Population dynamics of the diamondback moth Plutella xylostella L. (Lepidoptera: Yponomeutidae) in the Sydney Region of Australia

Abstract

The population dynamics of the diamondback moth (DBM), Plutella xylostella L. (Lepidoptera: Yponomeutidae) was investigated at three farms on the Western side of the Sydney Basin, Australia, from November 2003 to October 2004. Adult populations were monitored fortnightly by counting the number that was trapped on yellow sticky traps, which peaked around November to December (summer) in all three farms, with virtually no trap catches in the winter months (June-August). The seasonal trend of adult DBM showed a higher number per trap in summer, ranging from 34.5-41.7 compared with the other seasons. Larval and pupal densities were highest in summer (2.0-4.0 and 3.3-5.1 per plant, respectively), while the lowest numbers were recorded in winter. Rainfall had a significant impact on the DBM populations. The activity (numbers and parasitism) of the DBM parasitoid Diadegma semiclausum Héllen (Hymenoptera: Ichneumonidae) was recorded in all three farms, with the population showing a synchrony with that of the DBM. The highest number of parasitoids per trap (36.8-53.8) was recorded in summer compared with the other seasons. Parasitism was highest in the non-sprayed farm (56.3%) in summer compared with 16.4% and 31.5% in the other farms which have been sprayed with insecnticides. Canonical correspondence analysis showed environmental variables accounting for 11.2% of the variability in the insect data, out of which 83.9% was explained along the first canonical axis.

Spatio-temporal distribution patterns of Plutella xylostella (Lepidoptera: Plutellidae) in a fine-scale agricultural landscape based on geostatistical analysis

“…These observations suggest that the temporal fluctuation of P . xylostella populations is related to different climatic variables, such as temperature, rainfall and relative humidity 2 , 14 , 15 . Host-plant type does not seem to affect the population size of P .…”

Diversité, abondance et comportement trophique des parasitoïdes contre le ravageur Helicoverpa armigera (Hübner 1808) en culture de tomates biologiques au Burkina Faso

“…Par contre l'application de flubendiamide 480 SC à 0,01% était relativement plus compatible favorisant 19,47% de parasitisme de Campoletis chloridae Uchida sur H. armigera dans l'écosystème du pois chiche (Nikoshe et al, 2014). Le parasitisme de Diadegma semiclausum Héllen sur Plutella xylostella L. s'est montré plus faible dans la ferme pulvérisée avec Fipronil, Indoxacarb, Regent, spinosad que dans celle non pulvérisée (Eziah et al, 2010). L'emploi des produits de synthèse créé donc des troubles physiologiques et écologiques dans divers écosystèmes.…”