Australian native flowering plants enhance the longevity of three parasitoids of brassica pests

Abstract

Floral resources from native plants that are adapted to the local environment could be more advantageous than the use of nonnative plants. In Australia, there is a dearth of information on the benefits of native plants to natural enemies and their selectivity against pests. Accordingly, we examined the longevity of the parasitoids Diaeretiella rapae (McIntosh) and Cotesia glomerata (L.) (both Hymenoptera: Braconidae), and Diadegma semiclausum (Hellen) (Hymenoptera: Ichneumonidae) exposed to flowering shoots from Australian native plants which was compared with the nonnative buckwheat (Fagopyrum esculentum), often used in conservation biological control. Longevity of parasitoids was significantly enhanced by the Australian natives Westringia fruticosa, Mentha satureioides, Callistemon citrinus, Leptospermum cv. 'Rudolph', Grevillea cv. 'Bronze Rambler', Myoporum parvifolium, Lotus australis, and nonnative F. esculentum. The highest mean survival by native plant species was 3.49 higher for D. rapae with Leptospermum sp. and 4.39 higher for D. semiclausum with M. parvifolium. For C. glomerata, Grevillea sp. increased longevity by 6.99 compared with water only. Longevity of Plutella xylostella (L.) (Lepidoptera: Plutellidae), a major crop pest, was enhanced by all plants against which it was screened except Acacia baileyana, a species that had no effect on parasitoid longevity. Several Australian native plant species that benefit parasitoids were identified. None of the plant species provided a selective benefit to the parasitoid D. semiclausum compared with its host P. xylostella; however, the benefit of M. parvifolium and Grevillea sp. on the longevity of D. semiclausum was relatively higher compared with the pest. These results suggest the need for field studies to determine whether native Australian plants increase P. xylostella impact in nearby brassica crops.

Alyssum (Lobularia maritima) selectively attracts and enhances the performance of Cotesia vestalis, a parasitoid of Plutella xylostella

“…Remnant non-crop habitats such as ground cover or wild plants can provide shelter, being a source habitat from which natural enemies can colonize crops 1,5 . The reintroduction of appropriate flowering plants into monocultures can promote longevity, fecundity, sex ratio and searching capacity of natural enemies such as parasitoids [6][7][8][9] . The addition of flowering plants within or around crop fields can enhance the impact of natural enemies by providing nectar, pollen [10][11][12] , alternative hosts or prey 13 , favorable microclimatic conditions 14 and shelter 1,15,16 .…”

Conservation biological control of the fruit fly parasitoid Fopiusa arisanus (Hymenoptera: Braconidae)

“…It followed closely the design and methodology of Pandey et al . (2018), who emphasised Australian native plants as possible food sources for parasitoids of Brassica pests. When it became obvious that F. arisanus was not floral feeding (see ‘Results’), the study was extended to fruit as another possible carbohydrate source following the work of Stuhl et al .…”

“…This experiment was initially designed exclusively as a flower trial, testing different flowers for possible companion planting within or adjacent to orchards to provide nectar sources for F. arisanus. It followed closely the design and methodology of Pandey et al (2018), who emphasised Australian native plants as possible food sources for parasitoids of Brassica pests. When it became obvious that F. arisanus was not floral feeding (see 'Results'), the study was extended to fruit as another possible carbohydrate source following the work of Stuhl et al (2011).…”

Economic analysis of habitat manipulation in Brassica pest management: Wild plant species suppress cabbage webworm

“…In recent years, however, interest in native plants has increased. Pandey et al (2018) showed the longevity of the parasitoids, Diaeretiella rapae (McIntosh), Cotesia glomerata (L.) (Hymenoptera: Braconidae), and Diadegma semiclausum (Hellen) (Hymenoptera: Ichneumonidae) exposed to flowers of Australian native plants was comparable with the longevity when exposed to the commonly used F. esculentum. Native species can outperform or provide similar resources as nonnatives and have several advantages such as local adaptation, habitat perpetuity, and enhanced native biodiversity value (Fiedler et al 2008).…”