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(一)引言 全世界的温室面积虽然很小(约10000—15000公顷),但这一栽培系统的发展在几个方面都颇有兴趣。主要方面是在保护地上种植蔬菜和观赏植物,成本昂贵,又是富有经验的农民的工作,因此仅有极少数专家指望利用天敌在温室中防治害虫。农民不会为了观念上的理由,例如生物防治比化学防治的不良副作用小,而去冒害虫为害损失的风险。如果化学防治方法比较好,他们当然采用化防。以番茄为例,病虫害的防治费用仅占番茄生产全部费用中
(I) Introduction Although the greenhouse area around the world is small (about 10,000-15,000 hectares), the development of this cultivation system is quite interesting in several aspects. The main aspect is the cultivation of vegetables and ornamental plants on protected soils that are costly and are also the work of experienced farmers. Therefore, very few experts are counting on the use of natural enemies to control pests in greenhouses. Peasants do not risk the loss of pest damage for conceptual reasons, such as the less adverse side effects of biological control than chemical control. If the chemical control method is better, of course, they use anti-defensive. To tomato, for example, pest control costs only accounted for the full cost of tomato production