The intercropping strategy has been widely explored in tea plantations in recent years. However, successful applications of intercropped trap plants in tea plantations remain limited. The effects of the trap plant on the tea aphid-ant-predator community and on tea quality and yield are unknown.
In a study published in Pest Management Science, researchers from the Xishuangbanna Tropical Botanical Garden (XTBG) of the Chinese Academy of Sciences tried to assess the impact of intercropped legumes on tea aphid, ant, and predator guilds and to examine dynamic changes in the networks over three consecutive years. They then investigated the potential impact of the legume on both tea quality and yield.
The researchers intercropped Flemingia macrophylla, a drought-tolerant, multi-purpose tropical shrub legume, in a tea plantation located in Dadugang town, Xishuangbanna, and then carried out experiments.
They found that the intercropped legume plant successfully trapped tea aphids (one of the most destructive insect pests in commercial tea plantations and gardens in southern China) and increased the complexity of aphid–ant–predator networks for three consecutive years compared to monoculture management. The legume significantly increased the abundance of natural predators and species richness.
Moreover, the intercropped F. macrophylla may indirectly benefit ant and predator guilds through cascade effects. The effects of F. macrophylla cascaded up to higher trophic levels of ants and predators through tea aphids, increasing both species richness and abundance of these two guilds by providing food resources and shelter, and increasing the complexity of the aphid–ant–predator network by increasing the number of nodes and strengthening connections.
F. macrophylla significantly increased the abundance of natural predators and species richness. The increased predators suppressed the aphid population and prevented its spread to neighboring tea plants. Consequently, F. macrophylla improved tea quality through an 8% increase in soluble sugars and a 26% reduction in the ratio of polyphenols to amino acids.
"Our study provides valuable insights into the use of trap legumes in tea plantations as an efficient integrated pest management strategy," said TANG Jianwei of XTBG.
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