The exotic status of Miscanthus and its current small area of cultivation is an advantage in terms of the number of pests and diseases found in native areas that might threaten its production [95,96]. However, as the area in Miscanthus cultivation increases new pest and disease threats are likely to emerge.

Fusarium has been implicated in Miscanthus crop failure but its significance has not yet been quantified [97].

The common rustic moth (Mesapamea secalis) and the ghost moth larvae (Hepialus humuli) have also caused production problems for Miscanthus crops [76]. In addition, the larvae of armyworms (Spodoptera frugiperda) have been shown to infest plots of Miscant­hus x giganteus [98] along with the aphid Rhopalosiphum maidis [99]. In the United States, plant-parasitic nematodes (Helicotylenchus, Xiphinema, Paratylenchus, Hoplo — laimus, Tylenchorhynchus, Criconemella, Longidorus, Heterodera, Paratrichodorus, Hemi — criconemoides, Pratylenchus) have been identified as potential pathogens in Miscanthus biofuel crops [100].

Many other insects such as Thysanoptera, Hexapoda, arthropods, Tetranychus, Tetrany — chidae, Prostigmata, mites, Acari, Arachnida have been identified in Miscanthus [101] but their prevalence is far less than insect pests of sugarcane [102]. In the United Kingdom, Clifton-Brown et al. [3] reported the presence of cereal leaf aphid Rhopalosiphum maidis, although this pest appears to be more of problem in greenhouses than the field. Bradshaw et al. [99] suggested aphids (Rhopalosiphum maidis, Siphaflava, Spodoptera frugiperda)

have the potential to damage young Miscanthus. Other cereal aphids and aphid-transmitted viruses could also be potential problems in Miscanthus. Finally, in comparison to sugar­cane, where more than 1500 insect species have been identified, it appears that few insects have been reported to feed on Miscanthus x giganteus [98].

In summary, although few pests and diseases of Miscanthus have been identified in the cultivation area (Figure 4.6), the species appears robust with a high tolerance to pests and diseases. This will hopefully reduce the requirement for chemical pest control [103] although the genetic basis for this apparent high pest tolerance still needs to be verified with the likely increase of the cultivation area.