perenne) and an endophytic fungus,Acremonium loliae. The endophyte–
plant association results in the production of complex tremorgenic
mycotoxins known as the lolitrems (Figure 8.21) which are responsible
for the staggering response and possible collapse of sheep under stress.
The endophyte is seedborne and completes its whole life cycle within the
plant, although it can be cultured with difficulty in the laboratory.
It is possible to eliminate the endophyte by careful heat treatment of
seed but, in New Zealand, the planting of endophyte-free ryegrass
provides pastures which are very susceptible to insect damage such as
that caused by the stem weevilListronotus bonariensis. It is almost certain
that the role of the endophyte in controlling insect damage is not due to
the production of lolitrems so the possibility remains that a genetically
engineered strain of Acremonium loliae, which no longer produces
lolitrems, could be used to replace the wild strain in perennial ryegrass.
Although there can be no doubt about the potential for the presence of
mycotoxins in food to cause illness and even death in humans, there are
Figure 8.19 Claviceps purpurea. (a) The alkaloid ergotamine, and (b) aspects of devel-
opment
298 Non-bacterial Agents of Foodborne Illness