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

AbstractPlant 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.

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Root maggots (Delia spp., Diptera: Anthomyiidae) in prairie canola (Brassica napus L. and B. rapa L.): Spatial and temporal surveys of root damage and prediction of damage levels

Canadian Journal of Plant Science ◽

10.4141/p02-174 ◽

2004 ◽

Vol 84 (4) ◽

pp. 1171-1182 ◽

Cited By ~ 23

Author(s):

J. J. Soroka ◽

L. M. Dosdall ◽

O. O. Olfert ◽

E. Seidle

Keyword(s):

Brassica Napus ◽

Survey Data ◽

Brassica Rapa ◽

Geographic Area ◽

Western Canada ◽

Regression Equations ◽

Root Damage ◽

Weather Variables ◽

Brassica Napus L ◽

Northern Edge

The levels of infestation and damage to canola taproots caused by crucifer-feeding root maggots (Delia spp.)(Diptera: Anthomyiidae) were determined through surveys of commercial crops across the canola growing regions of western Canada. Canola root damage caused by Delia spp. maggots was measured at the end of the season by determining the percentage of plants infested (PPI) per field and estimating average damage levels (DL, on a scale of 0 to 5) to taproots. Over the course of the survey, 2890 canola fields were sampled. Infestation by root maggots occurred wherever canola is grown in western Canada. In the study, 96% of the fields surveyed in Manitoba and Saskatchewan and 99.8% of the fields in Alberta showed evidence of root maggot feeding, with PPI much higher than in provincial surveys of a decade previously. Geographical ecoregion significantly affected both PPI and DL. The greatest amount of damage over the largest area was found in western and northwestern Alberta, although localized areas with severely damaged roots occurred along the northern edge of the entire Parkland ecoregion. Over the entire survey area, Brassica rapa L. roots had greater PPI and DL than B. napus L. roots, although species differences were not significant in Saskatchewan or Manitoba. Data from the survey were correlated with weather variables to develop a model predicting the levels of damage inflicted by root maggots to canola roots. Of the weather variables investigated, temperature, especially the average temperature in the preceding July and August, had the greatest in fluence on PPI and DL. The warmer the temperatures of the preceding July and August, the lower the PPI and DL in the current year. Likewise, previous year’s July and August precipitation influenced PPI and DL negatively. Other weather parameters had little consistent influence on PPI and DI. The predictive model for PPI and DL, developed from the 1995–1998 survey data, incorporated canola species, ecoregion, previous July-August and September-October temperatures and precipitation. The validity of the model was assessed using a set of survey data collected in Alberta from 1981 to 1983. Regression equations of predicted results on actual results were significant. However, r2 values for the regressions were low, in part because of the few ecoregions surveyed and the lack of canola species data recorded in the earlier survey, and because of the large increase in infestation levels since the earlier data were collected. The study is a first step in forecasting the effects of root maggots across a wide geographic area featuring many different canola production practices. Key words: Crucifer-feeding root maggots, Delia spp., canola, Brassica rapa, Brassica napus, pest forecasting, distribution of damage

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Seasonal occurrence, species composition, and parasitism of Lygus spp. in alfalfa, canola, and mustard

The Canadian Entomologist ◽

10.4039/ent133565-4 ◽

2001 ◽

Vol 133 (4) ◽

pp. 565-577 ◽

Cited By ~ 19

Author(s):

L. Braun ◽

M. Erlandson ◽

D. Baldwin ◽

J. Soroka ◽

P. Mason ◽

...

Keyword(s):

Brassica Napus ◽

Species Composition ◽

Medicago Sativa ◽

Sinapis Alba ◽

Seasonal Occurrence ◽

Lygus Lineolaris ◽

Late Season ◽

Predominant Species

AbstractField collections of over-wintering and summer adults and nymphs of Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), Lygus borealis (Kelton), and Lygus elisus Van Duzee were made weekly in five fields in Saskatchewan in 1998 and 1999. The crops sampled were alfalfa, Medicago sativa L. (Leguminosae), canola, Brassica napus L. (Cruciferae), and mustard, Sinapis alba L. (Cruciferae), at Vonda, and alfalfa and canola at Saskatoon. In alfalfa, the most abundant Lygus spp. found in May and June were over-wintering adult L. lineolaris and (or) L. borealis; the predominant species in mid-June to early July was L. borealis; and the population from mid-July to late August was dominated by L. lineolaris. In canola, adult populations of Lygus spp. were not found until mid-June. The predominant species, L. lineolaris, probably over-wintering adults, was first detected in canola at the early bud stage in late June to early July; high numbers of L. lineolaris adults occurred in canola in mid-August. Populations of Lygus spp. in organic mustard were negligible. Dissections of field-collected Lygus spp. nymphs revealed parasitism in up to 70% of the midsummer population in alfalfa. In contrast, less than 1% of the late-season Lygus spp. population, primarily L. lineolaris in canola and L. lineolaris and L. borealis in alfalfa, was parasitized.

