Allium leafminer (Diptera: Agromyzidae) host preference: implications for developing a trap cropping strategy.

Area of Science:

• Agricultural Entomology
• Invasive Species Management
• Horticultural Entomology

Background:

• The Allium leafminer (Phytomyza gymnostoma) is an invasive pest impacting Allium crop production in the eastern US since 2015.
• Economic losses occur in leek crops due to larval tunneling, rendering them unmarketable.
• Limited cost-effective management options exist, particularly for organic leek production.

Purpose of the Study:

• To evaluate the host preference of Phytomyza gymnostoma among various Allium crop species.
• To assess the potential of using other Allium species as trap crops for P. gymnostoma management.
• To determine if scallion size/age influences P. gymnostoma preference.

Main Methods:

• Controlled environment choice tests and field trials were conducted in 2021 and 2022.
• Evaluated host preference of P. gymnostoma for chives, scallion, an onion/scallion hybrid, and leek.
• Assessed P. gymnostoma preference for scallions of varying sizes and ages.

Main Results:

• Field trials showed chives had significantly more oviposition marks, eggs, larvae, and pupae than leeks.
• Controlled tests indicated larger/older scallions attracted more P. gymnostoma than smaller ones.
• This size/age preference in scallions was not observed in field trials.

Conclusions:

• Chives are a potential trap crop for Phytomyza gymnostoma in leek cultivation.
• Utilizing chives may help reduce P. gymnostoma damage in commercial leek crops.
• Further research could optimize trap cropping strategies for this invasive pest.