Spatial and Host-Related Variation in Prevalence and Population Density of Wheat Curl Mite (Aceria tosichella) Cryptic Genotypes in Agricultural Landscapes

Abstract

The wheat curl mite (WCM), Aceria tosichella Keifer, is a major pest of cereals worldwide that also comprises a complex of at least 16 genetic lineages with divergent physiological traits, including host associations and specificity. The goal of this study was to test the extent to which host-plant species and landscape spatial variation influence WCM presence and population density across the entire area of Poland (>311,000 km2). Three important findings arose from the results of the study. (1) The majority of WCM lineages analyzed exhibited variation in patterns of prevalence and/or population density on both spatial and host-associated scales. (2) Areas of occurrence and local abundance were delineated for specific WCM lineages and it was determined that the most pestiferous lineages are much less widespread than was expected, suggesting relatively recent introductions into Poland and the potential for further spread. (3) The 16 WCM lineages under study assorted within four discrete host assemblages, within which similar host preferences and host infestation patterns were detected. Of these four groups, one consists of lineages associated with cereals. In addition to improving basic ecological knowledge of a widespread arthropod herbivore, the results of this research identify high-risk areas for the presence of the most pestiferous WCM lineages in the study area (viz. the entirety of Poland). They also provide insight into the evolution of pest species of domesticated crops and facilitate testing of fundamental hypotheses about the ecological factors that shape this pest community.

Wheat streak mosaic virus: a century old virus with rising importance worldwide

“…The WCM was identified as the agent transmitting WSMV by Slykhuis (), and the recent use of DNA sequence data and experimental host bioassays has shown that the WCM is, in fact, a species complex consisting of several divergent genetic lineages (probably cryptic species) (Miller et al ., ; Skoracka et al ., ). Some lineages are highly host specific to single wild‐growing grass species, whereas others are less host specialized and feed on several plant species, including cereals (Skoracka et al ., ). The genetic and host range variability within the WCM complex corresponds to the virus vectoring ability amongst WCM lineages (Hein et al ., ; Schiffer et al ., ).…”

“…In Poland, these two WCM biotypes also differ in colonization strategy, and biotype 1 (MT‐8) has a uniform distribution, whereas biotype 2 (MT‐1) occurs unexpectedly in only a few localities within the country, but attains very high densities there (about 30% higher than MT‐8) (Skoracka et al ., ). All results obtained to date now suggest that biotype 2 (MT‐1) is able to multiply more rapidly and transmit WSMV more efficiently than biotype 1 (MT‐8).…”

The Interface Between Wheat and the Wheat Curl Mite, Aceria tosichella, the Primary Vector of Globally Important Viral Diseases

“…MT-8 and MT-1 have been found coexisting in mixed populations in wheat-producing areas in North America, Australia, and Europe, where plants from a single wheat field contained both MT-1 and MT-8 ( Siriwetwiwat, 2006 ; Schiffer et al, 2009 ; Hein et al, 2012 ; Skoracka et al, 2017 ), further complicating management of viruses vectored by WCM. This sympatry combined with differential virus-transmission accentuates the need for efficient identification methods.…”

Barley Varieties Stoneham and Sydney Exhibit Mild Antibiosis and Antixenosis Resistance to the Wheat Curl Mite, Aceria tosichella (Keifer)

“…Two biotypes of A. tosichella that co-occur in North America exhibit different virulence responses to Cmc wheat mite-resistant genes and genetic variability [9,11]. Although A. tosichella biotype composition and distribution in U.S. barley production areas has yet to be determined, biotypes 1 (MT-8) and 2 (MT-1) collected from barley in Poland's agrarian landscape occurred at mean densities of 9.7 and 19.3 mites per shoot, respectively [12]. Furthermore, the Polish biotype 2 collected from wheat and reared on susceptible barley plants exhibited a >40-fold increase in population growth rate in 14 days [10], providing evidence that this biotype has the ability to use barley as a host.…”