ABSTRACT The cultivation of vegetables under tunnels is considered a promising alternative to the use of chemicals to manage insect pests. However, higher temperatures under covers hinder their use in warm regions. We investigated the effect of high tunnels covered with plastic film or small or large mesh insect-nets on the performances of tomato plants in Tanzania over two years. Control plants were grown in open field plots. The temperature during the day was 4°C and 15°C higher under the nets and under the plastic than in the open. The total number of insect pests per plant over the season was generally lower under the nets than in open, with the small mesh better than the large mesh. The nets promoted plant growth compared with the open plots, with higher leaf area, plant dry weight, and plant height. Marketable yields were lower in open (2.7 and 10.8 t.ha−1), intermediate under the large mesh (7.9 and 38.4 t.ha−1), and high under the small mesh (16.8 and 50.1 t.ha−1). Higher productivity under the nets was associated with better plant growth and fewer insects than in the open. Contrasting results could be obtained in warmer climates because of the increase in temperatures recorded under tunnels.

中文翻译：

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小网眼保护番茄植株免受虫害并提高东非的产量

摘要 在隧道下种植蔬菜被认为是使用化学品来控制害虫的一种有前途的替代方法。然而，覆盖物下较高的温度阻碍了它们在温暖地区的使用。两年来，我们调查了覆盖有塑料薄膜或小或大网眼昆虫网的高隧道对坦桑尼亚番茄植株性能的影响。对照植物在开阔地中生长。白天，网下和塑料下的温度比露天高 4°C 和 15°C。整个季节单株害虫总数普遍低于网下，小网优于大网。与空地相比，网促进植物生长，具有更高的叶面积、植物干重和植物高度。公开市场的可销售收益率较低 (2. 7 和 10.8 t.ha-1)，在大网格下中间（7.9 和 38.4 t.ha-1），在小网格下高（16.8 和 50.1 t.ha-1）。与露天相比，网下更高的生产力与更好的植物生长和更少的昆虫有关。由于隧道下记录的温度升高，因此在温暖的气候下可以获得对比结果。