Last week I visited Tan Tru district in Long An province and saw numerous rice fields destroyed by planthoppers. I interviewed the farmers and found that some have been using 10 insecticide applications, one seed treatment, one granular application and 8 sprays.
Broad spectrum pyrethroid, organo phosphates among others have been used in mixtures. Crops were near harvesting and yet have numerous freshly hatched nymphs which imply that the adult populations were very high, after 10 sprays.
It seems like the more sprays farmers use the more generations occur. I think if farmers had not sprayed in the early crop stages, they will not have experienced such heavy attacks. Crops were sprayed when seedling were 7-15 days old.
I continue my TV programs once or twice a week urging farmers to avoid early season spraying but it seems my messages have been completely overpowered by the more frequent pesticide advertising. Pesticide adverting messages are as frequent as one every hour in Vietnam.
And in addition, the pesticide company agents are organizing farmer groups, farmer field school (FFS)-style teaching farmers about pesticides and giving out free samples. With the rice price so high, most farmers are anxious about their crops and companies are extending their promotion activities.
I fear that at the present rate of excessive pesticide spraying, the Mekong Delta will once again experience huge planthopper outbreaks before or during the Tet (Vietnamese New Year) holidays in late January.