Muhammad Muhsin, Plant Pathologist
Indonesian Centre for Food Crops Research and Development
Karawang, Subang, Indramayu and Cirebon are important rice areas in West Java Province. They supply rice to other provinces and the capital of Indonesia, Jakarta. Recently the rice fields in these areas had been threatened by brown planthopper (BPH) attacks. Areas attacked increased from 450 ha in Februaryi to ca.10,000 ha in March 2010. About 250 ha were total loss amounting to about US$125,000. There are indications that the two virus diseases, rice ragged stunt and rice grassy stunt, are increasing. Hundreds of hectares in Sukamandi had been affected.
In Subang, an area of nearly 200 ha managed by the hybrid seed company, SHS, were severely affected (see pictures) and harvest was only 20%. Probably 3 factors triggered the outbreaks: (1) farmers follow continuous cropping pattern, rice-rice-rice, (2) they primarily grow susceptible varieties, such as Ciherang, IR42, Mekongga, etc., and (3) mismanagement of insecticides, like using wrong insecticides and wrong spraying techniques. Farmers were using IR42, and were infested by BPH just 1-2 days after insecticide application.
In Sukamandi many plants were infected by both viruses that BPH vector. About 30-40% were infected and these would become the virus sources, unlike the infected plants were eradicated.