Use of the parasitoid Diaeretiella rapae (McIntoch) to control the cabbage aphid Brevicoryne brassicae (L.)

Abstract

The parasitoid Diaeretiella rapae accepted all stages of the cabbage aphid Brevicoryne brassicae. The average number of mummies produced per female parasitoid was 42.8. Diaeretiella rapae did not show preference between young (first-second instars) and old (fourth instars) nymphs of the aphid. Nymph aphids younger than 4 days (third instars) produced no offspring after parasitism. The average number of offspring per aphid that was parasitized at day 5-6 (third-fourth instars) and day 7 (adults) were 3.1 and 15.3, respectively, which were much less compared with the aphid that was not parasitized (38.1). The average reproduction period for the aphids that were parasitized at day 5-6 and day 7 were 1.9 and 4.4 days, respectively and that for non-parasitized aphids was 14.9 days. Cage experiments showed that at the ratio of 1.2 : 1 (six female wasps : five aphid adults), with three releases on day 1, 3 and 6, the percent parasitism of the offspring on day 20 was 88.9%, and the aphids were successfully controlled by the second generation of the released parasitoids. Release of cabbage plants that included both mummies and young aphids in a broccoli field, with a dose of about 2 mummies/m 2 , resulted in higher percentage of the broccoli plants with mummies in the treated plot compared with the control plot. The percent parasitism of the aphids on broccoli plants in the treated plot was also, with one exception, significantly higher. Seven weeks after the release of the parasitoid, the percentage of the broccoli plants with mummies was 93.3% in the treated plot and 56.7% in the control plot; the percent parasitism of the aphids were 6.7 and 1.4% in the treated and control plots, respectively. These results indicated that one release of the cabbage plants with mummies enhanced the spread of the parasitoid D. rapae and increased parasitism of the aphids in the field. More releases of the parasitoid are needed to control the aphid effectively.

Effect Host Plants on Parasitism Rate of the Parasitoid Diaeretiella rapae (M'intosh) on the Aphid Brevicoryne brassicae L.,

“…These results are in general agreement with the work of Zhang and Hassan (2003); Abou El-Naga et al (2008) and Abdul Rahman and Powell (2010) who indicated that the females of D. rapae attacked all stages of the cabbage aphid B. brassicae. The first and second instars of cabbage aphid B. brassicae produced no offspring after parasitism of D. rapae.…”

Parasitism of canola aphids in France in autumn

“…Diaeretiella rapae could be considered as a good candidate for IPM programs because it is a specialist of cruciferous crops and could be particularly efficient in detecting Brassica plants infested by aphids (Read et al 1970;Reed et al 1995). Moreover, it was shown in a recent study that this aphid parasitoid was able to limit aphid population growth in Brassica fields when mummies were released (Zhang and Hassan 2003). As D. rapae was the most common parasitoid on B. brassicae and was always present on M. persicae, it could be considered as a useful natural enemy against these aphids.…”

“…This study determined that these aphid parasitoid species could develop on aphids on canola and were present in autumn. Nevertheless, the parasitism rate was low in autumn, so an option could be to use these parasitoids in augmentative release biological control programs (as successfully shown on cabbage by Zhang and Hassan 2003) or in an IPM project on canola fields in autumn.…”

Effects of prey species and its density on larval performance of two species of hoverfly larvae, Episyrphus balteatus de Geer and Eupeodes corollae Fabricius (Diptera: Syrphidae)

“…/aez.2006 predators (Rotheray, 1989). We know that these predators play an important role in the suppression of aphid abundance (Dixon, 1970;Wratten, 1973;Chambers and Adams, 1986;Lucas et al, 1997;Zhang and Hassan, 2003;Lee and Kang, 2004). However, most studies have focused on the impact of ladybirds over aphids, and few experimental studies have been completed on other aphid predators.…”