Published online by Cambridge University Press: 10 July 2009
Brenthia leptocosma is a Microlepidopteron which feeds upon the Boraginaceous bush, Cordia macrostachya. This plant, since its accidental introduction into Mauritius about 1900, has become a pest of considerable agricultural importance. Other food-plants are C. myxa, C. abyssinica and C. holstii, which are all unimportant trees. B. leptocosma has been recorded only from Mauritius. It is not likely to be indigenous for it is restricted to Cordia species, none of which are considered to be native to Mauritius.
The morphology and biology of the various stages are described.
The distribution of B. leptocosma is that of its food-plants: it is extremely numerous in all regions below about 1,500 feet, which is the upper limit for C. macrostachya. The abundance of the moth is due to the excessive growth of C. macrostachya. Owing to its mode of life, it is of no value as a controlling agent of C. macrostachya.
Larval and pupal parasites are recorded.