Ecology and biology of nuisance algae in rice fields

Our project began by looking at both green and brown slime, as both types of slime were thought to be due to nuisance algae. We soon found that farmers can control green slime which is caused mainly by green algae such as Spirogyra and Anabaena. However, we found that for some rice farmers, brown slime is still a problem.

Current methods of sowing pre-germinated rice seed into fertilised and flooded rice bays and more intensive cropping have increased the incidence of brown slime. Farmers are concerned that brown slime which forms large mats in rice bays during rice establishment may lead to a lower yield.

We enlisted the help of farmers to find out when brown slime is a nuisance and what farmers do to prevent it from becoming a nuisance. We also examined samples of brown slime to identify the organisms responsible. We then determined the conditions that cause it to increase so that practical strategies could be devised to prevent it from becoming a problem. 

A. Grant, M. Pavlova, L. Wilkinson-White, I. Grant & D. Ko, IREC Farmers' Newsletter, No. 171, Summer 2006