Assessing Feeding Damage from Two Leaffooted Bugs, Leptoglossus clypealis Heidemann and Leptoglossus zonatus (Dallas) (Hemiptera: Coreidae), on Four Almond Varieties.

Apurba K Barman,David Doll,Andrea L Joyce,Bradley S Higbee

doi:10.3390/insects10100333

Apurba K Barman, David Doll + Show 2 more

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https://doi.org/10.3390/insects10100333

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Journal: Insects	Publication Date: Oct 7, 2019
Citations: 10	License type: CC BY 4.0

Affiliation: University of Georgia, University of California, Merced

Abstract

Leaffooted bugs (Leptoglossus spp; Hemiptera: Coreidae) are phytophagous insects native to the Western Hemisphere. In California, Leptoglossus clypealis and Leptoglossus zonatus are occasional pests on almonds. Early season feeding by L. clypealis and L. zonatus leads to almond drop, while late season feeding results in strikes on kernels, kernel necrosis, and shriveled kernels. A field cage study was conducted to assess feeding damage associated with L. clypealis and L. zonatus on four almond varieties, Nonpareil, Fritz, Monterey, and Carmel. The objectives were to determine whether leaffooted bugs caused significant almond drop, to pinpoint when the almond was vulnerable, and to determine the final damage at harvest. Branches with ~20 almonds were caged and used to compare almond drop and final damage in four treatments: (1) control branches, (2) mechanically punctured almonds, (3) adult Leptoglossus clypealis, and (4) adult Leptoglossus zonatus. Replicates were set up for eight weeks during two seasons. Early season feeding resulted in higher almond drop than late season, and L. zonatus resulted in greater drop than L. clypealis. The almond hull width of the four varieties in the study did not influence susceptibility to feeding damage. The final damage assessment at harvest found significant levels of kernel strikes, kernel necrosis, and shriveled almonds in bug feeding cages, with higher levels attributed to L. zonatus than L. clypealis. Further research is warranted to develop an Integrated Pest Management program with reduced risk controls for L. zonatus.

Highlights

Leaffooted bugs in the genus Leptoglossus Guérin-Méneville (Hemiptera: Coreidae) are large phytophagous insects native to the Western Hemisphere
2019, 10, xin the controls was similar to L. clypealis, and both were lower than the L. zonatus
This study examined the impact from feeding by two Leptoglossus species, L. clypealis and L. zonatus, on developing almonds in four varieties during the growing season

Summary

Introduction

Leaffooted bugs in the genus Leptoglossus Guérin-Méneville (Hemiptera: Coreidae) are large phytophagous insects native to the Western Hemisphere. At least 61 species are known [1], and several species are pests in forests or agricultural systems [2,3,4,5,6,7]. Many Leptoglossus spp. are multivoltine, which allows them to exploit multiple hosts per year [8]. Direct damage to crops is caused when. Leptoglossus spp. feed by probing their stylets into fruits and seeds, and secondary damage can occur through the transmission of pathogens at the feeding site [6,9,10]. Field studies assessing the feeding damage of insects can provide information about the phenology of the pest and pinpoint when during the growing season insect feeding occurs, as well as determine when the crop is susceptible to damage or losses [11,12,13,14].

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