Submitted to: Biocontrol Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/10/2003
Publication Date: 2/20/2004
Citation: February 2004, vol. 14, no. 1, pp. 39-50(12)
Interpretive Summary: Creosote bush (Larrea tridentata (DC) Coville) is a common woody, perennial and slow-growing weedy shrub, covering 19 million ha in the U.S. that competes with rangeland forage plant species. In New Mexico, it was found that good stands of grasses rapidly appeared after Larrea plants were killed with herbicides. The genus Larrea originated in South America, and has four South American, and one North American species: L. tridentata. Biological control of creosote bush could be feasible by introducing phytophagous insects from the South American species of Larrea to the United States. The biology of this family, which contains more than 100 species, is poorly known. The purpose of this research was to document the biology and assess the natural and potential host plant range of A. bidentata and A. saltense through field and laboratory tests to evaluate their potential as biocontrol agents for creosote bush in the United States. The study showed that A. bidentata is restricted to creosote bush, and has some biological attributes that make it a good candidate for biological control of creosote bush. Studies are recommended to establish the behavior of A. bidentata on L. tridentata. Other species close to creosote bush should be included in the host range tests to avoid effects on non target native plants. Regarding A. saltense, this species has a wide host range, so we recommend that it should not be considered as a biological control agent for creosote bush.
Technical Abstract: Two stick-like acridids (Orthoptera: Proscopiidae) from Argentina, Anchocoema bidentata Mello-Leitao and Astroma saltense Mello-Leitao, were evaluated as potential biological control agents of creosote bush (Larrea tridentata (DC.) Coville) in the southwestern United States. Biology, behavior and geographic distribution of those species were studied. The host plant ranges for both insects were established by conducting nymph feeding preference and development tests in the laboratory and in the field. A total of 33 species of plants belonging to 13 families were tested. The laboratory multiple-choice feeding test showed that A. bidentata preferred Larrea divaricata Cav., whereas A. saltense preferred L. divaricata and L. cuneifolia Cav. In the nymph development test (no choice), A. bidentata was able to complete its development only on L. divaricata and L. cuneifolia, while Astroma saltense completed its development on six plant species: L. divaricata, L. cuneifolia, Bulnesia retama (Gillies ex Hooker et Arnott), B. schickendantzi Hieron (all Zygophyllacea), Zuccagnia punctata Cav., and Prosopis torquata (Cav. Ap. Lag.) (both Fabaceae). Anchocoema bidentata could be a biocontrol agent for L. tridentata because the first instar can complete its development only on Larrea spp. Regarding A. saltense, this species showed a wide host range and should not be considered as a biological control agent of L. tridentata.