Philip Weyl

Background. Smallholder farmers have a significant role in contributing to improving the establishment and effectiveness of biological control agents through their on-farm management practices. Biological control offers a long-term sustainable solution but requires farmer engagement and support to ensure effectiveness through a coordinated area-wide management approach. The stem-boring weevil, Listronotus setosipennis, has been approved for release as a classical biological control agent for Parthenium hysterophorus L. (Asteraceae) (“parthenium”), a major weed in Pakistan. The objective of this study was to investigate men and women smallholder farmers’ knowledge, attitudes and practices towards parthenium and biological control. Methods. Household surveys using a structured questionnaire were conducted with 562 farmers (62% men and 38% women) in Khyber-Pakhtunkhwa (KP), Punjab and Azad Jammu and Kashmir (AJK). Stratified random sampling was used to select participants from distinct districts within each of the three locations. Seven focus group discussions were conducted with separate men’s and women’s groups in each district and key informant interviews were conducted with 17 extension agents and 31 agro-dealers. Results. In all survey areas, women and men farmers reported parthenium present on their farming land, abundant on common land, and rapidly spreading. Women reported higher levels of land covered by parthenium, likely due to their frequent presence within the field during hand weeding. Women farmers and farmers in KP, more frequently reported negative health effects due to contact with parthenium. The two key management methods used for parthenium were hand weeding and chemical herbicides, the former used more frequently by women. Extension agents have an important role in advising farmers and promoting the use of alternatives such as biological control, but women do not engage in many extension activities. Conclusions. Biological control of parthenium using L. setisopennis offers an opportunity to engage with farmers and strengthen their knowledge of biological control while demonstrating its use at a landscape level. Targeted awareness campaigns using face-to-face and other verbal methods of communication are recommended. Increasing women’s access to information would improve their knowledge of parthenium, effective management approaches, and ways to protect their own and their family members health.

Cabomba caroliniana A. Gray, an ornamental submerged plant indigenous to tropical America, has been introduced to numerous countries in Europe, Asia, and Oceania, impacting native aquatic ecosystems. Given this species is a popular aquarium plant and widely traded, there is a high risk of introduction and invasion into other environments. In the current study the potential global geographic distribution of C. caroliniana was predicted under the effects of climate change and human influence in an optimised MaxEnt model. The model used rigorously screened occurrence records of C. caroliniana from hydro informatic datasets and 20 associated influencing factors. The findings indicate that temperature and human-mediated activities significantly influenced the distribution of C. caroliniana. At present, C. caroliniana covers an area of approximately 1531×10⁴ km² of appropriate habitat, especially in the south-eastern parts of South, central and North America, Southeast Asia, eastern Australia, and most of Europe. The suitable regions are anticipated to expand under future climate scenarios; however, the dynamics of the changes vary between different extents of climate change. For example, C. caroliniana is expected to expand to higher latitudes, following global temperature increases under SSP1–2.6 and SSP2–4.5 scenarios, however, intolerance to temperature extremes may mediate invasion at higher latitudes under future extreme climate scenarios, e.g., SSP5–8.5. Owing to the severe impacts its invasion causes, early warning and stringent border quarantine processes are required to guard against the introduction of C. caroliniana especially in the invasion hotspots such as, Peru, Italy, and South Korea.

Parthenium hysterophorus L. (Asteraceae) is an aggressive annual herbaceous weed which causes severe yield losses on a global scale. However, the precise impact of this weed in several countries is not yet known. To assess the impact of P . hysterophorus on maize crop losses in Pakistan, a 2 year field experiment was carried out at the CABI Rawalpindi campus in 2019 and 2020. Yield was measured on maize plants planted along with different densities (0, 1, 2, 4, 8, and 16 plants per m ² ) of P . hysterophorus . The trial was laid in a randomized complete block design with five replicates per density each year. The highest maize seed yield was obtained in weed-free plots (4256.5 ± 118 kg ha ⁻¹ ), while maize yield at weed infestation levels of 1, 2, 4, 8 and 16 plants m ⁻² was reduced by 14, 22, 29, 38 and 46%, respectively, compared to weed free plots. In the light of these findings, to reduce yield losses to non-significant levels it is proposed to reduce P . hysterophorus densities below 2 plants per m ² in maize fields.

CABI is a not-for-profit international organization with the mission of improving people’s lives worldwide by solving problems in agriculture and the environment, while engendering trust and facilitating science. As an organisation CABI is both a provider and a user of biological control agents and regularly acting as an intermediary between provider and user countries. As a way of building trust between both sides, access and benefit sharing (ABS) policy and ABS best practices developed around the principles of the Nagoya protocol should be publicly accessible. CABI aims to facilitate compliance with national legislation on ABS through its best practices for the countries in which we work and those that we provide genetic resources. CABI adopted the position to share benefits whether the provider country is party to the Nagoya Protocol or not. We use a case study on the biological control of the coffee berry borer (Hypothenemus hampei (Ferrari)) to illustrate the implementation of ABS best practices for the overlap between biological control and ABS. In respect to Digital Sequence Information (DSI) associated with genetic resources CABI contributes to the ongoing global debate and evaluates how this may impact biocontrol research and delivery. The current view is that publishing sequence data is sharing descriptive information and thus delivers benefit-sharing from its generation. However, if DSI is used in a product placed on the market, there is justification for benefit sharing.

