The wheat curl mite (Aceria tosichella, Prostigmata: Eriophyidae) could establish in South Africa

Biological invasions by agricultural pests can have serious negative impacts, including decreases in crop yield and economic losses. The MT-1 and MT-8 genotypes of the wheat curl mite (Aceria tosichella) (hereafter ‘WCM’ refers to these two genotypes) are globally distributed pests of wheat and maize that have not been recorded in South Africa. This study examined whether WCM could be introduced to, and establish in, South Africa. Trade data were used to determine whether viable pathways of introduction are present. A species distribution model and data on wheat and maize production were used to determine whether WCM could establish where its hosts are grown. WCM is most likely to be introduced to South Africa as a contaminant of maize from Argentina, Brazil, Uruguay, and USA; on live plant imports from China and Germany; and on seed imports from Brazil and Australia. Some of these pathways are not currently prominent, but could increase in the future. Parts of South Africa were predicted by the species distribution model to be climatically suitable for WCM, and within some of these areas the host crops are grown. Therefore, if WCM is introduced, it is likely to establish and cause extensive damage to agriculture. We recommend that WCM be considered for inclusion in South Africa’s import conditions as a quarantine pest.The South African Department of Environment, Forestry and Fisheries (DEFF)https://www.tandfonline.com/loi/tafz202022-03-09hj2022Zoology and Entomolog

A survey of scale insects (Sternorryncha: Coccoidea) occurring on table grapes in South Africa

Increasing international trade and tourism have led to an increase in the introduction of exotic pests that pose a considerable economic threat to the agro-ecosystems of importing countries. Scale insects (Sternorryncha: Coccoidea) may be contaminants of export consignments from the South African deciduous fruit industry to the European Union, Israel, United Kingdom and the United States, for example. Infestations of immature scale insects found on South African fruit destined for export have resulted in increasing rates of rejection of such consignments. To identify the risk posed by scale insect species listed as phytosanitary pests on table grapes to the abovementioned importing countries, a field survey was undertaken in 2004–2005 in vineyards throughout all grape-producing regions in South Africa. Coccoidea species found during the current field survey were Planococcus ficus (Signoret), Pseudococcus longispinus (Targioni Tozzetti), Coccus hesperidum L. and Nipaecoccus viridis (Newstead). With the exception of Pl. ficus, which has only been collected from Vitis vinifera (Vitaceae) and Ficus carica (Moraceae) in South Africa, these species are polyphagous and have a wide host range. None of the scale insect species found to occur in vineyards in South Africa pose a phytosanitary risk to countries where fruit are exported except for Ferrisia malvastra (McDaniel) and N. viridis that have not been recorded in the USA. All scale insects previously found in vineyards in South Africa are listed and their phytosanitary status discussed. The results of the survey show that the risk of exporting scale insect pests of phytosanitary importance on table grapes from South Africa is limited.Keywords: mealybugs, Sternorrhyncha: Coccoidea, post harvest pests, scale insects, table grapes, South Afric

Complex patterns of global spread in invasive insects: eco-evolutionary and management consequences

The advent of simple and affordable tools for molecular identification of novel insect invaders and assessment of population diversity has changed the face of invasion biology in recent years. The widespread application of these tools has brought with it an emerging understanding that patterns in biogeography, introduction history and subsequent movement and spread of many invasive alien insects are far more complex than previously thought. We reviewed the literature and found that for a number of invasive insects, there is strong and growing evidence that multiple introductions, complex global movement, and population admixture in the invaded range are commonplace. Additionally, historical paradigms related to species and strain identities and origins of common invaders are in many cases being challenged. This has major consequences for our understanding of basic biology and ecology of invasive insects and impacts quarantine, management and biocontrol programs. In addition, we found that founder effects rarely limit fitness in invasive insects and may benefit populations (by purging harmful alleles or increasing additive genetic variance). Also, while phenotypic plasticity appears important post-establishment, genetic diversity in invasive insects is often higher than expected and increases over time via multiple introductions. Further, connectivity among disjunct regions of global invasive ranges is generally far higher than expected and is often asymmetric, with some populations contributing disproportionately to global spread. We argue that the role of connectivity in driving the ecology and evolution of introduced species with multiple invasive ranges has been historically underestimated and that such species are often best understood in a global context

