by
Ho Van Chien, Southern Regional Plant Protection Center, Long Dinh, Tien Giang, Vietnam,
M.M. Escalada, Visayas State University, Baybay, Leyte, Philippines
Rice farmers often spray their crops early in the season which do more harm making fields vulnerable to hopper attacks
Farmers’ insecticide use is often based on beliefs and is strongly influenced by advertising and pesticide retailers. Advertising strategies target at creating emotional buying resulting in misuse. Misuse is defined as “improper or incorrect use”. Thus, when a wrong insecticide is sprayed for the target pest or the right insecticide may be used but at the wrong time or both, it is considered a misuse. In addition, incorrect use can also be from applying insecticide in a prophylactic manner when there is no pest present, or mixing an insecticide with other chemicals, like herbicides or fungicides or fertilizers. In an earlier study done in the Philippines, about 77% of the insecticide sprays was applied incorrectly or misused (Read: Heong et al 1995). Insecticide misuse has become extremely rampant inducing massive planthopper outbreaks in Thailand and Indonesia. Farmers fall into a vicious cycle of misuse that tend to lead to more misuse because of weak pesticide marketing policies – or a house with no roof.
We surveyed 1009 rice farmers in Tien Giang province in March 2011 and recorded their insecticide sprays; timing, active ingredient and intended target pests. More than half of the sprays (total = 4886) were targeted at two insect pests, 49.4% at the brown planthopper and 43.0% at the leaf folder. The next three pests that farmers were spraying for were panicle mites (3.8%), green horn caterpillars (1.2%) and thrips (1.0%). A total of 46 different chemicals and mixtures were used and the 3 most common chemicals were abamectin (16.8%), “Chief” (mix of chlorfluazuron+emamectin) (14%) and fenobucarb (13.3%). In Thailand the most commonly used insecticides were abamectin and cypermethrin (Read: Luecha et al). The next most commonly used were buprofezin (9.4%), “Dragon” (cypermethrin+ chlorpyrifos ethyl) (7.4%), dinotefuron (6.6%), indoxacarb (4.6%), “Penalty” (acetamiprid+buprofezin) (4.2%), quinalphos (3.3%) and polytrin (profenophos+cypermethrin) (2.6%). About 3% did not know the names of the chemicals they had used.
Distribution of farmers’ insecticide sprays in the crop stages - more than half of the sprays were applied in the first 40 days.
More than half of farmers’ sprays (57.9%) were applied in the early crop stages (first 40 days after sowing). About (47.9%) were targeted at leaf folders and the other half (45.8%) at brown planthoppers. The 3 most common insecticides used were abamectin (17.%), “Chief (chlorfluazuron+emamectin) (14.6%) and fenobucarb (14.6%). Insecticide sprays during this period have little or no economic benefits and in fact can make rice fields more vulnerable to BPH outbreaks. The high use of abamectin in the early crop stages is one of the causes of the huge BPH outbreaks in Thailand. The Rice Department and the Thai pesticide industry on 3 June 2011 launched a campaign to stop the use of abamectin and cypermethrin to reduce risks to planthopper outbreaks. The other insecticide, fenobucarb, has been used in Vietnam for more than 20 years and recent monitoring showed that Mekong Delta populations were about 36 times more resistance than the most susceptible population in Thailand (See Fabellar et at, 2010).
The misuse of insecticides in Tien Giang remains high despite the “no early spray” and the 3 reductions, 3 gains campaigns. These communication campaigns conveyed the message to farmers not to use any insecticides in the first 40 days after sowing as this is the critical period of biodiversity development and insect damages have little or no effects on yields because of plant compensation. The spraying instead continues to make fields vulnerable to hopper invasions. This is due in part to the unregulated marketing of pesticides being sold as FMCGs that use emotional appeals to motivate farmers to spray. The Mekong Delta is enjoying a bumper crop (see
http://www.saigon-gpdaily.com.vn/Business/2011/7/94337/) this season and more efforts to reduce insecticide misuse will help sustain future bumper crops.
Reference
Heong, K.L., Escalada, M.M. and Lazaro, A.A. 1995. Misuse of pesticides among rice farmers in Leyte, Philippines. Pp 97-108. In P.L. Pingali and P.A. Roger (Eds) Impact of Pesticides on Farmers’ Health and the Rice Environment. Kluwer Press, San Francisco.
