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The litchi moth, Cryptophlebia peltastica (Meyrick) (Lepidoptera: Tortricidae), is endemic to sub-Saharan Africa and certain Indian Ocean islands. It is an important pest of litchis and to a lesser extent macadamias. Litchis are exported to certain markets that consider C. peltastica as a phytosanitary pest. Consequently, an effective postharvest phytosanitary treatment is required. This study sought to develop a cold disinfestation treatment for this purpose. First, it was established that the fifth instar was the most cold-tolerant larval stage, as it was the only instar for which there was still some survival after 12 d at 1°C. It was then determined that cold treatment trials could be conducted in artificial diet, as there was no survival of fifth instar C. peltastica in litchis after only 9 d at 1°C, whereas it took 15 d at this temperature before no survival of fifth instar C. peltastica was recorded in artificial diet. Consequently, cold susceptibility of fifth instar C. peltastica and the most cold-tolerant larval stages (fourth and fifth instar) of false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae), were compared in artificial diet. There was no survival of C. peltastica after 13 d at 1°C, whereas this was only so for T. leucotreta after 16 d. Consequently, it can be concluded that any cold treatment that has been proven effective against T. leucotreta would be as effective against C. peltastica. Finally, it was confirmed that the cold susceptibility of T. leucotreta in artificial diet did not overestimate the effect of cold on T. leucotreta larvae in litchis.

The species of Cryptophlebia occurring in Hawai‘i are reviewed, resulting in the discovery of a previously unrecognized native species, described here as C. alaula, sp. nov. The discovery of C. alaulaand its status as the putative sister species of C. illepida (Butler) supports the endemicity of C. illepida, a species whose status in Hawai‘i has historically been contested, and is often treated as an invasive pest of unknown origin. Cryptophlebia alaula is hypothesized to be a specialist on fruits and seeds of ‘a‘ali‘i (Dodonaea viscosa). This raises interesting questions regarding the evolution of monophagy and polyphagy in Cryptophlebia and patterns of speciation in Hawaiian Tortricidae more broadly. The conservation status of C. alaula is briefly discussed. All species occurring in Hawai‘i are described or redescribed, figured, with a key to species of both sexes provided.

Baculovirology has been studied on the African continent for the development of insect virus-based biopesticides and, to a much lesser extent, vaccine production and delivery, since the 1960s. In this review, we focus only on baculoviruses as biopesticides for agricultural pests in Africa. At least 11 species of baculovirus have been discovered or studied on the African continent, some with several distinct isolates, with the objective in most cases being the development of a biopesticide. These include the nucleopolyhedroviruses of Helicoverpa armigera, Cryptophlebia peltastica, Spodoptera exempta, Spodoptera frugiperda, Spodoptera littoralis, and Maruca vitrata, as well as the granuloviruses of Cydia pomonella, Plutella xylostella, Thaumatotibia (Cryptophlebia) leucotreta, Choristoneura occidentalis, and Phthorimaea operculella. Eleven different baculovirus-based biopesticides are recorded as being registered and commercially available on the African continent. Baculoviruses are recorded to have been isolated, researched, utilised in field trials, and/or commercially deployed as biopesticides in at least 13 different African countries. Baculovirus research is ongoing in Africa, and researchers are confident that further novel species and isolates will be discovered, to the benefit of environmentally responsible agricultural pest management, not only in Africa but also elsewhere.

The genetic diversity of baculoviruses provides a sustainable agronomic solution when resistance to biopesticides seems to be on the rise. This genetic diversity promotes insect infection by several genotypes (i.e., multiple infections) that are more likely to kill the host. However, the mechanism and regulation of these virus interactions are still poorly understood. In this article, we focused on baculoviruses infecting the codling moth, Cydia pomonella: two Cydia pomonella granulovirus genotypes, CpGV-M and CpGV-R5, and Cryptophlebia peltastica nucleopolyhedrovirus (CrpeNPV). The influence of the order of ingestion of the virus genotypes, the existence of an ingestion delay between the genotypes and the specificity of each genotype involved in the success of multiple infection were studied in the case of Cydia pomonella resistance. To obtain a multiple infection in resistant insects, the order of ingestion is a key factor, but the delay for ingestion of the second virus is not. CrpeNPV cannot substitute CpGV-R5 to allow replication of CpGV-M.

