Growing vegetables in developing countries for local urban populations and export markets: problems confronting small-scale producers

Vegetables attract high applications of pesticides, and farmers in developing countries use many acutely toxic insecticides to control pests on these crops. With the liberalisation of agricultural markets in developing countries, the number of small-scale farmers growing vegetables for both domestic and export markets is increasing. Demand for supplies of year-round and exotic fruit and vegetables has grown in industrialised countries, but with rising quality standards and traceability requirements it is difficult for small-scale farmers to benefit from this lucrative non-traditional agricultural export trade. The demand is high for vegetables in the expanding cities in developing countries, and farmers in peri-urban areas, or rural areas with good access to the cities, are in a position to find a growing market for their produce. Poor storage facilities will often mean that farmers are forced to sell at peak times when prices are low. Farmers rarely have access to training in pesticide use, and have only limited or no access to advice on the complicated management of pesticides. The Food and Agriculture Organisation of the UN is concerned about high levels of poor quality and adulterated pesticides on sale in developing countries. Surveys repeatedly show that without training, farmers are unable to make good crop decisions: recognition of pests and their predators is generally low, leading to decisions to spray to kill any insect; knowledge of product selection, application rates and timing is poor; different products are often combined in the belief that the effect will be greater; re-entry periods after spraying and essential harvest intervals are not known; and without knowledge of alternatives, farmers will often assume that the only solution to pest problems is to spray more frequently. From a consumer's point of view, few developing countries are able to monitor pesticide residues, particularly for produce grown for home consumption: most countries do not have laboratories for even simple residue testing. Changes in European Maximum Residue Limits means that export crops will be rejected if they contain residues at the Limit of Detection of pesticides not registered in Europe. Season-long field level training in Integrated Pest Management can help farmers to become better decision-makers, and to greatly reduce pesticide use while reducing risks to their own health and environment, producing safer products for consumers, maintaining yields, and increasing incomes.     

Growth and Apparent Absorption of Minerals in Broiler Chicks Fed Diets with Low or High Tannin Contents

Sorghum grains with low (0.28 per cent catechin equivalent (%CE) or high (1.36 %CE)) tannin contents were used to study the effect of tannin on growth and on the apparent absorption of Ca, P, Mg, Na, K, Fe and Co by chickens. High-tannin sorghum caused a highly significant (p0.01) reduction in the weight gain and feed intake of broiler chicks compared to low-tannin sorghum and increased the feed conversion ratio (p0.01). The amount of tannin did not affect mortality. The apparent absorption of Ca, P, Mg, Na, K, Fe and Co was reduced (p0.01) by feeding sorghum grains with a high tannin content.     

The effects of low doses of Senna occidentalis seeds on broiler chickens

The effects of 0.5%, 0.3% and 0.1% w/w concentrations of Senna occidentalis (So) seed mixed with commercial ration were studied in 18 groups of 32 broiler chicks each, from 1 day to 49 days of age. Three groups were fed one of the rations throughout their lives (TL). Three other groups were fed one of the rations from the 1st to the 28th day of life (starter phase, SP), and the final 3 groups were fed one of the rations from the 29th to 49th day (finisher phase, FP). Each experimental group was matched by a control group fed the same diet over the same period but without the inclusion of So. All the animals were killed at 49 days of age, and blood was collected from 10 birds in each group for biochemical studies (ALT, AST, GGT, LDH, UA). A complete necropsy was performed on 3 birds from each group. No significant differences in the biochemical parameters in the serum were found between the control and experimental chicks, but animals treated with 0.5% So in groups FP and TL, gained less weight and chicks that received 0.3% So or 0.5% So in the ration throughout life (TL) had a larger feed conversion ratio. Besides this, degenerative changes were found in the striated skeletal muscle in the chest, in the myocardium and in the liver in the animals that received the higher concentrations of So seeds.     

Effects of Supplementing a Basal Diet of Chloris gayana Hay with One of Three Protein-rich Legume Hays of Cassia rotundifolia,Lablab purpureus and Macroptilium atropurpureum Forage on Some Nutritional Parameters in Goats

Growth and digestibility experiments were conducted on growing East African type goats offered Chloris gayana hay supplemented with one of three high-protein (119–128 g CP/kg DM) legume hays, Cassia rotundifolia (cassia), Lablab purpureus (lablab) or Macroptilium atropurpureum (siratro), and crushed maize to investigate the feed intake, digestibility, growth and urinary excretion of purine derivatives. Goats in the supplemented groups had higher total dry matter and nitrogen intakes and higher N retention and body mass gains than unsupplemented counterparts. The digestibility of dry matter, organic matter and neutral detergent fibre were increased by protein supplementation. Animals on supplemented diets had higher fractional outflow rates of particulate matter from the rumen. The production of protein by ruminal microbes and the efficiency of microbial N production were increased by supplementation. It was concluded that a mixture of low-quality grass hay (61.9 CP/kg DM) and either cassia, lablab or siratro hay, and maize grain can provide a productive balanced diet for growing goats.     

