Prioritizing plant parasitic nematode and mollusca species likely to be introduced and threaten agriculture, forestry, and biodiversity in Zambia: A horizon scanning approach

Introduction of invasive alien species (quarantine pests) through intentional or unintentional human-mediated activities has caused enormous economic and environmental impacts necessitating forward planning to identify, prioritise, and prevent their introduction. Using CABI’s Horizon Scanning Tool, 26 mollusca and 199 plant parasitic nematode (PPN) species not reported as present in Zambia were identified. The list was refined to focus on species affecting Zambia’s important value chains resulting in final lists of 130 PPN and 20 mollusca species that were subjected to risk assessment using agreed guidelines. The possible highest and lowest overall risk scores expected were 250 and 2 respectively. The highest overall score was 140 obtained for Arion hortensis, Cornu aspersum, and Deroceras reticulatumi (mollusca) and Pratylenchus penetrans, P. thornei, and Rotylenchulus reniformis (PPN) and the lowest for mollusca was 10, recorded for Arion ater and for PPN, three, recorded by for Peltamigratus luci. Nine (45%; N=20) and 58 (45%; N=130) of the assessed mollusca and PPN species respectively, attained a suggested minimum overall risk score of 54 necessary for instituting phytosanitary measures that limit pest introduction. All assessed mollusca species were likely be introduced through the contaminant and stowaway pathways. The majority (54%; n=70; N=130) of the PPN species were likely to be introduced via contaminant or stowaway pathways, 7 (5%) and 53 (41%) solely as contaminants and stowaways, respectively. Eleven of the PPN are known vectors of pathogenic organisms. Five of the vectored viruses recorded overall risk scores above 54 and included Tomato ringspot virus (105), Tobacco rattle virus (90), Pea early-browning virus (72), Tomato black ring virus (70), and Arabis mosaic virus (60). The assessed PPN were also vectored by insects (order Coleoptera and families, Cerambycidae, Curculionidae, and Dryophthoridae), three of which recorded overall risk scores above the suggested minimum, Monochamus galloprovincialis (60) Orthotomicus erosus (100), and Rhynchophorus palmarum (72). Actions to limit introduction were also suggested for pathogenic organism vectored by PPN and vectors of PPN. The information from this assessment will guide a number of interventions aimed at developing strategies that prevent introduction and spread of assessed mollusca and PPN specie

Rapid risk assessment of plant pathogenic bacteria and protists likely to threaten agriculture, biodiversity and forestry in Zambia

A prioritisation study was conducted to address the lack of adequate information about potential pests likely to be introduced in Zambia and become invasive. The study was conducted by subject matter experts from relevant institutions in and outside Zambia. Although this study focused on major pest categories, this paper only addresses bacteria and Protista. A list of 306 bacterial and 10 Protista species adjudged to affect plants was generated using CABI’s Horizon Scanning Tool. The 316 (total) pest species were refined to focus on pests that affect value chains important to Zambia’s economy. This resulted in a final list of 133 bacteria and eight Protista. Four additional bacteria species considered of phytosanitary interest were added and all 137 bacteria and eight Protista species were subjected to a rapid risk assessment using agreed guidelines. Vectors reported to transmit any of the pathogenic organisms were also subjected to a risk assessment. A proportion of 53% (n = 77 of 145) comprising 73 bacteria and four Protista species were reported as present in Africa. Of these, 42 (57%, n = 73) bacterial species and two (n=4) Protista species were reported in neighbouring countries. Considering a cut-off of 54, the highest scoring pests were 40 bacteria (highest score of 140) and three Protista (highest score of 125). Three actions were suggested for high-scoring pests, a detection surveillance, a pest-initiated pest risk analysis (PRA) or a detection surveillance followed by pest-initiated PRA. A “no action” was suggested where the risk was very low although, for some pathogenic organisms, a “no action” was followed by periodic monitoring. This information will contribute towards proactive prevention and management of biological invasions

Rapid Risk Assessment of plant pathogenic bacteria and protists likely to threaten agriculture, biodiversity and forestry in Zambia

A prioritisation study was conducted to address the lack of adequate information about potential pests likely to be introduced in Zambia and become invasive. The study was conducted by subject matter experts from relevant institutions in and outside Zambia. Although this study focussed on major pest categories, this paper only addresses bacteria and Protista. A list of 306 bacterial and 10 Protista species adjudged to affect plants was generated using CABI’s Horizon Scanning Tool. The 316 (total) pest species were refined to focus on pests that affect value chains important to Zambia’s economy. This resulted in a final list of 133 bacteria and 8 Protista. Four additional bacteria species considered of phytosanitary interest were added and all 137 bacteria and 8 Protista species were subjected to a rapid risk assessment using agreed guidelines. Vectors reported to transmit any of the pathogenic organisms were also subjected to a risk assessment. A proportion of 53% (n=77 of 145) comprising 73 bacteria and 4 Protista species were reported as present in Africa. Of these, 42 (57%, n=73) bacterial species and 2 (n=4) Protista species were reported in neighbouring countries. Considering a cut-off of 54, the highest scoring pests were 40 bacteria (highest score of 140) and three Protista (highest score of 125). Three actions were suggested for high-scoring pests, a detection surveillance, a pest-initiated pest risk analysis (PRA) or a detection surveillance followed by pest-initiated PRA. A “no action” was suggested where the risk was very low although for some pathogenic organisms, a “no action” was followed by periodic monitoring. This information will contribute towards proactive prevention and management of biological invasions