Effects Of Intercropping Of Cabbage With Non-cruciferous Vegetables On Arthropod Community In Cabbage Fields

Based on the field experiments and systematic field investigation, the effects of intercropping of cabbage with three kinds of non-cruciferous vegetables, garlic, tomato and garland chrysanthemum, on the arthropod community in cabbage fields were studied in this paper. The main results were as follows:1Effects of intercropping of cabbage with several non-cruciferous vegetables on arthropod community in cabbage fields1.1Effects of intercropping of cabbage with several non-cruciferous vegetables on major dominant insect pests in cabbage fieldsThe experiments were conducted in vegetable fields of Sanshigang village, Hefei in2009. The results of systematic investigation showed that there were20species of arthropods in spring cabbage fields, including9species of insect pests and11species of predatory enemies. The major dominant insect pests were Pieris rapae and Lipaphis erysimi. During the period of investigation, the population of Pieris rapae was on the rise and the average density reached some40head per cabbage plant in peak period in the middle and late ten days of May. The population of Lipaphis erysimi reached the highest level in the middle ten days of May. The intercropping of cabbage with garlic or tomato had certain control effects on Pieris rapae and Lipaphis erysimi and the total populations of Pieris rapae and Lipaphis erysimi were only35.6%and64.8%of that of check plot respectively. The intercropping of cabbage with garland chrysanthemum had no control effects on Pieris rapae and Lipaphis erysimi.The results of systematic investigation showed that there were22species of arthropods in autumn cabbage fields, including10species of insect pests and12species of predatory enemies. The major dominant insect pests were Prodenia litura and Lipaphis erysimi. Prodenia litura happened seriously in the late period of cabbage growth. During the period of investigation, the total populations of Prodenia litura and Lipaphis erysimi in intercropping fields of cabbage with garlic, tomato and garland chrysanthemum were50.1%,76.8%and93.2%of that of check plot respectively.1.2Effects of intercropping of cabbage with several non-cruciferous vegetables on major characteristic indices of arthropod communities in cabbage fieldsThe research results showed that the intercropping of spring cabbage with garlic or tomato was able to reduce the concentration of the arthropod community in cabbage fields raise the evenness and diversity of the community. The intercropping of spring cabbage with the three non-cruciferous vegetables, garlic, tomato and garland chrysanthemum was able to raise the richness of the community. The effects of intercropping of autumn cabbage with garlic, tomato and garland chrysanthemum on arthropod community in autumn cabbage fields were similar to those in spring cabbage fields.1.3Effects of intercropping of cabbage with several non-cruciferous vegetables on the ratio of natural enemies to insect pests in cabbage fieldsThe research results showed that the intercropping of cabbage with several non-cruciferous vegetables had certain effects on the ratio of natural enemies to insect pests in cabbage fields.The ratio of natural enemies to insect pests rose significantly in the intercropping fields of cabbage with garlic. The effects of intercropping of cabbage with tomato or garland chrysanthemum on the ratio of natural enemies to insect pests in autumn cabbage fields were better than those in spring cabbage fields-Overall, the intercropping of cabbage with the three non-cruciferous vegetables was able to raise the ratio of natural enemies to insect pests and was helpful to protect and enhance the natural control effects of natural enemies on insect pests in cabbage fields.2Effects of intercropping of cabbage with garlic in different ways on the arthropod community in cabbage fields2.1Effects of intercropping of cabbage with garlic in different ways on the main dominant insect pests in cabbage fields.The research results showed that all the three ways of intercropping of spring and autumn cabbage with garlic, which were1line cabbage×1line garlic,5line cabbage×1line garlic and10line cabbage×1line garlic, had evident control effects on Pieris rapae and Lipaphis erysimi.The total populations of Pieris rapae and Lipaphis erysimi were only59.0%,81.3%and83.1%of those in single cropping fields of spring cabbage respectively and were only45.6%,57.5%and90.0%of those in single cropping fields of autumn cabbage respectively.2.2Effects of intercropping of cabbage with garlic in different ways on major characteristic indices of arthropod communities in cabbage fieldsThe research results showed that all the three ways of intercropping of spring and autumn cabbage with garlic, which were1line cabbage×1line garlic,5line cabbage×1 line garlic and10line cabbage×1line garlic, were able to reduce the concentration and raise the richness, evenness, and diversity of the arthropod community in cabbage fields.2.3Effects of intercropping of cabbage with garlic in different ways on the ratio ofnatural enemies to insect pests in cabbage fieldsThe research results showed that the ratios of natural enemies to insect pests in cabbage fields were significantly improved under the intercropping of1line cabbage with1line garlic. The intercropping of5line or10line cabbage with1line garlic was able to raise the ratio of natural enemies to insect pests in cabbage fields in the late growth period of cabbage. Overall, the intercropping of cabbage with garlic was able to improve the ratio of natural enemies to insect pests in cabbage fields and was helpful to protect and enhance the natural control effects of natural enemies on insect pests.