Irrigated rice is a native, long established crop in Southeast Asia that harbors a large number of beneficials, which keep pest species under effective natural biological control when left undisturbed. The program came into being as a response to a crisis situation because of pest resurgence and secondary pest outbreaks, mainly the brown plant hopper, which had been brought about by decimation of the potential of natural biological control through abuse and overuse of chemical pesticides in the wake of the green revolution. At the root of the crisis was not lack of research information but failure of using available knowledge on induced outbreaks in training farmers and changing crop protection policies. Demonstration of beneficial action of predators and parasitoids proved to be an eye-opener for most farmers, providing a strong impetus to their acceptance of the participatory training method. In comparison, many vegetables grown in Asia and Africa are not indigenous.
Protection often leans heavily on chemical control.
Pesticides, mostly insecticides but also fungicides, are usually applied to the calendar and often much more frequently than is really necessary. However, this does not mean that treatments with pesticides can be halted altogether. The strategy of chemical non-intervention clearly has a more limited applicability in vegetables than in rice. Therefore, cultural control methods such as crop rotation and intercropping and the use of resistant varieties should be more strongly part and parcel of IPM training in vegetables than in rice. Furthermore the lack of non-chemical control options implies that research should be much more involved in the development of vegetable IPM programs.