# Evaluation of Trap Systems for Monitoring of Odontothrips loti and Frankliniella occidentalis: A Pilot Field Trial

## TL;DR

A new trap system using plant chemicals effectively captures two major thrips pests in alfalfa, offering a sustainable alternative to insecticides.

## Contribution

A novel trapping system using p-Menth-8-en-2-one for monitoring Odontothrips loti and Frankliniella occidentalis in alfalfa fields is introduced.

## Key findings

- White sticky traps baited with p-Menth-8-en-2-one captured the highest number of both thrips species.
- Optimal concentrations of 1 µg/µL and 50 µg/µL were effective for O. loti and F. occidentalis, respectively.
- PVC pipes dispensing p-Menth-8-en-2-one at 1 µg/µL effectively attract both species when they co-occur.

## Abstract

Thrips cause severe damage to alfalfa, leading to substantial production and economic losses. With chemical insecticides resistance escalating due to overuse, sustainable control alternatives are needed. We evaluated a novel trapping system using alfalfa-derived semiochemicals for thrips management. Our results demonstrated that white sticky traps baited with p-Menth-8-en-2-one dispensed through polyethylene vials, positioned at canopy height, captured the highest number of Odontothrips loti and Frankliniella occidentalis. This preliminary field trial offers a science-based approach to support timely decisions for implementing control strategies in the early stage before crop damage becomes significant and to reduce the number of insecticide applications required for control.

Plant-derived volatile organic compounds (VOCs) are widely used as insect attractants for population monitoring, offering an efficient and eco-friendly approach to pest management. Since thrips are the dominant pest species in alfalfa fields, this study aimed to identify a suitable attractant trap design that could be employed to monitor Odontothrips loti and Frankliniella occidentalis. The field experiment showed that p-Menth-8-en-2-one, dispensed through PE (Polyethylene) vials positioned at the top of the alfalfa canopy, attracted the most thrips, with the optimal concentrations of 1 µg/µL for O. loti and 50 µg/µL for F. occidentalis, respectively. When both species occur in alfalfa, PVC pipes dispensing p-Menth-8-en-2-one at a concentration of 1 µg/µL provide an effective attractant for both species, offering an indication of presence and relative abundance. Understanding the incidence and abundance of both species in the field provides growers an opportunity to target treatments to protect crops before significant damage occurs, reduce insecticide overuse, and support integrated pest management strategies for these two high-impact pests.