CHAPTER 3: EFFECTS OF A NEEM-AMENDED PRODUCT ON PLANT-PARASITIC
3.3 RESULTS
3.3.2 Plant-parasitic nematode data from 30 g roots
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Table 3.9: Ring nematode (Criconematidae) population densities in 250 ml soil for three sampling intervals. (Significance level for Repeated measures ANOVA in capital letters; different letters indicate significant differences across rows for sampling intervals; different small letters per column indicate significant differences among treatments per individual sampling interval).
Treatment Treatment name Sampling
interval 1:
Pre-plant
Sampling interval 2:
10 WAE
Sampling interval 3:
19 WAE (Harvest) 1 Untreated control 0.01 (0)2 aA 1.74 (194) aAB 1.92 (306) aAB 2 Nemacur® 400 EC, Fenamiphos @ 400
g / L, IRAC: 1B
0.97 (169) aAB 1.12 (106) aAB 1.06 (76) aAB 3 Nemacur® 400 EC + Kalahari 3:1 0.68 (25) aAB 0.59 (56) aAB 0.87 (88) aAB 4 Nemacur® 400 EC +Velum® Prime 400
SC
1.09 (94) aAB 0.77 (50) aAB 1.22 (163) aAB 5 Nemacur® 400 EC +Velum® Prime 400
SC + Kalahari 3:1
1.35 (131) aAB 0.77 (56) aAB 0.65 (113) aAB 6 Velum® Prime 400 SC, Fluopyram @
400 g / L, IRAC: 25; FRAC: 7
0.95 (44) aAB 0.95 (181) aAB 0.93 (119) aAB 7 Velum® Prime 400 SC + Kalahari 3:1 0.93 (288) aAB 2.21 (206) aB 0.55 (63) aAB 8 Kalahari 3:1, organic fertiliser 1.64 (481) aAB 0.86 (75) aAB 0.99 (294) aAB
F-ratio: 1.439 2.091 0.938
P-value: 0.208 0.059 0.485
Interaction: Treatments x Sampling intervals
F-ratio: 2.238
P-value: 0.010
1Log-transformed mean of nematode population density; 2Real means of nematode population density.
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The increase was evident for all the treatments, except treatments 2 and 4 where population densities declined when compared to the 10 WAE sampling interval.
Table 3.10: Root-knot nematode (Meloidogyne) population densities (all life stages, except eggs) in 30 g roots for two sampling intervals. (Significance level for Repeated measures ANOVA in capital letters; different letters indicate significant differences across rows for sampling intervals;
different small letters per column indicate significant differences among treatments per individual sampling interval).
Treatment Treatment name Sampling interval 2:
10 WAE
Sampling interval 3:
19 WAE (Harvest)
1 Untreated control 0.991 (171)2 aA 1.54 (915) aA
2 Nemacur® 400 EC, Fenamiphos @ 400 g / L, IRAC: 1B
0.66 (256) aA 1.42 (137) aA
3 Nemacur® 400 EC + Kalahari 3:1 0.0 (0) aA 0.82 (97) aA
4 Nemacur® 400 EC +Velum® Prime 400 SC
0.90 (688) aA 0.31 (38) aA 5 Nemacur® 400 EC +Velum® Prime 400
SC + Kalahari 3:1
0.36 (103) aA 0.90 (114) aA 6 Velum® Prime 400 SC, Fluopyram @ 400
g / L, IRAC: 25; FRAC: 7
1.25 (203) aA 1.11 (1201) aA 7 Velum® Prime 400 SC + Kalahari 3:1 0.0 (0) aA 0.64 (143) aA 8 Kalahari 3:1, organic fertiliser 0.90 (101) aA 1.60 (1025) aA
F-ratio: 1.415 0.890
P-value: 0.218 0.521
Interaction: Treatments x Sampling intervals
F-ratio: 0.642
P-value: 0.720
1Log-transformed mean of nematode population density; 2Real means of nematode population density.
3.3.2.2 Lesion nematodes
No significant differences were evident among the treatments per sampling interval, nor did a significant interaction exist for treatments x sampling times (Table 3.11) indicating that LN population densities in 30 g roots were fairly similar for all treatments and sampling times although it did decrease for most treatments over the sampling times.
Population densities for LN in 30 g root samples were high ranging between 168 to 933/30 g roots at 10 WAE (sampling interval 2). By the harvest sampling date (19 WAE; Sampling interval 3), most of the treatments showed a decrease in LN counts but still did not differ significantly from each other. This was evident for all the treatments, except treatments 3, 4 and 7 where population densities increased slightly.
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Table 3.11: Lesion nematode (Pratylenchus) population densities in 30 g roots for two sampling intervals. (Significance level for Repeated measures ANOVA in capital letters; different letters indicate significant differences across rows for sampling intervals; different small letters per column indicate significant differences among treatments per individual sampling interval).
Treatment Treatment name Sampling interval 2:
10 WAE
Sampling interval 3:
19 WAE (Harvest)
1 Untreated control 2.101 (933)2 aA 1.33 (414) aA
2 Nemacur® 400 EC, Fenamiphos @ 400 g / L, IRAC: 1B
1.50 (336) aA 0.86 (205) aA 3 Nemacur® 400 EC + Kalahari 3:1 1.25 (183) aA 0.95 (196) aA 4 Nemacur® 400 EC +Velum® Prime 400 SC 0.96 (181) aA 0.91 (192) aA 5 Nemacur® 400 EC +Velum® Prime 400 SC
+ Kalahari 3:1
1.47 (247) aA 0.58 (55) aA 6 Velum® Prime 400 SC, Fluopyram @ 400 g
/ L, IRAC: 25; FRAC: 7
0.99 (171) aA 0.33 (57) aA 7 Velum® Prime 400 SC + Kalahari 3:1 0.98 (168) aA 0.90 (214) aA 8 Kalahari 3:1, organic fertiliser 2.09 (931) aA 0.91 (218) aA
F-ratio: 0.967 0.433
P-value: 0.464 0.877
Interaction: Treatments x Sampling intervals
F-ratio: 0.466
P-value: 0.855
1Log-transformed mean of nematode population density; 2Real means of nematode population density.