A Survey of Scale Insects (Sternorryncha: Coccoidea) Occurring on Table Grapes in South Africa

Increasing international trade and tourism have led to an increase in the introduction of exotic pests that pose a considerable economic threat to the agro-ecosystems of importing countries. Scale insects (Sternorryncha: Coccoidea) may be contaminants of export consignments from the South African deciduous fruit industry to the European Union, Israel, United Kingdom and the United States, for example. Infestations of immature scale insects found on South African fruit destined for export have resulted in increasing rates of rejection of such consignments. To identify the risk posed by scale insect species listed as phytosanitary pests on table grapes to the abovementioned importing countries, a field survey was undertaken in 2004–2005 in vineyards throughout all grape-producing regions in South Africa. Coccoidea species found during the current field survey were Planococcus ficus (Signoret), Pseudococcus longispinus (Targioni Tozzetti), Coccus hesperidum L. and Nipaecoccus viridis (Newstead). With the exception of Pl. ficus, which has only been collected from Vitis vinifera (Vitaceae) and Ficus carica (Moraceae) in South Africa, these species are polyphagous and have a wide host range. None of the scale insect species found to occur in vineyards in South Africa pose a phytosanitary risk to countries where fruit are exported except for Ferrisia malvastra (McDaniel) and N. viridis that have not been recorded in the USA. All scale insects previously found in vineyards in South Africa are listed and their phytosanitary status discussed. The results of the survey show that the risk of exporting scale insect pests of phytosanitary importance on table grapes from South Africa is limited

Agistemus collyerae Gonzalez-Rodrigues 1963

<i>Agistemus collyerae</i> González-Rodrigues (Figs. 1-8) <p> <i>Agistemus collyerae</i> González-Rodrigues, 1963: 349; 1965: 34; Fan & Zhang, 2005: 41; Ferreira <i>et al.</i>, 2007: 56; Rahmani <i>et al.</i>, 2012: 105; Beyzavi <i>et al.</i>, 2013: 397; Yeşilayer and Çobanoğlu, 2013: 96; Fan <i>et al.</i>, 2016: 31. <i>Zetzellia collyerae</i> (González-Rodrigues) Wood, 1967: 131.</p> <p>Material examined — Eight females, two males and one deutonymph from grapevine, Wellington, 16 April 2015; one female from Malmesbury, 16 March 2015; and one female from Riebeek West, 17 April 2015. All these locations are within the Western Cape Province, South Africa. Specimens are deposited in the National Collection of Arachnida (NCA) in Pretoria, South Africa. Measurements are given in Table 1. Other features are described below.</p> <p> Diagnosis (Female) — Dorsal shields reticulated, setae <i>c1</i> and <i>d1</i> shorter than distances to setae <i>d1</i> and <i>e1</i>, respectively; setal formulae of genua 3-0-0-0, femora 4-4-2-2 and tibiae 6-6-6-4, coxa IV with one seta.</p>Published as part of <i>Saccaggi, Davina L. & Ueckermann, Edward A., 2018, Agistemus collyerae (Acari: Trombidiformes: Stigmaeidae) in South Africa: first record, introduction pathways and a re-description including additional life stages, pp. 116-130 in Acarologia 58 (1)</i> on page 118, DOI: 10.24349/acarologia/20184235, <a href="http://zenodo.org/record/4487453">http://zenodo.org/record/4487453</a&gt

Agistemus collyerae (Acari: Trombidiformes: Stigmaeidae) in South Africa: first record, introduction pathways and a re-description including additional life stages

