Population dynamics of Plutella xylostella (Lep., Yponomeutidae) and its parasitoids in the region of Brasilia

Abstract

The diamond back moth Plutella xylostella (L.) is the most serious pest of Brassicaceae in the world. It is resistant to many insecticides which has led to a search for alternative techniques of control, principally biocontrol‐based pest management. The impact of P. xylostella and its parasitoids was analysed in a 6‐month study of cabbage crops in the Brasilia region of Brazil, from June to November 1998. The population of the pest and its guild of parasitoids were quantified on two experimental plots at the Embrapa‐Hortaliças research station by weekly samplings. In the first cropping (June to early September), populations of P. xylostella followed a logistic growth curve leading to the destruction of the crops. In the second cropping, rains prevented the development of P. xylostella. Seven species of parasitoids were observed, Diadegma leontiniae (Brethes) and Apanteles piceotrichosus (Blanchard) being dominant. Cotesia plutellae (Kurdjumov) and Actia sp., previously more abundant, became very minor parasitoids. Significant differences were observed in specific parasitism rates between the plots. The combined parasitism rates were identical on both plots (around 23%) and were insufficient to regulate the populations of P. xylostella. Six species of hyperparasites were reared from Diadegma leontiniae and Apanteles piceotrichosus, showing a high diversity of natural enemies in this region of recent colonization by P. xylostella.

New records of natural enemies of Plutella xylostella (L.) (Lepidoptera: Plutellidae) in Pernambuco, Brazil

“…Among the parasitoids found in this study, C. pseudofulvovariegata and C. plutellae were previously found in Brasília, DF by Guilloux et al (2003) and Monnerat et al (2000), respectively. Therefore, this is only the second time they are reported in Brazil parasitizing DBM.…”

Biological control of the diamondback moth,Plutella xylostella: A review

“…collectively accounted for 93% parasitism in Victoria, Australia (Goodwin 1979). Seven species were observed in Brasilia with D. leonitiniae (Brethés) and Apanteles piceotrichosus (Blanchard) as dominant parasitoids but the total parasitisim was insufficient to regulate DBM populations (Guilloux et al 2004). In the Eastern Cape (South Africa), four species viz., Diadegma mollipla (Holmgren), C. plutellae , D. collaris and O. sokolowskii were major parasitoids and DBM parasitism rates varied throughout the year ranging from 10 to 80% (Smith & Villet 2004).…”

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

“…It is therefore not surprising that the CCA showed a negative association between the DBM, temperature and rainfall. Talekar et al (1986) and Guilloux et al (2003) report of heavy rainfall as one of the key mortality factors among all stages of the pest, especially the neonate larvae which are highly susceptible to drowning during rainfall. The larvae are easily disturbed by droplets of rain and wriggle into leaf axles or the ground where they get submerged in pools of water.…”

“…Iga (1985) reported that seasonal fluctuation of DBM populations depended mainly on the action of natural enemies. Guilloux et al (2003) have also reported that precipitation severely affected survival of early instar stages of the DBM. Extreme temperatures have also been shown to adversely affect both the DBM and D. semiclausum (Wakisaka et al, 1991).…”