Mikania micrantha H.B.K. (Asteraceae), or mile-a-minute weed, is a neotropical invasive plant found in many countries within the tropical moist forest zones of South and Southeast Asia. In India, it is a highly problematic species in the Western Ghats of Kerala and in Assam. Since conventional cultural and chemical control options are expensive, can have non-target effects, and are unsustainable, the UK–Department for International Development funded a program to develop and implement a classical biological control strategy for M. micrantha in India. Phase I of the program resulted in the selection of a rust fungus Puccinia spegazzinii as the candidate agent. A full risk assessment of an isolate of this rust from Trinidad was undertaken in CABI-UK containment facilities. The rust was found to be specific to Mikania (more than 55 nontarget plant species were tested) and is very damaging, causing leaf, petiole and stem infections, leading to plant death. The rust also has environmental requirements compatible with those prevailing in the invasive range of the weed. The results of this work were presented in a Dossier to the Plant Protection Advisor to the Government of India, and permission to import the rust into quarantine in New Delhi was obtained. Under Phase II of the program, additional host-specificity testing was successfully completed in New Delhi (74 species were screened), prior to issuing the release permit. The rust was initially released in the field in Assam late in the rainy season of 2005 (October) with subsequent releases at the start of the rains (March) in 2006. Preliminary observations show the rust to be spreading from the initial release site. The potential efficacy of the rust and follow-up field studies are discussed.
Ellison, C.A.; Puzari, K.C.; Sreerama Kumar, P.; Dev, U.; Sankaran, K.V.; Rabindra, R.J.; Murphy, S.T. Sustainable control of Mikania micrantha &#8211; implementing a classical biological control strategy in India using the rust fungus Puccinia spegazzinii. In: Lai PoYung; Reddy, G.V.P.; Muniappan, R. (Eds). Proceedings of the Seventh International Workshop on Biological Control and Management of Chromolaena odorata and Mikania micrantha, National Pingtung University of Science and Technology, Taiwan, 12-15 September 2006. (2007) 94-105.