**3. Results**

*3.1. Evaluation of Nematode Density in the Soil*

The managemen<sup>t</sup> and the time had a significant effect on the total number of nematodes (F = 13.641, df = 2, 81, *p* < 0.0001 and F = 38.563, df = 1, 81, *p* < 0.0001, respectively). Moreover, there was a significant interaction between managemen<sup>t</sup> and time (F = 8.086, df = 2, 81, *p* < 0.0001). In T0 no differences were found among managements (U, C, and T), confirming the similar distribution of nematodes in the experiment area. In T1, the number of nematodes were again similar in C and U, while a significant reduction was assessed in T (Table 1, Figure 2).

**Table 1.** Pairwise comparisons among managements (Uncultivated: U, Control: C, and Treated: T) before (T0) and after (T1) the trap crop experiment. Significant differences are indicated in bold.


**Figure 2.** Interactive effect of time (before = T0 and after = T1 the three-trap crop cycles) and managements (Control: C, Uncultivated: U, and Treated: T) on the total number of *Meloidogyne graminicola* (eggs and juveniles) (average and 95% confidence interval are shown).

#### *3.2. Evaluation of the Plant Population Density*

The managemen<sup>t</sup> had a significant effect on the plant population density per unit area (F = 21.509, df = 2, 72, *p* < 0.0001). Density was higher in treated plots (T) in comparison to both plant density in the U (*p* < 0.0001) and those in the C plots (*p* < 0.001). No significant difference was found when comparing density between C and U plants (*p* = 0.114) (Figure 3). Effect size: d = 0.20 (T vs. U) and d = 0.16 (T vs. C).

**Figure 3.** Influence of the managements (Uncultivated: U, Control: C, and Treated: T) on plant population density.

*3.3. Evaluation of Root-Gall Index and Plant Growth*

There was a significant difference in the root-gall index among managemen<sup>t</sup> (H = 63.81, df = 301, *p* < 0.0001). In particular, C vs. U (U = 4284; *p* = 0.03), C vs. T (U = 2766; *p* < 0.0001), and U vs. T (U = 1919; *p* < 0.0001) (Figure 4).

**Figure 4.** Influence of the managements (Uncultivated: U, Control: C, and Treated: T) on rootgall index.

The managemen<sup>t</sup> had a significant effect on plant growth (F = 37.107, df = 2, 300, *p* < 0.0001). Plants were higher in T than both plants in U (*p* < 0.0001) and C (*p* < 0.0001). No significant difference was found when comparing plant growth between C and U (*p* = 0.105) (Figure 5). Effect size: d = 0.12 (T vs. U) and d = 0.10 (T vs. C).

**Figure 5.** Influence of the managements (Uncultivated: U, Control: C, and Treated: T) on plant growth. Bars indicate mean ± standard error.
