CABI scientists help discover new biological control for noxious parthenium weed in Pakistan

March 04, 2020

CABI scientists, as part of an international team of researchers, have discovered a new biological control in the fight against the highly noxious and invasive weed parthenium (Parthenium hysterophorus) in Pakistan.

As outlined in a new paper published in the journal BioInvasions Records, the scientists report the first record of the rust species Puccinia abrupta var. partheniicola - more commonly known as winter rust - in the Punjab and Khyber Pakhtunkhwa Provinces.

The presence of winter rust marks the second natural enemy, in addition to the leaf-feeding beetle Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae), which could help the management of parthenium in Pakistan.

According to the CABI Evidence Note 'Parthenium: Impacts and coping strategies in Central West Asia', parthenium is an aggressively-spreading weed, now classed as a 'superior weed', which is extremely prolific and capable of producing up to 30,000 seeds per plant.

CABI scientists say parthenium can cause severe allergic reactions in humans and livestock, may harbour malaria-carrying mosquitoes, displace native plant species and reduce pasture carrying capacities by as much as 80% to 90% where in India, for example, the cost of restoring grazing land is around USD 6.7 billion per annum.

The evidence note also highlights that parthenium weed can have a significant impact on crop yields - through direct competition as well as by inhibiting germination of seeds - where, for instance, in Ethiopia sorghum grain yield was reduced from 40 to 97 percent.

The researchers conducted surveys for winter rust covering 65 sites in 19 districts of Punjab and Khyber Pakhtunkhwa. The species was recorded at 21 sites in 8 districts. The most severe attack was found in the northern part of Punjab including Lahore, Attock and Narowal districts, while in Khyber Pakhtunkhwa medium rust infection was recorded only in Manshera district. In other districts rust infection was considered low or absent.

Dr Philip Weyl, a co-author on the paper and Research Scientist, Weed Biological Control at CABI, said, "Parthenium weed is considered to be a dominant weed species of natural ecosystems and agriculture in Pakistan and is also highly allergic to humans and toxic to livestock.

"Management options in Pakistan are limited and have tended to focus on manual removal and the application of herbicides. However, manual removal of the weed without protective clothing is very risky due to contact dermatitis while large-scale control using herbicides is economically and environmentally unsustainable."

The scientists reveal that while winter rust has previously been introduced deliberately to tackle parthenium in Australia in 1991 it has also appeared unintentionally in China, India, Ethiopia, Kenya, Mauritius, Nepal, South Africa and Tanzania. They believe the rust could have entered Pakistan via India or Nepal.

Lead author Iram M. Iqbal, from the University of the Punjab, said, "While the winter rust may not kill the parthenium it can significantly reduce biomass and seed production, especially when applied at the rosette stage of the weed.

"Furthermore, the suppressive effect of the rust was enhanced in the presence of competitive pasture plants and is likely to maintain its effectiveness under elevated CO2 concentrations. We believe that the presence of winter rust in Pakistan will aid the management of parthenium weed."
-end-
Additional information

Main photo: scientist examines parthenium weed - credit: Asim Hafeez.

Full paper reference

Iqbal IM, Ali K, Evans HC, Rehman A, Seier MK, Shabbir A, Weyl P, (2020) The first record of Puccinia abrupta var. partheniicola, on Parthenium hysterophorus an invasive alien plant species in Pakistan. BioInvasions Records 9 (in press).

The paper is available as an open access publication in BioInvasions Records, a journal of the International Association for Open Knowledge on Invasive Alien Species (INVASIVESNET), and can be found here: https://doi.org/10.3391/bir.2020.9.1.01.

For more information about INVASIVESNET, please visit their website (http://www.invasivesnet.org) or contact their Media and Communications Officer at media@invasivesnet.org.

For more information on parthenium see the CABI Evidence Note: 'Parthenium: Impacts and coping strategies in Central West Asia', 2019.

CABI

Related Species Articles from Brightsurf:

A new species of spider
During a research stay in the highlands of Colombia conducted as part of her doctorate, Charlotte Hopfe, PhD student at the University of Bayreuth, has discovered and zoologically described a new species of spider.

Two new species of parasite discovered in crabs -- discovery will help prevent infection of other marine species
Two new species of parasite, previously unknown to science, have been discovered in crabs in Swansea Bay, Wales, during a study on disease in the Celtic and Irish Seas.

Marine species are outpacing terrestrial species in the race against global warming
Global warming is causing species to search for more temperate environments in which to migrate to, but it is marine species -- according to the latest results of a Franco-American study mainly involving scientists from the CNRS, Ifremer, the Université Toulouse III-Paul Sabatier and the University of Picardy Jules Verne -- that are leading the way by moving up to six times faster towards the poles than their terrestrial congeners.

Directed species loss from species-rich forests strongly decreases productivity
At high species richness, directed loss, but not random loss, of tree species strongly decreases forest productivity.

What is an endangered species?
What makes for an endangered species classification isn't always obvious.

One species, many origins
In a paper published in Nature Ecology and Evolution, a group of researchers argue that our evolutionary past must be understood as the outcome of dynamic changes in connectivity, or gene flow, between early humans scattered across Africa.

Species on the move
A total of 55 animal species in the UK have been displaced from their natural ranges or enabled to arrive for the first time on UK shores because of climate change over the last 10 years (2008-2018) -- as revealed in a new study published today by scientists at international conservation charity ZSL (Zoological Society of London).

Chasing species' 'intactness'
In an effort to better protect the world's last ecologically intact ecosystems, researchers developed a new metric called 'The Last of the Wild in Each Ecoregion' (LWE), which aimed to quantify the most intact parts of each ecoregion.

How do species adapt to their surroundings?
Several fish species can change sex as needed. Other species adapt to their surroundings by living long lives -- or by living shorter lives and having lots of offspring.

Five new frog species from Madagascar
Scientists at Ludwig-Maximilians-Universitaet in Munich and the Bavarian State Collection of Zoology have named five new species of frogs found across the island of Madagascar.

Read More: Species News and Species Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.