摘要:

Farmer surveys were conducted in the Yaqui Valley, Sonora, Mexico during 1983 and 1985 to investigate the relationship between agronomic practices used by the farmers and the incidence of Karnal bunt (Tilletia indica)disease of wheat.The variables investigated included soil type, land preparation, origin of seed, irrigation, nitrogen fertilizer, weed control and crop rotations. None of these variables were found to have a significant influence on the disease. This indicates that although management practices may have some effect on the incidence of the disease they are not the primary factor. The coincidence of rainfall and/or high humidity at flowering time appears to be of more importance than agronomic practices.

ISSN:0143-6147    

DOI:10.1080/09670878809371280

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Cigar‐end disease of banana,Verticillium theobromaehas become apparent in the southern region of Oman, and is prevalent under warm and humid conditions. Benomyl and thiabendazole were found to effectively controlV. theobromaein artificially induced cigar‐end disease.

ISSN:0143-6147    

DOI:10.1080/09670878809371281

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Short duration legumes such as cowpea(Vigna unguiculata) urdbean (Vigna mungo) and mungbean (Vigna radiata) intercropped with pigeonpea suppressed weed flora by 20–45% over sole pigeonpea (unweeded check) and proved more productive under rainfed conditions. Intercropping under uniform row planting pattern (pigeonpea rows at 60 cm with one row of intercrop in between) was more efficient in weed suppression as well as in total productivity compared with paired row planting at 40/80 cm distance. Unchecked weeds caused yield loss of 678 kg/ha in sole pigeonpea which was compensated by intercroppping mungbean. This postulates that one can overlook weed control in rainfed pigeonpea without any economical loss if mungbean is intercropped. This information is of immense significance in view of high cost of weed control measures.

ISSN:0143-6147    

DOI:10.1080/09670878809371282

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Imazapyr rapidly penetrates and translocates throughoutImperata cylindrica(L.) Raeuschel in the first four days after treatment. Leaf elongation ceases within one day after treatment and water usage, on both a per plant basis and a per leaf basis, decreases to approximately 20% of the untreated plant within 5 days after treatment.

ISSN:0143-6147    

DOI:10.1080/09670878809371283

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Root‐knot nematode,Meloidogyne incognita(Kofoid and White, 1919) Chitwood, 1949, Race 1, is widely distributed in agricultural soils of northern Nigeria and has been shown to limit production of various commonly grown crops such as tomato, chilli, okra, cowpea, yam, rice etc. Certain cultivars of maize (Zea maysL.), the third most important cereal crop in Nigeria after rice and sorghum, have been found to be resistant to this nematode in varying degrees elsewhere in the world. In the absence of any such information in Nigeria, 30 cultivars of maize were tested for their reaction to the infection of this nematode under screenhouse conditions and all were found to be resistant and, therefore, suitable for inclusion as poor or nonhosts in any crop rotation programme.

ISSN:0143-6147    

DOI:10.1080/09670878809371284

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Bird predation of pod borers of field beans (Lablab niger) was determined in Bangalore. The house crowCorvus splendensappeared the most important predator and its feeding rate (4 ± 0·2 larvae/min) and numbers (>200/Km2) at the study sites were higher than other insectivorous birds. Multiple cropping patterns promoted higher predation rates than pure stands ofL. niger.Seed‐yield loss in field beans was negatively correlated with the index of species richness. Seed yields in the site with the highest species index were almost 39% greater than those in the site with the least number of bird species.

ISSN:0143-6147    

DOI:10.1080/09670878809371285

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Eleven young indigenous sheep and 11 goats in an extensive rangeland were kept virtually tick free for six months with a long acting synthetic pyrethroid ‘pour‐on’ formulation. Their performance in terms of liveweight gain (LWG) was compared with an untreated group. All animals in the trial were intensively dewormed. The total LWG in sheep was 0–7 kg and in goats 0·8 kg greater than the control groups (P= 1·0), despite the significantly different tick numbers they were carrying. Tick control did not increase productivity. The ‘pour‐on’ ectoparasiticide was a more economical and effective method than dipping. However, the results do not suggest any economic need for tick control on indigenous small ruminants in this environment.

ISSN:0143-6147    

DOI:10.1080/09670878809371286

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Twelve Insecticides were evaluated for comparative toxicities toApanteles taragamaea common parasite of several lepidopterous pests particularly the black headed caterpillar,Opisina arenosellawlk.

ISSN:0143-6147    

DOI:10.1080/09670878809371287

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The reproducibility of topical application data is influenced by test duration and the definition of death. These parameters were varied in tests with fall armyworms,Spodoptera frugiperda(J. E. Smith), to determine conditions which gave the most uniform results. Assessments where moribund insects are considered dead most closely approximate ‘actual’ mortality (i.e. at 7 days both methods gave equivalent results). With this criterion, reliable data can be obtained within 48 h. We recommend combining the ESA guidelines for test duration with the FAO guidelines for evaluating mortality. A method for analyzing the reliability of probit data from repeated tests, where the same insects are evaluated under different mortality criteria, is developed.

ISSN:0143-6147    

DOI:10.1080/09670878809371288

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Psalydolytta fuscais the most serious pest of pearl millet among ten meloid species feeding on millet spikes in The Gambia. It occurs countrywide with distinct ‘hot spot’ areas. The average abundance varies from 0·lb2 to 2·lb4 beetles per millet hill, but maxima of 30 beetles per hill have been recorded. Screen‐house experiments showed a destruction capacity per beetle of one 35–40 cm sized early millet spike in 15 days. With an average of 5 spikes per hill, the total damage to early millet in The Gambia may range between 4 and 48% per year. Varieties of millet with long‐bristled spikes were shown to be far less susceptible toP. fuscathan varieties with very short‐bristled spikes. A local long‐bristled variety of early millet was not only less susceptible toP. fuscathan the normafly used short‐bristled varieties in various parts of the country, but also to the millet spike borerRaghuvaweaverbirds and, possibly, smut. The long‐bristled variety yielded more in most localities. A traditional control method using fires in the fields was shown to repelP. fuscafrom spikes when a fuel which produced heavy smoke (groundnut Shells, moist wood) was used. Pesticide control trials showed that carbaryl, trichlorphon and probably malathion can controlP. fuscasatisfactorily.

ISSN:0143-6147    

DOI:10.1080/09670878809371289

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor