Alkaline Hydrolysis. Effect of high pH spray solutions on some commonly used pesticides
| Chemical | Common name | Comments |
|---|---|---|
| Dyrene® | Anilazine | Subject to hydrolysis |
| Difolitan® | Captafol | Decomposes rapidly above 9.0. |
| Furadan® | Carbofuran | Unstable under alkaline conditions. |
| Dylox® | Trichlorfon | Degrades rapidly (approx. 99% of applied degraded in 2 hrs) in alkaline pond water (pH 8.5) at room temperature. |
| Proxol® | ” | |
| Dipterex | ” | |
| Counter® | Terbufos | Subject to hydrolysis under alkaline conditions. |
| Systox® | Demeton | Subject to hydrolysis under alkaline conditions. |
| Cygon® | Dimethoate | pH 6.0 ½ life = 12 hours. Unstable in alkaline water. |
| Diazinon® | Diazinon | pH 6.0 ½ life = 37 hours. Hydrolysis rapid in strong acid or alkaline water. |
| Imidan® | Phosmet | pH 8.0 ½ life = 4 hours |
| pH 7.0 ½ life = 12 hours | ||
| pH 4.5 ½ life = 13 days | ||
| Captan® | Captan | pH 10.0 ½ life = greater than 2 minutes |
| pH 4.0 ½ life = 4 hours | ||
| Malathion® | Malathion | Stable at pH 5.0-7.0 but rapid hydrolysis in more acidic or alkaline solutions |
| Polyram® | Polyram | Unstable under strongly acidic or alkaline conditions |
The truth about a couple of fungicides commonly maligned about alkaline hydrolysis.
BENLATE® or TERSAN® 1991. Benomyl is systematically fungicidal and quite stable in mildly acid to slightly alkaline water solutions. The first breakdown of benomyl is MBC (Methyl 2-benzimidazole carbamate) which is essentially as effective fungicidally. fungicidally.
BRAVO® . pH 7.0 or lower: no hydrolysis in aqueous solutions. pH 9.0: Rate of decline 1.8% per day (half life = 38.1 days).