饲料对乳制品风味的影响

低脂奶牛日粮会提高风味干酪内源脂肪酸中硬质脂肪水平、蓝干酪风味甲基酮和桃色椰子风味δ-内酯的前体物,而高脂奶牛日粮则与之相反。日粮在瘤胃中产生的丙酸代谢能从日粮油酸中形成芳香味的γ-十二烷内酯、从日粮亚油酸中形成芳香味的γ-十二-顺-6-内酯。味美牧草会产生富含颜色的奶脂肪,并把植醇、二氢植醇、植物烯、植二烯以及它们的低等同族体引入到奶脂肪中。无蛋白合成日粮会降低动物风味的吲哚和粪臭素。     

仔猪断奶应激及其营养调控

综述了断奶应激对仔猪的影响,分析了应激发生的原因,阐述了相应的饲养调控措施,以期为早期断奶应激综合症的防治和科学饲养管理断奶仔猪提供理论依据.     

Resistance in water yam (Dioscorea alata) cultivars in the French West Indies to anthracnose disease based on tissue culture-derived whole-plant assay

Reactions of 60 water yam ( Dioscorea alata ) cultivars to three isolates of the yam anthracnose fungal pathogen ( Colletotrichum gloeosporioides ) were evaluated using tissue culture-derived whole-plant assay. Three disease parameters: single score on a scale of 0–6 at the seventh day after inoculation (SD7); area under the disease progress curve (AUDPC); and disease progress rate ( R _d) were compared, and cultivars were classified into disease-response groups using a rank-sum method based on AUDPC scores for the two most virulent isolates. A wide range of variation in resistance of the D. alata cultivars, and significant effects of pathogen isolate and isolate–cultivar interactions, were observed for all disease parameters. The three disease parameters were positively correlated; however, four cultivars showed great dispersions from the regression lines for comparisons of SD7 with the multiple assessments based AUDPC and R _d. The 60 cultivars were separated into resistant ( n  = 12), moderately resistant ( n  = 19), moderately susceptible ( n  = 18) and susceptible ( n  = 11) groups. The potential of the tissue culture-derived whole-plant assay to resistance breeding programmes and further understanding of the yam anthracnose pathosystem is discussed.     

First report of the Q biotype ofBemisia tabaci in Japan by mitochondrial cytochrome oxidase I sequence analysis

The recent upsurgence ofBemisia tabaci (Genn.) as an important insect pest and vector ofTomato yellow leaf curl virus (TYLCV) is directly linked to serious damage to tomato crops grown throughout Japan. The molecular genetic identification and phylogenetic relationships of 12B. tabaci populations collected from representative locations in Japan were determined based on the mitochondrial cytochrome oxidase I (mtCOI) sequence. Phylogenetic analysis of the whitefly mtCOI sequence indicated that both the invasive B and Q biotypes now occur in Japan. The Q biotype was found at four locations: Mihara in Hiroshima, Nishigoshi in Kumamoto, Miyanojo and Okuchi in Kagoshima prefectures; the remaining eight collections were identified as the B biotype. This is the first report of the introduction of Q biotype in Japan. http://www.phytoparasitica.org posting July 21, 2006.     

Evaluation of turnip-rooted parsley (Petroselinum crispum ssp. tuberosum) for root and foliage production under a warm,Mediterranean climate

Two experiments were undertaken in southern Greece during 2000–2002 in which turnip-rooted parsley was tested for its suitability for cultivation in comparison with locally grown curly-leafed and plain-leafed forms. Plants were harvested when the foliage was acceptable for marketing, rather than on completion of the vegetative cycle, hence root size was relatively small. In year 1, the foliage development of plain-leafed parsley was significantly higher than that of the other two forms, irrespective of sowing date. In year 2, both plain-leafed and curly-leafed parsley produced more foliage than turnip-rooted parsley in the early sowing (November), but not in subsequent sowings (December and February). During both years, root development was higher in turnip-rooted parsley than in curly-leafed parsley, although in the November and February sowings of year 1 the root weight of both plain-leafed and turnip-rooted forms were similar. In all three types of parsley, foliage yield fell off significantly in the spring sowing (February), and in year 1 there was a considerable decrease in root production as well. In most cultivars, foliage weight was higher when plants were grown from transplanted seedlings rather than by direct sowing, whereas the effect of sowing method on root weight was sowing date dependent. Cultivar differences in the foliage weight of direct sown and transplanted plants were reflected by differences in plant height and, in some cases, by leaf number. It is concluded that although overall turnip-rooted parsley produced rather less foliage than that plain-leafed parsley, this was compensated for by the satisfactory production of roots and therefore turnip-rooted cultivars may constitute a suitable crop for introduction to the Mediterranean region.     

比哈小爪螨在3种南方果树上的发育与繁殖

为了探明比哈小爪螨在龙眼、荔枝、杧果上的种群增长情况,采用以上3种果树叶片为寄主材料进行饲养,以观察其发育、存活及繁殖。结果表明,比哈小爪螨取食龙眼世代发育历期最短为14.57d,取食杧果最长为20.71d;世代存活率龙眼最高为93.8%,荔枝最低为83.8%;产卵量以龙眼最高为46.63粒,杧果最低7.32粒;内禀增长率以龙眼最大为0.1328,杧果最小为0.0467;种群趋势指数的顺序为:龙眼>荔枝>果。