Off topic:How do i reorder the bars in a grouped barplot

Question

[Efolorunso]

I want the bars to be in the order:10% runoff, 20% runoff, NOEC, LC50. Thank you in anticipation.

Below is my code:

ggplot(pest_ana, aes(x = Pesticides, y = `Concentration (ug/L)`, fill= Concentrations)) + 
  geom_bar(stat = 'identity', position='dodge') + scale_x_discrete(guide = guide_axis(n.dodge=2)) + scale_y_continuous(trans = log10_trans(),
    breaks = trans_breaks("log10", function(x) 10^x),
    labels = trans_format("log10", math_format(10^.x)))

Pesticides  Concentrations  Concentration (ug/L)    Individual
Cypermethrin       NOEC                               4.8                      1
Deltamethrin       NOEC                               3.37                     2
Actara             NOEC                               20000            3
Carbofuran     NOEC                               40.6                     4
Methomyl       NOEC                               260                      5
Endosulfan     NOEC                               10.2                     6
Fenvalerate    NOEC                               6.02                     7
Glyphosate     NOEC                               5000                     8
Mancozeb       NOEC                               301                      9
Cypermethrin       LC50                               0.03                     1
Deltamethrin       LC50                               0.032                    2
Actara             LC50                               322000               3
Carbofuran     LC50                               500                      4
Methomyl       LC50                               4015                     5
Endosulfan     LC50                               0.05                     6
Fenvalerate    LC50                               15                       7
Glyphosate     LC50                               36800            8
Mancozeb       LC50                               11680            9
Cypermethrin       20% runoff                         3.95                     1
Deltamethrin       20% runoff                         0.69                     2
Actara             20% runoff                         3.95                     3
Carbofuran     20% runoff                         78.99                    4
Methomyl       20% runoff                         10.86                    5
Endosulfan     20% runoff                         41.47                    6
Fenvalerate    20% runoff                         8.85                     7
Glyphosate     20% runoff                         14.22                    8
Mancozeb       20% runoff                         74.05                    9
Cypermethrin       10% runoff                         1.97                     1
Deltamethrin       10% runoff                         0.35                     2
Actara             10% runoff                         1.97                     3
Carbofuran     10% runoff                         39.49                    4
Methomyl       10% runoff                         5.43                     5
Endosulfan     10% runoff                         20.73                    6
Fenvalerate    10% runoff                         4.42                     7
Glyphosate     10% runoff                         7.11                     8
Mancozeb       10% runoff                         37.03                    9