Asian Smallholder Vegetable Farmers As IPM Experts: Experiences from the FAO Regional Vegetable

Asian Smallholder Vegetable Farmers as IPM Experts: Experiences from the FAO Regional Vegetable IPM Programme

Jan Willem KetelaarPrabhat Kumar

FAO Asia Regional IPM ProgrammeAgricultural Systems and Engineering

FAO Regional Office for Asia and PacificSchool of Environment, Resources and

Bangkok, Thailand Development, PO Box4, Klong Luang

Email: athumthani 12120, Thailand

Email:

Keywords: IPM, Asia, Pesticide mis-use, FFS, Vegetables, GAP

ABSTRACT

Pesticide use in vegetable production among smallholder farmers in Asia remains unnecessary high. Enduring concerns over farmer health and environmental pollution caused by indiscriminate use of pesticides, call for safer and more sustainable crop protection strategies. New concerns over food safety in relation to pesticide residues on fresh and processed vegetables intended for domestic and export markets provide momentum for further development and application of Integrated Pest Management as part of Good Agricultural Practices promotion efforts.At the same time, climate change is facilitating the spread of new invasive pest species, often prompting farmers to use more pesticides.Sucking pests, many of them vectoring important and new plant diseases, are now dominating the complex of pest problems that vegetable farmers face on a day-to-day basis.FAO has been working with Asian governments, civil society organizations and the private sector to develop robustIPM strategies for a range of economically important vegetable cropsduring the last decade.Case studies of successfully employed vegetable IPM strategies, resulting into major crop production improvements and reductions in pesticide use,will be detailed in this paper.Apart from assistance to governments to strengthen pesticide regulatory systems, FAO also continues to assist National IPM Programmes in the Asia region to implement farmer IPM training, using the innovative and successful Farmers Field School approach. This paper will therefore also outline training achievements to date and results from this important training work, aimed at turning vegetable farmers into IPM experts. For further details on FAO’s Regional IPM Programme, see website:

INTRODUCTION

Vegetables are an important part of a complete diet of Asians, adding valuable nutrients that would otherwise be insufficiently available in staple food crops such as rice, wheat or maize. A number of vegetable crops are commonly grown, consumed and traded in most Asian countries including Cambodia, China, Indonesia, Lao PDR, Philippines, Thailand and Vietnam (see table 1). The realization of optimal yields, particularly in the warm humid lowlands, is often constrained by pests and diseases. Poor horticultural practices further exacerbate these problems. Rather than ameliorate the situation, the application of pesticides frequently causes resurgence of pest populations due to the destruction of their natural enemies (Shepard et al., 2009). The changing climatic conditions and its possible effects on insect-pests and natural enemies, yet another set of emerging challenge confronted by smallholder communities, which is expected to expected to facilitate the emergence and resurgence of invasive pests and plant disease vectors (e.g. whitefly, Bemisia tabaci; thrips (many species), aphids (several species) and plant hoppers. Imbalances in host-natural enemy population synchrony are some of the commonly observed impacts of climate change, which are upsetting the natural ecosystem balances across crops and geographical regions (Kiritani, 2006, Thomason et al., 2009). To deal with these ever increasing levels of biotic and abiotic stress, quantum changes in knowledge-attitude-practice of smallholder farmers will be of paramount importance as to enable them to continue to grow healthy, safe and high-yielding crops with minimal inputs of agro-chemicals.

The misuse and overuse of chemical pesticides among the majority of smallholder vegetable farmers in tropical Asia remain serious and acute (Shepard et al., 2009). In the year 2005, 790,000 ton of various pesticide active ingredients, worth more than US$ 8.3 Billion, were used in Asian countries. Yields are highly variable whereas market prices can vary considerably on a day-to-day and season-to-season basis. Vegetable production has become an ever riskier business providing a clear stimulus for farmers to minimize risk and maximize preventive pesticide applications. In summary, the region is facing seriouschallenges to contain the overuse and misuse of pesticides (SUSVEG Asia, 2007; Srinivasan, 2008) and to better regulate the distribution and use of pesticides in the Asia region.