In the last 15 years, extensive work on the Cryptophlebia leucotreta granulovirus (CrleGV) has been conducted in South Africa, initially in the laboratory, but subsequently also in the field. This culminated in the registration of the first CrleGV-based biopesticide in 2004 (hence, the 10 years of commercial use in the field) and the second one three years later. Since 2000, more than 50 field trials have been conducted with CrleGV against the false codling moth, Thaumatotibia leucotreta, on citrus in South Africa. In a representative sample of 13 field trials reported over this period, efficacy (measured by reduction in larval infestation of fruit) ranged between 30% and 92%. Efficacy was shown to persist at a level of 70% for up to 17 weeks after application of CrleGV. This only occurred where the virus was applied in blocks rather than to single trees. The addition of molasses substantially and sometimes significantly enhanced efficacy. It was also established that CrleGV should not be applied at less than ~2 × 1013 OBs per ha in order to avoid compromised efficacy. As CrleGV-based products were shown to be at least as effective as chemical alternatives, persistent and compatible with natural enemies, their use is recommended within an integrated program for control of T. leucotreta on citrus and other crops.

Yeasts associated with lepidopteran pests have been shown to play a role in their survival, development, and oviposition preference. It has been demonstrated that combining these yeasts with existing biological control agents can enhance their efficacy. The tortricid Thaumatotibia leucotreta is a phytosanitary pest in the South African citrus industry, with the baculovirus Cryptophlebia leucotreta granulovirus (CrleGV) being one of the components that can control this pest. Several yeast species were shown to be associated with T. leucotreta larvae, which affected their behaviour and development. A series of detached fruit bioassays were performed to determine whether the combination of yeast with CrleGV enhances its efficacy. These assays included determining the optimal yeast/virus ratio, testing all isolated yeast species in combination with CrleGV, and further improving yeast/virus formulation by adding an adjuvant. The optimal yeast concentration to use alongside CrleGV was determined to be 106 cells·mL−1. Pichia kluyveri, P. kudriavzevii, Kluyveromyces marxianus, and Saccharomyces cerevisiae in combination with CrleGV reduced larval survival compared to CrleGV alone. The addition of molasses and BREAK-THRU® S 240 to P. kudriavzevii and S. cerevisiae in combination with CrleGV did not notably improve their effectiveness; however, there was an observed decrease in larval survival. In future studies, field trials will be conducted with combinations of CrleGV and P. kudriavzevii or S. cerevisiae to investigate whether these laboratory findings can be replicated in orchard conditions.

Matsumuraeses phaseoli is a Lepidopteran pest that primarily feeds on numerous species of cultivated legumes, such as Glycine and Phaseolus. It is widely distributed in northeast Asia. A novel granulovirus, designated as Matsumuraeses phaseoli granulovirus (MaphGV), was isolated from pathogenic M. phaseoli larvae that dwell in rolled leaves of Astragalus membranaceus, a Chinese medicinal herb. In this study, using next-generation sequencing, we report the complete genome of MaphGV. MaphGV genome comprises a double-stranded DNA of 116,875 bp, with 37.18% GC content. It has 128 hypothetical open reading frames (ORFs). Among them, 38 are baculovirus core genes, 18 are lepidopteran baculovirus conserved genes, and 5 are unique to Baculoviridae. MaphGV has one baculovirus repeat ORF (bro) and three inhibitors of apoptosis proteins (iap), including a newfound iap-6. We found two atypical baculoviral homologous regions (hrs) and four direct repeats (drs) in the MaphGV genome. Based on phylogenetic analysis, MaphGV belongs to Clade b of Betabaculovirus and is closely related to Cydia pomonellagranulovirus (CpGV) and Cryptophlebia leucotretagranulovirus (CrleGV). This novel baculovirus discovery and sequencing are invaluable in understanding the evolution of baculovirus and MaphGV may be a potential biocontrol agent against the bean ravaging pest.

