Assessment of coconut bug, <i>Pseudotheraptus wayi</i> Brown (Hemiptera: Coreidae) damage on litchis in the Limpopo and Mpumalanga provinces of South Africa

The enigma of litchi toxicity: an emerging health concern in southern Asia.

This is the first record of the coconut bug Pseudotheraptus wayi on litchis in South Africa. Although damage on immature fruit was often in excess of 50%, chemical control of P. wayi did not necessarily increase yields. Litchi trees flower profusely and are probably able to compensate for damage which occurs early in the production season. Because litchis have a strong tendency towards biennial bearing, it was speculated that P. wayi could have a detrimental effect in orchards producing below-average yields. Since P. wayi damaged approximately 50% of the immature fruit in the Nelspruit region, it is safe to assume that litchi is a good alternative host for this insect. Producers of other subtropical fruit should take cognizance of this observation and adapt control programmes for hemipterans in adjoining orchards if necessary.

The interactions of Holymenia clavigera (Herbst) and Anisoscelis foliacea marginella (Dallas) with their hosts (Passifloraceae) in southern Brazil are poorly understood. Previous studies have indicated that both species use several host species and plant parts and have superior performance on wild hosts. This study evaluated feeding preferences and host plant use under both laboratory and field conditions. Choice tests were performed to determine preference for Passiflora suberosa parts, preference for P. suberosa and Passiflora misera immature and ripe fruits, and preference for P. suberosa, P. misera, and Passiflora edulis shoots. A field survey was carried out to assess H. clavigera and A. foliacea marginella use of P. suberosa parts. In addition, immature and ripe fruits of P. suberosa and P. misera were characterized in relation to pH, phenols, and anthocyanins. First-instar nymphs preferred the terminal buds, shifting to immature fruits in the second instar. Both coreids more frequently fed on immature fruits than on ripe ones. Neither species showed a significant preference among host species. The immature fruits presented higher phenol content as compared with the ripe fruits; the opposite was observed for anthocyanins. In the field, immature fruits and mature leaves were selected for feeding and resting. Thus, this study confirms the food mixing condition of these coreids, as well as the importance of fruits for their nutrition. Phenols, and presumably water, in the fruits may play a role in their feeding choices.

The interactions of Holymenia clavigera (Herbst) and Anisoscelis foliacea marginella (Dallas) with their hosts (Passifloraceae) in southern Brazil are poorly understood. Previous studies have indicated that both species use several host species and plant parts and have superior performance on wild hosts. This study evaluated feeding preferences and host plant use under both laboratory and field conditions. Choice tests were performed to determine preference for Passiflora suberosa parts, preference for P. suberosa and Passiflora misera immature and ripe fruits, and preference for P. suberosa, P. misera, and Passiflora edulis shoots. A field survey was carried out to assess H. clavigera and A. foliacea marginella use of P. suberosa parts. In addition, immature and ripe fruits of P. suberosa and P. misera were characterized in relation to pH, phenols, and anthocyanins. First-instar nymphs preferred the terminal buds, shifting to immature fruits in the second instar. Both coreids more frequently fed on immature fruits than on ripe ones. Neither species showed a significant preference among host species. The immature fruits presented higher phenol content as compared with the ripe fruits; the opposite was observed for anthocyanins. In the field, immature fruits and mature leaves were selected for feeding and resting. Thus, this study confirms the food mixing condition of these coreids, as well as the importance of fruits for their nutrition. Phenols, and presumably water, in the fruits may play a role in their feeding choices.

Pericarp browning is the major cause of deterioration of harvested litchi fruit. Water loss plays a role in pericarp browning of litchi fruit. This study investigated the effects of humidification with dry fog on pericarp browning and quality of litchi fruit stored at low temperature. Litchi fruit were stored in a non-humidified cold chamber (control) or in a humidified cold room using Tabor atomizer system that generated 95% relative humidity (RH) without depositing water on the fruit surface at 4°C. Control fruit stored in cold room without added humidity underwent rapid weight loss, accompanied by severe pericarp browning after 25 d of storage. However, slight weight loss and no obvious pericarp browning were found in humidified-fruit. Moreover, humidification maintained well the integrity of cell membrane and inhibited polyphenol oxidase activity during early storage. In addition, respiration rate was obviously inhibited in humidified-fruit compared with control fruit. This study might provide a convenient approach to reduce pericarp browning of harvested litchi fruit by humidifying the fruit using the Tabor atomizer at low temperature instead of packaging with film. Keywords: litchi, pericarp browning, dry fog, high relative humidity, cold storage DOI: 10.25165/j.ijabe.20191204.4420 Citation: Xiao L, Li T T, Jiang G X, John A, Zhang D D, Jin W Y, et al. Effects of dry fog humidification on pericarp browning and quality of litchi fruit stored at low temperature. Int J Agric & Biol Eng, 2019; 12(4): 192–196.

Epilepsy is a disorder that disturbs nerve cell activity in the brain, resulting in seizures. It was noted that it occurs mostly in children, especially at the primary school level, and could result from a genetic condition. The aim of this study was to develop and validate life skills education guidelines for primary school learners of Limpopo and Mpumalanga provinces in South Africa to educate them about epilepsy with the aim of reducing stigma and discrimination towards people with epilepsy. The guidelines were developed by adapting the World Health Organization (WHO) guideline development guide, which included the formulation of PICOS (population, intervention, comparison, outcome, study design) questions, conducting a systematic review of the literature, and using GRADE (grading of recommendations assessment, development, and evaluation) to develop evidence-based recommendations. The recommendations that informed the guideline development were that epilepsy education should be included in the primary school life skills curriculum to improve learners' understanding, attitudes, and skills related to epilepsy. This epilepsy education should be tailored to the needs of primary school learners and cover topics such as seizure recognition, management, medication, and coping strategies. Collaboration between healthcare providers, educators, and policymakers is crucial to developing culturally appropriate and evidence-based epilepsy education guidelines. Teachers and healthcare providers should also receive training on how to support learners living with epilepsy. The resulting guidelines provide clear and concise guidance on epilepsy education in life skills for primary school learners, caregivers, and teachers. The guidelines are expected to improve the quality of epilepsy life skills education and contribute to the overall well-being and inclusion of learners with epilepsy in Mpumalanga and Limpopo provinces, South Africa.

Litchi fruits are a nutritious and commercial crop in the Indian state of Bihar. Litchi fruit contains a toxin, methylene cyclopropyl-glycine (MCPG), which is known to be fatal by causing encephalitis-related deaths. This is especially harmful when consumed by malnourished children. The first case of litchi toxicity was reported in Bihar in 2011. A similar event was recorded in 2014 among children admitted to the Muzaffarpur government hospital, Bihar. Litchi samples sent to ICMR-NIN were analyzed and MCPG was found to be present in both the pulp and seed of the fruit. Diethyl phosphate (DEP) metabolites were found in the urine samples of children who had consumed litchi fruit from this area indicating exposure to pesticide. The presence of both MCPG in litchi and DEP metabolites in urine samples highlights the need to conduct a comprehensive investigation that examines all factors of toxicity.

Litchi fruits are a nutritious and commercial crop in the Indian state of Bihar. Litchi fruit contains a toxin, methylene cyclopropyl-glycine (MCPG), which is known to be fatal by causing encephalitis-related deaths. This is especially harmful when consumed by malnourished children. The first case of litchi toxicity was reported in Bihar in 2011. A similar event was recorded in 2014 among children admitted to the Muzaffarpur government hospital, Bihar. Litchi samples sent to ICMR-NIN were analyzed and MCPG was found to be present in both the pulp and seed of the fruit. Diethyl phosphate (DEP) metabolites were found in the urine samples of children who had consumed litchi fruit from this area indicating exposure to pesticide. The presence of both MCPG in litchi and DEP metabolites in urine samples highlights the need to conduct a comprehensive investigation that examines all factors of toxicity.

