Optimizing Trap Characteristics to Monitor the Leaffooted Bug Leptoglossus zonatus (Heteroptera: Coreidae) in Orchards

Abstract

The leaffooted bug, Leptoglossus zonatus (Heteroptera: Coreidae), has become a key pest of almonds, pistachios, and pomegranates in California. Adults and nymphs directly feed on nuts and fruits, which reduces crop yield and quality and can facilitate pathogen infections. Current monitoring strategies require growers to actively sample the tree canopy, with no economic thresholds being developed for this pest. To improve monitoring of L. zonatus, a three-year study was conducted to identify an optimal trap. A hanging cross-vane panel trap was identified as the best trap type in Year 1, and subsequent work in Years 1–3 focused on refining its use by modifying surface texture and color. Results indicated that coating trap surfaces with the lubricant fluon improved trap catching ability, and adults were most frequently recovered in yellow traps. A hanging cross-vane panel trap with these features could serve as the basis for the development of a new monitoring system for this pest in orchards, which could be improved further if semiochemical lures will be developed.

Identification and Synthesis of Leptotriene, a Unique Sesquiterpene Hydrocarbon from Males of the Leaffooted Bugs Leptoglossus zonatus and L. occidentalis

“…1-((1R,8S)-10,10-Dimethyl-7-methylenebicyclo[6.2.0]decan-4-yl)ethanone (2). Trilead tetraoxide (137.12 g, 200 mmol) was added in portions to a mixture of (−)-trans-β-caryophyllene (TCI America, product number C0796, purity >90.0% (GC), 40.87 g, 200 mmol), acetic acid (366 mL), and acetic anhydride (127 mL), keeping the temperature below 60 °C.…”

“…It is polyphagous, and over its broad range it can be an important pest of a variety of crops, including maize, sorghum, citrus, and tree nut crops. Over the past two decades, it has become a major pest in California’s multibillion dollar almond and pistachio industries, in part because large populations can rapidly migrate into crops, causing substantial damage before appropriate controls can be applied . A congeneric species, Leptoglossus occidentalis Heidemann 1910, whose native range encompasses western North America, was introduced into Europe in the 1990s, and it has since spread rapidly throughout the continent .…”

“…In both its native and invasive ranges, it can be a major pest in conifer seed orchards and in Europe is of particular concern to growers of edible pine nuts, Pinus pinea L. , For both of these species, the development of better methods to monitor and control bugs would be of major benefit to growers and forest managers. Whereas recent research has produced optimized trap designs, the development of effective attractants to use as lures in these traps has remained elusive.…”

Irrigated trap crops impact key hemipteran pests in organic pistachio orchard

“…Trap crops have been used in tree crops in California's Central Valley (Tomaseto et al 2019), but average high summer temperatures of 37.2 °C and little to no precipitation between May and November lead to dry-down of annual groundcover during the summer months. This leads to insects migrating from the drying groundcover up into the canopy (da Silva et al 1997;Wilson et al 2020a), potentially causing damage at key periods during the season (Stahl et al 2020). In this study, we propose the use of irrigated trap crops to prevent groundcover dry-down in mid-season.…”

Closer view of antennal sensory organs of two Leptoglossus species (Insecta, Hemiptera, Coreidae)

“…Both Leptoglossus species overwinter as adults in aggregations formed most often in sheltered areas, such as evergreen trees, shrubs, and residential structures, and in the spring disperse in search of food and reproduction sites 19,21 . Sexually mature males produce a number of aldehydes, esters, and sesquiterpenes, which probably constitute an aggregation pheromone attractive to both sexes 22,23 .…”