The Nagoya Protocol actions the third objective of the Convention on Biological Diversity and provides a framework to effectively implement the fair and equitable sharing of benefits arising out of the use of genetic resources. This includes microorganisms used as biological control agents. Thus biological control practitioners must comply with access and benefit-sharing regulations that are implemented by countries providing microbial biological control agents. A review of best practices and guidance for the use and exchange of microorganisms used for biological control has been prepared by the IOBC Global Commission on Biological Control and Access and Benefit-Sharing to demonstrate commitment to comply with access and benefit-sharing requirements, and to reassure the international community that biological control is a very successful and environmentally safe pest management strategy that uses biological resources responsibly and sustainably. We propose that best practices include the following elements: collaboration to facilitate information exchange about the availability of microbial biological control agents and where they may be sourced; freely sharing available knowledge in databases about successes and failures; collaborative research with provider countries to develop capacity; and production technology transfer to provide economic opportunities. We recommend the use of model concept agreements for accessing microorganisms for scientific research and non-commercial release into nature where access and benefit-sharing regulations exist and where regulations are not restrictive or do not exist. We also recommend a model agreement for deposition of microbial biological control agents into culture collections.

The third objective of the Convention on Biological Diversity, the fair and equitable sharing of benefits arising out of the use of genetic resources was further developed when the Nagoya Protocol on Access and Benefit Sharing came into effect in 2014. Interpretation of how this agreement is being implemented is wide-ranging and there are implications for biological control. A survey of biological control workers indicated that while some countries have facilitated access to biological control genetic resources, requirements in other countries have impeded biological control implementation. There was consensus that benefits to provider countries should be in the form of supporting local research communities. There was also agreement that the free use and exchange of biological control genetic resources has provided benefits to the global community, including to both providers and recipients of the agents. It is recommended that consideration of the free use and exchange principal should be a key element of Access and Benefit Sharing measures for the future.

The Nagoya Protocol on Access and Benefit Sharing (ABS) was implemented to further develop the third objective of the Convention on Biological Diversity, the fair and equitable sharing of benefits arising out of the utilization of genetic resources. Interpretation of this agreement is wide-ranging and there is concern that if ABS measures are poorly implemented biological control and the resultant public good will be greatly impeded. The ethos of multilateral use and exchange of genetic resources used in classical biological control will be particularly affected. In the spirit of the fair and equitable sharing of benefits arising out of the utilization of genetic resources, we propose a simple practical solution in the form of an international agreement on the use and exchange of classical biological control genetic resources.

A 2-yr field experiment was conducted to explore the effects on weed growth and crop productivity of intercropping sweet corn with summer savory. Five cropping patterns were set up: sweet corn alone (16 seeds m⁻², in rows, 75 cm apart), summer savory alone (40 seeds m⁻², broadcasted), and three intercropping ratios of 75% sweet corn, 25% summer savory (75%C:25%S), 50%C:50%S, and 25%C:75%S, of plant densities used in respective monocultures. When intercropping, weed biomass decreased as the proportion of summer savory increased, with a reduction of 48%, 61%, and 70 % in 75%C:25%S, 50%C:50%S, and 25%C:75%S, respectively, compared to sweet corn alone. In parallel, sweet corn yield was higher under intercropping compared to its monoculture and increased as the proportion of summer savory decreased, with yield increases compared to corn monoculture of 38%, 32%, and 15% in the first year and 48%, 23%, and 14 % in the second year in 75%C:25%S, 50%C:50%S, and 25%C:75%S, respectively. However, the intercropping pattern had the opposite effect on summer savory yield, with a significant reduction in yield with an increasing ratio of sweet corn. Our results indicate that intercropping sweet corn with summer savory can increase both weed suppression and yield of sweet corn compared to crop monoculture.

Biological control (biocontrol) against invasive macrophytes is one of the longest standing programmes in South Africa, initiated in the 1970s against water hyacinth, Pontederia crassipes Mart. (Pontederiaceae). Since then, 15 agent species (13 insects, one mite and one pathogen) have been released against six weeds, most of which are floating macrophytes, with excellent levels of success. The release of the water hyacinth planthopper Megamelus scutellaris Berg (Hemiptera: Delphacidae) in particular, has improved biocontrol prospects for water hyacinth since 2018. In the last decade, however, a new suite of submerged and rooted emergent invasive macrophytes has been targeted. The first release against a submerged macrophyte in South Africa, and the first release against Brazilian waterweed, Egeria densa Planch. (Hydrocharitaceae), anywhere in the world, was achieved with the release of a leafmining fly, Hydrellia egeriae Rodrigues-Júnior, Mathis & Hauser (Diptera: Ephydridae). Yellow flag, Iris pseudacorus L. (Iridaceae) and Mexican waterlily, Nymphaea mexicana Zucc. (Nymphaeaceae), have also been targeted for biocontrol for the first time worldwide, and are in the early stages of agent development. Post-release evaluations, long term monitoring and controlled experiments have highlighted the need for a more holistic approach to managing aquatic invasive plants in South Africa, whose presence is largely driven by eutrophication, resulting in regime shifts between floating and submerged invaded states.