Recently, the presence of methylenecyclopropylglycine (MCPG) found in litchi seeds and ripe and unripe litchi fruit pulp proved to be a breakthrough finding as it causes hypoglycemic encephalopathy leading to death of under nourished/starved children. Earlier methods of isolation and detection of MCPG in litchi fruit were tedious and time-consuming. To reduce the complexity, we developed a better and straightforward methodology using ultra performance liquid chromatography-tandem mass spectrometer (UPLC-MS/MS) and QuEChERS technique to quantify MCPG without derivatization in litchi samples. The UPLC system included a Thermo C8 column with a mobile phase 0.1% formic acid in acetonitrile and water (gradient flow) at a flow rate of 0.3 ml/min. MCPG levels were determined using an API 4000 mass spectrometer with electrospray ionization (ESI) source. Other parameters were also determined following the quantitation by multiple reaction monitoring mode. The method was validated for selectivity, specificity, linearity, limit of quantification (LOQ), limit of detection (LOD), intra-inter day precision and accuracy, stability, and ruggedness. Calibration curve ranged from 7.8 to1000 ng/ml linearly while the LOD value for MCPG was 0.66 ng/ml. The percent accuracy and precision ranged from 92.98 to 105% and 1.78 to 8.43%, respectively. Validated method was applied for the determination of MCPG in litchi samples which provided a better and novel method for the determination of MCPG.

Those studies were conducted to investigate litchi（Litchi chinensis Sonn.）fruits micro-cracking occurring during development and the postharvest treatments to control pericarp browning. SEM（Scanning electron microscope）was used to observe the pericarp micro-cracking. Micro-cracking with 200μm length in‘Yuh Her Bau’ was first observed 40 days after anthesis and with 500μm length afer 47 days. However, micro-cracking with 400μm length in ‘Hak Ip’was first observed 42 days after anthesis. Those results showed that the micro-cracking occurring of litchi fruits during development occurred around 40 days after anthesis. The litchi fruits were treated with 1%, 2%, 4% and 6% HCl and dipped for 1 min, 2 min, 4 min and 6 min, respectively. Results showed that the higher HCl concentration and the longer duration of dip had the highest effect to extend storage life and pericarp colour retention and had no significant influence or the fruit quality. The different chemical treatments included sodium pyrosulfite, tartaric acid, citric acid and oxalic acid. The 6% sodium pyrosulfite combined with HCl treatment showed the highest extending fruit storage life and reducing decay. Its effect was more positive than high concentration of HCl treatment alone. The best effect among several organic acid treatments was tartaric acid combined with 1% chitosan. The treatment also showed that it was effective in reduceing pericarp browning, but could not reduce fruit decay. When using the different packings combined with chemical treatments, the Ag-fiber bag packing was more effective in reducing fruit decay than PE bag packing, but it had no effect in reducing pericarp browning. The Ag-fiber bag combined with sodium pyrosulfite and HCl dipping showed more effect in extending storage life than other packings. The litchi fruits were dipped in various temperatures of hot water, including 80℃, 85℃, 90℃, 95℃ and 98℃ with 1~30 seconds, and then dipped with 4% HCl. Results showed that all treatments had more than 30 days of storage life at 5℃, and effective control on pericarp browning and fruit decay. In all hot water temperature treatments, there were no significant effects on fruit quality.

Conopomorpha sinensis Bradley is a host-specific pest of Litchi chinensis and Euphoria longan. Here, we demonstrated that C. sinensis has evolved special physical and chemical mechanisms for host plant location that enable it to survive and reproduce. Females favored laying their eggs on the convex surface of litchi fruit that had particular volatile characteristics. Experiments using a H-type olfactometer showed that female C. sinensis were attracted to litchi flowers, tender shoots, immature fruits, and mature fruits, with the highest attraction rate to mature fruits (74.67 ± 2.31%). There were no significant differences in the attraction of male C. sinensis to different litchi tissues. Further oviposition preference tests using the pericarp, pulp, and seeds of mature litchi fruits revealed that female C. sinensis prefer to lay their eggs on the pericarp. Litchi volatiles were found to be important in attracting C. sinensis to fruits for oviposition. Analysis of volatiles from different litchi tissues by HS-SPME-GC-MS revealed 31 similar volatiles, some of which may be important in the oviposition preference choices of C. sinensis on litchi fruit.

