Leaffooted Bugs, Leptoglossus phyllopus (Hemiptera: Coreidae), Are Attracted to Volatile Emissions from Herbivore-Damaged Cotton Bolls

TL;DR

Leaffooted bugs are attracted to specific chemicals released by cotton bolls damaged by their feeding, which could help create lures for pest control.

Contribution

The study identifies specific volatile compounds that attract leaffooted bugs and explores their potential for pest management.

Findings

Leaffooted bug herbivory increases emissions of six specific volatile compounds from cotton bolls.

Adult leaffooted bugs are attracted to herbivore-induced VOCs and to synthetic benzaldehyde or α-pinene.

The combination of synthetic benzaldehyde and α-pinene repels leaffooted bugs.

Abstract

Insect herbivores often use plant-produced VOCs to select suitable host plants for feeding and oviposition. The leaffooted bug probes and feeds on tissues of many plant species, including developing cotton bolls, causing seed damage and boll abscission. Field observations of abundant adult leaffooted bugs on cotton bolls suggest that bugs aggregate at feeding sites. The goal of this study was to characterize VOCs from leaffooted bug-damaged cotton bolls and evaluate how these VOCs affect adult bug foraging behavior. A portable dynamic headspace sampling method was used to collect VOCs from developing cotton bolls in the field and VOC samples were analyzed using gas chromatography-mass spectrometry. Leaffooted bug herbivory induced volatile emissions from cotton bolls, with significant increases in the emissions of six compounds (benzaldehyde, α-pinene, β-pinene, β-myrcene, p-xylene, and (E)-β-caryophyllene). Dual-choice olfactometer assays revealed that adult leaffooted bugs were attracted to herbivore-induced VOCs, as well as being attracted to synthetic benzaldehyde or α-pinene individually. These findings suggest that selected cotton VOCs could contribute to the development of attractive lures.

The leaffooted bug, Leptoglossus phyllopus (L.) (Hemiptera: Coreidae), probes and feeds on tissues of many plant species, including developing cotton bolls, causing seed damage and abscission. Insecticides are the primary tool for managing leaffooted bugs, but concerns about resistance and environmental harm highlight the need for alternative management strategies. One promising approach is using semiochemicals, such as plant- and insect-produced volatile organic compounds (VOCs), to trap or repel pests. Insect herbivores often use plant-produced VOCs to select suitable host plants for feeding and oviposition. Field observations of abundant adult leaffooted bugs on cotton bolls suggest that bugs aggregate at feeding sites. The goal of this study was to characterize VOCs from developing cotton bolls with and without leaffooted bug herbivory and evaluate how these VOCs affect adult bug foraging behavior. A portable dynamic headspace sampling method was used to collect VOCs from developing cotton bolls in the field, and VOC samples were analyzed using gas chromatography–mass spectrometry. Leaffooted bug herbivory induced volatile emissions from cotton bolls, with significant increases in the emissions of six compounds (benzaldehyde, α-pinene, β-pinene, β-myrcene, p-xylene, and (E)-β-caryophyllene). Dual-choice olfactometer assays revealed that adult leaffooted bugs were attracted to VOCs from damaged cotton bolls, as well as being attracted to synthetic benzaldehyde or α-pinene individually. In contrast, leaffooted bugs were repelled by the combination of synthetic benzaldehyde and α-pinene. These findings suggest that VOCs from cotton bolls are attractive to leaffooted bugs and could contribute to the development of attractive lures for integrated pest management.

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