摘要:

The location and climate of Zambia are described, together with the types of farming practiced and the organisation of the plant pathology diagnostic and advisory services. The phytosanitary arrangements are discussed. The main diseases, in Zambia, of maize, rice and other cereal crops, groundnut, cassava, cotton and kenaf, sugarcane, tobacco and other field crops, potato, tomato, brassicas, cucurbits, phaseolus beans and other vegetables, coffee and fruit crops are reviewed and the currently recommended control practices are given.

ISSN:0030-7793    

DOI:10.1080/09670877409413629

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Leaf scald of rice (Rhynchosporium oryzaeHashioka & Yokogi) is reported from Brunei. The influence of cultivation system and fertiliser regime on the severity of the disease is discussed. The presence of adequate nitrogen appears to increase the severity of the disease. Leaf scald has the potential of becoming a serious threat to rice in the area.

ISSN:0030-7793    

DOI:10.1080/09670877409413630

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Phytopathogens have characteristics that make them desirable candidates as biological control agents for aquatic weeds: 1. numerous and highly diverse, 2. easily disseminated and self-maintaining, 3. often host-specific, 4. non-pathogenic to animals and 5. capable of limiting populations without eliminating the species. Phytopathogens have been little investigated for the biological control of water weeds. Recent efforts have revealed several diseases with the potential for exerting a degree of control over populations of water hyacinth (Eichhornia crassipes), hydrilla (Hydrilla verticillata) and alligator-weed, (Alternanthera philoxeroides). These include a blight and leafspot of water hyacinth caused byRhizoctonia solaniandCephalosporium zonatumrespectively, a root and crown rot of water hyacinth of unknown cause, a virus-induced stunt of alligator-weed, aPenicilliumlysogenic to hydrilla and a pythium-induced blight of hydrilla.

ISSN:0030-7793    

DOI:10.1080/09670877409413631

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Paraquat applied as a directed inter-row spray gave economical control of weeds in cassava for a period of three months or more. Applications were made at rates of 0.2–0.4 kg/ha post-emergence in young cassava of 3 months or more with 15–20 cm of brown bark at the base of the stems; a repeat application was made after an interval of 10–14 days. Usually, one further spray was required to obtain acceptable weed control until harvesting, weed control being facilitated by the increased shade given by the developing crop canopy.

ISSN:0030-7793    

DOI:10.1080/09670877409413632

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Organochlorine, organophosphate (o.p.) and carbamate insecticides have been extensively used in Australia to combatLucilia cuprinaWied. the main initiator of fly-strike of sheep occurring wherever sheep are run on the continent. The improved mules operation, mid-season crutching and insecticides are important in the management of Merino sheep. Insecticides are particularly valuable against body strike, especially in young sheep, in years with intermittent rain during the warmer months. Resistance to larvicides developed in the blowfly over a period of 10y from 1957. The time between the introduction of various insecticides and development of resistance is considered and a comparison made between the emergence of resistance problems to the newer synthetic insecticides in the housefly in Denmark, and in the blowfly in Australia. To provide a complete history of insecticides against the blowfly reference is made to arsenicals, to which there was no suspicion of resistance until low order cross resistance was diagnosed in o.p.-carbamate resistant strains. Some seven years after their introduction DDT and γ BHC were replaced by cyclodiene insecticides in 1954/1955. Reasons are advanced to explain the non-emergence of resistance to DDT and BHC in that period. Resistance to dieldrin and aldrin developed in late 1957 after which diazinon was introduced. The resistance has a typical BHC/dieldrin resistance spectrum and is due to a semi-dominant gene which has persisted in the field in the absence of pressure from cyclodiene insecticides. Non-specific resistance to o.p. insecticides developed in two steps. Low order resistance, diagnosed in 1965, was supplemented by an additional resistance mechanism in 1966, three alleles on two chromosomes are involved. The carbamate, butacarb, was effective against o.p. resistant strains of the blowfly when introduced in the 1966/67 season. In 1967, resistance to butacarb was diagnosed and rapidly became widespread. For the past three fly seasons larvae have been used to monitor resistance levels to o.p. and carbamate insecticides; resistance factors to both these classes of insecticide are significantly higher in larvae than adult females. Resistance levels to o.p. insecticides have stabilised. By contrast resistance levels to butacarb have doubled. A combined o p.-carbamate resistance generally applies in field samples. Larvae from o.p.-carbamate resistant strains form artificial strikes earlier than susceptible larvae, particularly on sheep treated with butacarb. It is concluded that registered o.p. insecticides, but not butacarb, will still give considerable protection against fly-strike, providing the maximum levels of o.p. resistance, reached in laboratory selection programmes, are not exceeded in the field. Investigation into o.p. resistance in the species suggests that the resistance mechanisms place their carriers at a disadvantage in the absence of selection pressure. Measures to minimise the amount of insecticide used against the blowfly are therefore strongly advocated—these include: the improved mules operation, mid season crutching and good animal husbandry.

