How widespread is Parthenium hysterophorus and its biological control agent Zygogramma bicolorata in South Asia?

Abstract

SummaryParthenium hysterophorus is a weed of global significance causing severe economic, environmental, human and animal health problems in Asia, Africa, Australia and the Pacific. In South Asia, P. hysterophorus occurs in India, Pakistan, Sri Lanka, Bangladesh and Nepal. A host-specific leaf-feeding beetle Zygogramma bicolorata from Me´xico was introduced into India in 1984, as a biological control agent for P. hysterophorus. In this study, a GIS-based distribution map of P. hysterophorus and its biological control agent Z. bicolorata in South Asia based on meta-analysis is presented. The map highlights the limited published information on P. hysterophorus incidence in many of the states and territories in India, as well as in neighbouring Bangladesh, Bhutan, Nepal and Pakistan. Incidence of Z. bicolorata was recorded as three distinct clusters, covering many states in India. In Pakistan, Z. bicolorata was recorded in the Punjab region bordering India. A CLIMEX model based on the current distribution of Z. bicolorata in India suggests that the geographic range of this agent in India and Pakistan can extend to other P. hysterophorus-infested areas in the region. The CLIMEX model also suggests that all of Bangladesh and Sri Lanka, and parts of Nepal are climatically suitable for Z. bicolorata.

Distribution of Parthenium hysterophorus and one of its biological control agents (Coleoptera: Zygogramma bicolorata) in Nepal

“…Even though the model was developed without using distribution data from Nepal for both organisms, the model output fitted well with their current distribution in Nepal. Therefore, our results support the previous findings that CLIMEX can be a useful tool both for invasive species and for their biological control agents (Dhileepan & Senaratne, ; McConnachie et al ., ). A few outlying weed populations near the northern border of Nepal can readily be attributed to the effect of microhabitats (McConnachie et al ., ).…”

“…CLIMEX uses average meteorological data of the world in a 0.5° grid scale, based on distribution and density of weather stations. This software has been used to predict the potential area of distribution and suitable habitat for P. hysterophorus as well as Z. bicolorata (Dhileepan & Senaratne, ; McConnachie et al ., ). The modelling method used in this study has been described in our previous publication (Shrestha et al ., ).…”

A Roadside Survey of the Invasive WeedParthenium hysterophorus(Asteraceae) in East Africa

“…CLIMEX is frequently used for conducting weed risk assessments (Kriticos & Randall, 2001;McConnachie et al, 2011) and is based on the assumption that during a year, some seasons may promote growth of plant and animal populations while others are unfavourable or may jeopardize persistence in a given area (Sutherst & Maywald, 1985). The model expresses the suitability of any one particular area as an Eco-climatic Index (EI), with areas having an EI of 1-5 considered marginal, 6-20 suitable, and >20 optimal for parthenium growth and persistence (Dhileepan & Wilmot, 2009). …”

Suppressive ability of selected fodder plants on the growth of Parthenium hysterophorus

“…Furthermore, a greatly increased distribution of P . hysterophorus within South Asia and Africa has been predicted in the future (Dhileepan & Senaratne, 2009; McConnachie et al. , 2011).…”