摘要:

Sprays of malathion and fenitrothion were used for the control of antestia bugs (Antestiopsisspp.), from 1961–74, in order to assess the effect of these insects on the yield and quality of smallholder arabica coffee in Bugisu district Uganda. Insecticide application nearly always gave economically worthwhile increases in yield of coffee cherry but these were not usually significant, except when the mean population of antestia was about two per tree or higher. Spraying also reduced the percentage of badly damaged beans and improved the yield from coffee cherry of good dry beans. Two or three sprays of fenitrothion 50% e.c. at 1.1l/ha were no more effective than a single spray in February but antestia populations were low in these particular trials.

ISSN:0309-7943    

DOI:10.1080/09670877909411653

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Endosulfan and trichlorphon at 0.03% and 0.06%; carbaryl (0.05% and 0.1%) and methomyl (0.025% and 0.05%) were used as treatments to controlSpodoptera lituraand, with and without sticker,Scrobipalpa heliopain nursery tobacco. Four treatments were applied; 14, 24, 34 and 44 days after germination. Carbaryl and trichlorphon gave the most effective control ofSpodoptera lituraand endosulfan was the only effective treatment forScrobipalpa heliopa.

ISSN:0309-7943    

DOI:10.1080/09670877909411654

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Of a range of insecticides evaluated in field trials for control of thrips on onions methomyl, malathion and phenthoate showed consistent effectiveness. Duration of insecticidal activity was short and only 10–14 days after application a rapid increase in the nymphal population occurred. For successful control of thrips on late transplanted onions initiation of spraying programmes was indicated when the level of infestation reached 5–10 nymphs per plant.

ISSN:0309-7943    

DOI:10.1080/09670877909411655

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Groundnut rust (Puccinia arachidis), which has long been considered as endemic to the Western Hemisphere, has spread to many countries in Asia, Australia and Africa in recent years. In India it was first observed in 1969 in Punjab State and subsequently in many other groundnut growing states. In our surveys we observed severe damage to the crop in Tamilnadu, Andhra Pradesh and parts of Karnataka and Maharashtra States. The pathogen is very well established in these States probably because of extensive and continuous cropping. Although we noted rust in Gujarat State the damage to the crop was negligible. This is the first report of groundnut rust in Gujarat. The disease was not found by us in Punjab State. Only uredospores were noticed on specimens collected from different parts of India.

ISSN:0309-7943    

DOI:10.1080/09670877909411656

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

A brief outline of the citrus industry in Belize is given, with reference to the crop cycle and its relationship to climate. The main pest, disease and cultural factors affecting production are reviewed. The history of premature fruitdrop disease caused byColletotrichum gloeosporioidesPenz. is traced, with a description of symptoms, epidemiology and the development of disease control programmes up to 1975. Problems encountered in the effective application of fungicide sprays are described, and the future research programme is outlined.

ISSN:0309-7943    

DOI:10.1080/09670877909411657

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

A serious decline of mukwa (Pterocarpus angolensisDC.), a timber tree of considerable economic importance, has caused concern in parts of southern Africa for many years. Dieback and deaths have variously been investigated in the past and attributed to a succession of drought years. A new and discrete vascular wilt disease, characterised by a combination of distinctive crown symptoms with streaks of vascular discolouration in the youngest sapwood, is described from Zambia.Fusarium oxysporumSchlect is provisionally regarded as the causal organism. The widespread decline phenomenon is interpreted in the light of this disease which is named mukwa wilt and now dominates the pathology of mukwa, and is the most important disease of an indigenous tree species in Zambia.

ISSN:0309-7943    

DOI:10.1080/09670877909411658

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Forty-seven plant nematode species were found associated with 33 crops, bringing the total number of plant nematode species reported from the state to 68.Meloidogyne incognita, M. arenaria, Pratylenchus zeae, Tylenchorhynchus brassicae, Tylenchulus semipenetrans, Rotylenchulus reniformis, Xiphincma americanum, Heterodera avenaeandH. zeaecause extensive damage. Vegetables were the most adversely affected of all the crops investigated.

ISSN:0309-7943    

DOI:10.1080/09670877909411659

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

The effectiveness of butralin (2.0 and 4.0 kg a.i./ha pre-plant, 2.0 and 4.0 kg a.i./ha pre-em), chlorthal-dimethyl (10.0 and 12.0 kg a.i./ha pre-em), trifluralin (0.6 and 1.1 kg a.i./ha pre-plant) chloramben (2.0 kg a.i./ha pre-em) and nitrofen (2.0 kg a.i./ha pre-em) in controlling weeds in transplanted ‘Kono Cross’ cabbage and the influence of these treatments on the yield and quality of marketable heads and on the economics of weed control were evaluated in three replicated field experiments on River Estate loam soil in Trinidad during the wet seasons of 1976 and 1977. While herbicides did not affect the size of the cabbage plant population or the date to maturity of the crops, they reduced the cost of weed control by over 30% and increased the net returns relative to the clean-weeded control by over 9%. Butralin at 4.0 kg a.i./ha pre-plant and pre-em and the trifluralin treatments were superior to nitrofen which gave good weed control up to five weeks and higher yields than the clean-weeded control. Chlorthal-dimethyl gave encouraging results but caused slight, temporary stunting. The application of one of these treatments followed by one hand weeding at about four weeks should give full-season weed control and an acceptable yield of marketable heads with increased financial returns. Chloramben was the least effective herbicide tested and its use may not be justified under similar conditions to those of this study.

ISSN:0309-7943    

DOI:10.1080/09670877909411660

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Pre-plant and pre-emergence herbicides were tested for effective weed control in a seed crop of okra during 1974–75 and 1975–76. All treatments significantly decreased the weed population and increased the seed yield as compared to the unweeded control. Fluchloralin (0.90 and 1.20 kg a.i./ha pre-plant), alachlor (2.50 kg a.i./ha pre-em) and EPTC plus alachlor (3.75 kg a.i./ha pre-plant and 1.25 kg a.i./ha pre-em) proved to be the most effective and economical treatments. No residual effects were observed with any herbicide on the succeeding crops of radish, carrot, turnips, peas and spinach.

ISSN:0309-7943    

DOI:10.1080/09670877909411661

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor

摘要:

Using patternators, the uniformity of coverage, the spray length and the possible contribution to drift problems were compared for two hydraulic cone nozzles and five ‘off-centre’ fan nozzles. The nozzles were fitted to high powered spraying equipment intended for use on horizontal targets such as water hyacinthEichhornia crassipes(Mart.) Solms. The distribution patterns obtained and the coefficients of the proportion of acceptably even coverage within the spray length (CAC) are presented. ‘Off-centre’ fan nozzles provided a longer acceptably even coverage over their spray length and contributed less to drift problems than cone nozzles.

ISSN:0309-7943    

DOI:10.1080/09670877909411662

出版商:Taylor & Francis Group    

年代:1979

数据来源: Taylor