The biological control of Parthenium hysterophorus L. in Pakistan: status quo and future prospects

• Published in: Management of biological invasions 2021-09, Vol.12 (3), p.509-526
• Main Authors: Weyl, Philip, Ali, Kazam, González-Moreno, Pablo, ul Haq, Ehsan, Khan, Kausar, Khan, Saad, Khan, Muhammad, Stewart, Janet, Godwin, Julien, Rehman, Abdul, Sultan, Amir
• Format: Article
• Language: English
• Subjects: Biological control; Diapause; Dispersal; Environmental conditions; Host range; Importation; Integrated control; Parthenium hysterophorus; Quarantine; Rust fungi; Weeds; Winter
• ISSN: 1989-8649; 1989-8649
• DOI: 10.3391/mbi.2021.12.3.02

Parthenium, Parthenium hysterophorus L. poses a serious environmental and socio-economic threat in Pakistan. It was identified as a priority for control in Pakistan and an integrated control programme has been launched against this invasive weed. In 2009 the biological control agent, Zygogramma bicolorata Pallister, was documented in Pakistan and thought to have naturally dispersed into the region. Despite the presence of this biological control agent for the past decade in Pakistan, the population level impact on parthenium weed has been limited by several factors, including climate, diapause and limited dispersal. A redistribution programme was initiated to promote this biological control agent in Pakistan. In addition to this, the parthenium winter rust, Puccinia abrupta Diet. & Holw. var. partheniicola (Jackson) Parmelee, was reported in Pakistan for the first time in 2019. Despite this rust being widespread there appears to be limited impact, most likely linked to environmental conditions and the timing of infection. Monitoring programmes for this rust have been initiated for the winter of 2020. CABI, through its Action on Invasives programme, has established a quarantine facility for the screening of complementary biological control agents not yet in Pakistan against parthenium and other invasive weeds in the country. With this quarantine facility the importation of the stem boring weevil, Listronotus setosipennis (Hustache) was possible and host range testing is underway. The biological control of parthenium in Pakistan is still at an early stage, and considerable effort is required to fill the management toolbox for this invasive weed.