cakes were not worth the extra labour. Analysis of catch by trap position suggested thatR. exulansis more common upon roofs,R. norvegicuswas absent from a semi-rural environment in whichR. r. diardiiwas common. In a control programme, wax-bound maize-based anticoagulant baits were used—distributed at 91/ha, replaced, at 2—4 day intervals if accepted, to total nine rounds and 818 baits/ha at a cost of M$21.00. Acceptance of baits was high initially, and further trapping showed that reasonable control had been obtained. This method seems more appropriate to the conditions than the permanent baiting stations used in temperate areas, because of the lack of discrete points in sewers etc., the disrupting influence of frequent tropical storms, rapid deterioration of baits, and competition from other animals, particularly ants. Drawbacks include the danger to non-target animals from the baits and the temporary stench of dead rats.

ISSN:0030-7793    

DOI:10.1080/09670877409411852

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

The present status of weed control in the major tropical root and tuber crops is reviewed. The importance of early weeding is emphasised and summaries of the results obtained with herbicides are given.

ISSN:0030-7793    

DOI:10.1080/09670877409411853

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Results of field experiments, with sodium, amine and ester formulations of 2,4-D, terbutryne, hand weeding and unweeded controls, with and without post sowing planking, showed that terbutryne applied post-emergence almost completely eliminated weed competition from wheat on a clay loam soil notorious for weed growth, and gave a significantly higher grain yield when compared with the standard 2,4-D treatments. As a result of terbutryne applied post-emergence mean increases in grain yield over the unweeded control, 2,4-D sodium, 2,4-D amine, 2,4-D ester and hand weeding were 14.53, 6.94, 9.54, 7.26 and 8.77 quintals (q)/ha; 41.70, 16.30 23.90, 17.20 and 29.06% respectively. Weed dry matter was reduced by 18.57, 6.26, 6.36, 6.31 and 5.87 q/ha respectively. Terbutryne also reduced difficult to control weeds likePhalaris minorandAvena fatua. The use of terbutryne was shown to be economically sound. Post sowing planking seemed to reduce seedling emergence, increase weed dry matter and slightly reduce grain production. On average post sowing planking decreased wheat yield by 1.73 q/ha, 4.23%.

ISSN:0030-7793    

DOI:10.1080/09670877409411854

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

More than 70 species of arthropods were found to feed on waterhyacinth,Eichhornia crassipes(Mart.) Solms, in South America, the United States, and India. Those that were destructive were divided into categories based on the type of damage produced, that is, (1) defoliators and external leaf feeders, represented byCornopsspp. (Orthoptera: Acrididae), and adultNeochetinaspp. (Coleoptera: Curculionidae); (2) petiole borers, represented byAcigona infusella(Walker) andEpipagis albiguttalis(Warren) (Lepidoptera: Pyralidae),Arzama densaWalker (Lepidoptera: Noctuidae), and larvalNeochetinaspp.; (3) leaf tunnel producers, represented byOrthogalumna terebrantisWallwork (Acarina: Galumnidae); and (4) scavenger species such asDyscinetusspp. (Coleoptera: Scarabaeidae), which enhance the effect of attack by other insects. This damage is also often amplified by pathogens and other less abundant arthropods.

ISSN:0030-7793    

DOI:10.1080/09670877409411855

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Tobacco in Malawi often suffers from outbreaks of anthracnose caused byColletotrichum tabacum(Boning); particularly at the seedling stage. In order to identify suitable sources of resistance for use in a breeding programme three varieties ofNicotiana tabacumand eight otherNicotianaspecies were tested in the greenhouse trials, three varieties ofN. tabacumand five otherNicotianaspecies were tested in seedbed trials. The most promising sources appeared to beN. sanderaeorN. debneyi, and possiblyN. nudicaulisorN. forgetiana.

ISSN:0030-7793    

DOI:10.1080/09670877409411856

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Screening tests on 162 tomato cultivars and hybrids conducted at the Division of Horticulture, Indian Agricultural Research Institute, New Delhi during 1967-8 indicated a high degree of resistance to root-knot nematodes in Nematex, VFN-8, 65N215-1, 65N255-1 and S1-120, under field and laboratory conditions. The degree of resistance varied with the species ofMeloidogyne. Nematex was immune toM. javanica, M. incognitaandM. arenaria. VFN-8, 65N215-1 and 65N255-1 were immune toM. incognitaandM. arenariaand resistant toM. javanica. S1-120, a commercial cultivar, showed a high degree of tolerance toM. javanica, M. incognitaandM. arenaria. The degree of resistance varied with nematode population density.

ISSN:0030-7793    

DOI:10.1080/09670877409411857

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

A survey of pesticide usage in India was conducted. Frequently poor or negative results were obtained from pesticide application as a result of improper use. A number of situations are discussed. Toxicity hazards to the crops and operators are also considered.

ISSN:0030-7793    

DOI:10.1080/09670877409411858

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

ISSN:0030-7793    

DOI:10.1080/09670877409411859

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor