Endophyte Isolate and Host Grass Effects on Chaetocnema pulicaria (Coleoptera: Chrysomelidae) Feeding
Ball, O. J-P., K. D. Gwinn, C. D. Pless, and A. J. Popay.  2011.  Journal of Economic Entomology, 104:665-672.

Endophytic fungi belonging to the genus Neotyphodium, confer resistance to infected host grasses against a range of insect pests. The effect of host species, in addition to the species and strain of endophyte, on feeding and survival of the corn flea beetle, Chaetocnema pulicaria, an insect thought to be adversely affected by N. coenophialum infection of tall fescue (Festuca arundinacea), was investigated. Most of the plants used in the study were derived from artificially created grass/endophyte associations and possessed varying arrays of the commonly examined endophyte-related alkaloids or alkaloid groups, peramine, lolitrem B, ergovaline, and the lolines. Preference and non-preference tests showed that feeding by, and survival of, C. pulicaria was reduced by infection of tall fescue with the wild-type strain of N. coenophialum, the likely mechanism being antixenosis rather than antibiosis. In the preference tests, endophyte and host species effects were observed. Of the 10 different Neotyphodium strains tested in artificially-derived tall fescue associations, eight strongly deterred feeding by C. pulicaria, while the remaining two strains had little or no effect. Infection of tall fescue with the p-endophyte had no effect. Perennial ryegrass (Lolium perenne) naturally infected with the wild-type strain of N. lolii was moderately resistant to C. pulicaria compared with endophyte-free grass, as were five of nine artificially-derived Neotyphodium/ryegrass associations. Six Neotyphodium/meadow fescue (Festuca pratensis) associations, including the wild-type N. uncinatum/meadow fescue combination, were very resistant, while three associations had little to no effect. Loline alkaloids appeared to play a role in antixenosis to C. pulicaria. However, effects not attributable to the lolines or any other of the alkaloids examined were also observed. This phenomenon has also been reported in tests with other insects, and indicates the presence of additional insect-active factors, the investigation of which should be a priority in future research.