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Figure 1:
Relative abundance (proportion of total field PPN population) for each sampled field in the Spring of 2022 or 2023. Each column represents one sampled field and the total community of PPNs found in that field. Fields are organized by grass species and colored by the proportion of each PPN genus detected in the field. A column with no color (i.e., white) had undetectable populations of PPN. * indicates a field with fewer than four individual nematodes for the total population count.
Figure 2:
Comparative PPN relative abundance (proportion of total field PPN population) in annual ryegrass and orchardgrass seed fields sampled in spring (top) and autumn (bottom) 2022. Each column represents one sampled field at either time point. Fields are organized by grass species and colored by the proportion of each PPN genus detected in a field. A column with no color (i.e., white) had undetectable populations of PPN. * indicates a field with fewer than four individual nematodes for the total population count.
Average plant-parasitic nematode species densities and diversity measures for all grass species sampled in 2022 and 2023.
Grass species
Nb
Sample time
Average Density (#/100 g soil)
Diversity Measuresa
Pratylenchus
Meloidogyne
Helicotylenchus
Paratylenchus
Tylenchorhynchus
Xiphinema
Alpha
Beta
Gamma
Annual ryegrass
14
Spring 2022
90
206
0
1
0
0
1.9
0.6
3
Autumn 2022
0
34
0
0
0
0
0.7
0.4
1
Bentgrass
3
Spring 2023
169
38
0
0
0
0
1.7
0.2
2
Fine fescue
3
Spring 2023
3
0
0
0
0
0
1.0
0.0
1
Orchardgrass
7
Spring 2022
227
58
22
14
1
0
2.1
1.4
5
Autumn 2022
0
20
7
0
0
1
1.1
1.7
3
Perennial ryegrass
5
Spring 2023
3
6
1
1
0
0
2.0
1.0
4
Tall fescue
5
Spring 2023
166
4
0
0
0
1
1.6
0.9
3
Percentage frequency of occurrence (%FO), mean population densities when present (# nematodes/100 g soil), and maximum population densities (# nematodes/100 g soil) of plant-parasitic nematodes associated with grass for seed crops in Oregon sampled in Spring 2022 or 2023.
Pratylenchus
Meloidogyne
Helicotylenchus
Paratylenchus
Tylenchorhynchus
Xiphinema
%FOa
97
54
16
8
3
3
Meanb
117 (30.2)
172 (61.7)
26 (18.2)
32 (26.4)
7
1
Maxc
1,984
2,496
288
556
24
2
Pratylenchus spp. identified on grass for seed crops in Oregon.a