Environmental Entomology (2006) 35, 1350-1357
A. Rossbach, B. Löhr and S. Vidal (2006)
Parasitism of Plutella xylostella L. feeding on a new host plant
Environmental Entomology 35 (5), 1350-1357
Abstract: The diamondback moth Plutella xylostella L. (Lepidoptera: Plutellidae) is known to be an oligophagous pest on crucifers. Recently, a population of diamondback moths was found to infest sugar snap and snowpea in the Rift Valley in Kenya, causing heavy damage. The effect of resident parasitoids on diamondback moths in snowpea (Pisum sativum L.) was studied in the field. In addition, parasitism of diamondback moths by the newly introduced parasitoid Diadegma semiclausum (Hellen) was evaluated. Snowpea provided an enemy-free space for diamondback moths. Local parasitoids attacked diamondback moths only sporadically and in very low numbers (mean of 0.25 individuals/20 plants during the first study period) on diamondback moths on pea compared with a mean of 15.4 individuals/20 plants on kale (Brassica oleracea acephala L.) However, diamondback moth density was higher on kale (mean of 61.1 larvae/20 plants) than on snowpea (mean of 11.4 larvae/20 plants). Differential diamondback moth infestation and level of parasitism might have been affected by a fungal infection (Ascochyta) of the pea plants. In both crops, the most abundant parasitoid was Oomyzus sokolowskii Kurdjumov. After the release of D. semiclausum, the number of diamondback moths in kale decreased drastically to <2 individuals/20 plants; however, the parasitoid had little effect on diamondback moths on snowpea. Percentage parasitism on snowpea increased from 2.3 to 4%, whereas on kale, it increased from 25.6 to 75.7%. A host plant expansion could be of future advantage for the diamondback moth to avoid higher enemy pressure caused by D. semiclausum.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Stefan Vidal, Bernhard L. Löhr
Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
environment/habitat manipulation
