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Impact of guttation fluid from perennial ryegrass infected with different strains of Epichloe festucae var. lolii endophyte on Microctonus aethiopoides adult longevity

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posted on 2024-06-26, 01:27 authored by Pip GerardPip Gerard, Ela Hiszczynska-SawickaEla Hiszczynska-Sawicka

Perennial ryegrass (Lolium perenne L.) grows in association with a fungal endophyte Epichloe festucae var. lolii (Latch, Christensen & Samuels) Bacon & Schardl, which produces alkaloids that protect the grass against grazing by mammals and insects. These alkaloids are found in guttation fluid (xylem sap exuded from leaves through special structures known as hydathodes) and have the potential to impact on beneficial invertebrates in pastoral ecosystems. Newly emerged adults of the parasitoid Microctonus aethiopoides Loan (Hymenoptera: Braconidae) were supplied with guttation fluid from pot-grown ryegrasses infected with three different strains of endophyte (standard, AR37, AR1) or no endophyte collected at different times of the year, or water, sucrose solution or no liquid. Longevity was compared when individuals were held in separate vials in controlled environment room at 20oC with 16:8 h light:dark photoperiod. An enzymatic method was used to measure sugars in guttation fluid samples collected on three dates. Guttation fluid from endophyte-infected grasses was found to have no detrimental effect on M. aethiopoides longevity and to contain glucose and fructose. Guttation fluid from AR37-infected ryegrass collected in autumn increased insect longevity compared to water and fluid from standard-type infected ryegrass by 26% and 24% respectively. The lack of available food sources in New Zealand ryegrass-dominant pastures means that guttation fluid from AR37-infected ryegrass in autumn may contribute to M. aethiopoides efficacy as a biocontrol agent through enhanced longevity.

Funding

New Zealand Ministry for Business, Innovation and Employment, LIN0804 Ecosystems Bioprotection

History

Rights statement

©2022 New Zealand Plant Protection Society (Inc.)

Publication date

2022-09-20

Project number

  • Non revenue

Language

  • English

Does this contain Māori information or data?

  • No

Publisher

New Zealand Plant Protection Society

Journal title

New Zealand Plant Protection

ISSN

1175-9003

Volume/issue number

75

Page numbers

50-56

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