摘要:

The application of deltamethrin (Decis) 2.5 EC, cypermethrin (Ripcord) 10 EC and malathion 57% EC at 10 day intervals (four sprays in total) significantly reduced the melon fly,Dacus cucurbitaeCoquillett, infestation on melon (4.8–7.9%) compared with the untreated control (14.1%). Malathion was the most effective insecticide. Mixing 2% molasses or 0.25% protein hydrolysate with the insecticides did not further reduce the infestation. In an experiment using squashmelon(Cucurbita melopepo)as a trap crop in melon, fruit infestation was about 1.5‐times greater than that on melon (15.5 compared to 10.2%). The infestation in the untreated control melon plots was 19.2%, indicating that intercropping squashmelon with melon can reduce fly attack on melon. By using pieces of melon treated with trichlorphon (Dipterex) 80SP (spot‐treatment) the fruit infestation was reduced by 50% compared with the untreated control. Based on the cost‐benefit ratio, the best control technique was the dusting of ash (1:9), followed by growing squashmelon in melon as a trap crop (1:7.9) and using poisoned cut‐melons (1:2.7).

ISSN:0143-6147    

DOI:10.1080/09670879209371705

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Prophylactic fungicidal seed treatment, foliar fungicidal sprays and insecticidal sprays were compared in different combinations against the major pea pest complex. The severity of powdery mildew(Erysiphe polygoni)rust(Uromyces vinciae‐fabae)and leaf blight (Ascochyta pisi)and damage caused by pod borer (Etiella zlnckenella)and leaf miner (Chromatomyia horticola)were recorded at their lowest level in treatments where fungicidal and insecticidal treatments were combined. The highest yield of 15.88 q/ha (quintals per hectare) was obtained when seeds were treated with carbendazim and thiram combined with two fungicidal foliar sprays each of mancozeb and dinocap followed by a single insecticidal spray of endosulfan. Results indicate that a combination of seed treatment, fungicidal sprays and insecticidal spray was more successful against the pea pest complex and increased yields compared to fungicides and insecticides used separately. Seed treatment alone did not reduce the severity of the diseases studied.

ISSN:0143-6147    

DOI:10.1080/09670879209371706

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The use of groundnut oil and steam treatment were compared with pirimiphos‐methyl treatment for control ofCallosobruchus maculatus(Coleoptera: Bruchidae) in stored cowpea grain in The Gambia, West Africa. One susceptible and two bruchid‐resistant varieties were compared under the different treatments. Steaming the cowpeas offered no permanent protection although it may be an effective sanitation technique. When used in conjunction with a bruchid‐resistant variety, groundnut oil appears nearly as effective as pirimiphos‐methyl applied to a local, non‐resistant variety and the combination could offer a simple, effective method for protection of cowpea grain in similar regions.

ISSN:0143-6147    

DOI:10.1080/09670879209371707

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

An early recommended control measure for cocoa pod borer (CBP) in Sabah was frequent thorough harvesting to a low standard of ripeness, here called regular complete harvesting (RCH). This reduces the opportunity for CPB to complete its development. Chemical sprays were also recommended, commonly five applications of BHC or a synthetic pyrethroid at 10 day intervals, during the period of trough crop, or recently, spraying in response to infestation levels. This paper reports a trial that demonstrated the effect of RCH. Economic control is achieved if 50% or fewer pods are infested and this can easily be achieved by RCH. A late commercial‐scale trial confirmed that it could bring infestation to much lower levels, whilst spraying made little difference. The trials assessed spraying in response to CPB thresholds. Initially spray was in response to moth capture in pheromone traps (January‐June 1986), later to pod infestation level. The field was split into two, with a low infestation threshold in one part (L), and a high one in the other (H). Infestation followed the expected pattern, rising in crop troughs (July to September), and declining in peaks. Despite frequent spraying in L area and very little in H, infestations were similar. In 1988, when RCH was stressed, infestation started low in both areas, crossing only the L threshold, on only two occasions. Other investigations confirmed increasing infestation towards ripeness (when colour change begins). Egg‐laying and subsequent emergence can continue from unharvested ripe pods. Practical difficulties for RCH include low harvester incomes in the trough, and a reluctance to harvest infested pods. RCH gives high cost per unit product in the trough, but this is counteracted by extra crop. RCH is a pest management technique without adverse side‐effects. Further work is needed on the economics of RCH strategies, including abandoning harvesting in trough periods, monitoring of harvesting efficiency and the critical number of unharvested pods compatible with satisfactory control.

