Broom snakeweed,Gutierrezia sarothrae(Pers.) Britt. and Rusby, and the closely related threadleaf snakeweed,G. microcephala(DC.) A. Gray were sampled for root-feeding insects at 18 sites in Lea Country and two sites in Lincoln County, New Mexico, in 1978 and at ten sites (nine sites revisited) in Lea County and one site in Guadalupe County in 1979. Of the 600 plants collected in 1978 nearly 60% of the dead or nearly dead plants (76–100% dead material) above 15.2 cm in height contained root borer holes. Less that 15% of the plants 15.2 cm or less in height, whatever their health classification, contained borer holes. Root borer holes were thus most closely correlated with taller, older, unhealthy plants. The longhorned beetleCrossidius pulchellusLeCont appeared to be the major root borer in these populations. Most of the plants collected in 1979 were healthy seedlings and much less borer activity was seen.