(Fig. 1A). Glucose (125.1% ± 5.5; P <0.001) and fructose (124.8% ± 5.4; P 61 <0.001) also triggered an elevated level of serotonin-triggered stylet thrusting in 62 treated juveniles; xylose failed to trigger any significant response (99.36% ± 10.87; P 63 >0.05) when compared with control treatments (Fig. 1B). Globodera pallida infective 64 stage juveniles were mildly repelled by glucose (CI: -0.23 ± 0.09; P >0.05), and did 65 not respond to fructose (CI: 0.15 ± 0.08; P >0.05), or xylose (CI: -0.19 ± 0.09; P 66 >0.05) as compared with control treated worms (Fig. 1C). Glucose (118.6% ± 9.7; P 67 >0.05), fructose (107.2% ± 7.3; P >0.05), or xylose (119.6% ± 8.6; P >0.05) had no 68 significant impact on the frequency of serotonin-triggered stylet thrusting in G. pallida 69 infective juveniles when compared with control treatments (Fig. 1D) Fig. 2A). 80Corresponding reductions in glucose and fructose exudate concentration were 81 observed for both STP1 (5.10 µg/ml ± 1.31; P <0.01 and 3.14 µg/ml ± 0.92; P <0.01, (Fig. 3B). 93When exoRNAi-treated seedlings were challenged by M. incognita infection, 94 significant reductions in percentage infection levels relative to control (neo) dsRNA 95 treatment were observed for both STP1 (14.15% ± 4.77; P <0.01) and STP2 96(27.08% ± 7.32; P <0.05) dsRNA treatments (Fig. 3C) (Fig. 3D). 100These data demonstrate that the exogenous application of aqueous dsRNA 101 onto tomato seedlings is sufficient to trigger specific gene knockdown. However, we 102 found that different experimental populations of tomato seedlings could display wide