Pest status, bio-ecology and management of the false codling moth, Thaumatotibia leucotreta (Meyrick) (Lepidoptera: Tortricidae) and its implication for international trade

The false codling moth (FCM), Thaumatotibia leucotreta (Lepidoptera: Tortricidae) is an insect pest which represents an important threat to the production and marketing of a wide range of agricultural crops in the African-Caribbean-Pacific (ACP) countries. The FCM reduces not only the yield and quality of the crop but also as a quarantine insect pest, restricts the trade of susceptible agricultural produce on the international market. In addition, little research has been conducted in the ACP countries on the bio-ecology and sustainable management of this pest, especially on vegetables for export. Thus, action-oriented research aimed at understanding the bio-ecology of this important pest is essential to achieve effective management. Various management interventions against this pest have been used in some parts of the world, especially in South Africa on citrus. Currently, farm sanitation is regarded as the key management strategy. Exploring and improving on other interventions such as Sterile Insect Technique, monitoring and mass trapping of male moths, augmentative biological control, use of bio-pesticides, protected cultivation and cold treatment may help to mitigate the expansion of FCM into other countries, especially in the European and Mediterranean Plant Protection Organization region where it has become a regulated insect pest since 2014. This review discussed the bio-ecology of FCM and highlighted some of the challenges and opportunities for its effective management and its implication for international trade, especially the export of chillies from the ACP countries into the European Union market which requires strict phytosanitary regulations.

The potential distribution of Bactrocera dorsalis: considering phenology and irrigation patterns

A species in the Bactrocera dorsalis (Hendel) complex was detected in Kenya during 2003 and classified as Bactrocera invadens Drew, Tsuruta & White. Having spread rapidly throughout Africa, it threatens agriculture due to crop damage and loss of market access. In a recent revision of the B. dorsalis complex, B. invadens was incorporated into the species B. dorsalis. The potential distribution of B. dorsalis has been previously modelled. However, previous models were based on presence data and did not incorporate information on the seasonal phenology of B. dorsalis, nor on the possible influence that irrigation may have on its distribution. Methyl eugenol-baited traps were used to collect B. dorsalis in Africa. Seasonal phenology data, measured as fly abundance throughout the year, was related to each location's climate to infer climatic growth response parameters. These functions were used along with African distribution records and development studies to fit the niche model for B. dorsalis, using independent global distribution records outside Africa for model validation. Areas at greatest risk of invasion by B. dorsalis are South and Central America, Mexico, southernmost USA, parts of the Mediterranean coast, parts of Southern and Eastern Australia and New Zealand's North Island. Under irrigation, most of Africa and Australia appear climatically suitable.

Comparison of five allopatric fruit fly parasitoid populations (Psyttalia species) (Hymenoptera: Braconidae) from coffee fields using morphometric and molecular methods

Morphometric studies of five allopatric parasitoid populations (genus Psyttalia Walker) from coffee plantations in Cameroon (Nkolbisson), Ghana (Tafo) and Kenya (Rurima, Ruiru and Shimba Hills) and one non-coffee population (from Muhaka, Kenya) were compared with individuals of Psyttalia concolor (Szépligeti), a species released in several biological control programmes in the Mediterranean Region since the 20th Century. Analyses of wing vein measurements showed the second submarginal cell of the fore wing and its adjoining veins had the heaviest principal component weights and served as the main contributing variables in the diagnostic differentiation of the populations. Two populations (Rurima and Ruiru) were found to be the closest to each other and with the strongest phenetic affinity toward P. concolor (and forming one cluster). Populations from Shimba Hills (of unknown identity), Nkolbisson (P. perproximus (Silvestri)) and Tafo formed a second cluster and were separated from P. concolor. Comparison using amplified fragment length polymorphism (AFLP) also showed the Shimba, Nkolbisson and Tafo populations forming a cluster in a dendrogram generated from their genetic distances, with the Shimba and Tafo populations placed as the most closely related species. Based on consistent morphological similarities, morphometric and ecological data coupled with the genetic evidence from AFLP data, the Shimba population is suggested as belonging to the P. perproximus group and, thus, represents a new occurrence record in Kenya. Our results also support earlier conclusion from cross mating data that populations from Rurima and Ruiru belong to the Psyttalia concolor species-group.

Molecular diagnostics of economically important Ceratitis fruit fly species (Diptera: Tephritidae) in Africa using PCR and RFLP analyses

The predominantly Afrotropical fruit fly genus Ceratitis contains many species of agricultural importance. Consequently, quarantine of Ceratitis species is a major concern for governmental regulatory agencies. Although diagnostic keys exist for identification of all described Ceratitis species, these tools are based on adult characters. Flies intercepted at ports of entry are usually immatures, and Ceratitis species cannot be diagnosed based on larval morphology. To facilitate identification of Ceratitis pests at ports of entry, this study explores the utility of DNA-based diagnostic tools for a select group of Ceratitis species and related tephritids, some of which infest agriculturally important crops in Africa. The application of the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method to analyse three mitochondrial genes (12S ribosomal RNA, 16S ribosomal RNA, and NADH-dehydrogenase subunit 6) is sufficient to diagnose 25 species and two species clusters. PCR analysis of the internal transcribed spacer region 1 (ITS-1) is able to distinguish three of the five species left unresolved by mitochondrial DNA analysis.