Agriculture Reference
In-Depth Information
Toxicity
PCNB, hexachlorobenzene (HCB), and dichloran have only slight irritant
effects and relatively low single-dose toxicity. Several formulated products of
chlorothalonil are classified in Toxicity Category I and are corrosive to eyes
and skin (Bravo, ClortoCaffaro, Daconil, Echo). Other formulations are clas-
sified in Toxic Category II as severe irritants to eyes and skin.
Table 5.31
Commercial products continuing substituted aromatics com-
pounds.
Active Ingredients
Trade Names
Hexachlorobenzene
HCB, Anticarie, Ceku C.B., No Bunt
Pentachloronitrobenzene
PCNB, Quintozene, Terraclor, Turfcide, Avicol, Botrilex, Earth-
cide, Folosan, Kobu, Kobutol, Pentagen, Tilcarex, Tri-PCNB
Chlorothalonil
Bravo, ClortoCaffaro, Clortosip, Daconil 2787, Exotherm Termil,
Tuffcide
Dichloran
DCNA, Ditranil, Botran, Allisan, Kiwi Lustr 277, Resisan
Formulations
PCNB—emulsifiable concentrates, wettable powders, and granules
.
Hexachlorobenzene—dusts and powders
.
Dichloran—wettable powder, dusts, and flowable powders
.
Chorothalonil—wettable powder, water dispersible granules, and flowable
powders.
e.
Dinitrophenols
The majority of phenols, especially those containing chlorine, are toxic to
microorganisms. However, the majority of phenols are too phytotoxic to
permit their use as agricultural fungicides. They are widely used as industrial
fungicides. Dinocap, a mixture of several compounds, was first introduced in
1946 as a non-systemic aphicide and contact fungicide. Dinocap is used to
control powdery mildew on major horticultural crops. Unlike the herbicide
DNOC and other chlorinated phenols, dinocap has relatively low mammalian
toxicity.
Mode of Action
The fungicidal activity of the various phenols depends on their ability to
uncouple oxidative phosphorylation and thus prevent the incorporation of in-
organic phosphate into ATP without effecting electron transport. The result
of this inhibition is cell death due to the lack of energy for cellular metabo-
lism.
