By Stu Taylor
Alkaline hydrolysis is a term used to explain the influence of the pH of spray water on various pesticides. Pesticides work better in an acid condition and a high pH can even knock out some chemicals, rendering them totally non-effective. Synthetic pyrethroids are particularly prone to this condition and herbicide efficacy is increased quite substantially. All pesticides have what is termed a “half-life,” where the efficacy of a chemical, once mixed with water, is reduced by 50%. Alkaline hydrolysis can reduce the half-life quite substantially, leading the farmer to presume that the chemical they are using is “useless”.
There are several chemicals termed “buffers” on the market, which will reduce spray water pH to the desired level (around 4.3 for most pesticides), giving the chemical better efficacy. One local chemical company has a product specially formulated for countering alkaline hydrolysis “Bladbuff” which also acts as a wetter/spreader. Farmers in the Great Dyke area have extremely high-pH levels in their water and this is an important considaration when using pestcides.