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Hugh D. Sisler
treatment is by no means exhaustive, but it is hoped that it will give a useful
overview of the subject.
6.2. TOXICITY OF FUNGICIDES TO NONTARGET
ORGANISMS
Apart from mercury compounds, cycloheximide, and a few other compounds of minor significance, fungicides have a low mammalian toxicity (Table
6.1). The acute oral LDso value of several important fungicides such as Bordeaux
mixture, thiram, and triphenyltin hydroxide lies between 100 and 1000 mglkg;
however, the value for most fungicides is greater than 1000 mg/kg. In view of
the low application rates and minor significance of cycloheximide and the discontinued or severely restricted use of mercury compounds in many countries,
the fungicides used in agriculture do not constitute a serious problem as acute
toxicity hazards to mammals. With the realization that fungicides, their contaminants, or their degradation products may have obscure or delayed toxic effects
on humans and other organisms or enter into food chains and become greatly
concentrated, we have become more concerned about the fate of fungicides in
the environment. In fact, the need to know the degradation characteristics as
well as the biological effects of new and existing agricultural fungicides is now
widely recognized.
Table 6.1. Fungicides Grouped According to Acute
Oral Mammalian Toxicity (LD50)(mg/kg)8
1-50
Cycloheximide (2.5)b
Mercuric chloride (7-9)
Phenylmercury salts (5-70)
Methyl mercury salts (16-32)
Ethyl mercury salts (16-28)
50--100
Cadmium chloride (88)
Diazoben (60)
100-1000
Bordeaux mixture (300)
Triphenyitin hydroxide (108-209)
Thiram (375-865)
Sodium pentachlorophenate (210)
1000 or greater
Anilazine
Benomyl
Captafol
Captan
Carboxin
Chloroneb
Chlorothalonil
Dichlone
Dodine
Ferbam
Folpet
Glyodin
Maneb
Thiabendazole
Zineb
Ziram
• Values for mercury compounds from Ulfvarson (1969); all others from the
United States Department of Agriculture guidelines (1974).
b Value(s) in parentheses: LO,. of fungicide(s).