# Efficiency of Unitraps in Capturing Corn Earworm Moths, Helicoverpa zea (Lepidoptera: Noctuidae), in the Field

## TL;DR

This study evaluates how well green Unitraps capture corn earworm moths compared to others and finds they capture about 11% of moths that approach.

## Contribution

The study introduces a novel assessment of trap efficiency for corn earworm moths, revealing low capture rates that impact monitoring effectiveness.

## Key findings

- Green Unitraps captured an average of 11% of moths that approached the trap.
- Green Unitraps captured more moths than Scentry Heliothis traps and clear Unitraps.
- Low trap efficiency may hinder detection of invasive corn earworm moth populations.

## Abstract

Monitoring efforts for moths often rely on pheromone-baited traps to capture males. Trap characteristics, including color and shape, are often compared by determining which design captures the most moths. However, few studies have investigated the number of moths captured compared to the number that approach the trap, i.e., trap efficiency. Three traps were compared for total number of moths captured, and the best trap, the green Unitrap, was then used in field observations to determine its capture efficiency. Moths were videoed at night, and the number approaching the trap was recorded and compared to the number trapped. On average, 11% of moths orienting to the trap were captured. Understanding the capture efficiency of traps will help in interpreting monitoring and surveillance efforts and set the stage for improvements to trap designs.

Pheromone-baited traps are commonly used to monitor and detect moths. Traps and lures are often compared to each other to identify the optimum set up and lure dosage. However, it is also important to understand the efficiency of a trap in capturing the moths that are attracted to it. In the present study, three pheromone-baited traps were placed at the edge of a cornfield to determine the one with the highest capture rate of Helicoverpa zea (Lepidoptera: Noctuidae): Scentry Heliothis traps, clear Unitraps, and green Unitraps. Once it was determined that green Unitraps captured more H. zea, field observations determined the number of moths captured in the traps compared to the number approaching, i.e., trap efficiency. Green Unitraps had a capture efficiency ranged from 5 to 11%, with an average of 11%. Unitraps, although useful for monitoring existing populations, may not be effective in detecting an invasive incursion. The implications of low capture efficiency in the surveillance of H. zea are considered, including possible explanations and next steps to improve monitoring efforts of heliothine moths.