A field guide to the management of economically important tephritid fruit flies in Africa

Abstract

Fruit and vegetabl~ production is one of the fastest-growing agricultural sectors in Africa, providing both income and employment to growers and exporters alike. The range of fruits and vegetables grown is diverse. Mangoes, citrus, apple, papaya, passion, guava, avocado, cucumber, pumpkin and watermelon are among the most common fruits and vegetables grown for domestic urban markets and for export to major outlets in Europe, the Middle East, Japan and USA. This growth is changing the dietary patterns leading to increased consumption of fruits and vegetables. However, different types of insect pests afflict production. in Africa, and perhaps none has gained greater notoriety than the fruit flies (Diptera: Tephritidae). The enormous losses they cause through direct damage to fruits and vegetables and loss of market opportunities through imposition of strict quarantine regulations by importing countries to prevent entry and establishment of fruit flies demand urgent need for implementation of sustainable management practices for fruit flies control. The introduction of uniform and strict quarantine restrictions and the maximum residue level (MRL) regulations in the European Union compound the existing fruit fly problem and jeopardise the lucrative export of fresh fruits and vegetables from Africa. Lack of local expertise in fruit fly management makes it difficult to respond in a timely and efficient manner to the challenges imposed by fruit flies. The correct identification of fruit flies occurring in a particular area and their damage symptoms is a first step towards developing appropriate management strategies. At the concluding meeting of the first phase of an FAO TCP project on surveillance and management of the invasive fruit fly species Bactrocera invadens in East Africa, and the Dutch Programme for Cooperation with International Institutions (Netherlands-S ill and !FAD-sponsored International Group Training Course on Fruit fly Management in October 2005, representatives of National Plant Protection Organisations (N PPOs) of participating countries expressed the need for development of a field manual for management of economically important tephritid fruit flies in Africa in view of the fruit fly-related trans-boundary invasions arising from increased travel and trade in fruits and vegetables. A request was therefore made to FAO to provide funds for the development of the 1st Edition of the manual in support of their fruit fly management activities in the region and the International Centre of Insect Physiology and Ecology (icipe) was mandated to develop the manual. The 1st Edition published in 2006 was well received as an indispensable reference book for agricultural scientists, extension workers and quarantine specialists involved in fruit fly monitoring, detection and management. Since the publication of the 1st Edition, many new advances have taken place in the various subjects especially on bioecology, monitoring and detection, field suppression and taxonomy of the economically important fruit flies in Africa. Th"is new information has been incorporated in the 2nd Edition generously funded by the USDA-APHIS and BMZ. The field guide provides information on the life cycle, damage symptoms, distribution and host plants of major fruit fly species of fruits and vegetables in Africa. The purpose, tools and methodology for fruit fly monitoring, suppression and host fruit processing and handling are also comprehensively covered. Additionally, brief sections on safety precautions during monitoring and suppression, and packaging, handling and shipment of specimens to facilitate identification are provided. The field guide also provides a simple, user-friendly taxonomic key to all the common fruit fly species to allow for rapid identificntion of the major species found on fruits in Africa. In addition to the four invasive Bactrocera species on the continent, other morphologically similar and closely related species to 8. invadens such as B. dorsalis, B. kandiensis and B. correcta have been included in this edition. Fortunately, these species are also strongly attracted to methyl eugenol, and it is therefore important that methyl eugenol catches are carefully examined (and not assumed to be only B. invadens) to avoid the possibility of any new detections going unnoticed. This manual is to be considered as a 'working document' to be regularly updated as fruit fly taxonomy and management techniques continue to improve and global experience in control programmes continues to expand.