Essential oil repellent action of plants of the genus Zanthoxylum against Bemisia tabaci biotype B (Homoptera: Aleyrodidae)

- This is the first demonstration of the chemical composition of the essential oils from fruits of Zanthoxylum riedelianum.
- By using repellency tests our results suggest that the essential oils from fruits of Z. rhoifolium and Z. riedelianum are promising for the management of Bemisia tabaci.
- It was observed that the higher the essential oil concentration, the lower the oviposition of adult whiteflies.

Several insects cause harm to agricultural production, increasing its cost. An insect of great interest is Bemisia tabaci, considered a major pest of tomatoes and other crops. Essential oils are alternative products for the control of agricultural pests. In this context, the objective of this work was to carry out chemical analyses of the essential oils of the fruits of Zanthoxylum rhoifolium and Zanthoxylum riedelianum and to evaluate their repellent activity against B. tabaci. The average yields of Z. rhoifolium and Z. riedelianum fruit were 0.44 and 0.21% (v/v), respectively. The major compounds in the essential oil of Z. rhoifolium were sabinene (55.9%), germacrene-D (17.1%) and β-myrcene (8.03%); the major compounds in the essential oil Z. riedelianum were γ-elemene (21.2%), D-germacrene (14.2%), sabinene (11.9%) and limonene (11.3%). Six (0.1; 0.2; 0.5; 1.0; 1.5 and 2.0%) and five (0.1; 0.2; 0.5; 1.0 and 1.5%) concentrations of essential oils of Z. rhoifolium and Z. riedelianum, respectively, were evaluated under no-choice and choice bioassay conditions. The best results obtained in the bioassays were achieved at concentrations ranging from 1.0 to 2.0% for both essential oils, with a reduced efficiency of egg laying between 85 and 98%. This is the first time that the chemical compositions of the essential oil from the fruits of Z. riedelianum have been described. The repellency tests suggest that these essential oils are promising for the management of B. tabaci.

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