Pests of Chinese water chestnut

Very little information is available about pest problems of Chinese water chestnut in Thailand. 

Farmers in Suphanburi who grow this crop mention a number of rice pests (brown plant hopper, green leaf hopper, stem borer, gall midge). Probably they consider these as pests because the crop is grown under similar conditions as rice. It is not clear however if these insects are really important as pests of water chestnut. A disease found in Chinese water chestnut was identified as a rust.

There are only very few documents available that refer to water chestnut. A thesis with the title "Morphological and Cytological Studies on Water Chestnut", written in 1979 by Ms. Chanima Sungkum, mentions aquatic weeds, rust and tiller worms as problems during crop cultivation.

To control insects and diseases, most farmers apply weekly a mixture of insecticides and fungicides. This is often repeated 20 times during one cropping season. Currently some farmers are experimenting with Neem and bio-extracts to replace the synthetic insecticides and fungicides. However, as they apply these botanical products as a calendar spray (20 weekly applications) the cost of these farm inputs is still very high and it is very likely that not so many applications are required.

To evaluate the importance of pests and diseases, these farmers will carry out more field experiments during the next cropping season.