variable input use, plus on crop and location dummies. Following Lichtenberg and
Zilberman (1986), a damage abatement function was specified, which captures the
fact that, unlike growth stimulating inputs, pesticides do not directly contribute to
crop yields. Of all alternative specifications for the damage abatement term, the
exponential specification was found to give the most plausible results.
The results showed an average private pesticide cost of 1,710 baht/ha/month for
leaf vegetables and 15,160 baht/ha/month for greenhouse vegetables,
corresponding to external costs of 490 and 3,210 baht/ha/month respectively.
Although the quantity of pesticide use in the watershed was high, pesticide costs
were relatively modest compared to the average output of 46,050 baht/ha/month for
leaf vegetables and 213,470 baht/ha/month for greenhouse vegetables.
Calculating the intersection of the marginal cost and marginal benefit curves, the
optimum level of pesticide use was determined for each plot observation.
Subtracting from this the actual quantity of pesticide use yielded an estimate of
pesticide overuse/underuse, as shown in Fig. 4.7.
Of the quantity of pesticides applied on leaf vegetables and greenhouse
vegetables, respectively 81 % and 79 % was shown to be overuse, suggesting that
vegetable farmers in the Mae Sa watershed could improve their profit margins by
substantially reducing the quantity of pesticides they use. However, the risk of a
potentially devastating pest attack, high levels of resistance among pests and a lack
of knowledge on good pest management practices, has resulted in a situation in
which farmers continue to deviate substantially from optimal input levels.
4.5.3 Good Agricultural Practices (GAP)
The Thai government in 2004 introduced a public GAP standard called Q-GAP
(with the Q standing for quality), to increase consumer confidence in the Thai food
sector through an improvement in food quality and food safety. A similar standard
Fig. 4.7 Economic levels of
pesticide overuse/underuse
for leaf and greenhouse
vegetables in the Mae Sa
watershed area in Thailand,
2010 (Source: Based on
Grovermann et al. 2012)
168
M. Lamers et al.
Zilberman (1986), a damage abatement function was specified, which captures the
fact that, unlike growth stimulating inputs, pesticides do not directly contribute to
crop yields. Of all alternative specifications for the damage abatement term, the
exponential specification was found to give the most plausible results.
The results showed an average private pesticide cost of 1,710 baht/ha/month for
leaf vegetables and 15,160 baht/ha/month for greenhouse vegetables,
corresponding to external costs of 490 and 3,210 baht/ha/month respectively.
Although the quantity of pesticide use in the watershed was high, pesticide costs
were relatively modest compared to the average output of 46,050 baht/ha/month for
leaf vegetables and 213,470 baht/ha/month for greenhouse vegetables.
Calculating the intersection of the marginal cost and marginal benefit curves, the
optimum level of pesticide use was determined for each plot observation.
Subtracting from this the actual quantity of pesticide use yielded an estimate of
pesticide overuse/underuse, as shown in Fig. 4.7.
Of the quantity of pesticides applied on leaf vegetables and greenhouse
vegetables, respectively 81 % and 79 % was shown to be overuse, suggesting that
vegetable farmers in the Mae Sa watershed could improve their profit margins by
substantially reducing the quantity of pesticides they use. However, the risk of a
potentially devastating pest attack, high levels of resistance among pests and a lack
of knowledge on good pest management practices, has resulted in a situation in
which farmers continue to deviate substantially from optimal input levels.
4.5.3 Good Agricultural Practices (GAP)
The Thai government in 2004 introduced a public GAP standard called Q-GAP
(with the Q standing for quality), to increase consumer confidence in the Thai food
sector through an improvement in food quality and food safety. A similar standard
Fig. 4.7 Economic levels of
pesticide overuse/underuse
for leaf and greenhouse
vegetables in the Mae Sa
watershed area in Thailand,
2010 (Source: Based on
Grovermann et al. 2012)
168
M. Lamers et al.