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Producers in the Western Cape province of South Africa are looking towards a push-pull strategy to reduce oviposition damage to plums by western flower thrips (WFT). White clover, Trifolium repens L., a favoured host plant of WFT, was investigated as a possible trap crop to provide the “pull” element. The attractiveness of collected volatiles of white clover flowers and of unopened (balloon stage) and open plum (Prunus salicina Lindl. cv. Sapphire) blossoms to WFT females was determined, using a Y-tube olfactometer. E-β-Farnesene, a known attractant for WFT, was included as positive control. Clover flower and open plum blossom volatiles exhibited statistically significant attraction of 69% and 71%, respectively, to WFT females. E-β-Farnesene and balloon stage plum blossom volatiles attracted 63% and 65% of WFT, respectively. When compared directly, 69% of WFT females chose the arm with the plum blossom volatiles over the clover flower volatiles. The clear preference shown by WFT for plum blossom volatiles indicates the use of a semiochemical to deter WFT from the plum blossoms would be required to enhance the efficacy of white clover as a trap crop in a push-pull strategy. [ABSTRACT FROM AUTHOR]

Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae) is an exotic ladybird, first recorded in South Africa in 2004, where it was introduced factitiously. In this study the seasonal occurrence of H. axiridis and other coccinellids were monitored in four vineyards and the adjacent windbreaks over three growing seasons in the Western Cape Province, South Africa. Harmonia axyridis made up the highest mean number of coccinellids collected per site over the collecting period, followed by Hippodamia variegata, Cheilomenes lunata, Exochomus flavipes and Micraspis sp. No indigenous parasitoids were observed attacking H. axyridis. The numbers of H. axyridis on the vines were negatively correlated with temperature but positively with rainfall. In view of the migration of H. axyridis from the vines in December, they appear not to pose any risk of contaminating grapes during harvest and tainting wine as most wine grapes are harvested from January onwards. [ABSTRACT FROM AUTHOR]

Grapevine leafroll disease is widely accepted to be the most damaging grapevine virus disease in South Africa. The current industry strategy to limit leafroll infection in new vineyards includes treating newly planted grapevines with a systemic insecticide like imidacloprid and rogueing all grapevines that exhibit leafroll symptoms. A tendency by some producers to eschew rogueing and rely solely on imidacloprid applications to control vine mealybug and so protect new vineyards from leafroll infection gave rise to this study. Two bioassays were conducted to determine if Planococcus ficus (Signoret) nymphs can transmit grapevine leafroll-associated virus 3 (GLRaV-3) to potted indicator grapevines treated with imidacloprid applied through the soil five months before exposure to viruliferous mealybugs. Ten of 21 leafroll-free grapevines treated with imidacloprid tested positive for GLRaV-3 seven to eight weeks after being exposed to viruliferous first- and second-instar P. ficus nymphs. This means that the systemic applications of imidacloprid to newly planted, virus-free vineyards will not necessarily protect the vines from GLRaV-3 if they become infested by viruliferous vine mealybugs, although the insecticide provides effective mealybug control and helps to prevent the secondary spread of leafroll infection in these vineyards. To control the spread of leafroll virus to newly planted, leafroll-free vineyards, all grapevines that serve as sources of infection should be removed. Where this is not feasible, vectors should be monitored and controlled rigorously in infested and disease-free vineyards alike, while all infected grapevines should be removed from new vineyards as they begin to develop leafroll symptoms. [ABSTRACT FROM AUTHOR]

Western flower thrips (WFT), Frankliniella occidentalis (Pergande), on table grapes in the Hex River Valley was monitored and its seasonal occurrence was investigated over three seasons. At the start of the growing season, blue sticky traps suspended from the overhead trellising structure to hang outside and under the vine canopy yielded similar WFT numbers. However, as the season progressed and vine canopies became denser, more WFT were caught on traps hanging outside the canopy in full sunlight than on traps hanging under the vine canopy. Female WFT became active in the vineyards after bud break and their numbers increased rapidly during flowering, peaking between October and January and declining rapidly thereafter. WFT were present in pre-bloom inflorescences and shoot tips before flowering, which means that monitoring should commence as soon as the first inflorescences are formed. No consistent relationship was found between economic damage at harvest and WFT numbers on sticky traps during flowering and berry set. Sticky traps should therefore only be used to determine the presence or absence of WFT in vineyards. The trap results suggest that there could be a constant influx of thrips into vineyards from alternate host plants in the surrounding area during the growing season. In vineyards with a history of WFT damage, control measures should be considered as soon as WFT is detected in order to prevent halo spot damage. [ABSTRACT FROM AUTHOR]