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DISTRIBUTION AND ABUNDANCE OF LYGUS SPP. (HETEROPTERA: MIRIDAE) ON ALFALFA AND CANOLA IN MANITOBAf

The Canadian Entomologist ◽

10.4039/ent1251033-6 ◽

1993 ◽

Vol 125 (6) ◽

pp. 1033-1041 ◽

Cited By ~ 14

Author(s):

B.H. Timlick ◽

W.J. Turnock ◽

I. Wise

Keyword(s):

Relative Abundance ◽

First Generation ◽

Second Generation ◽

Abundant Species ◽

Agricultural Area ◽

Lygus Lineolaris ◽

The South ◽

The North ◽

Physiographic Regions

AbstractLygus species were sampled from alfalfa and canola fields in Manitoba from 1988 to 1990. Lygus lineolaris (Palisot de Beauvois), L. borealis (Knight), and L. elisus (Van Duzee) were found consistently throughout the agricultural area. The relative abundance of these species varied among crops, physiographic regions, years, and date of collection. The most abundant species in alfalfa and canola fields tended to be L. borealis in the north and west, L. elisus in the south, and L. lineolaris in the east. Each of the species was the most abundant in some collections, however L. borealis tended to be more abundant in alfalfa and L. lineolaris and L. elisus in canola. First-generation nymphs of Lygus species were found on alfalfa and those of the second generation on canola.

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Deep amplicon sequencing highlights low intra-host genetic variability of Echinococcus multilocularis and high prevalence of the European-type haplotypes in coyotes and red foxes in Alberta, Canada

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0009428 ◽

2021 ◽

Vol 15 (5) ◽

pp. e0009428

Author(s):

Maria A. Santa ◽

Andrew M. Rezansoff ◽

Rebecca Chen ◽

John S. Gilleard ◽

Marco Musiani ◽

...

Keyword(s):

North America ◽

Relative Abundance ◽

Echinococcus Multilocularis ◽

Population Expansion ◽

Amplicon Sequencing ◽

Intraspecific Diversity ◽

Mixed Infections ◽

Western Canada ◽

Red Foxes ◽

The North

Echinococcus multilocularis (Em) is a zoonotic parasite considered a global emergent pathogen. Recent findings indicate that the parasite is expanding its range in North America and that European-type haplotypes are circulating in western Canada. However, genetic analyses are usually conducted only on a few parasites out of thousands of individuals within each definitive host, likely underestimating the prevalence of less common haplotypes. Moreover, mixed infections with several mtDNA haplotypes in the same host have been reported, but their relative abundance within the host was never estimated. We aimed to 1) estimate the frequency of co-infections of different Em haplotypes in coyotes (Canis latrans) and red foxes (Vulpes vulpes) from western Canada and their relative abundance within the definitive hosts, 2) detect less prevalent haplotypes by sampling a larger proportion of the parasite subpopulation per host, and 3) investigate differences in the distribution of Em haplotypes in these main definitive hosts; foxes and coyotes. We extracted DNA from ~10% of the worm subpopulation per host (20 foxes and 47 coyotes) and used deep amplicon sequencing (NGS technology) on four loci, targeting the most polymorphic regions from the mitochondrial genes cox1 (814 bp), nad1 (344 bp), and cob (387 bp). We detected the presence of mixed infections with multiple Em haplotypes and with different Echinococcus species including Em and E. granulosus s.l. genotypes G8/G10, low intraspecific diversity of Em, and a higher abundance of the European-type haplotypes in both hosts. Our results suggest a population expansion of the European over the North American strain in Alberta and a limited distribution of some European-type haplotypes. Our findings indicate that deep amplicon sequencing represents a valuable tool to characterize Em in multiple hosts, to assess the current distribution and possible origins of the European strain in North America. The potential use of next-generation sequencing technologies is particularly important to understand the patterns of geographic expansion of this parasite.

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EVIDENCE FOR SUCCESSFUL OVERWINTERING OF DIAMONDBACK MOTH, PLUTELLA XYLOSTELLA (L.) (LEPIDOPTERA: PLUTELLIDAE), IN ALBERTA

The Canadian Entomologist ◽

10.4039/ent126183-1 ◽

1994 ◽

Vol 126 (1) ◽

pp. 183-185 ◽

Cited By ~ 16

Author(s):

Lloyd M. Dosdall

Keyword(s):

Brassica Napus ◽

Brassica Rapa ◽

Plutella Xylostella ◽

Diamondback Moth ◽

Larval Feeding ◽

Western Canada ◽

Population Densities ◽

Feeding Sites ◽

Three Generations ◽

Significant Yield

Diamondback moth, Plutella xylostella (L.), commonly occurs at relatively low population densities in areas of canola (oilseed rapes, Brassica rapa L. and Brassica napus L.) production in western Canada, but occasionally can reach outbreak densities (Madder and Stemeroff 1988). The most severe outbreak of P. xylostella in recent years occurred in Alberta and Saskatchewan in 1985 when approximately 467 860 ha were treated with insecticide, at a cost of approximately $11.9 million (Madder and Stemeroff 1988).Damage to canola is the result of larval feeding. Leaves are the preferred feeding sites, and plants can withstand substantial damage before yield is affected (Philip and Mengersen 1989). However, late in the season when the leaves become senescent, larvae feed on pods and this can result in significant yield reductions. Plutella xylostella is multivoltine, capable of completing at least three generations per year in Alberta (Philip and Mengersen 1989), and four to five in Ontario (Harcourt 1986).

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