Role of volatile compounds emitted from the first and second trophic levels in host finding behavior of Tamarixia radiata (Hym.: Eulophidae)

Abstract

Odors play an important role in the seeking behavior of wasp parasitoids and enhances their performance in biological control programs. This study was intended to determine the olfactory response of Tamarixia radiata (Waterston) to chemical cues that emanates from various stages of Asian citrus psyllid, Diaphorina citri Kuwayama, in Y-tube olfactometer in laboratory conditions (27 ± 1°C, 60 ± 10% RH, 1600 lux light intensity and constant airflow of 300 ml/min). The effect of green leaf volatiles (GLVs) and herbivore-induced plant volatiles (HIPVs) of four varieties of the rutaceous plants, Mexican lime, Citrus aurantifolia, Campbell Valencia orange, C. sinensis, Marsh grapefruit, C. Paradisi, and sour orange, C. aurantium, were also evaluated based on separately release of 30 females and 30 males of T. radiata. The results indicated that the females were significantly attracted to the volatiles emanating from D. citri nymphs and HIPVs resulted from the feeding of nymphs and adults of D. citri. The males were not responsive to the odors emanating from various stages of D. citri, GLVs or HIPVs. It is found that the female parasitoid wasps use chemical cues emanating from the nymphs of Asian citrus psyllids and HIPVs for host seeking. Using the synthetic volatile compounds could increase the viability of the biological control agents in integrated pest management programs.

Keywords

• olfactometer
• asian citrus psyllid
• diaphorina citri
• herbivore
• induced plant volatiles
• green leaf volatiles
• rutaceous plants