''Phrydiuchus tau'' is a species of
true weevils known as the Mediterranean sage root weevil. It is used as an agent of
biological pest control
Biological control or biocontrol is a method of controlling pests, such as insects, mites, weeds, and plant diseases, using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also invo ...
against
noxious weed
A noxious weed, harmful weed or injurious weed is a weed that has been designated by an agricultural or other governing authority as a plant that is injurious to agricultural or horticultural crops, natural habitats or ecosystems, or humans or liv ...
Mediterranean sage (''Salvia aethiopis'').
The adult weevil is dark gray to black and has a marking on its back that looks like a white letter
T, or
tau
Tau (uppercase Τ, lowercase τ, or \boldsymbol\tau; el, ταυ ) is the 19th letter of the Greek alphabet, representing the voiceless dental or alveolar plosive . In the system of Greek numerals, it has a value of 300.
The name in English ...
, hence its scientific name. The weevil is about 5 millimeters long. The female lays eggs at the base or on the underside of the leaf. The
larva
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
The ...
emerges in three to four weeks and burrows into the plant tissue. It tunnels all the way down to the root crown where it feeds and develops. The adult weevil does feed on the foliage, but most of the damage to the plant is done by the larva's feeding activity. Small plants can be killed by just the larval damage; larger plants may be stunted or unable to reproduce. The weevil favors Mediterranean sage, but it will also readily attack
clary sage (''Salvia sclarea''), a similar but less troublesome weed in the area.
This weevil is native to southern Eurasia. It was first introduced to the United States for invasive sage biocontrol in 1971. It is now established in much of the western United States.
References
* Coombs, E. M., et al., Eds. (2004). ''Biological Control of Invasive Plants in the United States''. Corvallis: Oregon State University Press, 264.
External links
CDFA: Invasive Sages
Ceutorhynchini
Insects used for control of invasive plants
Biological pest control beetles
Beetles described in 1969
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