Prioritization of invasive alien species with the potential to threaten agriculture and biodiversity in Kenya through horizon scanning

Invasive alien species (IAS) rank among the most significant drivers of species extinction and ecosystem degradation resulting in significant impacts on socio-economic development. The recent exponential spread of IAS in most of Africa is attributed to poor border biosecurity due to porous borders that have failed to prevent initial introductions. In addition, countries lack adequate information about potential invasions and have limited capacity to reduce the risk of invasions. Horizon scanning is an approach that prioritises the risks of potential IAS through rapid assessments. A group of 28 subject matter experts used an adapted methodology to assess 1700 potential IAS on a 5-point scale for the likelihood of entry and establishment, potential socio-economic impact, and impact on biodiversity. The individual scores were combined to rank the species according to their overall potential risk for the country. Confidence in individual and overall scores was recorded on a 3-point scale. This resulted in a priority list of 120 potential IAS (70 arthropods, 9 nematodes, 15 bacteria, 19 fungi/chromist, 1 viroid, and 6 viruses). Options for risk mitigation such as full pest risk analysis and detection surveys were suggested for prioritised species while species for which no immediate action was suggested, were added to the plant health risk register and a recommendation was made to regularly monitor the change in risk. By prioritising risks, horizon scanning guides resource allocation to interventions that are most likely to reduce risk and is very useful to National Plant Protection Organisations and other relevant stakeholders

Microbial control of the greenhouse whitefly (Trialeurodes vaporariorum) using a standardised bioassay method

Greenhouse whitefly (Trialeurodes vaporariorum) are a major insect pest throughout Europe, causing damage to >300 plant species by consuming sap, secreting honeydew and transmitting plant viruses (Capinera, 2001). The most effective microbial pesticide against T. vaporariorum are entomopathogenic fungi and a fundamental step in identifying entomopathogenic fungi with potential to control T. vaporariorum is to determine their pathogenicity. In his study, eighteen different entomopathogenic fungal isolates were used in laboratory based mortality bioassays to assess pathogenicity against third instar greenhouse whitefly nymphs. Beauveria, Cordyceps, Akanthomyces and Metarhizium species were taken from commercially available biopesticides and the USDA Agricultural Research Service collection. A uniform coverage of solution was applied to the target area using a novel, calibrated spray tower. All isolates were pathogenic to the T. vaporariorum population tested. However, there were significant differences in total mortality and the mortality rates caused by each isolate. Whitefly mortality ranged 8-89% with half of the isolates resulting in <40% T. vaporariorum population mortality. The methods employed in this study could be utilised in the screening of isolates for microbial control of T. vaporariorum and other phloem feeding pests. This assay approach is a simple and affordable method to assess entomopathogenic fungi for the control of T. vaporariorum. References: Capinera, J. L. (2001). Order Homoptera—Aphids, Leaf- and Planthoppers, Psyllids and Whiteflies. Handbook of Vegetable Pests, 279–346. https://doi.org/10.1016/B978-012158861-8/50009-

Screening potential entomopathogenic fungi for the control of the greenhouse whitefly (Trialeurodes vaporariorum)

Greenhouse whitefly (Trialeurodes vaporariorum) (GHWF) are a globally important pest, causing significant damage to >250 plant species by consuming sap, secreting honeydew and transmitting viral plant diseases. Entomopathogenic fungi (EPF) are being developed for biological control of whitefly in integrated pest control strategies which include reducing chemical applications and increasing the use of sustainable alternatives. Whitefly have piercing-sucking mouthparts, therefore EPF are the most promising microbial natural enemies to be exploited for whitefly control as they can infect directly through the integument. Temperature conditions within temperate greenhouses vary from 10 to 35°C which presents a challenging abiotic environment for EPF and impacts greatly on pest mortality. EPF used as biological control for GHWF need to be highly virulent and work across a range of temperatures, therefore, we compared temperature profiles of eighteen EPF originating from temperate, subtropical or tropical regions. In vitro germination, growth and spore production experiments were conducted as well as an investigation into the pathogenicity of these EPF isolates to third instar greenhouse whitefly using a novel standardised bioassay design, with a bespoke benchtop sprayer. Using the data collected, we were able to rank isolates based on growth rate, germination and spore production at a range of temperatures to select those with distinctive temperature profiles. The methods employed in this study could be utilised in the selection of isolates for microbial control of whitefly and in particular, selecting pathogens to be co-applied with the potential to improve virulence or cause an increase in workable climatic conditions

Assessing Biopesticides for Managing Fall Armyworm <i>(Spodoptera frugiperda)</i> in Africa

In the last 6 years, the fall armyworm (FAW) has spread to the Middle East, Asia and the Pacific, as well as most nations in Africa. This case focuses on sub-Saharan Africa, where more than 300 million people depend on maize, as a staple crop, and the preferred host plant of FAW. Synthetic pesticides against FAW are not always used safely or effectively. Here we assess work on the current state of knowledge on biopesticides for FAW in Africa, document information gaps, including compatibility with other recommended management practices, and list biopesticides that are a priority for research, development and promotion. The case incorporates two earlier assessments, one from 2018 on the status of biopesticide options against FAW, and one from 2020 that led to recommendations for field trials for eight active ingredients – Bacillus thuringiensis subsp. kurstaki , Beauveria bassiana , Dysphania ambrosioides , ethyl palmitate, eugenol, garlic extract, Metarhizium anisopliae and Steinernema spp. Field trials for some of these pesticides have now been carried out but other trials are still ongoing. The team also recommended bioassays to determine the effectiveness of four active ingredients against FAW – GS-omega/kappa-Hx-tx-Hv1a, canola oil, capsaicin and D-limonene. Information © CAB International 202

Diversity and distribution of entomopathogenic nematodes in Chile

A systematic programme of surveys for entomopathogenic nematodes (EPN) was done in Chile between 2006 and 2008. The survey spanned the principal ecosystems of mainland Chile as well as a number of islands, and covered a wide range of habitats including the Atacama Desert, Andean Altiplano, temperate rainforests and subpolar territory. Nearly 1400 soil samples were collected, of which 7 % were positive for EPN. Of 101 EPN isolates obtained, 94 were Steinernema spp. and seven were Heterorhabditis sp. Of the 94 Steinernema isolates, 39 were identified as Steinernema feltiae, the remainder being distributed between two new species, S. unicornum (52 records) and S. australe (three records). The Heterorhabditis isolates, all designated as Heterorhabditis sp.1, are referred to herein as H. cf. safricana. Steinernema feltiae and S. unicornum were collected predominately in the south of Chile and were obtained from a range of habitats, including forests, open grassland, montane soils and coastal zones; neither species was recovered from the far north of the country (viz., desert soils in the Norte Grande region). Steinernema australe was found in only three soil samples, all from humid, cool, coastal localities in the south. Heterorhabditis cf. safricana was recovered from the northern regions, with most isolates found in or on the periphery of the Atacama Desert; they were not recovered from cooler, more humid regions of southern Chile. Molecular information indicated there were two subgroups of both S. unicornum and S. feltiae, with a geographical, intraspecific split of subgroups between the most southerly and the more central survey zones. All isolates were collected by ex situ baiting with waxmoth larvae and the natural hosts are unknown

PolStar - An Explorer-Class FUV Spectropolarimetry Mission to Map the Environments of Massive Stars

International audiencePolStar is an Explorer-class far ultraviolet (FUV) spectropolarimetry mission designed to target massive stars and their environments. PolStar will take advantage of resonance lines only available in the FUV to measure for the first time the magnetic and wind environment around massive stars to constrain models of rotation and mass loss