Saccaggi, Davina L., Ueckermann, Edward A. (2018): Agistemus collyerae (Acari: Trombidiformes: Stigmaeidae) in South Africa: first record, introduction pathways and a re-description including additional life stages. Acarologia 58 (1): 116-130, DOI: 10.24349/acarologia/2018423

Contaminant organisms recorded on plant product imports to South Africa 1994–2019

CITATION: Saccaggi, D. L. et al. 2021. Contaminant organisms recorded on plant product imports to South Africa 1994–2019. Scientific Data, 8:83, doi:10.1038/s41597-021-00869-z.The original publication is available at https://www.nature.com/sdataBiosecurity interception records are crucial data underlying efforts to predict and manage pest and pathogen introductions. Here we present a dataset containing information on imported plant products inspected by the South African Department of Agriculture’s laboratories between 1994 and 2019 and the contaminant organisms found on them. Samples were received from border inspectors as either propagation material (e.g. plants) or material for immediate use (e.g. fruit). Material for immediate use was further divided into two sample categories, depending on if contaminants were seen/suspected by the border official or not: intervention or audit samples. The final dataset consists of 25,279 records, of which 30% tested positive (i.e. had at least one contaminant) and 13% had multiple contaminants. Of the 13,731 recorded contaminants, fungi (41%), mites (37%) and insects (19%) were most common. This dataset provides insight into the suite of taxa transported along the plant import pathway and provides an important resource for analyses of contaminant organisms in international trade, which can inform strategies for risk assessment, pathway management and biosecurity protocols.Publisher's versio

The wheat curl mite (Aceria tosichella, Prostigmata: Eriophyidae) could establish in South Africa

Biological invasions by agricultural pests can have serious negative impacts, including decreases in crop yield and economic losses. The MT-1 and MT-8 genotypes of the wheat curl mite (Aceria tosichella) (hereafter ‘WCM’ refers to these two genotypes) are globally distributed pests of wheat and maize that have not been recorded in South Africa. This study examined whether WCM could be introduced to, and establish in, South Africa. Trade data were used to determine whether viable pathways of introduction are present. A species distribution model and data on wheat and maize production were used to determine whether WCM could establish where its hosts are grown. WCM is most likely to be introduced to South Africa as a contaminant of maize from Argentina, Brazil, Uruguay, and USA; on live plant imports from China and Germany; and on seed imports from Brazil and Australia. Some of these pathways are not currently prominent, but could increase in the future. Parts of South Africa were predicted by the species distribution model to be climatically suitable for WCM, and within some of these areas the host crops are grown. Therefore, if WCM is introduced, it is likely to establish and cause extensive damage to agriculture. We recommend that WCM be considered for inclusion in South Africa’s import conditions as a quarantine pest. Keywords: agricultural pests, alien species, biosecurity, biological invasions, pathways of introduction, species distribution modelling

Towards Solving the “Colomerus vitis Conundrum”: Genetic Evidence Reveals a Complex of Highly Diverged Groups with Little Morphological Differentiation

Colomerus vitis is a pest of grapevine worldwide that includes three strains recognised by plant symptoms (bud, erineum, and leaf curl), which could represent cryptic species. We approached this long-standing question by integrating genetic and morphological methods. COI sequences of mites from South Africa and other countries showed five phylogenetic groups (G1 to G5) with intergroup p-distances up to 23% and intragroup divergence lower than 2%. The three groups found in South Africa (G1, G2, and G3) were screened from a variety of grapevine samples using a novel multiplex PCR method. Only G1 and G3 were significantly associated with erinea and buds, respectively, and the three groups were frequently co-present in the same plant sample. Cryo-SEM showed adults with five- and six-rayed empodia, variable microtubercle shape, and prodorsal shield patterns. Specimens with six-rayed empodia and a smooth prodorsal shield were more often associated with buds, while specimens from erinea were variable. These results support the genetic evidence in that particular groups or morphotypes are not associated exclusively with specific plant niches. We propose that C. vitis is a complex of at least five genetically distinct but morphologically similar species, and that no one species can be assigned to a particular grapevine symptom