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

Parthenium 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 Mexico 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

Insect diversity on Calotropis gigantea (L.) in Sri Lanka

Calotropis gigantea is a drought-resistant and salt-tolerant medicinal plant native to Sri Lanka. Although C. gigantea is widely distributed in Sri Lanka, information on insects associated with the plant is less understood. The objective of the study is to identify the diversity of insect fauna associated with C. gigantea. Surveys were conducted in 120 sites covering all provinces of Sri Lanka to document the insect fauna associated with C. gigantea and their biotic associations. The insects found in C. gigantea were cataloged as pests, pollinators, and occasional visitors. A total of thirteen morphospecies of phytophagous pests, six species of pollinators, and fourteen species of occasional visitors were documented. Dacus persicus and Paramecops farinosa were the highly damaging pests while Sphaeroderma sp. was more widespread. Xylocopa spp. were the most abundant insect pollinators. Dacus persicus and P. farinosa were identified as monophagous species of C. gigantea. Occasional visitors belonged to five orders and their diversity was very high. As the initial record from Sri Lanka, the findings of the study provide information on the identification of the insect fauna associated with Calotropis and their association with C. gigantea

Gall thrips Acaciothrips ebneri (Thysanoptera: Phlaeothripidae) from Ethiopia, a promising biological control agent for prickly acacia in Australia

Based on climatic and plant phenotype matching, native-range surveys were conducted in Ethiopia to identify prospective biological control agents for prickly acacia, a serious weed of grazing areas in northern Australia. Surveys identified a gall thrips, Acaciothrips ebneri (Karny) (Thysanoptera: Phlaeothripidae), as a prospective biological control agent for prickly acacia, based on damage potential, field host range and geographic range in Ethiopia. The gall thrips was imported into a high security quarantine facility at the Ecosciences Precinct, Brisbane,Australia in December 2015 and host-specificity tests are in progress. If approved, the gall thrips would be the first gall insect to be released against prickly acacia in Australia.The Meat & Livestock Australia, Rural Industries Research & Development Corporation and Rural Research & Development for Profit Programme of the Australian Government (Department of Agriculture and Water Resources).http://www.journals.co.za/content/journal/entohttp://www.bioone.org/loi/afen2020-04-01am2018Forestry and Agricultural Biotechnology Institute (FABI

The host range and biology of Cometaster pyrula; a biocontrol agent for Acacia nilotica subsp. indica in Australia

Prickly acacia, Acacia nilotica subsp. indica (Benth.) Brenan, a major weed of the Mitchell Grass Downs of northern Queensland, Australia, has been the target of biological control projects since the 1980s. The leaf-feeding caterpillar Cometaster pyrula (Hopffer) was collected from Acacia nilotica subsp. kraussiana (Benth.) Brenan during surveys in South Africa to find suitable biological control agents, recognised as a potential agent, and shipped into a quarantine facility in Australia. Cometaster pyrula has a life cycle of approximately 2 months during which time the larvae feed voraciously and reach 6 cm in length. Female moths oviposit a mean of 339 eggs. When presented with cut foliage of 77 plant species, unfed neonates survived for 7 days on only Acacia nilotica subsp. indica and Acacia nilotica subsp. kraussiana. When unfed neonates were placed on potted plants of 14 plant species, all larvae except those on Acacia nilotica subsp. indica and Acacia nilotica subsp. kraussiana died within 10 days of placement. Cometaster pyrula was considered to be highly host specific and safe to release in Australia. Permission to release C. pyrula in Australia was obtained and the insect was first released in north Queensland in October 2004. The ecoclimatic model CLIMEX indicated that coastal Queensland was climatically suitable for this insect but that inland areas were only marginally suitable

Studies on the fruit feeding weevil, paramecops farinosa (Coleoptera: Curculionidae) in Sri Lanka as a prospective weed biological control agent of invasive weed, calotropis spp

