Variation of Lygus species assemblages in canola agroecosystems in relation to ecoregion and crop stage

Abstract

Plant bugs in the genus Lygus (Hahn) (Hemiptera: Miridae) are sporadic pests of canola, Brassica napus L. (Brassicaceae) and Brassica rapa L., in western Canada and infestations appear to have become increasingly common and severe in recent years. Surveys conducted from 1998 to 2000 identified a "northern" assemblage in the boreal ecoregion that was dominated by Lygus lineolaris (Palisot de Beauvois), with minor representation of Lygus borealis (Kelton), Lygus elisus (Van Duzee), and Lygus keltoni (Schwartz). A "southern" assemblage in the grassland ecoregions was dominated by L. keltoni, with a substantial abundance of L. elisus and L. borealis and with few L. lineolaris in the driest areas. The assemblage from the parkland ecoregion was variable but with few L. elisus. The boreal plains and parkland ecoregions of Alberta had the most serious and persistent infestations of Lygus spp. Relative species composition of the Lygus assemblage at the bolting stage was not related to the overall abundance of these bugs at the early pod stage. Lygus species assemblages were similar in terms of composition and relative abundance at the bolting and early pod stages of canola. A shift in species proportions in favour of L. lineolaris in the north and L. keltoni in the south and a decrease of L. elisus has taken place relative to studies conducted in the 1980's.

A single-step multiplex PCR assay for the detection of EuropeanPeristenusspp., parasitoids ofLygusspp.

“…Feeding damage by Lygus nymphs and adults can cause flower bud and fruit abortion, sideshoot abscission, leaf tissue perforation and deformation or death of meristem tissue (Strong 1970;Broadbent et al 2002). In North America, Lygus have historically been recorded as destructive pests (Craig & Loan 1984;Young 1986;Coulson 1987), and recent literature demonstrates their continued pest status on a variety of crops, including wheat , oilseed flax , cotton (Layton 2000), canola (Boyd & Lentz 1999;Braun et al 2001;Carcamo et al 2002), alfalfa (Braun et al 2001;May et al 2003;) and strawberry (Rhainds & English-Loeb 2003).…”

Habitat or temporal isolation: Unraveling herbivore–parasitoid speciation patterns using double digest RADseq

“…The apparently narrow host range of L. borealis could be a by-product of our sampling, as they have been collected from other host plants such as canola (Brassica spp.) in other studies (Cárcamo et al, 2002;Otani & Cárcamo, 2011). These results show that Lygus species are truly generalists as we found no genetic divergence based on host.…”

“…Although HAD has been recorded from other Miridae (Hereward, Walter, Debarro, Lowe, & Riginos, 2013), no evidence of HAD has been shown in Lygus species despite the detection of population-level differences based on geography (Burange, Roehrdanz, & Boetel, 2012;Zhou, Kandemir, Walsh, Zalom, & Lavine, 2012). Lygus have one to three generations per year depending on the temperature, where southern populations in warmer climates are multivoltine and northern populations in cooler climates tend to be univoltine (Cárcamo et al, 2002;Haye et al, 2013). The Canadian prairies ecosystem is a major agricultural growing region where Lygus is an economically relevant pest on several field crops, such as canola, alfalfa, and mustard.…”

Bioclimatic analyses of distributions of a parasitoid Peristenus digoneutis and its host species Lygus spp. in Europe and North America

“…Plant bugs of the genus Lygus (Hemiptera: Miridae) are highly polyphagous pests of field and greenhouse crops throughout North America, including vegetable and fruit crops (Broadbent et al , 2002), alfalfa (Soroka, 1997), cotton (Layton 2000) and canola (Cárcamo et al , 2002). Lygus nymphs are commonly parasitized by various species of the genus Peristenus Förster (Hymenoptera: Braconidae) (Loan & Bilewicz‐Pawinska, 1973; Goulet & Mason, 2006).…”