Use of pesticides creates widespread environmental pollution and has an important impact on quality of natural resources (e.g. soils, water and fish populations, see Settle & Whitten, 2000) and ecosystem services(natural biological control, pollination). The health hazards of chemical pesticide applications to farmers and their families are serious. This is documented in various innovative health studies conducted among farmers who have been exposed to chemical pesticides (e.g. Murphy et al., 1999, Mancini et al, 2009). Greater awareness among consumers in urban communities of the dangers of toxic residues on vegetables has created an ever growing demand for vegetables free of pesticide residues. In line with the FAO Codex Alimentarius (see governments in many Asian countries have established Maximum Residue Levels (MRLs) for pesticides on imported vegetables.

Integrated Pest Management has evolved in many developing countries from a mix of various technical components (Smith & Reynolds, 1966) to a farmer-led program (FAO, 2002). Successful IPM has always followed an ecological approach (Kogan, 1998). In the last decade or so, advances in IPM in a number of Asian countries took the form of farmer education through Farmer Field Schools (FFSs) and follow-up activities. In recent years the development of effective vegetable IPM strategies and the training of millions of smallholder farmers have had a clear impact on pesticide risk reduction and more responsible use in many communities across Asia (

To argue our case for the continued need of ‘turning more and more farmers into IPM experts, several innovative IPM case studies are presented, demonstrating the robustness of the IPM strategies developed and the eagerness of farmers to adopt these strategies when having had the opportunity to participate in IPM Farmers Field Schools. Finally, the paper concludes with some key lessons learnt and recommendations proposing the way-forward for the development ofsustainable vegetable production in Asian region.

MATERIALS and methods

Scope and Rationale for the FAO Regional Vegetable IPM Programme in Asia

The above described problems associated with misuse and overuse of pesticides in vegetable production in tropical Asia provide the rationale for FAO implementing a Regional Programme for the Development and Application of Vegetable IPM in Vegetable Production Systems in South and Southeast Asia. The FAO Programme operates currently in 10 member countries, e.g. Bangladesh, Bhutan (recently joined), Cambodia, China PR, Indonesia, Lao PDR, Nepal, Philippines, Thailand and Vietnam (see website: for more background and details).

Training Strategy and Methodology

The standard training approach employed in all FAO IPM Programmes is the so-called ‘Farmers Field School (FFS)’ approach. Farmers Field Schools are ‘schools without walls’ which are held in farmers’ fields. Typically,a group of about 25 to 30 vegetable farmers meet on a weekly basis and grow and study together in a vegetable crop of local relevance and choice from sowing to harvest[1] (for more details please refer to KetelaarKumar, 2011)

Results and DISCUSSION

One of the most important lessons of FAO’s involvement in the development and application of IPM relates to the need for farmers to become IPM Experts. If vegetable IPM is to establish itself in a sustainable manner, it will need to depend on farmers themselves making vegetable IPM work on their farms. In the following sections, three case studies derived from the work of FAO in collaboration with various partner institutions are presented in order to illustrate this point.

1 Brassica IPM in Highland Production Systems in Thailand

The DBM (Plutella xylostella)(L.) is probably the most important pest of crucifer crops in sub-tropical and tropical Asia including Thailand. The continuous cultivation and short lifecycle (14 days) can result in more than 25 generations of DBM a year being exposed to the synthetic insecticides routinely used by growers. This high level of selection pressure and the high fecundity of DBM are key factors which have contributed to this species developing resistance to a wide range of insecticides in the field (Wright, 2004), including novel insecticides such asspinosadand,indoxacarb(Zhao etal., 2002 and 2006) as well as some strains of the bacterial insecticide,Bacillus thuringiensis(Shelton etal., 2007). Clearly an alternative is urgently needed to minimize the pesticide related negative externalities to address the sustainable DBM management. .

