Tomato Leaf Miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) Detected in Namibe Province Angola

Aim: The aim of this study is to detect the presence of the South American tomato leaf miner Tuta absoluta (Meyrick 1917) (Lepidoptera: Gelechiidae) in Angola. This pest has recently attracted attention to the scientific community of Africa and worldwide due to its tomato destructive nature and its rapid spread. The invasion of T. absoluta in an area has negative impact on food safety, security and livelihood. Additionally, this may have ecological impact due to the loss of beneficial organisms by pesticides use, competition or co-existence with native arthropods and thereby perturbs the natural ecosystem. Chidege Methodology: Between 3 rd to15 th February 2017 the survey was conducted in tomato farms in order to determine the presence of the pest in the province. Result: During the survey, larvae were detected on the aerial parts of tomato ( Solanum lycopersicum L) plants and created blotched leaf galleries and superficial mines on fruits. Additionally, the adult male was investigated under stereo microscope which captures by a specific pheromone traps (TUA optima lure), thereby confirming and indicating the presence or absence of T. absoluta in the tomato fields. Conclusion: This is the first study on detection of tomato leaf miner, T. absoluta in Angola with its attendant destructive ability on tomatoes which should necessitate quick surveillance methods and management tactics before the situation gets out of control.

Methodology: Between 3 rd to15 th February 2017 the survey was conducted in tomato farms in order to determine the presence of the pest in the province.

Result:
During the survey, larvae were detected on the aerial parts of tomato (Solanum lycopersicum L) plants and created blotched leaf galleries and superficial mines on fruits. Additionally, the adult male was investigated under stereo microscope which captures by a specific pheromone traps (TUA optima lure), thereby confirming and indicating the presence or absence of T. absoluta in the tomato fields. Conclusion: This is the first study on detection of tomato leaf miner, T. absoluta in Angola with its attendant destructive ability on tomatoes which should necessitate quick surveillance methods and management tactics before the situation gets out of control.
Keywords: Detection; tomato; Invasive; Tuta absoluta; Namibe; Angola.  [1]. It is a native pest of South America but has spread to Africa, Asia and Central America. Since its introduction to Spain in 2006, it has invaded most of the countries in Europe, Mediterranean, Middle East, Northern, western and Eastern Africa and India in South Asia [2,3]. In Northern Africa, it was reported in Tunisia in 2008 [4], north of the Sahel in 2008 [3], Western Africa in 2010, Sudan and Ethiopia in 2011 [5], Kenya and Tanzania 2014 [6]. In these countries, it causes 80 to 100% crop loss when proper management technologies are not implemented [7]. The pest can reproduce 10-12 generations a year and each female can lay 250-300 eggs in her life span [3,8]. There are four (4) larval instars; the first two (2) instars mine the leaves by feeding on the mesophyll and leaving the epidermis intact, thus creating tunnels on the leaf commonly known as "mines". These mines reduce the photosynthetic surface of the leaves and result in early drying and eventual death of the plant. Later the third and fourth instar larvae leave the mines and bore into stalks, apical buds, and fruits. Pupation takes place in the mines, dried leaves or in soil [2]. This study reports the detection of T. absoluta in Namibe province of Angola.

Sampling, Data Collection and Identification
Tomato farms were surveyed based on the damage symptoms as directed by the officer incharge of province agriculture and rural development of Namibe province. In a crosssection pattern, 100 plants were examined in each field, with percent damages determined by counting number of damaged plants against the undamaged ones. Thus; % plant damages = No. damaged plants x 100/ total no. of plants examined [6]. These data were analysed using Ms-excel software to determine the Mean percent damages in each field surveyed.
The larval-infested tomato fruits, leaves and other plant debris were examined with the aid of hand lens and stereomicroscope. Furthermore, Tuta absoluta specific pheromone traps (TUA optima rule) from Russell IPM was installed on 09 March 2017 to catch adult male moths of the pest (Plate 1).

RESULTS AND DISCUSSION
In the survey, it was observed that, two out of four tomato farms were heavily infested. The mean plant damages inflicted by the pest in the two tomato farms were scored to be between 85% to 100% (Plate 2 and Table 1). This is a typical damage characteristic feature of T. absoluta when it invades an area as also reported by other arthors [9]. The fruit damages were observed to have characteristic holes in the surface and the leave's mesophyll tissues were mined between the upper and lower epidermis. The larva from the dissected tomatoes and leaves were creamy-white in the early instars an d green or pinkish with dark brown head in later instars. The adults were small (less than 7 mm in length), had grey to brown scales and black spots on anterior wings and filiform antennae (alternating white and black bands).
The larva mined the leaves (Plate 3), producing large galleries and later burrow into fruits.

CONCLUSION
The invasion of South American tomato leaf miner, T. absoluta (Meyrick 1917) (Lepidoptera: Gelechiidae) in Angola will impact negatively on the tomato industry as it has been reported many other countries if the government and other stakeholders does nothing about it The yield of marketable fruits will go down and production cost will go higher due to purchase of pesticides. Measures such as surveillance, awareness creation, capacity building and phytosanitary measures are crucial at this stage of invasion. Therefore, there is no time to keep quiet or wait for invasion by the pest before concrete steps are taken to combat the infestation. The country should therefore devise appropriate pest management approaches before it spread all over the country and beyond.
In view of the foregoing, we recommend the following measures: The government of Angola and research institutions should collaborate with other local or international organizations to undertake surveillance, develop and train growers and extension officers on environmentally-friendly management strategies against this pest including the possibility of utilizing local or exotic natural enemies to combat this pest.