Submitted to: Journal of Entomological Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/8/2010
Publication Date: 7/1/2010
Citation: Clement, S.L., Elberson, L.R. 2010. Variable Effects of Grass-Neotyphodium Associations on Cereal Leaf Beetle (Coleoptera:Chrysomelidae) Feeding, Development and Survival. Journal of Entomological Science 45:1-7. Interpretive Summary: A group of fungi called Neotyphodium endophytes infect many forage and turf grasses without causing diseases. In fact, endophyte infection can be beneficial for grass hosts if the endophyte strain protects the grass from damage by grazing livestock and insect pests. These protective traits of some grass endophytes have led public and private sector scientists in the U.S. and New Zealand to introduce them into new forage grass cultivars for drought tolerance and insect resistance. In view of new research initiatives to use endophyte strains from different grasses to protect cereal crops from insect pests, more information on the effect of diverse strains on the most important insect pests of cereals is required. This research address this need with experimental results showing that the survival and development of an important pest called the cereal leaf beetle is adversely affected by some endophyte strains in wild grasses. This research also is important because it increases the number of wheat and barley insect pests adversely affected by some grass endophyte strains to five (Russian wheat, bird cherry-oat aphid, rose grass aphid, Hessian fly, cereal leaf beetle).
Technical Abstract: Although cereal grains are the preferred food plants of the cereal leaf beetle, Oulema melanopus (L.), several other graminoid species are acceptable feeding hosts of larvae and adults of this chrysomelid beetle. In view of the potential for expanding the use of diverse endophytic fungi (Neotyphodium Glenn, Bacon and Hanlin) to protect forage and cereal grasses from insect pests, more information on the effect of Neotyphodium-infected (E+) grasses on the behavior and performance of the most important graminoid pests, including O. melanopus, is required. In feeding and oviposition choice experiments, adult O. melanopus fed readily on E+ and uninfected (E-) plants of wild tall fescue (Lolium arundinaceum (Schreb.) S.J. Darbyshire) and alpine timothy (Phleum alpinum L.), while exhibiting a feeding preference for E- over E+ plants of one fescue accession. In larval survival and development experiments, low survival on E+ plants of one tall fescue accession and alpine timothy (averaged 3.75 – 12.5%) was not linked to slow development of surviving larvae because developmental periods were similar on E- (averaged 11.31 – 12.73 days) and E+ (11.33 – 11.7 days) plants. Larval mortality was 100% on E+ plants of tall fescue from Morocco. Thus, O. melanopus feeding and survival is significantly reduced on some E+ wild grasses. Our results expand our knowledge of the anti-insect properties of fungal endophytes in diverse grasses for possible use in protecting forage and cereal grass cultivars from O. melanopus and other important pests.