Rodents can not only make people jump in fright, but can also pose serious problems to food security. Although only 20 out 1700 rodent species are qualified as pests, each year they cause harvest losses of approximately 17%, enough to feed more than 25 million Indonesians for a year.
In the article “Rodent outbreaks and rice pre-harvest losses in Southeast Asia”, published in the latest issues of Food Security Journal, SIANI Member Adam John looks into the ways of ecologically based rodent management and discusses its constraints and opportunities.
Rice, the greatest food commodity produced for human consumption, is particularly vulnerable to rodent outbreaks, especially in the changing climate: rodent outbreaks intensify with early rainfall in wet season.
“This topic gives a clear example of how more irregular climate conditions will make it more difficult for farmers to control pests. It is not simply the abiotic factors like the availability of water and the impact of increased temperatures which farmers need to adapt to but many other factors too”, comments John.
Traditionally rodent outbreaks have been treated with the use of chemicals – rodenticides. However, this type of managements has certain issues: chemicals can be unaffordable for smallholders or extremely toxic substances can be used as cheaper options; lack of knowledge among farmers in the applications of chemicals can have a reverse effect on pest control; rodenticides can kill other species and, finally, chemical treatments can affect human health as in some places rodents are part of the diet.
Ecologically Based Rodent Management (EBRM) can help avoid all harmful features of rodenticides and has proven to be more effective than chemical pest control. For example, Average yield loss was 16.8 % in rice fields in the Mekong region of Vietnam where EBRM was applied compared to a 30.3 % loss where traditional rodent control techniques were used.
Although EBRM appears to be a better option, its application is not widespread, and social constraints are listed among the most challenging. John comments “We understand the ecology of rodents and their impact on our cropping systems a lot better than we did only two decades ago. The challenge now is to convince policymakers that more attention needs to be given to confronting this problem”.
Adam John is a PhD economics candidate at the Agricultural and Food Policy Studies Institute at Universiti Putra Malaysia in Kuala Lumpur, Malaysia and is based in Stockholm. His thesis is entitled “Price relations between world rice markets”. He also holds a Master’s degree in Economic Development from Reading University.