Occurrence of the South American Tomato Leaf Miner, Tuta absoluta (Meyrick) in Southern Shan, Myanmar.

Aung Kyaw Oo,Ni Ni Htain,Sopana Yule,Paola Sotelo-Cardona,Ramasamy Srinivasan

doi:10.3390/insects12110962

Abstract

Simple SummaryTomato is the most important vegetable grown in Myanmar. However, its production is threatened by the invasion of the new insect pest, the South American tomato leaf miner, Tuta absoluta. Preliminary surveys on pest occurrence on tomato crops in Myanmar suggested the presence of T. absoluta in Southern Shan State, but there was no official survey conducted until the end of 2019. Therefore, this study aimed to confirm the presence of T. absoluta in Myanmar. Tuta absoluta presence was confirmed in all fields and locations surveyed in Myanmar, under two cultivation methods, (i.e., floating-and land cultivation). Higher infestation levels recorded at theKalaw location (land cultivation) seemed to correspond with plants at flowering and early harvesting stages. Moreover, information collected from the survey showed that the amount of T. absoluta larvae was significantly higher in the lower third of the plants followed by the middle section and upper section, respectively, in three fields of the survey.The South American tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), one of the most important invasive insect pests affecting tomato production worldwide, was for the first time detected in Myanmar. Preliminary surveys on pest occurrence on tomato crops in Myanmar suggested the presence of T. absoluta in Southern Shan State, but there was no official survey conducted until the end of 2019. Therefore, this study aimed to confirm the presence of T. absoluta in Myanmar. The presence of T. absoluta was specifically observed in the Southern Shan State, which is the largest tomato production area in Myanmar, where tomato is grown under two cultivation methods, floating and land cultivation. The highest T. absoluta infestation was recordedat Kalaw with (82%), followed by Inle Lake (i.e., floating cultivation) (20%) and Pin Ta Ya (10%). The amount of T. absoluta larvae was significantly higher in the lower third of the plants, followed by the middle section and upper section, respectively, in three fields surveyed. Potential and severe economic damage may be expected if management practices are not in place to reduce the presence of this invasive pest. It is of immediate importance that plant protection and quarantine offices of ASEAN member states coordinate their response to T. absoluta and build their capacity to monitor the pest and develop a strategy for when it arrives. In addition, a suitable management strategy is needed to reduce the occurrence of this invasive pest.

Highlights

Tomato is the most important vegetable grown in Myanmar, with three times more area harvested compared to the second and third vegetable crops, mustard and cabbage, respectively [1]
The presence of T. absoluta was observed in the Southern Shan State, which is the largest tomato production area in Myanmar, where tomato is grown under two cultivation methods, floating and land cultivation
Tuta absoluta was recorded in Southern Shan State in December 2019 (Figures 1 and 2)

Summary

Introduction

Tomato is the most important vegetable grown in Myanmar, with three times more area harvested compared to the second and third vegetable crops, mustard and cabbage, respectively [1]. Since T. absoluta has been already detected throughout India and Central Asia, there is a high possibility that sooner or later this pest will spread across borders to tomato production areas in Southeast Asian countries. Tuta absoluta larva feeds on the mesophyll of aerial parts of the plant and creates mine blotches on leaves, stems, buds and fruits [11,12] This insect feeds primarily on tomato (Solanum lycopersicum L.), but other solanaceous and non-solanaceous crops including potato (Solanum tuberosum L.), eggplant (Solanum melongena L.), melon pear (Solanum muricatum Aiton), spinach (Spinacia oleracea L.), alfalfa (Medicago sativa L.), beet (Beta vulgaris L.), watermelon (Citrullus lanatus (Thunberg) Matsumura & Nakai) and common bean (Phaseolus vulgaris L.) can serve as secondary hosts [13,14,15]. If management strategies are not in place, direct economic losses can be up to 80–100% on tomato production [14,16]

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