ISSN:0030-7793    

DOI:10.1080/09670877409413633

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

A new pest of cocoa in the British Solomon Islands,Megaceresium horniHeller (Cerambycidae), is described. The larvae cause severe damage to branches by tunnelling through the pith and sapwood, one larva may kill up to 3 m of branch in 4–6 weeks. In the outbreak reported, up to 5 branches per tree were infested on 58% of the trees. An intensive campaign of pruning and burning infested branches at 3–4 day intervals for one month, followed by pruning at two weekly intervals for three months, reduced the level of infestation from over 100 larvae per 100 trees to 2 per 100.

ISSN:0030-7793    

DOI:10.1080/09670877409413634

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

ULV applications of technical malathion (0.15–0.58l/ha), using a Cessna 300B Agwagon fitted with four AU 3000 Britten Norman Micronair units, gave satisfactory control of mosquitoes (Aedes taeniorhynchus) in mangrove swamp habitats on Grand Cayman. Spraying began just prior to sunset when conditions were most suitable. Using swath widths of 182 m, 1600 ha could be sprayed in one sortie. The vmd of the droplets in all trials was between 56–92 μm for outputs of 3.8–15.2l/min. Between 0.07 and 0.58l/ha the mean number of droplets varied between 8 and 34/cm2. After applications of 0.15–0.58l/ha light trap and vehicle operated cone trap mosquito counts were reduced. Satisfactory reductions of mosquitoes occurred after an application of 1% synergised pyrethrum in diesoline (0.73l/ha). Spraying 0.5% bioresmethrin in diesoline at 0.73l/ha initially reduced mosquito numbers considerably, but a brood of adults emerging immediately after spraying compensated for the losses.

ISSN:0030-7793    

DOI:10.1080/09670877409413635

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

摘要:

Snakes are very common in many tropical countries, especially in rural areas, although most are not poisonous, a minority are highly venomous. Snakebite can be a serious medical problem for agricultural workers, fishermen, and so on because they encounter venomous snakes during their work. Thus, snakebite is a rural and an occupational hazard. Only a few of the many different types of venomous snakes are known to constitute a serious hazard to human beings, and the commoner species are briefly described. Snake venoms are highly toxic and all the poisonous snakes mentioned have more than enough venom to kill a man if this venom were all injected by the bite. Fortunately, when a venomous snake bites man, it is a defensive or warning bite when little or even no venom is usually injectedhence most human victims do not have serious poisoning.In rarer cases, significant amounts of venom may be injected leading to serious, even fatal poisoning. A brief account is given of the two main types of poisoning—general bleeding in viper bites, and paralysis in bites by elapid snakes (cobras, mambas, and so on). Prevention of snakebite is a matter mainly of common sense. First-aid treatment is discussed: 1. Do not panicl 2. Cover the site of the bite (but do not incise). 3. Apply a tourniquet. 4. Go to the nearest hospital. Antivenom is a specific medical treatment, needed only in serious poisoning when it is highly successful if correctly used (even many hours after the bite), if wrongly used, its effects can be more dangerous than those of the snakebite. Generally therefore, antivenom plays no part in the first-aid treatment of snakebite.

ISSN:0030-7793    

DOI:10.1080/09670877409413636

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

ISSN:0030-7793    

DOI:10.1080/09670877409413637

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor

ISSN:0030-7793    

DOI:10.1080/09670877409413638

出版商:Taylor & Francis Group    

年代:1974

数据来源: Taylor