153
Miscanthus Feeding Insects and Nematodes
Two families Pratylenchus and Helicotylenchus in survey samples represented endoparasite and semi-endoparasite nematodes. Four species of the
lesion nematodes Pratylenchus were recovered in both countries. Population
densities of P. crenatus and P. neglectus were greater than the estimated damage thresholds (50–100 individuals per 100 cm 3 of soil) and can be viewed as
the potential pathogen of M. × giganteus. Pratylenchus spp. are known as very
dangerous plant pathogens responsible for lesion disease that rank third
place in the world list of the most economically important species (Jones &
Fosu-Nyarko, 2014). This finding for Ukraine and Poland was in agreement
with results obtained earlier by Mekete et al. (2011a) in the US.
Spiral nematodes Helicotylenchus were found in densities of 300 individuals per 100 cm 3 , that is, lower densities than the established threshold value.
Hyphal and root feeders were represented by nematodes from four genera:
Cylindrolaimus, Rhabditis, Plectus, and Anaplectus that were recovered from
samples with population densities up to 25 individuals per 100 cm 3 of soil.
The characteristics of PPNs associated with M. × giganteus demonstrated
(Mekete et al., 2011b) that economically important nematodes, specifically needle
Longidorus elongates (Longidoridae) and root-lesion nematodes Pratylenchus crenatus and Pratylechchus neglectus (Pratylenchidae), share with M. × giganteus other
hosts from the same plant family (Gramineae). The fact that all PPNs reported to
feed on M. × giganteus are pests of corn, sugarcane, or sorghum raises concerns
that the production of that crop in the large scale may increase pests not only on
M. × giganteus but also on the numbers in existing food and feed crops.
8.4.3 The Indication of M. × giganteus Plantation
State with Plant-Feeding Nematodes
M. × giganteus as a perennial grassland crop generally shows its maximum
productivity in the third year of cultivation (Lewandowski et al., 2018).
Knowledge based on interaction between PPNs and Miscanthus stands
in different age is important to predict biomass productivity during the
long-term growing. The PPNs community is determined both by temporal
changes and environmental factors (Zhukov et al., 2018). Temporal stages of
M. × giganteus plantations development in a wide geographical district by
PPN species impact the plant damage under representative soil types.
The distribution of nematodes recorded in study in Ukraine and Poland
was evaluated by applying the nonmetric multidimensional scaling approach
(NMDS) indicated spatial heterogeneity of sampling points and community
dynamics (Figure 8.3).
The relationships among the hyphal and root hair feeders, semi-endoparasites, and ectoparasites were suggested as indicators for assessing the state of
M. × giganteus plantations with different years of cultivation with two aspects
which were considered. It was determined (Figure 8.3) that the abundance of
hyphal and root hair feeders expanded with increasing of plantation age,
whereas the abundance of ectoparasites decreased. The increase in hyphal