The Royal Thai Government –through its National and Regional Biological Control Centers, coordinated by the Bangkok-based Pest Management Division at the Department of Agricultural Extension- has been on the forefront of mass rearing, introduction and promotion of various natural enemies (seetable 2) among smallholder farmers in Thailand since many years. Beginning 2005, the Thai Government, with technical and financial support from the FAO Regional Vegetable IPM Programme and a DANIDA-funded IPM project, engaged in the introduction, rearing and field releases of the parasitoid Diadegma semiclausum for the control of DBM in highland brassica production systems in both Thap Boek (Lomkao district, Phetchabun province) and the organic farms of the Royal Project Foundation (RPF) in Doi Angkhang, Chiangmai.

During the early 1990s, AVRDC had introduced D. semiclausum from Taiwan and releases took place in Tap Boek, Phetchabun. The introduction failed, most likely as a result of farmers’ continued pesticide sprays. In 2004/5, the DoAE conducted surveys to ascertain the status of DBM parasitoids prevalent in highland brassica production systems in Thailand (DoAE/FAO, 2005). The survey also served to assess farmer’s knowledge on DBM management (Upanisakorn et al., 2009). The surveys confirmed the absence of D. semiclausum and the rationale for introduction of this parasitoid. D. semiclausum was subsequently introduced from the Cameron Highlands in Malaysia with CABI/MARDI assistance. Following IPPC ISPM-3 guidelines for the introduction of biological control agents, the parasitoids underwent quarantine screening and basic rearing at the Department of Agriculture prior to introductions in brassica crops on the organic farms operated by the Royal Project Foundation in Doi Angkhang, in Northern Thailand. Rearing efforts in RPF-Doi Angkhang were successful (DoA/RPF, 2006) and parasitoid shipments were handed over to the Department of Agriculture Extension in Phetchabun Province for mass rearing and field releases in cabbage farms in conjunction with season-long IPM Farmer Field Schools (FFS). A field survey carried out in 2008 (Upanisakorn et al., 2009) confirmed the establishment of D. semiclausum in the farmers’ fields and the satisfactory regulation of DBM populations (table 3).

2 Potato IPM in Lowland rice-based Production Systems in Vietnam

Potato is an important food crop in Vietnam, which is increasingly providing raw materials for the food-processing industry and stable income to the smallholder farmers in the Red-River Delta region. There has been sluggish growth on account of area and total production during recent years in Vietnam (table 4). This could be primarily attributed to the lack of quality seeds and high labor costs. Generally, low level of mechanization leads to very high labor requirement for potato cultivation i.e. soil preparation, intercultural operations and pest management.

With these multiple objectives including reducing labor costs, an innovative pilot project was set up under the auspices of the Vietnam National IPM Program/ Plant Protection Sub Department with the purpose to promote rice-potato farm system development. Whereas Vietnamese farmers generally burn rice stubbles after harvest, there is good potential for growing potatoes on these rice stubble crops as practiced elsewhere in the region (e.g. Guangxi, China PR). A group of five IPM farmers (four women and one man) of Phat Loc Tien hamlet, Thai Giang Commune, Thai Thuy District, Thai Binh province carried out a field study on minimum tillage on potato production during the Winter – Spring season (2008-9). In this experiment the ‘minimum tillage’ (MT) system was compared with conventional farmer’s practices (FP) in potato production. Farmers gathered data on indicators like plant height, number of plant/hill; pests, natural enemies, yields and conducted an economic analysis as to determine differences among treatments.

A total yield of 760 Kg/Sao (360m2) was obtained in MT against 702 Kg in FP treatment (See table 5a). The economic comparison provided the most important results, where the MT treatment resulted in much higher net return compared to the farmer’s practice (see table 5b). Clearly, these profit gains are due to reduction in labor cost component of the economic analysis. In terms of insect-pest (army worm, Spodoptera spp) or pathogen (late blight, Phytophthora infestans), no significant differences were found in both treatments.