ISSN:0143-6147    

DOI:10.1080/09670879209371708

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Among the major insect pests of potato, the potato tuber mothPhthorimaea operculella(Zeller) is important in both field and storage. The biology of the pest, studies of spatial distribution, sampling technique, effect of density dependent and Independent factors, losses caused and economic threshold levels are reviewed. Various management strategies such as agronomic practices, biological and chemical control are discussed. Attempts to identify the potential components of management of potato tuber moth are made.

ISSN:0143-6147    

DOI:10.1080/09670879209371709

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Trials conducted over 6 years in rainfed hoe‐farming system cotton(Gossypium hirsutumL.) production at Samaru, northern Nigeria, showed that pre‐plant application of glyphosate at 0.75–1.0 kg a.e./ha without further land preparation was a suitable substitute for the labour‐intensive traditional method involving ridge‐splitting. Glyphosate was particularly effective when established perennial weeds such asCynodon dactylon(L.) Pers. andDigitaria cilliaris(Retz) Koel were predominant. Following pre‐plant glyphosate there was no further need for a grass weed herbicide as a pre‐emergence treatment. Paraquat, fluazifop‐butyl, haloxyflop and amitrole were not as effective in pre‐plant use. After pre‐plant glyphosate, diuron alone at 0.8–1.2 kg a.i./ha was adequate as a pre‐emergence treatment with one supplementary hoe‐weeding at 6 weeks after sowing (w.a.s.). A supplementary application of glyphosate was not significantly different from a hoe‐weeding at 6 w.a.s. in most situations examined. In one season, fluazifop‐butyl plus diuron, post‐emergence at 6 w.a.s., was comparable to a supplementary hoe‐weeding.

ISSN:0143-6147    

DOI:10.1080/09670879209371710

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Activated charcoal provided protection against toxicity caused by butachlor in upland rice and increased the crop stand and yield as compared to control. Band placement or soil mixing of this material at 50 kg/ha was the most effective method followed by seed pelleting methods with 2 kg/ha. The latter was much more economical than band placement.

ISSN:0143-6147    

DOI:10.1080/09670879209371711

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

Two field experiments were conducted to determine the safety of repeated applications of several pre‐emergence herbicides in coffee from the recently transplanted stage to 1 year old. Oryzalin and oxyfluorfen had at least a four‐fold selectivity margin to coffee at two locations; these herbicides had a greater safety margin than simazine, atrazine and diuron, which all injured young coffee at 4.5 kg a.i./ha. Oxyfluorfen, atrazine, simazine and diuron provided better control of the weed species than oryzalin. Oxyfluorfen did not provide complete control of weeds in the Compositae family which were completely controlled by atrazine and diuron. Oxyfluorfen and oryzalin were shown to be effective management tools for weed control in young coffee because of their excellent selectivity.

ISSN:0143-6147    

DOI:10.1080/09670879209371712

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

The critical period of weed interference was investigated from 1982–1985 In two local cassava cultivars in Cameroon. Unweeded plots had more than 90% losses and were infested by birds and rodents which caused much damage to the fresh storage roots. One weeding round was not an effective treatment. Two weeding rounds at 4 and 12 weeks after planting (WAP) gave yields twice that with two weedings at 12 and 20 WAP. Three weedings at 4, 12 and 20 WAP gave the best yields: 11 t/ha and 17 t/ha for the red and white‐skinned cultivars, respectively. The highest storage root number was also recorded for the same treatment.

ISSN:0143-6147    

DOI:10.1080/09670879209371713

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor

摘要:

In a preliminary experiment a single treatment of 2 kg ha−1glyphosate was found to be as effective as higher rates of application in reducingCyperus rotundusshoot numbers. Single applications of 11–2 kg ha−1bromacil and 976 kg ha−1methyl bromide were compared with multiple applications of 2 kg ha−1glyphosate, 4.5 kg ha−12,4‐D, 4 kg ha−1EPTC, 2.4 kg ha−1vernolate, 5 kg ha−1pebulate, 2–9 kg ha−1amitrole and eight successive rotary hoeings during dry weather, all over a 19‐month period. Most treatments reduced shoot and tuber populations and tuber weights but the most efficient treatments were bromacil, cultivation, glyphosate and 2,4‐D. At the end of the experiment the percentage of tubers with shoots was similar for many treatments but was higher on the thiocarbamate treatments and tended to be lower on the glyphosate treatment. The percentage of dormant or moribund tubers was higher on the glyphosate treatment than on other treatments. The greatest effect of most treatments was on the shallowest tubers (0–10 cm), except for 2,4‐D which affected tubers uniformly over the three depth ranges studied.

ISSN:0143-6147    

DOI:10.1080/09670879209371714

出版商:Taylor & Francis Group    

年代:1992

数据来源: Taylor