Articles
CHALLENGES TO IMPLEMENTING VEGETABLE IPM IN SOUTHEAST ASIA
An ecological approach was initiated in 1970s and eventually resulted in importation of effective parasitoids that help keep DBM in check in the cooler highlands.
Lessons learnt served to help build up a strategy for vegetable IPM in Southeast Asia.
Ecological studies: Most of the problems with insecticide resistance were attributed to a lack of ecological information.
Farmers were encouraged to spray even when there was no pest problem.
Ecological studies in vegetables and soybean show that often the common armyworm, Spodoptera litura, was perceived as a pest because of the large number of larvae emerging from an egg mass.
Spraying insecticides killed off predators and parasitoids which would have reduced the armyworm population to a non-pest level. ecological studies helped in a better understanding of non-pests and often minimise spraying.
Biological control capabilities: Most of the insect pest problems in vegetables are exotic ones.
Besides existing introduced pests such as P. xylostella and Pieris rapae, new pests continue to arrive in Southeast Asia.
Recently, Liriomyza huidobrensis arrived causing serious outbreaks due to inadequate effective natural ennemies.
Hence, in the foresecable future, classical biological control will continue to be an important feature of IPM in this region and hence there is a need to enhance the capability of national programmes to import effective natural ennemies, evaluate their effectiveness and educate farmers to understand them.
Biological control by farmers: Often, biological control programmes are hampered due to a lack of understanding by farmers.
Farmers who understand biological control will tend to work to conserve natural ennemies in their fields.
Otherwise, an effective biological control programme may take more than 12 years to come to fruition.
Providing opportunities to farmers (who are graduates of farmer Field Schools) to study biological control will help in a faster establishment of exotic natural ennemies as well as their conservation.