Abundant natural enemies in tropical Asian irrigated rice usually prevent significant insect pest problems. Integrated pest management (IPM) extension education of depth and quality is required to discourage unnecessary insecticide use that upsets this natural balance, and to empower farmers as expert managers of a healthy paddy ecosystem. Farmers' skill and collaboration will be particularly important for sustainable exploitation of the potential of new, higher-yielding and pest-resistant rice. IPM "technology transfer" through training and visit (T&V) extension systems failed, although mass media campaigns encouraging farmer participatory research can reduce insecticide use. The "farmer first" approach of participatory nonformal education in farmer field schools, followed by community IPM activities emphasizing farmer-training-farmer and research by farmers, has had greater success in achieving IPM implementation. Extension challenges are a key topic for rice IPM research, and new pest management technology must promote, rather than endanger, ecological balance in rice paddies.
This pilot program was designed to: 1) determine whether farmers could use a simple self-reporting system to estimate the incidence of occupationally related, self-limited pesticide poisonings; 2) describe the frequencies and types of pesticide products used in spraying operations; and 3) assess whether self-reporting and feedback would influence spraying behaviors. For 12 months, 50 farmers in northern Vietnam recorded after every spraying session any adverse health effect and the pesticide used. Data were also gathered from 50 controls. Of the 1,798 recorded spray operations, 8% were asymptomatic, 61% associated with vague ill-defined effects, and 31% accompanied by a least one clear or symptom of poisoning. After six months, the self-reporting farmers' spraying frequency and use of highly hazardous products (Ia/Ib) had declined more significantly than in the controls, as had their moderate adverse health effects. This low-cost surveillance method influenced the behaviors of farmers given access to IPM farmer field schools. The study also demonstrated the value of farmers as informants.
Major insect pests and their natural enemies were sampled on cowpea in monocrop and cereal intercrop plots in southern and northern Nigeria. Populations of flower thrips, Megalurothrips sjostedti (Trybom), were reduced by 42% and predators, mostly Orius spp. (Anthocoridae), by 23% on cowpea in maize intercrop plots at Ofiki in the south. Infestation by pyralid pod borer, Maruca testulalis Geyer, was unaffected by cropping system. The results suggest that tasselling maize attracts flower-eating beetles (Meloidae) to intercrop plots, and that pod-sucking Hemiptera were increased by cereal intercrops at Yankara in the north. Three u.l.v. applications of permethrin at 150 g a.i./ha to monocrop cowpea reduced pest populations by 50 to 85% in the south and increased yield sevenfold. However, the sprayed crop in the north was lost due to a heavy infestation of pod-sucking bug, Clavigralla tomentosicollis Stål, and outbreaks of Aphis craccivora Koch on sprayed plots in both localities suggested damage to natural enemies. It is concluded that the pest management potential of intercropping is variable and dependent on environmental factors, but it is recommended that intercropping be used in integrated pest management systems with the progressive decrease in insecticide use.
The interrelationship of an Iranian ecotype of Trioxys pallidus (Hal.) (Hymenoptera: Aphidiidae) and the walnut aphid, Chro1114" phis juglandicola (Kalr.), (Hornoptera: Callaphididae), was as.. sessed over a 4-year period at two localities in California. Limited additional data were obtained from other localities. Trioxys pallidus, a highly efficient parasite, which is biologically adapted to and phenologically synchronized with C. iuglandieola, has brought about substantial biological control of this pest. Trioxys pallidus substantially dampens the aphid's vernal oscillation, and normally restrains the amplitude of the summer and autumnal oscillations. Major economic benefits have been realized by the elimination of the aphid as a pest in springtime. Trioxys pallidus is at times heavily attacked by non-specific hyperparasites, but these, at most, hinder it but slightly. Certain insecticides can disrupt T. pallUlus activity, permitting aphid outbreaks. Prolonged aphid scarcity, possibly abetted by hyperparasitism, also may cause a breakdown in parasite activity and a temporary aphid resurgence in midseason. During the 4 years of investigation, this occurred on one occasion in one of the study plots. More than one-half million dollars have accrued annually to the California walnut industry as a result of the C. juglandieola biological control program.
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