I went to a one dayer on glyphosate run by FAR - Foundation for Arable Research about 5 years ago, and they said that the most important thing in using glyphosate is to never increase the strength of dilution in the used product. In many countries, they kept doubling the strength, effectively rendering it useless. They quoted Thailand and surrounding countries where up to 16 times our dilution rate now kills very little. The message was 'more is not better'.