Generational growth rate estimates of Diabrotica virgifera virgifera populations (Coleoptera: Chrysomelidae)

Abstract

Modelling population dynamics of the maize pest Diabrotica virgifera virgifera LeConte (western corn rootworm; Coleoptera: Chrysomelidae) requires knowledge on the growth rate (=net reproductive rate) of the species. We investigated the generational (=annual) growth rate of D. v. virgifera in isolated maize fields in southern Hungary and eastern Croatia over several years. The population densities of D. v. virgifera were assessed by absolute counts of emerging adults in 90 gauze cages per study field. Emergence ranged from 1.3 to 30.7 adults per m 2 in continuous maize field sections, and from 0.3 to 5.1 adults per m 2 in adjacent first-year maize sections. The annual growth rates of D. v. virgifera ranged from 0.5 to 13, and averaged in close to 4. These experimentally assessed growth rates could complement growth estimates in population dynamic models, particularly those for forecasting the population growth to economic thresholds or for estimating population build-ups after new introductions of this alien species in Europe. As an example, the determined growth rate was used to estimate that the first documented successful introduction of this species into Europe occurred between 1979 and 1984, which is 8-13 years before the detection of this species and its larval damage in maize fields near Belgrade, Serbia, in 1992.

Multitrophic Interaction in the Rhizosphere of Maize: Root Feeding of Western Corn Rootworm Larvae Alters the Microbial Community Composition

“…Since the beginning of the 1980s the WCR was accidentally and repeatedly introduced into Europe [2], [3], infesting more than 20 countries by the end of 2010 [4]. In case of establishment of this pest in European maize growing regions, damage costs are expected of about 450 million Euro per year [5].…”

Neonate larvae of the specialist herbivore Diabrotica virgifera virgifera do not exploit the defensive volatile (E)-β-caryophyllene in locating maize roots

“…Annual yield loss and control costs are estimated at $2 billion in the USA Corn Belt (Mitchell 2011). After multiple introductions in Europe (Ciosi et al 2008;Miller et al 2005;Szalai et al 2011), WCR has established in much of the maize cropping regions (Bermond et al 2012;Ciosi et al 2011) and is estimated to annually cost ca. €0.5 billion to European maize growers (Wesseler and Fall 2010).…”

Quantifying inter-field movements of the western corn rootworm (Diabrotica virgifera virgiferaLeConte) — A Central European field study

“…In the mid-20 th century, parallel with the intensification of maize cultivation, western corn rootworm performed further spatial expansion from Nebraska, Colorado and Kansas towards the East Coast of the USA (Chiang 1973). First European report of this pest dates back to 1992 (Baca 1994), however, western corn rootworm is assumed to have arrived 8-13 years earlier (Szalai et al 2011). Genetic variability studies indicated that multiple independent introduction events occurred in Europe (Miller et al 2005).…”