Thai training instils best practice

Training Thai farmers in safe practicesAn assessment of the benefits of training Thai farmers in the safe use of crop protection products such as paraquat has shown that good product stewardship


The responsible and ethical management of a crop protection product in a way that takes full and balanced account of the interests of users, future generations, and other species.

Authoritative On-line References and Resources CropLife International is a global federation representing the plant science industry and a network of regional and national associations in 91 countries. These organisations are committed to sustainable agriculture through innovative research and technology in the areas of crop protection, non-agricultural pest control, seeds and plant biotechnology.
clearly has positive effects on the care farmers take in storage, handling and spraying.
The survey conducted by Kasetsart University also revealed the rich diversity of crops grown in western Thailand. The training was conducted as part of a wider project, ‘The Safe and Sustainable Production of Horticultural Crops’, aimed at improving the quality of vegetable production systems in Thailand according to internationally recognised standards of Good Agricultural Practice


Refers to the package of recommendations and available knowledge to address environmental, economic, and social sustainability for on-farm production and post-production processes resulting in safe and healthy food and non-food agricultural products. GAP may consist of guidelines addressing issues of site selection, adjacent land use, fertilizer use, water sourcing and use, pest control and pesticide monitoring, harvesting practices (including worker hygiene, packaging, storage, field sanitation, and product transportation), and cooler operations.

Authoritative On-line References and Resources The UN FAO provides independent information on GAP programmes, practices and standards.
. Export markets are important to the country and its farmers, so meeting stringent requirements for quality and sustainability are essential.

Successful training

Two hundred farmers participated in the training. They were shown how to store, mix and apply crop protection products safely. The post-training survey indicated that participants are now much more likely to store products in dedicated and secure chemical stores, and to use appropriate personal protective equipment (PPE), such as gloves, aprons and face shields when pouring and mixing with water in the sprayer. In the fields when spraying, again they are now much more likely to use the right PPE .

Farming in western Thailand

Asparagus growing in ThailandThe average size farm size of participants was about 2.4 rai which is less than half a hectare. Asparagus was the most popular crop, being grown by almost all farmers. In recent years the value of the asparagus export market, especially to Japan and Taiwan, has increased at an annual rate of 60%1. Agronomically, asparagus is interesting because it is recognised as the most salt tolerant vegetable crop2. In the surrounding fields a huge number of crops were recorded in the survey. Sugar cane and corn were most widely grown. The next largest group comprised rice, bananas, cassava, taro, aubergines, shallots, Chinese parsley and chilli peppers. Smaller areas were down to many other vegetables including okra, cabbages, tomatoes and several types of beans; fruit including mango, guava, papaya and dragon fruit; and exotic herbs such as bergamot and roselle.

Paraquat’s versatility

Paraquat is a versatile product for an enormous number of crops because it can be used to control weeds growing between crop rows. If necessary, a simple shield can be used around spray nozzles, but even if spray droplets land on crop leaves there is no effect on yield or quality because paraquat is a contact-only herbicide. Unlike glyphosate it does not move systemically within plants, so cannot reach developing grain or fruit. Immediately on contact with soil paraquat is deactivated. It is bound extremely tightly to soil particles, so cannot leach


The natural process by which water soluble substances are carried downward through the soil into groundwater.
. Therefore, it does not affect the roots of growing crops and any following crop can be planted without any delay. Similarly, paraquat allows a new generation of weeds to grow, which helps to anchor the soil on sloping fields prone to erosion. Young weeds can then be quickly and easily removed by a further application of paraquat before they are large enough to compete with the crop.
Although termed a non-selective


A chemical product used for eliminating all types of weeds (annual and perennial grasses and broadleaved weeds).

Authoritative On-line References and Resources An invaluable source of contemporary information about herbicides and weeds from Iowa State University.
herbicide, because of its contact-only action and inactivation in soil, it can be used before planting and in between crop rows with complete safety to whatever crop. Selective herbicides


A chemical product used for eliminating certain types of weeds only (ie either grasses or broadleaved weeds) and not affecting specified crops.

Authoritative On-line References and Resources An invaluable source of contemporary information about herbicides and weeds from Iowa State University.
are generally for use on only one crop or on a few closely related ones. Thai farmers rely on paraquat to control weeds in their diverse cropping systems.


  1. World Bank (2005). Shrimp, fresh asparagus and frozen green soybeans in Thailand. Agriculture and Rural Development. Discussion Paper 16.
  2. Shannon, M C and Grieve, C M (1999). Tolerance of vegetable crops to salinity. Scientia Horticulturae, 78, 5-38.


The brand name for the leading paraquat product is Gramoxone