Exposure to the toxins methylene cyclopropyl acetic acid (MCPA) and methylene cyclopropyl glycine (MCPG) of unripe ackee and litchi fruit can lead to hypoglycemia and death; however, the molecular mechanisms by which MCPA and MCPG cause hypoglycemia have not been established in vivo To determine the in vivo mechanisms of action of these toxins, we infused them into conscious rodents and assessed rates of hepatic gluconeogenesis and ketogenesis, hepatic acyl-CoA and hepatic acetyl-CoA content, and hepatocellular energy charge. MCPG suppressed rates of hepatic β-oxidation as reflected by reductions in hepatic ketogenesis, reducing both short- and medium-chain hepatic acyl-CoA concentrations. Hepatic acetyl-CoA content decreased, and hepatic glucose production was inhibited. MCPA also suppressed β-oxidation of short-chain acyl-CoAs, rapidly inhibiting hepatic ketogenesis and hepatic glucose production, depleting hepatic acetyl-CoA content and ATP content, while increasing other short-chain acyl-CoAs. Utilizing a recently developed positional isotopomer NMR tracer analysis method, we demonstrated that MCPA-induced reductions in hepatic acetyl-CoA content were associated with a marked reduction of hepatic pyruvate carboxylase (PC) flux. Taken together, these data reveal the in vivo mechanisms of action of MCPA and MCPG: the hypoglycemia associated with ingestion of these toxins can be ascribed mostly to MCPA- or MCPG-induced reductions in hepatic PC flux due to inhibition of β-oxidation of short-chain acyl-CoAs by MCPA or inhibition of both short- and medium-chain acyl-CoAs by MCPG with resultant reductions in hepatic acetyl-CoA content, with an additional contribution to hypoglycemia through reduced hepatic ATP stores by MCPA.

Combined effect of Debaryomyces hansenii and Bacillus atrophaeus on the physicochemical attributes, defense-related enzyme activity, and transcriptomic profile of stored litchi fruit

During parasitological field surveys of freshwater fish, sebekiid and subtriquetrid pentastome larvae were recovered from the body cavity or swim bladder of several fish species from various localities in Limpopo and Mpumalanga Provinces, South Africa. Sebekia wedli was recovered from the body cavity of Marcusenius macrolepidotus (Mormyridae) from Flag Boshielo Dam, Limpopo Province, and Alofia sp. and Subtriquetra rileyi were found in the swim bladder of Oreochromis mossambicus (Cichlidae) from the Phalaborwa Barrage, Limpopo Province. The latter species was also collected from the swim bladder of O. mossambicus in dams in the Phalaborwa region and the Ga-Selati River, Limpopo Province. A single specimen of Sebekia okavangoensis was present in the body cavity of Clarias gariepinus (Clariidae) in a dam on a sugarcane farm in the Komatipoort region, Mpumalanga Province. Pentastomid infections in the Mormyridae and Clariidae represent new host records.

BackgroundRabies is a fatal zoonotic disease that is maintained in domestic dogs and wildlife populations in the Republic of South Africa. A retrospective study was conducted to improve understanding of the dynamics of rabies in humans, domestic dogs, and wildlife species, in relation to the ecology for three northern provinces of South Africa (Limpopo, Mpumalanga, and North-West) between 1998 and 2017.MethodsA descriptive epidemiology study was conducted for human and animal rabies. Dog rabies cases were analyzed using spatio-temporal scan statistics. The reproductive number (Rt) was estimated for the identified disease clusters. A phylogenetic tree was constructed based on the genome sequences of rabies viruses isolated from dogs, jackals, and an African civet, and Bayesian evolutionary analysis using a strict time clock model. Several ecological and socio-economic variables associated with dog rabies were modeled using univariate analyses with zero-inflated negative binomial regression and multivariable spatial analyses using the integrated nested Laplace approximation for two time periods: 1998–2002 and 2008–2012.ResultsHuman rabies cases increased in 2006 following an increase in dog rabies cases; however, the human cases declined in the next year while dog rabies cases fluctuated. Ten disease clusters of dog rabies were identified, and utilizing the phylogenetic tree, the dynamics of animal rabies over 20 years was elucidated. In 2006, a virus strain that re-emerged in eastern Limpopo Province caused the large and persistent dog rabies outbreaks in Limpopo and Mpumalanga Provinces. Several clusters included a rabies virus variant maintained in jackals in Limpopo Province, and the other variant in dogs widely distributed. The widely distributed variant maintained in jackal populations in North-West Province caused an outbreak in dogs in 2014. The Rt was high when the disease clusters were associated with either multiple virus strains or multiple animal species. High-risk areas included Limpopo and Mpumalanga Provinces characterized by woodlands and high temperatures and precipitation.ConclusionCanine rabies was maintained mainly in dog populations but was also associated with jackal species. Rural communities in Limpopo and Mpumalanga Provinces were at high risk of canine rabies originating from dogs.