3 Vector and virus management in Tomatoes in the Philippines and Lao PDR

Bemisia tabaci is currently the most serious pest of tomatoes (Kumar et. al. 2005; Kumar and Poehling, 2010), causing direct damage as well as transmitting tomato leaf curl virus (ToLCV) in processing tomato production in Ilocos Norte & Sur, Northern Philippines. The virus has seriously threatened the processing tomato industry in the Philippines. The leaf curl incidence is positively correlated both with the numbers of B. tabaci present and with yield loss (Saikia & Muniyappa, 1989). When populations of B. tabaci are high early in the season, 90 - 100% of plants can become infected, resulting in a yield loss of 40 - 100% (Saikia & Muniyappa, 1989). With associated risks both to their health and the environment, farmers currently use large quantities of costly broad-spectrum insecticides in increasingly unsuccessful attempts to control B. tabaci and ToLCV.

3.1 Philippines

Upon request of the Northern Food Corporation (NFC), a semi-private sector that contracts tomato growers producing for its processing plant, and the Philippine National IPM Programme/Department of Agriculture, FAO provided technical assistance for better management of ToLCV in processing tomato production. These action research and training activities led to the development of reliable and effective management options for this vector and virus. Based on technical advice from Asian Institute of Technology, Bangkok and US-based Campbell Soup –and its Seed Research/IPM unit based in Davis, California in particular-, a two-tier strategy of vector and virus management was developed; first, to minimize the virus acquisition at seedling stage (see fig.1a) and second, to reduce vector immigration to the open tomato field crops by using reflective mulches and mineral oils.

3.2 Laos

Similarly the National IPM Programme in Laos, which has been focusing on developing the locally adapted technologies for the wet-season vegetable production particularly tomatoes, has started a series of farmer’s trainer lead-action research to minimize losses caused to the farmers. The activities in past years included series of trainings to the farmer trainers on lifecycle, ecologyof vectors, virus symptoms with a range of management options focusing on ‘raisinghealthy seedlings’ and delaying of virus infections in the field to enhance the overall yield and profitability.Accordingly, seedlings were raised inside low-cost tunnels (TG seedlings) and compared with open-field grown seedlings, which is commonly practiced by farmers. The results obtained clearly demonstrated that tunnel raised seedlings are able to reduce virus infection at seedling stage, which is very common in the case of open-field raised seedling, and could be a good strategy for delaying infections. Data collected at 45 days after transplanting shows that only 8% of the tomato plans showing virus symptoms as against 20% in the case of fields where seedlings came from the open-field sources (fig. 1b). More studies are underway in this regard as to validate the positive results obtained so far.

Conclusion

1 Brassica IPM in Highland Production Systems in Thailand

The parasitoid D. semiclausum is now established and provides effective biological control of DBM populations in Tap Boek, Petchabun. Despite of arguments to the contrary provided by Grzywacz et al, 2009, this most recent successful case study of effective ecosystem services for biological control of DBM negates the need for introduction of Bt-brassica crops, at least in highland brassica production systems. As the technical capacity and rearing facilities are in place, the parasitoid will now also be distributed to other highland cabbage fields in Thailand by the pest management center staff. As a result of participation in Farmers Field School, the IPM farmers in Tap Boek have learned to appreciate -and make sustainable use of- biological control for pest management. Farmers have adopted IPM and reduced pesticide sprays, gaining an overall higher profit from their farm production. The higher quality brassica produce has also been Q-GAP certified and better market access is thus guaranteed. As for the Thai Government, lessons learned include the notion that successful biological control implementation needs to be done step by step as per internationally agreed upon guidelines (IPPC-ISPM-3). An important lesson learned was also that parasitoid field introductions need to be undertaken simultaneously with farmer education efforts as to ensure that farmers appreciate and make optimal use of the introduced parasitoids for biological control of pest problems. A similar result was recently reported from Da lat, Vietnam, where FFS-based farmer training coupled with introduction of parasitoids supported by FAO in the early 1990s, has resulted in a decline of pesticide use and increased income of smallholder farmers (Nga and Kumar, 2008). Finally, the collaborative nature of this work supported by a wide variety of Thai government and international partner organizations also established that it is possible to work together on a successful biological control project that ultimately benefits smallholder farmers