Despite the agricultural importance of species in the Grapholitini (Lepidoptera: Tortricidae), and the value of gene expression analysis for improved population management, few gene expression studies based on quantitative real-time PCR (qPCR) have been conducted for this tribe. Part of the reason for this lack of information is that suitable reference genes, which are fundamental for accurate normalization of qPCR studies, have not been identified for the tribe. Thus, the expression stability of six potential reference genes (ACT, AK, COI, EF1, ENO and TUB) was assessed in three different tissues (whole body, midgut and cuticle) of Cryptophlebia peltastica (Meyrick), Cydia pomonella (L.) and Thaumatotibia leucotreta (Meyrick). Additionally, these reference genes were tested using T. leucotreta at different temperatures (15°C, 25°C and 35°C) with and without baculovirus infection. Suitable reference genes were identified for the whole body and midgut tissue of all three species, and for cuticle tissue of Cy. pomonella and T. leucotreta. When T. leucotreta was infected with the virus at all temperature conditions ACT, AK and EF1 were found to be the most suitable reference genes for experimental normalization. In general, for all tissue types, species and stress conditions, AK and EF1 were the best-performing reference genes. However, even though the three species analysed were closely related and within the same tribe, each species required varying gene combinations for suitable normalization. This study provides the first reference gene evaluation for the Tortricidae, and paves the way for future qPCR analysis in Tortricidae.

Cryptophlebia leucotreta granulovirus (CrleGV), a double-stranded DNA virus (genus Betabaculovirus, family Baculoviridae), is highly infective to the citrus insect pest Thaumatotibia leucotreta. The South African isolate CrleGV-SA is formulated into a commercial biopesticide and registered for use in several countries. In South Africa, it is used as a biopesticide in a multi-faceted integrated pest management approach for citrus crops involving chemical and biological control methods. The virus nucleocapsid is surrounded and protected by an occlusion body (OB) composed of granulin protein in a crystalline matrix. Like all other baculoviruses, CrleGV is susceptible to ultraviolet (UV) radiation from sunlight. This reduces its efficacy as a biopesticide in the field and necessitates frequent respraying. UV damage to baculovirus biopesticides is detected by means of functional bioassays. However, bioassays do not give an indication of whether any structural damage has occurred that may contribute to functional loss. In this study, transmission electron microscopy (TEM) was used to observe damage to the OB and nucleocapsid (NC) of CrleGV-SA, following controlled UV irradiation in the laboratory to mimic field conditions. The resultant images were compared with images of non-irradiated CrleGV-SA virus. TEM images of irradiated CrleGV-SA samples revealed changes to the OB crystalline faceting, a reduction in the size of the OBs, and damage to the NC following UV exposure for 72 h.

Comparative studies of the population genetic structures of agricultural pests can elucidate the factors by which their population levels are affected, which is useful for designing pest management programs. This approach was used to provide insight into the six Tortricidae of major economic importance in South Africa. The population genetic structure of the carnation worm E. acerbella and the false codling moth T. leucotreta, analyzed using amplified fragment length polymorphism (AFLP) analysis, is presented here for the first time. These results were compared with those obtained previously for the codling moth Cydia pomonella, the oriental fruit moth Grapholita molesta, the litchi moth Cryptophlebia peltastica and the macadamia nut borer T. batrachopa. Locally adapted populations were detected over local geographic areas for all species. No significant differences were found among population genetic structures as result of population history (whether native or introduced) although host range (whether oligophagous or polyphagous) had a small but significant effect. It is concluded that factors such as dispersal ability and agricultural practices have the most important effects on genetically structuring populations of the economically important Tortricidae in South Africa.