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In order to assess the economic benefits of reduced fungicide application for the control of paprika diseases under dryland conditions, on-farm experiments were conducted in the Chinyika Resettlement Area in the Eastern province of Zimbabwe in the 2000/2001 and 2001/2002 seasons. The six fungicide application regimes that were assessed include: weekly interval sprays; Sulphur at 2 weeks after transplanting (WAT) and copper oxychloride-Mancozeb mixture at 6 WAT; spraying after scouting; alternating Sulphur and copper oxychloride- Mancozeb every two weeks; Acibenzolar-s-methyl and unsprayed check. Parameters recorded were disease severity and yield; after harvest an economic analysis was performed. The highest added profit of Z$ 75930/ha was recorded in the weekly sprayed plots which was not statistically different (p > 0.05) from Z$ 59410/ha achieved by alternating copper oxychloride and Mancozeb fortnightly at Dengedza site in 2000/2001 season. There were no statistical differences (p > 0.05) between spraying after scouting and Acibenzolar-s-methyl application treatments as they added the least profits of Z$ 990/ha and Z$ 17250/ha respectively at the same site in the same season. These have serious implications for smallholder farmers in terms of cost savings. Neither were there differences (p > 0.05) in added profits from different spraying regimes at Dengedza site in the 2001/2002 rainy season.
Water bodies are the final sinks of all pollution with more than 90% of contaminants found in suspended particulates and bottom sediments. Only less than 10% is retained in the water column yet it attracts and receives great research attention. The pollution status and the potential ecological risk of three pools of water along a stream due to heavy metal enrichment from a nearby active gold mining tailings dam were assessed. The upstreamdownstream and sedimentological approaches to ecosystem health assessment were used. Potential uses of pool water were also evaluated based on measured water quality parameters. Heavy metals in water and sediment were determined using Flame Atomic Absorption Spectrometry. Results revealed that salinisation, acidification and heavy metals were exported from a mining tailings dam to the stream. The degree of contamination of pool water by heavy metals dictated water uses. Heavy metal concentrations imposed water use restrictions for aquatic life in a pool which directly received discharge from the mine tailings dam. The average heavy metal concentrations in sediments were lower than the standard shale values. Sediment quality guidelines and pollution indices showed that the stream was not polluted with heavy metals, thus posed no potential ecological risk. Continuous monitoring of tailings discharge and wash off is important to safeguard aquatic ecosystem and public health.
On-farm trials were conducted in the Chinyika Resettlement Area of Zimbabwe under dryland conditions to investigate the effects of different weed management methods on disease incidence, severity and paprika (Capsicum annuum) pod yield. The weed control treatments included hand weeding at 2 and 6 weeks after transplanting (WAT); ridge re-moulding at 3,6 and 9 WAT; application 4l/ha Lasso (alachlor) immediately after transplanting, and Ronstar (oxidiazinon) at 2l/ha tank mixed with Lasso at 2l/ha one day before transplanting. The herbicide-water solution was applied at the rate of 200l/ha using a knapsack sprayer. Major diseases identified were bacterial leaf spot (Xanthomonas campestris pv. vesicatoria), cercospora leaf spot (Cercospora unamunoi), grey leaf spot (Stemphylium solani) and powdery mildew (Leveillula taurica) in both seasons. For the 2000/2001 season hand weeding at 2 and 6 WAT and ridge re-moulding at 3, 6 and 9 WAT had the greatest reduction effect on the area under disease progress curve (AUDPC) and the highest marketable fruit yield. In the 2001/2002 season, both herbicide treatments had the same effect as hand weeding and ridge re-moulding on AUDPC and marketable fruit yield. The least weed density was obtained by ridge re-moulding at 3, 6, and 9 WAT in the 2000/2001 season. Weed density was statistically the same across all treatments except the check treatment in 2001/2002 season. Hand weeding operations were significantly (p < 0.05) effective and consequently gave the highest added profits mainly because of their effect on major weeds such as Datura stramonium.
The results of a nine year inventory of jumping spiders in a suburban study-site, a one-hectare garden in Harare, Zimbabwe, are presented. The full list of garden salticids comprises 47 species, among them 12 are described as new: Dendryphantes arboretus, D. hararensis, Evarcha ignea, E. zimbabwensis, Langelurillus ignorabilis, L. orbicularis, Phlegra procera, Pseudicius elegans, P. refulgens, Rhene cancer, Thyenula hortensis and Tularosa arcana. For two species, Evarcha prosimilis (Wesołowska et Russell-Smith, 2000) and Xuriella prima Wesołowska et Russell-Smith, 2000, the previously unknown females are described. Nomen novum, Evarcha prosimilis is proposed for Evarcha similis, Wesołowska et Russell-Smith, 2000, preoccupied by E. similis Caporiacco, 1941. Four specific names are synonymised: Quekettia georgii Peckham et Peckham, 1903 with Hispo inermis (Caporiacco, 1947), Heliophanus clarus Peckham et Peckham, 1903 with Phintella aequipes (Peckham et Peckham, 1903), Thyene magdalenae Lessert, 1927 with Thyene australis Peckham et Peckham, 1903 and Viciria morigera Peckham et Peckham, 1903 with Viciria mustela Simon, 1902. The last species was transferred to the genus Evarcha, new combination E. mustela is proposed. New combination Mexcala natalensis is proposed (ex Cosmophasis natalensis Lawrence, 1942). The generic name Quekettia Peckham et Peckham, 1903 is recognized as a junior synonym of Hispo Simon, 1886 by synonymisation of the only species of Quekettia. Eight species are recorded from Zimbabwe for the first time: Bianor albobimaculatus, Heliophanus pygmaeus, Hispo inermis, Icius insolidus, Mexcala natalensis, Sonoita lightfooti, Thyene thyenoides and Xuriella prima. The natural history (micro-habitat, behaviour and phenology) of each species is presented where available.
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