Do targeted bans of insecticides to prevent deaths from self-poisoning result in reduced agricultural output?

Abstract

Background: The pesticides monocrotophos, methamidophos, and endosulfan were a very common cause of severe poisoning in Sri Lanka during the 1980s and early 1990s, before they were banned in 1995 and 1998. Now, the most commonly used insecticides are the less toxic World Health Organization Class II organophosphorus pesticides and carbamates. These bans were followed by a large reduction in both fatal poisonings and suicide in Sri Lanka.

Objective: We aimed to see if these bans adversely affected agricultural production or costs.

Methods: We used data from the World Resources Institute to compare the yields of the main crop groups in Sri Lanka with those from surrounding South Asian countries for 1980-2005. We also examined data from the Sri Lankan Department of Census and Statistics to examine the yields of 13 specific vegetable crops and rice for 1990-2003, along with the costs of rice production.

Results: We found no drop in productivity in the years after the main bans were instituted (1995, 1998). We observed substantial annual fluctuation in estimated yields in all data sources, but these did not coincide with the bans and were no larger than the fluctuations in other countries. Also, there was no sudden change in costs of rice production coinciding with bans.

Conclusions: Countries aiming to apply restrictions to reduce deaths from pesticide poisoning should evaluate agricultural needs and develop a plan that encourages substitution of less toxic pesticides. If farmers have an affordable alternative for pest control for each crop, there is no obvious adverse effect on agricultural output.

Keywords: food production; pesticide poisoning; pesticide regulation; public health policy; suicide prevention.

Figure 1

Change in suicide rate and deaths from poisoning between 1975 and 2005. Vertical lines indicate the years when all Class I insecticides (1995) and endosulfan (1998) were banned. Adapted from Gunnell et al. (2007).

Figure 2

Yields of cereals (A), pulses (B), and roots and tubers (C) in south Asian countries during 1980–2005.

Figure 3

Longitudinal changes in Sri Lankan yields of 13 vegetable crops during 1990–2004. MT, metric tons. Vertical lines indicate the years when all Class I insecticides (1995) and endosulfan (1998) were banned.

Figure 4

Longitudinal changes in paddy production and costs of production in two districts (Anuradhapura and Polonnaruwa) of the NCP and correlation with external major cost items. Abbreviations: CCPI, Colombo Consumer Price Index; LKR, Lanka rupees; MT, metric tons. Vertical lines indicate the years when all Class I insecticides (1995) and endosulfan (1998) were banned.