3.3.2.3 Spiral nematodes
No significant differences were evident among the treatments per sampling interval, nor did a significant interaction exist for treatments x sampling times (Table 3.12) indicating that spiral nematode population densities in 30 g roots were similar for all treatments and sampling times, although it did increase over the sampling times in some treatments.
Population densities for spiral nematodes in 30 g root samples were low, ranging from zero to 8/30 g roots at 10 WAE (sampling interval 2). By the harvest sampling date (19 WAE; Sampling interval 3), only treatments 2, 4, 6 and 7 showed a slight increase in population densities, although the numbers in all treatments remained very low, from 0 to 63/30 g root and did not differ significantly among the treatments.
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Table 3.12: Spiral nematode (Hoplolaimidae) population densities in 30 g roots for two sampling intervals. (Significance level for Repeated measures ANOVA in capital letters; different letters indicate significant differences across rows for sampling intervals; different small letters per column indicate significant differences among treatments per individual sampling interval).
Treatment Treatment name Sampling interval 2:
10 WAE
Sampling interval 3:
19 WAE (Harvest)
1 Untreated control 0.01 (0)2 aA 0.0 (0) aA
2 Nemacur® 400 EC, Fenamiphos @ 400 g / L, IRAC: 1B
0.0 (0) aA 0.24 (10) aA
3 Nemacur® 400 EC + Kalahari 3:1 0.0 (0) aA 0.0 (0) aA
4 Nemacur® 400 EC +Velum® Prime 400 SC 0.0 (0) aA 0.24 (12) aA 5 Nemacur® 400 EC +Velum® Prime 400 SC
+ Kalahari 3:1
0.0 (0) aA 0.0 (0) aA 6 Velum® Prime 400 SC, Fluopyram @ 400 g
/ L, IRAC: 25; FRAC: 7
0.22 (8) aA 0.32 (54) aA 7 Velum® Prime 400 SC + Kalahari 3:1 0.0 (0) aA 0.34 (63) aA
8 Kalahari 3:1, organic fertiliser 0.0 (0) aA 0.0 (0) aA
F-ratio: 1.000 0.585
P-value: 0.441 0.765
Interaction: Treatments x Sampling intervals
F-ratio: 0.381
P-value: 0.910
1Log-transformed mean of nematode population density; 2Real means of nematode population density.
3.3.2.4 Plant-parasitic nematode eggs
Population densities of the plant-parasitic eggs extracted from roots were substantially higher than those of the vermiform nematodes for RKN, LN and spiral nematodes per 30 g roots discussed above (Tables 3.10, 3.11 and 3.12). Some significant differences were evident among some of the treatments per sampling interval and a significant interaction existed for treatments x sampling times (Table 3.13) indicating that the number of PPN eggs in 30 g roots differed for some treatments and sampling times. The number of PPN eggs increased for all treatments over the sampling times.
Plant-parasitic egg numbers in 30 g root samples varied between six to 4238/30 g roots at 10 WAE (sampling interval 2). The untreated control (treatment 1) differed significantly from all the treatments, except treatments 4 and 8. By the harvest sampling date (19 WAE; Sampling interval 3), most of the treatments showed an increase in PPN egg counts, with treatment 8 differing significantly from treatment 7 but not from the other treatments. This increase was evident for all the treatments, except treatment 4 where PPN egg counts declined.
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Table 3.13: Plant-parasitic nematode egg densities in 30 g roots for two sampling intervals.
(Significance level for Repeated measures ANOVA in capital letters; different letters indicate significant differences across rows for sampling intervals; different small letters per column indicate significant differences among treatments per individual sampling interval).
Treatment Treatment name Sampling interval 2:
10 WAE
Sampling interval 3:
19 WAE (Harvest)
1 Untreated control 2.52 (1288) bBCD 3.57 (14327) abCD
2 Nemacur® 400 EC, Fenamiphos @ 400 g / L, IRAC: 1B
0.38 (164) aA 2.91 (1094) abBCD 3 Nemacur® 400 EC + Kalahari 3:1 0.21 (6) aA 3.10 (2040) abBCD 4 Nemacur® 400 EC +Velum® Prime 400 SC 1.44 (4238) abAB 2.53 (1413) abBCD 5 Nemacur® 400 EC +Velum® Prime 400 SC +
Kalahari 3:1
0.24 (9) aA 2.60 (1126) abBCD 6 Velum® Prime 400 SC, Fluopyram @ 400 g /
L, IRAC: 25; FRAC: 7
0.37 (119) aA 2.14 (3368) abABCD 7 Velum® Prime 400 SC + Kalahari 3:1 0.30 (34) aA 1.89 (1140) aABC 8 Kalahari 3:1, organic fertiliser 1.56 (450) abAB 3.94 (20376) bD
F-ratio: 5.065 2.653
P-value: 0.000 0.019
Interaction: Treatments x Sampling intervals
F-ratio: 1.390
P-value: 0.227
1Log-transformed mean of nematode population density; 2Real means of nematode population density.