164
Substance group
Active ingredient
(a.i.)
Target pests
Typical application
rates [grams (g) of
active ingredient
(a.i.) per hectare
(ha)] (g a.i. ha
−1
)
Mode of action
Factors determining pesticides fate in the environment
Solubility in
water
(mg L
−1
)
a
Half-life
in soil
(DT50:
days)
b
Organic
carbon
sorption
constant
(K
oc )
c
Dissociation
constant at
25 °C (pKa)
Ethylene generator
(ethephon)
Flower suppressant 480
Plant growth regulator with
systemic properties
1,000,000
13.4
–
2.82
Phenylpyrazole
(fipronil)
Various insect pests
and mites
Broad spectrum with contact
and stomach action.
GABA-gated chloride channel
antagonist
3.78
142
–
No dissociation
Phenylureas (diuron) Weeds and mosses 1600
Inhibits photosynthesis
35.6
89
813
–
Organophosphate
(profenofos)
Lepidopteran pests
and mites
440
Acetylcholinesterase (AChE)
inhibitor
28
7
2016
–
a
Highly soluble pesticides have large solubility values
b
Soil half-life: <30 days implies nonpersistent, 30–100 days means moderately persistent and >100 days shows pesticide is highly persistent
c
The higher the K
oc value, the more strongly the pesticide is sorbed
d
“- “indicates data not available
Sources: PPDB (2017); Kerle et al. (2007); EU (2004); Kasambala Donga and Eklo (2018); EXTOXNET (1994)
Table 2 (continued)
T. K. Donga et al.
Substance group
Active ingredient
(a.i.)
Target pests
Typical application
rates [grams (g) of
active ingredient
(a.i.) per hectare
(ha)] (g a.i. ha
−1
)
Mode of action
Factors determining pesticides fate in the environment
Solubility in
water
(mg L
−1
)
a
Half-life
in soil
(DT50:
days)
b
Organic
carbon
sorption
constant
(K
oc )
c
Dissociation
constant at
25 °C (pKa)
Ethylene generator
(ethephon)
Flower suppressant 480
Plant growth regulator with
systemic properties
1,000,000
13.4
–
2.82
Phenylpyrazole
(fipronil)
Various insect pests
and mites
Broad spectrum with contact
and stomach action.
GABA-gated chloride channel
antagonist
3.78
142
–
No dissociation
Phenylureas (diuron) Weeds and mosses 1600
Inhibits photosynthesis
35.6
89
813
–
Organophosphate
(profenofos)
Lepidopteran pests
and mites
440
Acetylcholinesterase (AChE)
inhibitor
28
7
2016
–
a
Highly soluble pesticides have large solubility values
b
Soil half-life: <30 days implies nonpersistent, 30–100 days means moderately persistent and >100 days shows pesticide is highly persistent
c
The higher the K
oc value, the more strongly the pesticide is sorbed
d
“- “indicates data not available
Sources: PPDB (2017); Kerle et al. (2007); EU (2004); Kasambala Donga and Eklo (2018); EXTOXNET (1994)
Table 2 (continued)
T. K. Donga et al.