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Dear Friends and Colleagues

Studies Find Insecticides Not Needed for Rice Farming

Current food production systems are heavily dependent on synthetic inputs that threaten the environment and human well-being. Two research teams studied the relationship between insecticide use and rice yields.

The first (Item 1) relates to multi-site field studies replicated in Thailand, China and Vietnam over a period of four years to test a simple intervention of growing nectar-producing plants around rice fields, and then monitoring the levels of pest infestation, insecticide use and yields. They found that the intervention significantly reduced populations of two key pests, reduced insecticide applications by 70%, increased grain yields by 5% and delivered an economic advantage of 7.5%. Additional field studies showed that predators and parasitoids of the main rice pests, together with detritivores, were more abundant in the presence of nectar-producing plants. The conclusion is that a simple diversification approach can contribute to the ecological intensification of agricultural systems.

The other study (Item 2) comprised eight farm survey data sets of 5,410 households in three provinces in the Mekong Delta between 2002 and 2012. Paired farmer experiments showed that farm yields were not correlated with the number of insecticide sprays used in most cases. In the paired experiments plots, there was no significant correlation between yield and number of sprays in both plots. A survey of farms in a rice planthopper outbreak area showed that farms that had applied insecticides in the early crop stages for leaf folder control were 10 times more vulnerable to crop failures caused by severe planthopper attacks known as “hopperburn”. Rice farmers apparently had continued to apply insecticides despite the poor productivity gain due to their overestimation of the losses that would be caused by insect pests and the aggressive marketing of pesticides.

The researchers conclude that, "Farmers would be better off if they were to completely avoid insecticides and conserve ecosystem services that will reduce farms’ vulnerability to secondary pest outbreaks like the planthoppers that could cause crop failures". They cite the FAO’s declaration that “Most tropical rice crops under intensification require NO insecticide use” (FAO, 2011) and Way & Heong’s (1994) conclusion that "rice pest management should be based on the contention that insecticides are not needed...". The researchers call on scientists and policy-makers to rethink future pesticide management strategies considering the acute and chronic health impacts and environmental costs of pesticides, including bee and bird mortalities.

With best wishes,

Third World Network
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10400 Penang
Malaysia
Email: twn@twnetwork.org
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Item 1

MULTI-COUNTRY EVIDENCE THAT CROP DIVERSIFICATION PROMOTES ECOLOGICAL INTENSIFICATION OF AGRICULTURE

Gurr et al.
Article Number: 16014 | DOI: 10.1038/NPLANTS.2016.14
http://www.nature.com/articles/nplants201614

Abstract

Global food security requires increased crop productivity to meet escalating demand. Current food production systems are heavily dependent on synthetic inputs that threaten the environment and human well-being. Biodiversity, for instance, is key to the provision of ecosystem services such as pest control, but is eroded in conventional agricultural systems. Yet the conservation and reinstatement of biodiversity is challenging and it remains unclear whether the promotion of biodiversity can reduce reliance on inputs without penalizing yields on a regional scale. Here we present results from multi-site field studies replicated in Thailand, China and Vietnam over a period of four years, in which we grew nectar producing plants around rice fields, and monitored levels of pest infestation, insecticide use and yields. Compiling the data from all sites, we report that this inexpensive intervention significantly reduced populations of two key pests, reduced

insecticide applications by 70%, increased grain yields by 5% and delivered an economic advantage of 7.5%. Additional field studies showed that predators and parasitoids of the main rice pests, together with detritivores, were more abundant in the presence of nectar-producing plants. We conclude that a simple diversification approach, in this case the growth of nectar-producing plants, can contribute to the ecological intensification of agricultural systems.


Item 2

CHAPTER 9. ARE THERE PRODUCTIVITY GAINS FROM INSECTICIDE APPLICATIONS IN RICE PRODUCTION?

Heong, KL.; Escalada, MM; Chien, HV; and Delos Reyes, JH 2015. Pp 181 - 192. Chapter 10
In Heong, KL, Cheng, JA and Escalada, MM. (eds) “Rice Planthoppers: Ecology, Management,
Socio Economics and Policy” Zhejiang University Press, Hangzhou and Springer Science+Business Media Dordrecht. DOI 10.1007/978-94-017-9535-7.
http://www.legato-project.net/files/DOWNLOAD/Chapter%209%20Heong%20et%20al.2015%20pdf.pdf

Abstract

Insecticides have always been viewed to be necessary inputs to achieve high rice production. However this notion has been challenged by ecologists and economists and they have shown that Asian farmers’ insecticide use has poor or no productivity gains. Farm surveys of more than 5000 households in the Mekong, Vietnam and paired farmer experiments showed that farm yields were not correlated with the number of insecticide sprays used in most cases. In the paired experiments plots there was no significant correlation between yield and number of sprays in both plots. A survey of farms in a rice planthopper outbreak area showed that farms that had applied insecticides in the early crop stages for leaf folder control had higher probability of heavy planthopper attacks or “hopper burn”. The reasons why rice farmers had continued to apply insecticides despite of the poor productivity gain might be due to their misperceptions that lead to overestimate losses caused by insects, the aggressive marketing of pesticides that heightens their loss aversion attitudes thus making them victims of insecticide abuse. Rice farmers appear to be “locked into” circumstances that continue to promote insecticide use despite the lack of productivity gains. With health costs from both acute and chronic long term impacts and environmental costs especially in causing bee and bird mortalities, scientists and policy makers need to rethink future pesticide management strategies to avoid pesticides becoming a threat to food security instead.

 


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