"Lou has been a coach with us during one of the most successful periods of the club," said secretary Kevin Shore on Tuesday.
"We won the Cornwall & Devon League while he was coaching and the Somerset Vase.
"Fortunately, he will be remaining with the club as corporate sponsorship director."
Evans said: " I have had eight splendid years with Wellington, four with the colts and four with the seniors. It is an incredible and friendly club. However, my body is not getting any younger.
"I will now be able to concentrate much more on my role as sponsorship director."
Photo: Lou with former captain Tim Jenkinson after the match at Tiverton.