Flowering Ocimum gratissimum intercropped in tea plantations attracts and reduces Apolygus lucorum populations

Apolygus lucorum is one of the most important piercing-sucking insect pests of the tea plant In this study, we assessed the attractiveness of basil plants to A. lucorum and the effectiveness of Ocimum gratissimum L. in the control of A. lucorum. The control efficiency of main volatile chemicals emitted from O. gratissimum flowers was also evaluated.

Among seven basil varieties, O. gratissimum was more attractive to A. lucorum adults and was selected as a trap plant to assess its attractiveness to A. lucorum and effects on natural enemies in tea plantations. The population density of A. lucorum on trap strips of O. gratissimum in tea plantations was significantly higher than that on tea at 10-20 m away from the trap strips. Intercropping O. gratissimum with tea plants, at high-density significantly reduced A. lucorum population levels. Eucalyptol, limonene, β-ocimene, and linalool were the four dominant components in the O. gratissimum flower volatiles, and their emissions showed a gradual upward trend over the sampling period. Olfactometer assays indicated that eucalyptol and dodecane showed attraction to A. lucorum. High numbers of A. lucorum were recorded on limonene, eucalyptol, and myrcene-baited yellow sticky traps in field trials in which 11 dominant volatiles emitted by O. gratissimum flowers were evaluated.

Our research indicated that the aromatic plant O. gratissimum and its volatiles could attract A. lucorum and planting O. gratissimum has the potential as a pest biocontrol method to manipulate A. lucorum populations in tea plantations. © 2024 Society of Chemical Industry.