Calotropis gigantea is a large shrub or a small tree native to Sri Lanka with an Ayurvedic medicinal value. The plant is considered as an invasive weed in countries where it has been introduced. Paramecops farinosa Schoenherr (Aak weevil) is a monophagous pest that feeds on C. gigantea. Present study was conducted to elucidate the life history and damage potential of P. farinosa, in order to assess its potential as a biological control agent against C. procera and C. gigantea in countries where the plants are invasive. The field sampling was done throughout Sri Lanka covering 120 sampling sites from December 2014 to October 2015, and C. gigantea fruits were examined for the incidence and intensity of damage by P. farinosa. It lays yellowish, oval and mostly one-clustered eggs in the inner-pericarp fibrous layer of the Calotropis fruit. Newly emerged larvae were apodous, pale yellowish-white with brown head capsule whereas developing larvae were creamy-white, curved and stout. Paramecops farinosa larvae voraciously feed on all Calotropis seeds (100%) and fifth larval instar pupated by forming silky cocoons within the seed chamber. The adults feed on leaves, buds and flowers and its damage is highly correlated with the amount of P. farinosa inhabit on trees. P. farinosa is a seed predator and highly damage reproductive structures of C. gigantea thus directly influences the reproductive ability of the plant. These results provide baseline information needed in adopting P. farinosa as potential biological control agent against C. procera and C. gigantea. © 2021, Informatics Publishing Limited. All rights reserved

A systematic approach to biological control agent exploration and prioritisation for prickly acacia (Acacia nilotica ssp. indica)

Agent selection for prickly acacia has been largely dictated by logistics and host specificity. Given that detailed ecological information is available on this species in Australia, we propose that it is possible to select agents based on agent efficacy and desired impact on prickly acacia demography. We propose to use the 'plant genotype' and 'climatic' similarities as filters to identify areas for future agent exploration; and plant response to herbivory and field host range as 'predictive' filters for agent prioritisation. Adopting such a systematic method that incorporates knowledge from plant population ecology and plant-herbivore interactions makes agent selection decisions explicit and allow more rigorous evaluations of agent performance and better understanding of success and failure of agents in weed biological control

Applications of CLIMEX modelling leading to improved biological control

Wilmot Senaratne, Bill Palmer and Bob Sutherst recently published their paper 'Applications of CLIMEX modelling leading to improved biological control' in Proceedings of the 16th Australian Weeds Conference. They looked at three examples where modern climate matching techniques using computer software produces decisions and results than might happen using previous techniques such as climadiagrams. Assessment of climatic suitability is important at various stages of a biological control project; from initial foreign exploration, to risk assessment in preparation for the release of a particular agent, through to selection of release sites that maximise the agent´s chances of initial establishment. It is now also necessary to predict potential future distributions of both target weeds and agents under climate change

Australia's newest quarantine for biological control

The paper describes the QC3 quarantine facility and supporting infrastructure which were purpose built for weed biological control at the Ecosciences Precinct. The quarantine is one of two new weed quarantine facilities in Australia and will service northern Australia. An account of the sharing philosophy between CSIRO and the Queensland Government and the necessity of working very closely with architects, project managers, builders and quarantine personnel is also given. This philosophy contributed to certification of the facility without any undue delays

The introduction and release of Chiasmia inconspicua and C. assimilis (Lepidoptera: Geometridae) for the biological control of Acacia nilotica in Australia

Two geometrid moths Chiasmia inconspicua and Chiasmia assimilis, identified as potential biological control agents for prickly acacia Acacia nilotica subsp. indica, were collected in Kenya and imported into quarantine facilities in Australia where laboratory cultures were established. Aspects of the biologies of both insects were studied and CLIMEX® models indicating the climatically favourable areas of Australia were developed. Host range tests were conducted using an approved test list of 74 plant species and no-choice tests of neonate larvae placed on both cut foliage and potted plants. C. inconspicua developed through to adult on prickly acacia and, in small numbers, Acacia pulchella. C. assimilis developed through to adult on prickly acacia and also in very small numbers on A. pulchella, A. deanei, A. decurrens, and A. mearnsii. In all experiments, the response on prickly acacia could be clearly differentiated from the responses on the non-target species. Both insects were approved for release in Australia. Over a three-year period releases were made at multiple sites in north Queensland, almost all in inland areas. There was no evidence of either insect's establishment and both colonies were terminated. A new colony of C. assimilis was subsequently established from insects collected in South Africa and releases of C. assimilis from this new colony were made into coastal and inland infestations of prickly acacia. Establishment was rapid at one coastal site and the insect quickly spread to other infestations. Establishment at one inland area was also confirmed in early 2006. The establishment in coastal areas supported a CLIMEX model that indicated that the climate of coastal areas was more suitable than inland areas