Inter-cultivar pollination is essential for high-quality blueberry production, as it increases both fruit set and fruit size. In commercial orchards, this is often achieved by alternating blueberry cultivars across rows, based on the assumption that honey bees move pollen between cultivars by switching rows. However, honey bee movement patterns in orchards remain understudied, and it is unclear whether this design effectively supports inter-cultivar pollination. To address this knowledge gap in a South African context, we determined the frequency of honey bee foraging movements across versus along blueberry rows. While observing a focal foraging honey bee, we recorded the number of flowers visited on a blueberry bush, whether the bee transitioned between plants, and whether these transitions occurred along or across a row. Our observations revealed that honey bees predominantly foraged along rows (over 90% of transitions), rarely switching across rows. Consequently, alternating cultivars by row is likely to limit inter-cultivar pollination in South African blueberry orchards, potentially reducing yield. We recommend interplanting compatible cultivars within rows to enhance pollen transfer and fruit production. Given that honey bees are used globally as the primary managed pollinator, similar movement patterns may occur in other regions, suggesting that modifying planting designs could increase yields of blueberries and other bee-pollinated crops with minimal additional cost. However, these findings are based on observations from a single commercial orchard and should be replicated across multiple farms and environmental conditions to determine the generality of these patterns.

Chnootriba hirta (Thunberg) feeds on the foliage of several native Solanum species in South Africa, with occasional associations with introduced congeners. In comparing the beetle’s performance and preferences across three exotic and one native Solanum species, this study produced an unusual result. During adult and larval no-choice tests, the exotic Solanum americanum Miller proved the most suitable host plant, followed by the native S. dasyphyllum Schumacher and Thonning, with the exotic cultivated S. lycopersicum Linnaeus (tomato) proving marginally suitable. In contrast, the exotic S. viarum Dunal, an invasive weed in the southern USA, did not support feeding and development. During adult choice tests, C. hirta did not discriminate between S. americanum and S. dasyphyllum, but avoided S. lycopersicum. These differences in host-plant suitability may relate, in part, to the presence of glandular leaf trichomes, renowned anti-herbivore defences, on S. viarum and S. lycopersicum, but not on S. americanum or S. dasyphyllum. Since C. hirta, a broadly oligophagous herbivore within the native Solanum insect community, cannot exploit S. viarum, the plant may well expand its range in South Africa due to an escape from insect herbivory.

A survey of the coconut bug, Pseudotheraptus wayi damage on litchi fruits was conducted on eight farms in the Limpopo and Mpumalanga provinces to assess infestation levels. Ten Mauritius litchi trees per study site/farm were randomly selected and monitored in November and December 2023. Fallen/aborted immature fruits were collected from the mature litchi trees. A total of 11 083 fruits were collected and inspected for coconut bug damage. A total of 5 262 fruits were found to be damaged by coconut bugs. The results of the predicted percentage means from the GLMM modelling of the damage caused by the coconut bugs ranged from 19.71% to 62.41% on aborted fruit from farms, with 33.77% and 57.53% in Limpopo and Mpumalanga provinces, respectively. An indication that the coconut bug caused an average annual loss of 45.65% on immature fruit that were subsequently aborted in production from the two provinces. These findings point towards the fact that there is a considerable presence of coconut bug on the farms and also that litchi is a very good host of the coconut bug. The coconut bug damage increased when other host plants are cultivated in close proximity. Further research to evaluate economic impact of this pest is therefore needed.

Southern African Moths & Their Caterpillars, Hermann Staude, Mike Picker and Charles Griffiths, 2023. Struik Nature/Penguin Random House South Africa. ISBN 978 1 77584 795 (Print), ISBN 978 177584 796 0 (ePub). Paper back R 550; Pelagic Publishing (UK) ISBN 99781784273477. Paper back ₤39.99. 464 pp.

Honey locust, Gleditsia triacanthos (Fabaceae) is a fast-growing deciduous tree native to North America. The tree has been introduced worldwide and has become invasive in South Africa. In 2017, it was listed as one of the nine fastest-spreading weeds in South Africa. Once established, it competes with and displaces indigenous species and dense stands can significantly reduce stream flow. The Asian seed-feeding bruchid, Megabruchidius tonkineus (Coleoptera: Chrysomelidae: Bruchinae) was introduced into South Africa and has subsequently taken honey locust as a host plant. The beetle damages honey locust seeds and is therefore considered a biological control agent, despite no host-specificity or impact studies having been conducted. This study shows that M. tonkineus has established across the entire G. triacanthos population range in South Africa, damaging approximately 9% of seeds. Laboratory studies show that M. tonkineus completes its larval development in the seeds of G. triacanthos in about 66.80 ± 0.69 SE days before emerging. This study is the first to describe the distribution and impact of this alien insect in South Africa.

Developing repeatable protocols for the in vitro liquid mass production of entomopathogenic nematodes (EPNs) is a difficult task and depends on the nematode species being cultured. Of critical importance is the establishment of a monoxenic population of nematodes as a stock culture for optimisation and experimental purposes. Establishing a new stock inoculum culture flask of pure infective juveniles (IJs) is challenging, particularly for the Heterorhabditis species, due to their affinity for developing into an amphimictic second generation that does not copulate in liquid culture flasks. Developing mass production protocols for multiple EPNs is advisable because different pest insects are susceptible to different species of EPN. This study attempted to mass-produce a South African isolate of Heterorhabditis zealandica and its symbiotic bacteria, Photorhabdus thracensis, using in vitro liquid culture technology methods previously developed for Steinernema species. The results indicate that the pre-culture protocols developed for Steinernema species are applicable to a H. zealandica isolate. Moreover, the results, in terms of the protein source optimisation experiments, confirm that different EPN species have different culture conditions and nutrient requirements, with H. zealandica seeming to prefer soy-based protein instead of egg yolk, having higher recovery and producing more hermaphrodites, using soy protein. This study illustrates the importance of developing dependable and infallible preculture methods, prior to the flask mass production process.

Megamelus scutellaris Berg (Hemiptera: Delphacidae) is the most recent of nine biological control agents developed to manage invasive water hyacinth, Pontederia (=Eichhornia) crassipes Mart. (Pontederiaceae), in South Africa. More than a million M. scutellaris have been mass-reared and released since the first introduction of the agent into South Africa in 2013, successfully establishing overwintering populations at 32 sites in seven of the nine provinces. Establishment has also been recorded at seven of these sites through natural dispersal from sites where they had established. Inundative releases, where large numbers of M. scutellaris are released regularly, have resulted in excellent establishment, and caused a significant reduction in water hyacinth cover in areas where, historically, biological control seemed unlikely due to excessive eutrophication. Although M. scutellaris has established well throughout South Africa through classical biological control methods, this study also showed that inundative releases of biological control agents over multiple seasons results in the most effective control of the weed, especially at cool temperate and eutrophic sites.

The southern and eastern parts of the African Fynbos region favour the production of honeybush tea. Honeybush biomass and extracts are used to prepare a beverage both locally and internationally, mainly as herbal tea with health benefits. Honeybush tea is mostly grown organically requiring natural control measures for pests and diseases. The leafhopper, Molopopterus sp., is one of the most important pests of cultivated honeybush in South Africa, as its feeding compromises the quality and quantity of the yield through leaf discolouration and reduction of the photosynthetic area. Local entomopathogenic fungi (EPF) can provide a pool of potential biocontrol agents for this pest. Therefore, a total of 98 soil samples were collected from organically grown honeybush fields and vegetation surrounding the honeybush fields in the Western Cape province of South Africa. Entomopathogenic fungi were isolated using the insect bait method and were characterised using molecular techniques. Twenty fungal isolates of Metarhizium anisopliae and Fusarium oxysporum were recovered from soil samples, of which 70% were from honeybush fields and 30% were from surrounding vegetation. Fusarium oxysporum isolates comprised 20% of the recovered isolates; M. anisopliae the remainder. Laboratory bioassays of the recovered isolates against adults and nymphs of the leafhopper, showed that F. oxysporum isolates caused 10–45% mortality and M. anisopliae isolates 30–80% mortality. Metarhizium anisopliae isolates J S1, KF S3, KF S11, KF S13, LS1 and LS2 were the most virulent and induced over 60% mortality in both nymphs and adults at a concentration of 1 × 107 conidia/ml.

Coffee berry borer, Hypothenemus hampei (Ferrari, 1867), is a serious insect pest of organic coffee plantation in São Tomé Island. To date, limited information regarding the seasonal phenology of this pest species on the islands limits the implementation of integrated pest management (IPM) programmes. As part of a coffee farmer training programme, three attractants were evaluated in red vs. transparent traps to assess olfactory and visual stimuli. The experiment was delineated in a split-block design with three types of attractants: commercial ethanol + 40 g of ripe Robusta coffee (A1), proportion 3:1 methanol and ethanol (A2), and commercial ethanol + 10 g of ground roasted Arabica coffee (A3); and two home-made transparent (D1) and red (D2) traps. The results showed that there was significant interaction between the trap model and the attractant for borer capture. The transparent trap baited with methanol and ethanol exhibited the best result with an average of 14.3 ± 5.4 adults/trap/week. Transparent traps baited captured more borers and largest numbers of beetles were trapped late May through September. In short, home-made traps alone are not effective for controlling the coffee berry borer, but they are useful in monitoring this species.

Spatial distribution of vector mosquitoes plays a critical role in the dynamics of associated diseases’ spread across diverse landscapes. In Botswana, six Districts are implicated as malaria endemic zones, one of which is the Central District comprising both malaria endemic and non-endemic sub-districts. Despite being the biggest in the country, mosquito diversity in this District is under-explored, more so in the malaria non-endemic sub-districts. Here, we thus sampled mosquito adults and larvae from the malaria endemic sub-district of Bobirwa and non-endemic sub-districts of Palapye and Serowe, to determine spatial mosquito abundance and diversity in the District. Overall, all the sub-districts had a representation of key mosquito taxa of medical and economic importance (Aedes, Culex and Anopheles), irrespective of malarial endemicity status. Bobirwa had the highest number of mosquitoes sampled (429) although the greatest species richness (0.8511) was observed from Palapye. Moreover, Palapye also recorded a species from another genus, Culiseta longiareolata, a known natural vector of avian malaria parasites. Given global climate shift projections for the region, there is a need for continuous area-wide surveillance for vector mosquitoes and associated parasites in curbing the risk of emerging and re-emerging infections. While the Anopheles-centric approach to mosquito control is still necessary, a holistic approach, incorporating other vector incriminated mosquito species is warranted, particularly given shifting climates and the presence of invasive disease associated vector mosquito species.