摘要:

The invasion of New South Wales for the first time on record by swarms of spur-throated locust,Austracris guttulosa, in 1973 and the course of the plague persisting for three seasons are described.

ISSN:0309-7943    

DOI:10.1080/09670877909412089

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Major pests of tea and their natural enemies on record in India and Sri Lanka are presented with emphasis on their utility. Mite pests of tea are subjected to predation mainly by coccinellids and phytoseiid mites to a considerable extent in those gardens where insecticidal applications are restricted. Effective control ofHomona coffeaein Sri Lanka was achieved with the larval parasiteMacrocentrus. In northeast India the leaf rollerGracillaria theivorawas kept in check by two efficient parasites, and a bacterial disease ofArdraca bipunctataalmost prevented outbreaks of that pest. The artificial dissemination of bacteria and granulosis virus could help to spread these diseases among nettle grubs. Insecticidal applications may adversely affect the parasites and predators of the untargeted pests and could cause outbreaks of minor pests such asHomona and Gracillaria. The use of chemical pesticides can be minimised by integrating with the other available methods of control.

ISSN:0309-7943    

DOI:10.1080/09670877909412090

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The toxicity and efficacy of the acute rodenticide zinc phosphide (Zn3P2) was evaluated in the laboratory against the lesser bandicoot rat (Bandicota bengalensis), from Rangoon, Burma. The acute LD50 and LD95 doses of orally-administered zinc phosphide forB. bengalensiswere found to be 25.0 mg/kg and 113.0 mg/kg of body weight respectively. When caged bandicoots were given a choice between plain and poison baits, the optimum rodenticidal concentrations in the bait was found to be 2.5%. Symptoms of poisoning appear from 32 minutes to 3 hours after feeding starts, giving individual animals time to consume from 10 to over 27 LD50 doses of 25% zinc phosphide before feeding stops. Death occurred in a minimum of 4 to 5 hours following either oral dosing or free choice feeding. There appears to be aversion to the poison at higher concentrations in food baits. The relative merits of zinc phosphide and pyriminyl as rodenticides against the lesser bandicoot in Rangoon will have to be determined in a series of comparative field trials.

ISSN:0309-7943    

DOI:10.1080/09670877909412091

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

There was a severe outbreak of rodents in the San Bernardo valley of southern Honduras in 1974–5. Extensive damage was inflicted on a variety of field crops grown in close proximity and maturing in succession. The identity of the rodent species concerned was not established during the outbreak but only the grey-bellied cotton rat,Sigmodon hispidus griseusAllen, was found later in rice, maize, sugarcane and cotton fields. Damage to these and to other crops grown in Central American countries and in southern areas of the USA has been similarly attributed to cotton rats, but there is no reliable data on the actual losses incurred. Crop damage is most severe when cotton rat populations have cycled to peak abundance or when there is large-scale movement due to exceptional climatic conditions. The outbreak in cultivated fields in Honduras followed the flooding of peripheral lowlands. In this paper widely scattered literature on the population biology and control of the cotton rat has been collated. The distribution, reproduction and behaviour of cotton rats is reviewed together with existing recommended land management and chemical control practices. Attention is drawn to potential preventative measures requiring further investigation.

ISSN:0309-7943    

DOI:10.1080/09670877909412092

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Weekly high volume (h.v.) captafol spray applications at 3 kg/ha have been compared with very low volume (v.l.v.) sprays at 3, 2 and 1 kg/ha. The v.l.v. sprays at 3 and 2 kg/ha were as effective as the h.v. treatment. An assessment of the v.l.v. spray drift indicated a maximum swath of 3 m. Further trials at four sites using h.v. and v.l.v. captafol sprays at 7- and 14-day frequencies showed that weekly sprays were more effective at the wetter locations, but at all sites captafol applications were economically viable.

ISSN:0309-7943    

DOI:10.1080/09670877909412093

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Many fungi have been associated withColasp. One of the most important fungi implicated in cola diseases isBotryodiplodia theobromaewhich causes a hard black rot of nuts and a shoot die-back of the twigs. Some of the fungi which attack the nuts infect them at an early stage in the development of the fruit, but remain latent until conditions become favourable for disease development.Fomesspp.,Phellinusspp. andRigidoporus lignosus, arethe major root pathogens causing rots which may lead to the death of the host. Virus diseases have been suspected on commercial cola, but transmission tests have so far failed to confirm their presence.

ISSN:0309-7943    

DOI:10.1080/09670877909412094

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Two diseases of African oil palm (Elaeis guineensisJacq.),marchitez sorpresivaand lethal spear rot, have caused sufficiently severe losses in South and Central America to limit further planting of this crop in some regions. The etiology of these diseases is still incompletely understood but resistance to both diseases is reported in the South American speciesE. oleifcra(E. melanococea) and hybrids between these andE. guineensis.

ISSN:0309-7943    

DOI:10.1080/09670877909412095

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Studies on weed control in chickpea revealed that weed control through cultural methods effectively reduced the crop-weed competition, resulting in higher grain production. Prometryne at 0.50 kg a.i./ha proved the most effective of a number of herbicide treatments and could provide an alternative control method for weeds in this crop.

ISSN:0309-7943    

DOI:10.1080/09670877909412096

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

There is a pattern of succession of weeds in man-made African lakes. Each phase of succession differs in each lake depending on the local environment. Floating weeds develop first, followed by sudd, a later decrease in floating weeds, an increase in submerged weeds, and finally an emergent drawdown flora. The stages in this sequence may be very pronounced in some lakes, or may be virtually absent in others.

ISSN:0309-7943    

DOI:10.1080/09670877909412097

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Chemical weed control is playing an increasing role in Nigerian agriculture due to the increasing cost and widespread unavailability of the labour required to carry out traditional practices. Nigeria's drive towards increased food production must involve a systematic approach to weed control based on a good understanding of weed biology and ecology. The objectives of such an approach must be the development of effective control methods which are efficient in the use of available resources and within the reach of the farmers. This paper reviews the major weed problems, the status of weed science research, and some constraints to herbicide use in Nigeria.

ISSN:0309-7943    

DOI:10.1080/09670877909412098

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor