Natural enemy surveys, especially for indigenous anthocorid predators of sugarcane thrips Fulmekiola serrata Kobus, were completed between 2008 and 2013 in and around sugarcane fields in the Mpumalanga and KwaZulu-Natal provinces of South Africa. Four Orius species were recorded during the surveys. First records for South Africa of Orius tantillus (Motchulsky) and Orius naivashae (Poppius) were made, and the presence of Orius thripoborus (Hesse) and Orius brunnescens (Poppius) in the country was confirmed. For each species, habitat and climate preferences are described. Orius thripoborus was the only anthocorid natural enemy which was observed preying on the sugarcane thrips in the field.

An area-wide integrated pest management (AW-IPM) programme was developed to improve management of Eldana saccharina Walker (Lepidoptera: Pyralidae), a major pest of South African sugarcane. Push-pull technology is an important component of this AW-IPM approach. The sugarcane push-pull programme uses plants which are both repellent (Melinis minutiflora P. Beauv. (Cyperales: Poaceae)) and attractive (Cyperus dives Delile and Cyperus papyrus L. (both Cyperales: Cyperaceae) to E. saccharina. Previous research demonstrated the efficacy of push-pull in the Midlands North region of KwaZulu-Natal (KZN), South Africa. To date, little research has been conducted in coastal sugarcane growing areas. The aim of this study was to assess the feasibility of using push-pull for management of E. saccharina in coastal KZN, using large-scale on-farm field trials conducted on five model farms. On each farm, wetland habitats were rehabilitated with pull plants (C. dives and C. papyrus) and fields were intercropped with the repellent grass M. minutiflora. Eldana saccharina damage and infestation levels were recorded to assess the efficacy of push-pull, using a multiple before-after-control-impact (mBACI) design. Push-pull treatment sites showed a significant reduction in mean percentage stalk damage and E. saccharina abundance relative to control sites. Furthermore, stemborer surveys in wetland habitats revealed higher numbers of E. saccharina within Cyperus spp. stands. Pull plants were therefore effective at attracting E. saccharina away from sugarcane. The success of the push-pull trials in this study indicates that it is a useful tool for managing E. saccharina populations in coastal sugarcane, especially in conjunction with other management practices.

The carcass milling technique (CMT) formulates specific diets from nutrient analyses of species to be reared and their natural host plants. The first of four diets developed used the minimum ingredient specifications (MS) of published diets for Eldana saccharina. The remaining were based on the ideal amino acid composition and profile (IAAP) of its second (IAAP2), third/fourth (IAAP3/4) and fifth/sixth (IAAP5/6) instar larvae. The control was a modified Ostrinia nubilalis diet. Survival to pupae of inoculated E saccharina neonates was high on all CMT formulations (>92% at day 20 and >97% at day 27). Larvae developed fastest on the IAAP3/4 and MS diets (25% and 17% prepupae and pupae on day 20, respectively). Pupal weights were not significantly influenced by CMT diets (0.1121 g male; 0.1864 g female). The control group produced heavier male and female pupae (0.1204 g; 0.2085 g, respectively). Adult emergence was highest from the MS (98%), then the IAAP3/4 (97%) and control (96%) diets. Sex ratio of adults from all diets was close to one. Males from the IAAP5/6 diet mated with significantly more females (six), and females from the MS diet mated with more males (three) than those from remaining formulations. All females produced in excess of 870 eggs, more than 90% were fertile after mating. The pH (4.79); moisture content (81.43%) and water activity (0.92 aw) of the diets were not significantly different, maintaining quality and stability throughout the larval period, ensuring optimal growth and development. The MS diet formulation was the preferred choice to replace the current E. saccharina diet.

Various combinations and concentrations of cholesterol (C) and stigmasterol (S) were added into a base diet developed for Eldana saccharina. Survival of inoculated neonate was high on all diets (>92% at day 20 and >95% at day 27). Fastest larval development occurred on the minimum specification (MS) (+1.0 gS) and MS (+0.2 gC: 0.2 gS) diets (72 and 70% pupation respectively at day 20). Significantly slower development (15% pupation) occurred on the control diet at day 20. Female pupal weight increased when larvae fed on the MS (+0.1 gC), (+0.1 gS) and (+0.2 gC:0.2 gS) diets (0.2143 ± 0.00 g, 0.2271 ± 0.01 g and 0.2252 ± 0.01 g, respectively) as compared with the control diet (0.1886 ± 0.00 g). Adult emergence was significantly higher (100%) from the MS (+0.1 gS) and MS (+0.2 gC:0.2 gS) diets, as compared with the remaining sterol (95%) and control diets (97%). To potentially increase E. saccharina’s cold tolerance, inclusion of cryoprotectants L-proline (P) and trehalose (T) into the MS diet was investigated. Males from the MS (0.2 gP:0.2 gT), MS (0.5 gP:0.5 gT) and MS (1.0 gT) diets recovered fastest from chill coma treatment (204 ± 44 s, 215 ± 7 s and 215 ± 9 s, respectively) than those from the remaining cryoprotectant diets (305 ± 22 s). The addition of cryoprotectants severely reduced female fertility (<44%) when mated with non-chill coma exposed males. In contrast, eggs from females not exposed to chilling treatment were 84% fertile when mated with males from the same source. The MS (0.2 gC:0.2 gS) diet is the preferred choice to replace the currently used diet, reducing the larval growth period by 60% without negative effects on key life cycle parameters of E. saccharina.

Organic orchards may have higher biodiversity and levels of ecosystem services compared to conventionally managed orchards. However, it is not well-understood how management decisions within organic orchards alter biotic communities and ecosystem services. The simultaneous provision of individual ecosystem services and mitigation of disservices is crucial for organic growers who cannot replace natural regulatory processes by artificial inputs. This study addresses one of the major constraints for organic fruit production in South Africa, namely the availability of strategies for pest control and nutrient management in soils. Partly due to these constraints, organic certification of deciduous fruits is very uncommon in South Africa and limited our selection of study plots. A field experiment on a single farm was established to study the impact of a treatment with dead organic mulch compared to controls on the composition of biotic communities, the simultaneous provision of ecosystem services, and the mitigation of disservices in five organic deciduous fruit orchards in the Western Cape province. Mulching did not significantly reduce weed cover or alter the taxonomic composition of weed communities, but affected soil organisms. Mulched subplots had significantly higher densities of Collembola and phytophagous nematodes and lower microbial activity and woodlice numbers. Independent of mulch treatment, both orchard type (conventional: apricot and organic: apricot, peach, plum, and quince) and weed cover had pronounced effects on the composition of biotic communities and ecosystem service and disservice potentials. The community composition of plants, microbes and web-building spiders differed significantly between organically and conventionally managed plots. The composition of communities and levels of ecosystem service and disservice potentials also differed significantly between organic orchards of different fruit type. Two potential pest groups (phytophagous nematodes and arthropods) were most abundant in peach subplots with high weed cover and tree age and least abundant in conventionally managed apricot plots. These results emphasize the crucial importance to consider weed-microbe-animal interactions when developing management practices in organic orchards. Management decisions in organic orchards hold the potential to affect biotic communities to the benefit of pest control and soil nutrient services, but can also result in unexpected detrimental effects on ecosystem services.

Entomopathogenic nematodes (EPNs) provide a potential alternative to chemical insecticides to control root feeding pests of agricultural and forestry crops. One of the challenges in using EPNs in these environments is low post-application survival. We evaluated the survival of infective juveniles (Us) of four EPN species (Heterorhabditis bacteriophora, H. baujardi, Steinernema sacchari and S. yirgalemense) in three different substrates for application. Survival of IJs was assessed directly by counting living Us and indirectly by baiting with Galleria mellonella larvae. The virulence of different native and non-native EPNs against the third-instar larvae of Heteronychus licas, an important soil-insect pest of agricultural crops in South Africa, was also tested. Nematode survival was highest in a gel medium, followed by a gel-soil mixture, and lowest in soil. Survival of Steinernema species was higher than Heterorhabditis species when considering direct nematode counts, but these results were not consistent when using wax moth mortality as a proxy for survival. The South African strain of H. bacteriophora gave the highest and most rapid levels of mortality in H. licas grubs, followed by a commercially applied strain of H. bacteriophora. The results suggest that native EPNs could provide an option for soil-insect management in South Africa and provide insights into effective means of application.

The objectives of this paper are to characterise South African sugarcane production for the 2017/18 milling season from an agricultural perspective. This is done to provide insight into successes and failures of recent production strategies, and identify priorities for improved efficiency in producing high quality sugarcane in South Africa. The lengthy and severe drought of 2014/15/16 was finally broken in 2017 with good rainfall bringing relief in rainfed production areas. Yields in these areas improved markedly from 2016. Cane quality also improved although it remained below the long term mean because of disruptive rainfall in May and in some parts in October. Irrigation water supplies remained constrained for a large part of the growing season but started improving from January 2017. This brought about improved yields, while excellent cane quality was achieved in these areas. Smut levels increased in the northern parts of the industry, but levels of other diseases were relatively low. Eldana levels also declined after good summer rainfall in coastal areas. A new pest, the longhorn beetle, posed a serious threat, but seems to have for the present been contained. Vigilance, especially in hotspot areas, remains a high priority. Substantial sugar imports combined with increased local production necessitated exports of locally produced sugar at low world prices, leading to low producers price and profitability, and threatening long term sustainability. Effective tariff protection is urgently required to turn this around. Overall, the 2017 production season will be remembered for a remarkable turnaround in sugarcane production from one of the most severe droughts ever experienced. Agronomic recovery, however, did not translate into financial recovery, due to a low product price. Continued efforts are needed to improve efficiencies along the value chain, for the industry to remain competitive.

AbstractUnderstanding pest population dynamics and seasonal phenology is a critical component of modern integrated pest-management programs. Accurate forecasting allows timely, cost-effective interventions, including maximum efficacy of, for example, biological control and/or sterile insect technique. Due to the variation in life stage-related sensitivity toward climate, insect pest population abundance models are often not easily interpreted or lack direct relevance to management strategies in the field. Here we apply a process-based (biophysical) model that incorporates climate data with life stage-dependent physiology and life history to attempt to predict Eldana saccharina life stage and generation turnover in sugarcane fields. Fitness traits are modelled at two agricultural locations in South Africa that differ in average temperature (hereafter a cold and a warm site). We test whether the life stage population structures in the field entering winter and local climate during winter directly affect development rates, and therefore interact to determine the population dynamics and phenological responses of E. saccharina in subsequent spring and summer seasons. The model predicts that: (1) E. saccharina can cycle through more generations at the warm site where fewer hours of cold and heat stress are endured, and (2) at the cold site, overwintering as pupae (rather than larvae) confer higher relative fitness and fecundity in the subsequent summer adult moths. The model predictions were compared with a large dataset of field observations from scouting records. Model predictions for larval presence (or absence) generally overlapped well with positive (or negative) scout records. These results are important for integrated pest management strategies by providing a useful foundation for future population dynamics models, and are applicable to a variety of agricultural landscapes, but especially the sugarcane industry of South Africa.

Populations of the leaf-feeding moth Pareuchaetes insulata from Florida (USA), Jamaica and Cuba were mass-reared by the South African Sugarcane Research Institute (SASRI) and released extensively in KwaZuluNatal (KZN) province of South Africa from 2001-2009 for biological control of the invasive shrub Chromolaena odorata. Establishment was first confirmed in 2004, at only a single site, near Umkomaas just south of Durban, at which the Florida population had been last released nearly two years earlier. A population outbreak and range expansion occurred during 2006, followed by a decline to a much lower level. Annual monitoring from 2006-2013, along a 100 km coastal stretch and slightly inland from the original established site, indicated gradual further spread within this range with time, although populations were generally low. In 2014 and 2015, additional populations and outbreaks were recorded further north in KZN, well beyond the area that had been regularly monitored, in a region that had been previously considered to be climatically unsuitable for the moth. In late 2015 and early 2016, surveys located the moth even further afield, in Swaziland and south-eastern Mpumalanga, having probably spread from KZN. To better understand the highly variable establishment and performance of P. insulata, various aspects of the moth's biology have been examined. The cross-breeding and molecular analysis of the Cuban, Jamaican and Floridian populations indicated the lack of a mating barrier between them. Studies on the moth's performance on C. odorata from South Africa and Florida showed that it is not affected by variation in host plant genotype. However, studies on the nutritional ecology and thermal physiology of P. insulata demonstrated that multiple factors, including low temperatures and spatio-temporal variations in the physical and phytochemical characteristics of C. odorata leaves, may cause variable performance of the moth. This paper discusses the results of monitoring and research activities on the moth, which has been established on C. odorata in South Africa for more than a decade, and the implications of these for the biocontrol of the weed in southern Africa.

Several factitious foods were assessed for rearing the anthocorid predators Orius thripoborus (Hesse) and Orius naivashae (Poppius) (Hemiptera: Anthocoridae) in the laboratory. Developmental and reproductive traits of both Orius species were examined when offered frozen eggs of the Mediterranean flour moth, Ephestia kuehniella Zeller, frozen processed eggs of the medfly, Ceratitis capitata Wiedemann, or mixed motile stages of the astigmatid mites Tyrophagus putrescentiae (Schrank) or Carpoglyphus lactis (L). Whereas C. lactis and T. putresecentiae proved to be an inferior food for rearing O. thripoborus and O. naivashae, eggs of C. capitata fully supported development and reproduction of both predators. Results on medfly eggs were similar or slightly inferior to those on E. kuehniella eggs, which is the standard food for culturing these anthocorid bugs. O. thripoborus could be maintained for 4 consecutive generations on C. capitata eggs indicating that processed medfly eggs can be a suitable and cheaper alternative to E. kuehniella eggs for prolonged rearing of these Orius spp.

At low doses of radiation, F-1 sterility of the sugarcane stalk borer, Eldana saccharina Walker (Lepidoptera: Pyralidae), can be attained. This bodes well for progression of the sterile insect technique (SIT) as part of an area-wide integrated pest management strategy against this pest of economic importance. However, success of the SIT is dependent on mating ability and performance of the mass-reared sterile insects once released into the field. Mating behaviour of non-irradiated laboratory-reared male E.saccharina moths and those subjected to radiation (150, 200, or 250Gy) was investigated in still-air cage laboratory trials. Video technology was used to determine whether mass rearing and irradiation of adult moths altered their performance in lek formation and mating success, compared to their untreated wild counterparts. Mating frequency, mating duration, onset of mating, and calling during the first two scotophase periods following adult eclosion were used to make these assessments. Results indicated that both irradiated and non-irradiated laboratory-reared males are able to form leks and mate with wild females, and are therefore as effective as their wild counterparts with regards to mating performance. However, a quantitative departure of male mating behaviour away from that exhibited by wild males was observed in the non-irradiated and irradiated laboratory males. These commenced calling and mating earlier than wild males in both scotophases, except for those irradiated at 250Gy in the case of mating onset. The mating duration of treated males was similar to that of the untreated wild males, except for those irradiated at 150Gy, which was significantly higher. Our study provides evidence that increasing radiation dose negatively impacts on performance of laboratory-produced moths relative to their wild counterparts, which in turn could affect the efficacy of the SIT. At 150 and 200Gy, these parameters are not affected significantly when compared to untreated wild males, and thus these radiation doses can be used safely. However, at higher doses negative effects do become evident.

In 1988, Eldana saccharine was found for the first time on six sugarcane farms in the Midlands North area. By 1994, the borer had spread to 32 farms, with a peak of 115 E. saccharine (e) per 100 stalks. In 2004, a further 14 farms were affected, the worst showing a level of 129 e/100 stalks. This prompted the region in 2005 to embark on an area-wide integrated pest management (AW-IPM) approach against E. saccharine. This included promoting already known management practices, resistant varieties, and a habitat management system (push-pull) to manage E. saccharine in sugarcane. However, uptake of AW-IPM was initially slow, and by 2009, a further 29 farms were affected. Where appropriate, growers were made aware of their incorrect varietal disposition, and were advised on planting recommended varieties on different soil types in the area to minimise plant stress. In addition, areas of high infestation risk were identified for preventive control measures. The Midlands North Local Pest, Disease and Variety Control Committee (MNLPD&VCC) continually expanded the push-pull approach by establishing nurseries for natural host plants of E. saccharina for distribution, and increased E. saccharina monitoring. Also, the principles of healthy sugarcane, community engagement, managing sugarcane according to climatic vagaries, and forward planning were emphasised. The proactive, well-informed and ecologically based area-wide approach that the region has taken in controlling E. saccharine since 2005 reflects that, despite extensive droughts and frosts in the past three years, the mean level of this pest in 2015 was 0.17 e/100 stalks, with a maximum of 52 e/100 stalks found in only one field.

Eldana saccharina Walker (Lepidoptera: Pyralidae: Gallerinae) occurs on many graminaceous crops and several wild grasses and sedges throughout Africa. It has been reared at the South African Sugarcane Research Institute (SASRI) since the 1970s to study its biology and behavior, as a host for natural enemies and to provide insect material for the plant breeding program. Studies were completed on laboratory-reared E. saccharina of South African origin to assess fecundity, fertility and male and female mating frequencies. Mean fecundity of E. saccharina was 518 +/- 27.5 (mean +/- SE) eggs per female, up to a maximum of 798 eggs. Mean egg hatch (fertility) of E. saccharina was 63.2 +/- 4.2%. In the laboratory, 56.7% of E. saccharina females mated only once but on average females mated 1.5 +/- 0.1 times (maximum of 3). Males mated with a maximum of 6 females per male but on average males mated 3.3 +/- 0.7 females. Most matings (93%) occurred on the first and second nights after male emergence, and the females oviposited most of their eggs (49.9 +/- 3.9%) on the second night after emergence. Eldana saccharina's high fecundity confirmed its potential as a crop pest. This study has, for the first time, confirmed that male and female E. saccharina were able to mate more than once under controlled laboratory conditions. This has important implications for calculating required release rates of sterilized males to obtain adequate sterile to wild male over-flooding ratios in area-wide integrated pest management programs that have a SIT component.

Since 2000, the groundnut leaf miner has increasingly become a pest of groundnut and soya bean on the African continent. The origin of the pest in Africa is uncertain. Early reports in South Africa assumed it was an invasion of Aproaerema modicella (Deventer) from the Asian continent, but subsequent mitochondrial DNA COI gene (mtDNA COI) fingerprinting matched it to Aproaerema simplexella (Walker, 1864) from Australia. Prior to this, reports in the 1950s recorded it in Africa under the name Stomopteryx subsecivella (Zeller, 1852). Furthermore,it was found that A. simplexella responded to the species-specific lure developed from the sex pheromone of A. modicella. As a result of these apparent anomalies, we examined the genetic relatedness of the above species from Africa, India and Australia. mtDNA COI analysis was performed on 44 specimens collected from South Africa, four from Mozambique, and three each from single locations in India and Australia. In the BOLD gene bank, 70 % of the specimens analysed matched with A. simplexella sequences from Australia (99-100 %), including all three specimens from both India and Australia, and two from Mozambique. In the remaining specimens, the match was 98-99 %. Two specimens, later to be identified as parasitoids, did not match with any sequences in the BOLD gene bank. In the NCBI gene bank, 81 % of the sequences matched 99-100 %, and a further 15 % matched 92-98 % with A. simplexella sequences. Based on these mtDNA COI analyses, and the similarities of the behavioural responses originally noted between the species, we thus suggest the re-examination of. the taxonomy and synonymisation of the three populations of the two species.

The cold hardiness and overwintering potential of the southern African pirate bugs, Orius thripoborus (Hesse) and Orius naivashae (Poppius) (Hemiptera: Anthocoridae), were assessed in the laboratory. Diapause traits were studied by observing nymphal development and reproductive performance of adults at 18 °C and three photoperiods (10:14, 12:12 and 14:10 (L:D) h). A 12 h light regime was also tested at 23 °C. A 12 h photoperiod and 18 °C induced reproductive diapause in 84 and 42 % of O. naivashae and O. thripoborus females, respectively. Cold tolerance of adults was measured by determining the supercooling point (SCP, the temperature at which the insect’s body fluids freeze) and lethal time (LT50, the time required to kill 50 % of the population) at 0 and 5 °C. All observed SCPs ranged from −21 to −17 °C. Significantly lower SCP values were observed for acclimated (seven days at 10 °C) O. naivashae females. LT50-values averaged 6.4 and 4.4 days at 0 °C and 11.6 and 7.8 days at 5 °C, for adults of O. thripoborus and O. naivashae, respectively. The findings indicate that O. naivashae is less cold tolerant and has a higher diapause incidence compared with O. thripoborus. Therefore, the latter species may have better potential for use in biological control programmes in the cooler regions of southern Africa or elsewhere.

Since its humble beginnings in the late 1990s, use of the sterile insect technique (SIT) in South African crop agriculture evolved from an underfunded ‘rag and bones’ operation in Stellenbosch for a single pest, Mediterranean fruit fly (Medfly), Ceratitis capitata (Wiedemann), on deciduous fruit and table grapes, to privatized programmes for three fruit pests, viz. Medfly, false codling moth (Thaumatotibia leucotreta (Meyrick)) on citrus, and codling moth (Cydia pomonella (Linnaeus)) on apples and pears.Afourth SIT programme, for the sugarcane stalkborers, Eldana saccharina Walker and Chilo sacchariphagus Bojer, is well under development. This review focuses mainly on the Medfly SIT programme, but gives brief summaries of the development and current status of SIT for the other pests mentioned. However, many of the hardships experienced by the Medfly SIT programme have also been experienced by those people that developed, or are still developing SIT for the other pests. During the last 15 years the Medfly programme has passed through many phases and evoked many emotions, including hope, despair, misunderstanding and mistrust; but it also bred perseverance, determination, empowerment and, later, confidence. It has also included an international DNA investigation to identify the origin of a Medfly outbreak in the SIT area. The Medfly SIT programme started at Agricultural Research Council (ARC) Infruitec-Nietvoorbij in Stellenbosch in the Western Cape Province with a feasibility study over some 5000 ha of table grapes in theHex RiverValley area, releasing by air 5 million sterile male Medflies per week, produced in a run-down outbuilding with questionable equipment. Fungal rot, ant invasions, severe rust, lack of funding, inexperience and ignorance were among the challenges. The feasibility project subsequently metamorphosed into a fully-fledged, privatized programme which now produces 25 million sterile male Medflies per week in a modern, state-of-the-art facility with high-specification equipment and highly qualified technicians, distributed weekly to three different production areas and released on the ground. The current objective of the Medfly SIT programme is population suppression, but this is merely a means to an end. Medfly is regarded as a pest of international quarantine importance, and a number of countries impose strict phytosanitary measures against this pest. The ultimate goal, therefore, is the creation of Medfly-free areas, leading to sustained and expanded international fruit markets without trade restrictions due to Medfly. Many challenges still remain, but there is a fierce determination by those involved that it will succeed. In the meantime, the false codling moth SIT programme, based in Citrusdal in the Western Cape Province, is very successful and has improved and expanded significantly. The pilot release phase of the sugarcane borer SIT programme is expected to be fast-tracked after the likely procurement of an irradiator in KwaZulu-Natal in 2015. However, for economic and other reasons the codling moth SIT programme had to be terminated in 2014. ‘Will SIT in South Africa fly?’ It is already flying, but it needs to fly much higher. With the necessity to export fruit from pest-free areas, to minimize crop losses of commercial and small-scale farmers, and considering the large investments already made in SIT in South Africa, there should be no going back.

During 2013, the yellow sugarcane aphid, Sipha flava (Homoptera: Aphididae), was recorded in the South African sugarcane industry for the first time. Initially discovered at Mount Edgecombe in the KwaZulu-Natal Province of South Africa, it was subsequently detected across the entire sugarcane industry and more recently in Swaziland and Zimbabwe. Morphological and molecular taxonomic techniques were employed to confirm its identity. Native to North America, it currently has a wide geographical distribution across Central and South America, as well as the Caribbean and Hawaiian Islands. It was first reported on sugarcane in Africa in Morocco in 2006. In the Americas, sugarcane, sorghum (commercial and wild species), rice, maize, cereal crops, several species of lawn and pasture grasses, and Carex and Cyperus have been recorded as hosts. It has been collected from sugarcane, Sorgum bicolor, Tragus berteronianus, Echinochloa colona, Digitaria ciliaris, D. ternata and D. citratus in South Africa; however, additional hosts are expected as it becomes more established. Sipha flava (2 mm) are yellow with dusky coloured spots, short stiff hairs and reduced cornicles. All stages feed in dense colonies on the lower leaf surface along the midrib, causing yellowing and reddening. In South Africa natural enemies such as ladybird beetles, earwigs, hover flies, predaceous ants and spiders prey on S. flava. The effect on final sugarcane yield due to S. flava infestations in South Africa remains to be determined. Management tactics have yet to be developed and, should natural enemies and weather fail to keep populations in check, then resistant/tolerant varieties and insecticides could be considered.