Communication,information sharing,and advisory services to raise awareness for fall armyworm detection and area-wide management by farmers

Journal of Plant Diseases and Protection - This is an opinion paper to the perspective paper “The spread of the Fall Army Worm Spodoptera frugiperda in Africa—what should be done...     

Field survival analyses of adult Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae)

Journal of Pest Science - The western corn rootworm (Diabrotica virgifera virgifera; Coleoptera: Chrysomelidae) is a major maize pest in North America and Europe. For developing population models...     

Streamlining leaf damage rating scales for the fall armyworm on maize

Journal of Pest Science - The fall armyworm (Spodoptera frugiperda, Lepidoptera: Noctuidae), which is native to the Americas, has recently invaded Africa and Asia. There, it has become a major pest...     

Generational growth rate estimates of <Emphasis Type="Italic">Diabrotica virgifera virgifera</Emphasis> populations (Coleoptera: Chrysomelidae)

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 m² in continuous maize field sections, and from 0.3 to 5.1 adults per m² 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.     

Efficiency of pheromone traps for monitoring Diabrotica virgifera virgifera LeConte

Mark–release–recapture trials with male western corn rootworm Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) beetles were conducted to better understand capture data of pheromone traps produced in Europe during monitoring programmes. Median recapture rate in maize fields in Hungary, Italy and Switzerland was 10%. Two types of sex pheromone trap (sticky sheet and non‐sticky container traps), placed inside or outside maize fields, showed no differences in efficiency. Logit analyses of recapture data in maize showed that at distances of <1 m fewer than 20% of beetles ended up in the traps. A beetle in a 1 ha maize field would have about a 5% chance of being caught in a trap placed in the centre of the field.     

Multiple transatlantic introductions of the western corn rootworm

The invasion of Europe by the western corn rootworm, North America's most destructive corn pest, is ongoing and represents a serious threat to European agriculture. Because this pest was initially introduced in Central Europe, it was believed that subsequent outbreaks in Western Europe originated from this area. Using model-based Bayesian analyses of the genetic variability of the western corn rootworm, we demonstrate that this belief is false: There have been at least three independent introductions from North America during the past two decades. This result raises questions about changing circumstances that have enabled a sudden burst of transatlantic introductions.     

Influence of soil on the efficacy of entomopathogenic nematodes in reducing <Emphasis Type="Italic">Diabrotica virgifera virgifera</Emphasis> in maize

The use of entomopathogenic nematodes is one potential non-chemical approach to control the larvae of the invasive western corn rootworm (Diabrotica virgifera virgifera LeConte, Coleoptera: Chrysomelidae) in Europe. This study investigated the efficacy of Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), Heterorhabditis megidis Poinar, Jackson and Klein (Rh., Heterorhabditidae) and Steinernema feltiae Filipjev (Rh., Steinernematidae) in reducing D. v. virgifera as a function of soil characteristics. A field experiment was repeated four times in southern Hungary using artificially infested maize plants potted into three different soils. Sleeve gauze cages were used to assess the number of emerging adult D. v. virgifera from the treatments and untreated controls. Results indicate that nematodes have the potential to reduce D. v. virgifera larvae in most soils; however, their efficacy can be higher in maize fields with heavy clay or silty clay soils than in sandy soils, which is in contrast to the common assumption that nematodes perform better in sandy soils than in heavy soils.