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Soil texture, infective juvenile concentration, and soil organic matter influence the efficacy of Steinernema feltiae isolate Lican Ray

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Figure 1:

Through the lateral opening of this t-shaped PVC matrix (A), a modified Petri dish containing soil and larvae is introduced. A removable lid with a metallic mesh for gas exchange covers the lateral opening (B). IJs are pipetted through the upper opening (C).
Through the lateral opening of this t-shaped PVC matrix (A), a modified Petri dish containing soil and larvae is introduced. A removable lid with a metallic mesh for gas exchange covers the lateral opening (B). IJs are pipetted through the upper opening (C).

Figure 2:

Boxplot showing percentage of last instar larvae Galleria mellonella mortality at (I) three, (II) six and (III) nine DAI, inoculated with 440, 2,200 or 4,400 IJs/5 mL of Steinernema feltiae LR in clay (C), loam (L) or sandy loam (S) soil, corrected according to the Schneider-Orelli’s formula). In (I) bars with different capital letters indicate statistical differences for soil texture (Tukey’s test; p ≤ 0.05). In (II) and (III) bars with different lower-case letter indicates statistical differences for the interaction between IJ concentration and soil texture (Tukey’s test; p ≤ 0.05). In Figs. 2–4, boxes represent the third quartile (75th percentile), median (50th percentile), first quartile (25th percentile), and mean percentage (x) of five replicates, with upper whiskers reaching Q3 +1.5×interquartile range (IQR) and lower whiskers Q1−1.5 × IQR.
Boxplot showing percentage of last instar larvae Galleria mellonella mortality at (I) three, (II) six and (III) nine DAI, inoculated with 440, 2,200 or 4,400 IJs/5 mL of Steinernema feltiae LR in clay (C), loam (L) or sandy loam (S) soil, corrected according to the Schneider-Orelli’s formula). In (I) bars with different capital letters indicate statistical differences for soil texture (Tukey’s test; p ≤ 0.05). In (II) and (III) bars with different lower-case letter indicates statistical differences for the interaction between IJ concentration and soil texture (Tukey’s test; p ≤ 0.05). In Figs. 2–4, boxes represent the third quartile (75th percentile), median (50th percentile), first quartile (25th percentile), and mean percentage (x) of five replicates, with upper whiskers reaching Q3 +1.5×interquartile range (IQR) and lower whiskers Q1−1.5 × IQR.

Figure 3:

Boxplot showing percentage of last instar larvae Galleria mellonella mortality at a distance of 10, 20, 30 or 40 cm horizontally from the inoculation point of IJ of Steinernema feltiae LR in clay (C), loam (L) or sandy loam (S) soil at (I) three, (II) six and (III) nine DAI. Bars with different letter in each evaluation time, indicate statistical differences, according to Tukey’s test (p ≤ 0.05).
Boxplot showing percentage of last instar larvae Galleria mellonella mortality at a distance of 10, 20, 30 or 40 cm horizontally from the inoculation point of IJ of Steinernema feltiae LR in clay (C), loam (L) or sandy loam (S) soil at (I) three, (II) six and (III) nine DAI. Bars with different letter in each evaluation time, indicate statistical differences, according to Tukey’s test (p ≤ 0.05).

Figure 4:

Boxplot showing percentage of last instar larvae Galleria mellonella mortality at a distance of 30, 50 or 70 cm vertically from the inoculation point of IJ of Steinernema feltiae LR in clay (C), loam (L) or sandy loam (S) soil at (I) three, six (II) and (III) nine DAI. Bars with different letter in each evaluation time, indicate statistical differences, according to Tukey’s test (p ≤ 0.05).
Boxplot showing percentage of last instar larvae Galleria mellonella mortality at a distance of 30, 50 or 70 cm vertically from the inoculation point of IJ of Steinernema feltiae LR in clay (C), loam (L) or sandy loam (S) soil at (I) three, six (II) and (III) nine DAI. Bars with different letter in each evaluation time, indicate statistical differences, according to Tukey’s test (p ≤ 0.05).

Figure 5:

Boxplots showing percentage of last instar larvae Galleria mellonella mortality caused by Steinernema feltiae LR in loam soil at two and four DAI with 0, 2, 4, 6 or 8% OM. Bars with different letters indicate statistical differences, according to Tukey’s test (p ≤ 0.05) (lower case for two DAI and capital letters for four DAI). In figs 5 and 6, boxes represent the third quartile (75th percentile), median (50th percentile), first quartile (25th percentile), and mean percentage (x) of 15 replicates, with upper whiskers reaching Q3 + 1.5 × interquartile range (IQR) and lower whiskers Q1−1.5 × IQR. Outliers beyond the boxes limits are plotted as individual points.
Boxplots showing percentage of last instar larvae Galleria mellonella mortality caused by Steinernema feltiae LR in loam soil at two and four DAI with 0, 2, 4, 6 or 8% OM. Bars with different letters indicate statistical differences, according to Tukey’s test (p ≤ 0.05) (lower case for two DAI and capital letters for four DAI). In figs 5 and 6, boxes represent the third quartile (75th percentile), median (50th percentile), first quartile (25th percentile), and mean percentage (x) of 15 replicates, with upper whiskers reaching Q3 + 1.5 × interquartile range (IQR) and lower whiskers Q1−1.5 × IQR. Outliers beyond the boxes limits are plotted as individual points.

Figure 6:

Boxplots showing percentage of last instar larvae Galleria mellonella mortality caused by Steinernema feltiae LR in loam soil at two and four DAI with OM at different decomposition degrees (initial, medium and advanced) control soil (unknown) and soil with no OM (calcined). Bars with different letters on bars indicate statistical differences, according to Tukey’s test (p ≤ 0.05) (lower case for two DAI and capital letters for four DAI).
Boxplots showing percentage of last instar larvae Galleria mellonella mortality caused by Steinernema feltiae LR in loam soil at two and four DAI with OM at different decomposition degrees (initial, medium and advanced) control soil (unknown) and soil with no OM (calcined). Bars with different letters on bars indicate statistical differences, according to Tukey’s test (p ≤ 0.05) (lower case for two DAI and capital letters for four DAI).

Physical properties of the soils used.

Volumetric water content (%) Texture (%)
Textural classes FC PWP AWC S C Si
Clay 39.0 19.0 20.0 19.0 52.0 19.0
Sandy loam 18.0 8.9 9.1 69.2 8.6 22.2
Loam 22.0 14.0 8.0 38.8 20.8 40.4

Chemical analysis of organic matter (OM) used, at different degrees of decomposition.

Content (%) Content (ppm)
OM decomposition degree OM Organic carbon Total nitrogen Nitrate Ammonium
Initial 85 49.7 2.66 147 142
Medium 18 10.5 1.26 495 28
Advanced 18 10.5 0.98 335 18
eISSN:
2640-396X
Langue:
Anglais
Périodicité:
Volume Open
Sujets de la revue:
Life Sciences, other