Table 1:
Rating scale for evaluating the level of resistance/susceptibility of citrus rootstocks based on the number of female nematodes per gram of root.
| Scale | Number of T. semipenetrans females/gram of root | Resistance rating |
|---|---|---|
| 0 | 0 | Immune (I) |
| 1 | 1–10 | Resistant (R) |
| 2 | 11–30 | MR |
| 3 | 31–60 | MS |
| 4 | 61–100 | Susceptible (S) |
| 5 | >100 | HS |
[i] Note: The resistance rating scale was adapted from established methods in nematology (e.g., Banihashemian et al., 2023c; Zoubi et al., 2024) and calibrated based on the distribution of nematode population counts observed in this study.
Figure 1:
Reaction of citrus rootstocks to infection by T. semipenetrans. (A) Number of females on roots; (B) number of J2s in the soil. Different letters denote statistically significant differences (P < 0.05). Error bars represent the SEM. SEM, standard error of the mean.
Figure 2:
Growth parameters of plants in response to infection by T. semipenetrans. (A) Fresh root weight; (B) dry root weight; (C) fresh shoot weight; and (D) dry shoot weight. Different letters indicate statistically significant differences (P < 0.05). Error bars represent the SEM. SEM, standard error of the mean.
Figure 3:
Relationships between the number of T. semipenetrans females and percentage of reductions in fresh and dry root (A) and shoot (B) weights of citrus plants. See the key within the figure for symbol and line identifications.
Figure 4:
Antagonistic effects of B. safensis strain Q.en and P. chlororaphis strain P.en against T. semipenetrans in citrus under greenhouse conditions. (A) Number of females per gram of root. (B) Number of second-stage juveniles (J2s) per 200 g of soil. Different letters denote significant differences (P < 0.05). Data are means of five replicates repeated twice independently (n = 10). Error bars represent the SEM. Untreated (nematode-inoculated); B + N = B. safensis + Nematode; P + N = P. chlororaphis + Nematode. SEM, standard error of the mean.
Figure 5:
Effects of B. safensis strain Q.en and P. chlororaphis strain P.en on citrus growth parameters under greenhouse conditions. Different letters denote significant differences (P < 0.05). Data are the mean of five replications that were repeated two times independently (n = 10). Error bars represent the SEM. Untreated (nematode-inoculated); B + N = B. safensis + Nematode; P + N = P. chlororaphis + Nematode. SEM, standard error of the mean.