“If it grows, it will stick you; if it crawls, it will bite you” has appeared on internet joke lists from the early 2000s. The saying is attributed to the Texas way of life, but the authorship is unknown.
 
       
Google Groups: alt.jokes
Newsgroups: alt.jokes, alt.humor
From: “Spammers eat this”

Date: Mon, 17 Sep 2001 06:35:46 -0500
Local: Mon, Sep 17 2001 7:35 am
Subject: Living in Texas
 
Things I’ve learned living in Texas .
(...)
If it grows, it sticks; if it crawls, it bites.
       
Google Groups: alt.med.cfs
Newsgroups: alt.med.cfs
From: .(JavaScript must be enabled to view this email address) (PATRICIA C MORTON)
Date: 26 Jun 2002 17:35:13 -0700
Local: Wed, Jun 26 2002 8:35 pm
Subject: Re: HUM: A True Texas  
 
A True Texan

As a true Texan I thought I would share a few of the things I have learned in my years of living in this Heaven on Earth located south of the Red River and north of the Rio Grande.

I can personally attest to the following points as being true:
(...)
If it grows, it’ll stick you.
If it crawls, it’ll bite you. 
 
Amarillo Globe-News
Web posted Sunday, October 5, 2003
12:00 a.m. CT
Texas: It’s really just a fact of life
By DAN PACKARD
(...)
During their journey, the contestants who survive long enough will learn many facts about Texas and Texans.

They will learn:
(...)
If it grows, it will stick you. If it crawls, it will bite you.   
 
Google Books
The Vampire Hunters Stalked
by William Hill
Ellen Hill, publisher
2006
Pg. 96:
He sprayed mosquito repellent on himself, recalling an old Texas saying, “If it grows it will stick you, and if it crawls, it will bite you.”