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Bangkok, Thailand

Riwthong S.,University of Hohenheim | Schreinemachers P.,The World Vegetable Center | Grovermann C.,University of Hohenheim | Berger T.,University of Hohenheim
Environmental Science and Policy | Year: 2015

Agricultural development in lower-income countries and resulting increases in agricultural productivity are generally accompanied by a shift from extensive to more intensive types of land use. The objective of this paper is to analyze how pest and plant disease management among smallholder farmers has changed along with the process of land use intensification, the aim being to identify constraints as well as possible approaches to the use of more sustainable pest and plant disease control practices. Using survey data from 240 smallholder farms located in the upland areas of northern Thailand, we show that land use intensification is accompanied by a reduction in the use of traditional methods of pest management and an increase in the use of synthetic pesticides. While farms with a low level of land use intensity sprayed on average twice a year and used a total of 1.4. kg of active ingredients per ha, farms with a high level of land use intensity sprayed on average 16 times and used 22.0. kg/ha. They also used a greater number of different products and tended to mix them together. The intensity of pesticide use was particularly high for cash crops such as tomatoes, chilies and strawberries. Many farmers experienced health problems related to pesticide use because pesticides were not correctly handled. Greater investment is needed in the development of integrated pest management in the long-term, and health problems may be reduced in the short-term by raising awareness among farmers regarding the risks they are exposing themselves to, as well as by promoting good agricultural practices. © 2014 Elsevier Ltd. Source

Grovermann C.,University of Hohenheim | Schreinemachers P.,The World Vegetable Center | Berger T.,University of Hohenheim
Crop Protection | Year: 2013

The rapid growth in pesticide use is a significant problem for Thailand, as it is in many other developing countries with an intensifying agriculture. The objective of this study was to quantify how much of the total quantity of pesticides is overused. The novelty of this research resides in the fact that it considered the social rather than the private optimum by including negative pesticide externalities in determining levels of overuse. Marginal benefits of pesticides are quantified by estimating Cobb-Douglas production functions with an exponential damage control specification. The marginal costs are calculated as the sum of private and external costs with the latter quantified using the Pesticide Environmental Accounting (PEA) tool. The method is applied using farm- and plot-level data from one intensive upland vegetable production system in northern Thailand. The findings show that about 80% of the applied pesticide quantity is used in excess of the social optimum, while the difference between the private and social level of overuse is small for this particular case study. Therefore results from the study area suggest that internalizing pesticide externalities into the price of pesticides would only have a small effect on reducing pesticide overuse. © 2013 Elsevier Ltd. Source

Srinivasan R.,The World Vegetable Center
Journal of Biopesticides | Year: 2012

Vegetables, cultivated on 4.65 million ha with annual production of 53.5 million t in South and Southeast Asia, are subject to severe yield losses from insect pests and diseases in the tropics. Chemical pesticides account for onethird to one-half of the total mean material input cost for vegetable production in the region. Extensive and inappropriate pesticide use has led to pests developing resistance to major groups of pesticides, resurgence of secondary pests, high pesticide residues in produce, and decimation of natural enemies. The adverse effects on human and environmental health cannot be ignored. Integrated pest management (IPM) strategies often have been suggested to mitigate such a problem. Although various IPM strategies have been developed and promoted for vegetables, adoption remains low due to IPM's limited effectiveness in managing insect pests compared with chemical pesticides. Moreover, IPM has been promoted as a combination of techniques without giving due consideration to the compatibility of each component. Biopesticides could play a crucial role in IPM strategies although they cover only about 4 percent of the global pesticide market. Biopesticides have high compatibility with other pest management techniques such as natural enemies, resistant varieties, etc. Integrating biopesticide could enhance performance of IPM strategies. For instance, with the adoption of Bacillus thuringiensis based biopesticides, parasitoids such as Diadegma semiclausum, Cotesia plutellae and Diadromus collaris established in several countries, and provided significant control of diamondback moth (Plutella xylostella) on brassicas in South- and Southeast Asia. An IPM strategy based on sex pheromone for managing the eggplant fruit and shoot borer (Leucinodes orbonalis) has reduced pesticide abuse and enhanced the activities of natural enemies including Trathala flavoorbitalis in Indo-Gangetic plains of South Asia. Thus, this paper reviews some of the most effective vegetable IPM strategies developed and/or promoted by AVRDC - The World Vegetable Center to manage insect pests on brassicas, eggplant, vegetable legumes and tomato in tropical Asia, and presents a discussion of an appropriate public - private partnership model in dissemination and adoption of vegetable IPM strategies. © JBiopest. Source

Quang D.V.,University of Hohenheim | Schreinemachers P.,The World Vegetable Center | Berger T.,University of Hohenheim
Agricultural Systems | Year: 2014

Agriculture in mountainous areas in Vietnam has much intensified since the introduction of market-based reforms in the mid 1980s. The adoption of hybrid maize varieties, mineral fertilizers and reduction in fallow periods has improved farm incomes, but has also led to a dramatic increase in soil erosion from sloping lands which has created a downward pressure on crop yields and has had adverse effects on downstream areas. This study explores the relationship between soil fertility, crop yields and the use of soil conservation methods by applying an agent-based modeling approach that combines whole-farm mathematical programming to simulate the decision-making of each individual farm household with a biophysical simulator of crop yields and soil fertility dynamics for each individual landscape unit. Simulation results suggest an average soil loss is 30. tons for maize fields and 27. tons for cassava fields per hectare per annum under present economic conditions, which is in the range of what other studies have measured, and a consequent decline in the average household incomes by 28.5% over a 25. years period. The introduction of three soil conservation methods in maize (vetiver grass strips, ruzi grass barriers and leucaena hedges) shows that these are not economical for farm households to adopt under present conditions, chiefly because of lower short-term maize yields. We explore the effect of giving farm households monetary incentives to adopt soil conservation and find that the payment needed for reducing 40. ±. 2% of the estimated soil loss would be about 12-16 USD per ton of soil saved. © 2013 Elsevier Ltd. Source

Agriculture is under pressure to produce greater quantities of food, feed and biofuel on limited land resources. Current over-reliance on a handful of major staple crops has inherent agronomic, ecological, nutritional and economic risks and is probably unsustainable in the long run. Wider use of today's underutilized minor crops provides more options to build temporal and spatial heterogeneity into uniform cropping systems and will enhance resilience to both biotic and abiotic stress. Many traditional vegetables and underutilized legume crops are an essential source of vitamins, micronutrients and protein and, thus, a valuable component to attain nutritional security. Vegetables in general are of considerable commercial value and therefore an important source of household income. Significant research, breeding and development efforts are needed for a range of promising crops to convert existing local landraces into competitive varieties with wide adaptation and promising commercial potential. Access to genetic diversity of these selected crops is a pre-condition for success. Three underutilized minor crops-amaranth, drumstick tree, and mungbean-are highlighted and briefly described. All three crops are well-represented in AVRDC's genebank with substantial inter- and intra-specific genetic diversity, and already have demonstrated their potential for wider adoption and commercial exploitation. © 2014 by the authors; licensee MDPI, Basel, Switzerland. Source

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