Author
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Smith, Lincoln |
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Submitted to: Biological Control
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/3/2005 Publication Date: 4/7/2005 Citation: Smith, L. 2005. Host plant specificity and potential impact of aceria salsolae (acari: eriophyidae), an agent proposed for biological control of russian thistle (salsola tragus). Biological Control.34(1):83-92. Interpretive Summary: Russian thistle (common tumbleweed) is an alien weed that has invaded about 80 million acres in the western U.S. Tumbling plants disrupt automobile traffic, clog irrigation systems and pile up against buildings and fences. It is a major weed in dryland farming systems, especially spring wheat. The weed harbors insect pests that transmit curly top virus, which affects many important vegetable crops. Two species of insect biological control agents have been introduced but they have not significantly controlled the weed. The mite, Aceria salsolae, was discovered in 1996, and passed preliminary evaluations as a prospective biological control agent. Quarantine laboratory studies were conducted to determine the host plant specificity and potential impact of the mite on the weed. Results show that the mite reproduces on only a few species of Salsola, all of which are alien weeds in North America. Therefore, the mite poses negligible risk to nontarget plant species. Under laboratory conditions the mite reduces the growth of Russian thistle plants by 66% and interferes with the development of flowers. The mite is recommended for introduction as a biological control agent. Technical Abstract: Russian thistle, Salsola tragus (Chenopodiaceae), is an alien weed that is widespread in the western United States. A population of the eriophyid mite, Aceria salsolae (Acari: Eriophyidae), was collected in Greece and evaluated for host plant specificity as a prospective biological control agent. The mite usually does not form galls, but is a vagrant that usually inhabits the crevices of leaf and flower buds. Feeding damage causes meristematic tissue to die, which stunts the plant. The mite was able to multiply only on species in the Salsola section kali subsection kali, which includes the alien weeds S. collina, S. kali, and S. pausenii. It did not damage or multiply on S. soda, which is in a different section, nor on Halogeton glomeratus, which is in the same tribe. The mite reduced the size of Russian thistle plants by 66% at 25 weeks post-infestation under artificial conditions. The results indicate that the mite poses negligible risk to nontarget native North American plants or economic plants, and it may substantially reduce the size of Russian thistle plants and their population density. |
