Thai partners undergo workshop on rodent management and damage assessment

By Trina Leah Mendoza

Alex Stuart (center) shows participants how to identify different rodent species
and determine their breeding condition. Photo by Duangporn Vithoonjit

Rodent damage during postharvest storage was one of the problems mentioned by Thai farmers when scientists from the Closing Rice Yield Gaps in Asia with Reduced Environmental Footprint (CORIGAP)
assessed their needs in May 2013. In December 2013, rat and mouse problems were widely reported by farmers, with damage to seedlings in one of the farmers’ fields in Nong Jik Ree Village, one of CORIGAP’s project sites. In other regions of Thailand, reports of rodent damage to rice have been increasing over the last few years, with outbreaks of rodent population recently reported in Central Thailand.

To strengthen the knowledge and capacity of rice researchers in Thailand, 38 staff members from the Thai Rice Department attended a workshop on rodent management and damage assessment on 31 March-01 April 2014 at the Chainat Rice Research Center in Chainat Province. These staff members represented 23 provinces from the north, south, center, and east of Thailand.

The 2-day workshop was led by rodent experts Grant Singleton (CORIGAP coordinator) and Alex Stuart (CORIGAP postdoctoral fellow). Seminars and training sessions were given on ecologically based rodent management and on how to conduct rodent damage assessments. Group discussions were facilitated to understand more about rodent issues throughout Thailand.

Two field visits to CORIGAP treatment plots in Nong Jik Ree Village in Nakhon Sawan Province wereconducted to demonstrate setting up and checking of traps, burrow counts, and damage assessment. The participants also experienced how to identify rodent species and determine breeding condition.

Three rodent species, Rattus argentiventer, Rattus sakeratensis  (formerly R. losea) and Bandicota savilei, were trapped in rice fields and another species, Rattus exulans, was trapped in a grain store at the Chainat Rice Research Center.

Workshop participants are guided on how to set up
rodent traps in the field. Photo by Duangporn Vithoonjit

“We estimated that fresh rodent damage at the ripening stage ranged from 1 to 3% per treatment plot, with an overall damage of about 2% per field site,” says Alex Stuart. “As majority of damage by rats occurs before the ripening stage, studies have shown that damage estimates made at the ripening stage should be multiplied by four to give a conservative estimate of yield loss. We then estimated the yield loss caused by rodents to be about 8%.”


The logistics for the workshop were organized by Ms. Ladda Viriyangkura and Ms. Duangporn Vithoonjitfrom the Thai Rice Department.Two Rice Department zoologists working on rodents, Ms. Urassaya Boonpramuk and Ms. Thasdaw Katenate, provided assistance throughout the workshop, and each presented a seminar on their current research activities.