Difference between revisions of "Cylas formicarius"

Revision as of 15:35, 13 March 2014

Cylas formicarius (click on image to enlarge it)
Author(s): Juliana Cardona-Duque, University of Puerto Rico
Source: IPM Images

Cylas formicarius (Fabricius, 1793) - (sweet potato weevil)
is an important and widespread pest of sweet potatoes. The adult feeds on the stems or young leaves and breed in the tubers or stems, preferring the former. It also infests the stored tubers. Losses can exceed 50% and total crop losses have been reported. Other plants of the genus Ipomoea are also attacked, as are some related species. The origin of the weevil is not clear but it has invaded several countries, e.g. Japan (first record in 1903) or U.S.A. (first record in Texas in 1890), and is still under quarantine in several regions. Insecticides are mainly used for control and sanitation (removal of infested plants) is also recommended. Several other control strategies are under development, like the sterile insect technique. Pheromone traps are effective for monitoring.

The adult lays single eggs near the border between roots and stem, after having chewed into the plant tissue. The development from egg, through 3 larval stages, to mature adult usually lasts around 5-6 weeks and it can complete 5-8 generations in a year. The adults remain inactive during the winter. The larvae are legless and the adult weevil is 5-8 mm long. It has an ant-like shape. The head is black, thorax and legs are orange or reddish brown and the elytra and abdomen are dark metallic blue.

Synonyms:
Cylas turcipennis

The literature database currently contains 118 publications for Cylas formicarius. (See box above/on left.)

• Other images of Cylas formicarius (Wikimedia Commons, IPM Images and PaDIL - click to enlarge)
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  larva

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  infested sweet potato tuber

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  head

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  pronotum

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  posterior end