Native egg parasitoids on Leptoglossus occidentalis Heidemann (Hemiptera: Coreidae) in Spain: Potential biological control agents?

Abstract

The western conifer seed bug (WCSB), Leptoglossus occidentalis Heidemann, (Hemiptera, Coreidae), is a pest of conifers, native to Western North America (Heidemann, 1910) that spread rapidly across Southern and Eastern North America (Gall, 1992;Koerber, 1963) and many other countries around the world (Olivera et al., 2020). This can be attributed to its wide host range (i.e. more than 40 conifer species) (Fent & Kment, 2011) and anthropogenic activities (Kim et al., 2020). The latest records

Damage caused by Leptoglossus occidentalis Heidemann (Hemiptera: Coreidae) on Pinus pinea L. cones varies with feeding season

“…According to our results and those of Bates, Lait, et al (2002) and Bates, Strong, and Borden (2002), controlling WCSB populations early in the growing season may help prevent severe cone and seed damage. Thus, control methods should be applied early in the season (from April to early June), coinciding with the end of the overwintering period of WCSB adults (Ponce‐Herrero et al, 2022). WCSB population management, however, should ensure cone protection throughout the growing season since cultivars are susceptible to reinfestation by adults from nearby stands, and even other pine species such as Pinus pinaster in the Central Plateau, due to the high dispersal capacity of the adult given its polyphagous nature and its ability to fly (Connelly & Schowalter, 1991; Fent & Kment, 2011; Koerber, 1963).…”

“…Domestication of the stone pine, based on the grafted experimental plantations established over the past 50 years in several Mediterranean countries (Mutke et al, 2005b; Mutke et al, 2012), may increase the final yield of stone pine crops by planting highly productive genotypes (Mutke et al, 2005a). The establishment of cultivars may enable the management of the stands for seed production (Afonso et al, 2020; Farinha, Silva, et al, 2018; Loewe‐Muñoz et al, 2023), the application of specific horticultural techniques (Mutke et al, 2013) and even the control of the local WCSB population through mass trapping (Blatt & Borden, 1996a; Millar et al, 2022), biological control (Ponce‐Herrero et al, 2022, 2023; Roversi et al, 2011) or spot application of insecticides or pollinator bags as protective barriers (Bracalini et al, 2013; Farinha et al, 2021; Strong, 2006; Strong, 2015; Strong et al, 2001). However, to make effective management decisions, it is necessary to develop an effective monitoring tool that can detect, quantify and define the population dynamics and density of the natural populations of the WCSB, since these populations are highly variable from year to year (Farinha et al, 2021; Ponce‐Herrero et al, 2022; Schowalter, 1994; Strong, 2015).…”

“…Lost insects were assumed to be dead (Bates, Strong, & Borden, 2002). Trials with females began in mid‐April, when WCSB imagoes emerge from hibernation and begin to reproduce (Barta, 2016; Ponce‐Herrero et al, 2022; Tamburini et al, 2012). Two nymphs (N3 and N4 stages) were bagged with one first‐year cone for 1 week (Trial 3).…”

“…According to our results and those of Bates, Lait, et al (2002) and Bates, Strong, and Borden (2002), controlling WCSB populations early in the growing season may help prevent severe cone and seed damage. Thus, control methods should be applied early in the season (from April to early June), coinciding with the end of the overwintering period of WCSB adults (Ponce-Herrero et al, 2022).…”