The genus Argopistes (Chrysomelidae: Alticini) is the only group of flea beetles specialized in plant hosts in the family Oleaceae. In southern Africa, Argopistes are often found feeding on African Wild Olive ( Olea europaea subsp. cuspidata ) and European cultivated olive ( O. e. subsp. europaea ), and heavy infestations can be devastating to mature trees and compromise the development of young trees. Despite their negative agricultural impact, African Argopistes are an understudied group for which no genetic data were available. We assessed the species diversity of olive flea beetles in the Western Cape province of South Africa, the largest olive-producing region in sub-Saharan Africa, by collecting adult specimens on wild and cultivated olive trees between 2015 and 2017. Argopistes sexvittatus Bryant, 1922 ( n = 289) dominated at all sampling sites, and Argopistes capensis Bryant, 1944 ( n = 2) was found only once. Argopistes oleae Bryant, 1922, a third species previously reported in the region, was not found. The complete mitogenomes of one A. capensis and two A. sexvittatus (striped and black morphotypes) individuals were sequenced for phylogenetic reconstruction in the context of other 64 species. The two olive flea beetle species form a monophyletic clade with other Argopistes , supporting the hypothesis that the exclusive feeding habit on Oleaceae is an evolutionary adaptation in this genus.

Anchonocranus oleae Marshall (Coleoptera: Curculionidae) is a seed-feeding weevil native to southern Africa; its larvae are known to develop in the fruits of the African Wild Olive and, more rarely, cultivated olives. The species has been mainly found in the Western Cape province of South Africa, but it has remained in relative obscurity because it does not seem to represent a current threat to commercial olive production. As part of an ongoing effort to produce baseline genetic data for olive-associated entomofauna in South Africa, we generated reference DNA barcodes for A. oleae collected from wild and cultivated olives and sequenced its mitogenome for assessment of the phylogenetic position of the species in the family Curculionidae. The mitochondrial phylogeny estimate indicated that A. oleae shares a common ancestor with Elaidobius (tribe Derelomini), but a definite and close relationship to this tribe and the precise tribal placement of A. oleae in the subfamily Curculioninae could not be inferred due to the lack of representative mitogenomes of other relevant curculionine tribes and genera. This study will assist future work on the DNA-based species identification, genetic diversity, and phylogenetic position of the genus Anchonocranus and related taxa.

Olive lace bugs (Hemiptera: Tingidae) are small sap-sucking insects that feed on wild and cultivated Olea europaea . The diversity of olive lace bug species in South Africa, the most important olive producer on the continent, has been incompletely surveyed. Adult specimens were collected in the Western Cape province for morphological and DNA-based species identification, and sequencing of complete mitogenomes. Cysteochila lineata , Plerochila australis , Neoplerochila paliatseasi and Neoplerochila sp. were found at 12 sites. Intra- and interspecific genetic divergences and phylogenetic clustering in 30 species in 18 genera of Tingidae using new and publicly available DNA barcodes showed high levels of congruity between taxonomic and genetic data. The phylogenetic position of the four species found in South Africa was inferred using new and available mitogenomes of Tingidae. Notably, olive lace bugs formed a cluster of closely related species. However, Cysteochila was non-monophyletic as C. lineata was recovered as a sister species to P. australis whereas Cysteochila chiniana , the other representative of the genus, was grouped with Trachypeplus jacobsoni and Tingis cardui in a different cluster. This result suggests that feeding on O. europaea may have a common origin in Tingidae and warrants future research on potential evolutionary adaptations of olive lace bugs to this plant host.

Olive lace bugs are small phytophagous Hemipteran insects known to cause agricultural losses in olive production in South Africa. Plerochila australis (Distant, 1904) has been reported as the species responsible for damage to olive trees; however, the diversity of olive lace bug species in the region has lacked attention. Adult olive lace bugs were collected incidentally from wild and cultivated olive trees in the Western Cape Province, and identified as P. australis and Neoplerochila paliatseasi (Rodrigues, 1981). The complete mitochondrial genome of a representative specimen of N. paliatseasi was sequenced, and used for comparative mitogenomics and phylogenetic reconstruction within the family. Furthermore, the value of DNA barcodes for species identification in Tingidae was assessed using genetic clustering and estimates of genetic divergence. The patterns of genetic clustering and genetic divergence of COI sequences supported the morphological identification of N. paliatseasi, and the utility of DNA barcoding methods in Tingidae. The complete mitogenome sequence had the typical Metazoan gene content and order, including 13 PCGs, 22 tRNAs, two rRNAs, and an AT-rich non-coding region. A+T content was high, as commonly found in Tingidae. The phylogenetic reconstruction recovered Agramma hupehanum (Drake Maa 1954) as basal to Tingini, and as a sister species to N. paliatseasi. Stephanitis Stål 1873 and Corythucha Stål 1873 were monophyletic, but Metasalis populi (Takeya 1932) was not recovered as sister to Tingis cardui (Linnaeus 1746), as expected. The mitochondrial phylogeny of the family Tingidae has been recovered inconsistently across different studies, possibly due to sequence heterogeneity and high mutation rates. Species diversity of olive lace bugs in South Africa was previously underestimated. The presence of P. australis was confirmed in both wild and cultivated olives, and N. paliatseasi is reported in cultivated olives for the first time. These results warrant further investigation on the diversity and distribution of olive lace bugs in the Western Cape to inform pest control strategies.

Wild and cultivated olives harbor and share a diversity of insects, some of which are considered agricultural pests, such as the olive fruit fly. The assemblage of olive-associated parasitoids and seed wasps is rich and specialized in sub-Saharan Africa, with native species possibly coevolving with their hosts. Although historical entomological surveys reported on the diversity of olive wasp species in the Western Cape Province of South Africa, no comprehensive study has been performed in the region in the molecular era. In this study, a dual approach combining morphological and DNA-based methods was used for the identification of adult specimens reared from olive fruits. Four species of Braconidae and six species of Chalcidoidea were identified, and DNA barcoding methodologies were used to investigate conspecificity among individuals, based on randomly selected representative specimens. Morphological identifications were congruent with DNA data, as NJ and ML trees correctly placed the sequences for each species either at the genus or species level, depending on the available taxa coverage, and genetic distances strongly supported conspecificity. No clear evidence of cryptic diversity was found. Overall seed infestation and parasitism rates were higher in wild olives compared to cultivated olives, and highest for Eupelmus spermophilus and Utetes africanus . These results can be used for early DNA-based detection of wasp larvae in olives and to further investigate the biology and ecology of these species.

1-(2,6-Difluorobenzyl)-3-[(2R)-amino-2-phenethyl]-5-(2-fluoro-3-methoxyphenyl)-6-methyluracil (6), a potent and orally active antagonist of the human gonadotropin-releasing hormone receptor, exists as a pair of atropisomers in solution, which was detected by NMR spectroscopy, and separable by HPLC. In addition to a (R)-configured benzylamine, there is a second stereogenic element due to the presence of a chiral axis between the substituted 5-phenyl group and the uracil core. The rate constant of the interconversion (k = 5.07 x 10(-5) s(-1)) of these two atropisomers was determined by proton NMR analysis of a diastereoisomer-enriched sample in aqueous solution at 25 degrees C, and the corresponding Gibbs free energy DeltaG(#) of rotation barrier (97.4 kJ mol(-1)) was calculated using the Eyring equation. The diastereoisomer half-life at physiological temperature (37 degrees C) in aqueous media was estimated to be about 46 min., (Copyright 2005 Wiley-Liss, Inc.)