First record of South American tomato moth, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) in Tamil Nadu, India

: The South American tomato moth (SATM), Tuta absoluta is a quarantine pest, native to South America which was detected first time in Maharastra, India in late 2014 and then in Karnataka.The border district of Tamil Nadu was under vigil to monitor the activity through regular surveillance from March 2015 to know the presence of SATM in Dharmapuri district and the occurrence of T. absoluta was first noticed in Karimangalam block in the tomato hybrid Sivam. The widely cultivated tomato hybrids Sivam and Sagar were equally susceptible to the SATM with 20-32 per cent leaf damage and 28 - 53 per cent fruit damage. The sex pheromone traps attracted more number of adults per day. The damage was mostly found in the middle and lower leaves and half ripened and ripened fruits. In a single fruit 8-12 holes were noticed during the survey. This is the first report of this pest in Tamil Nadu. Main characteristics of the species are briefly reviewed, with notes on biology, distribution and damage. © 2016 Association for Advancement of Entomology

Non-native invasive insect species are a significant threat to biodiversity and their ecological impacts are difficult to reverse.They also affect economic interests particularly within agriculture, horticulture and forestry (Mace and Kunin, 1994).The South American tomato moth (SATM), Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is one such pest, originating from South America, that devastates tomato and closely related solanaceous crops in the world since, 1960since, 's (EPPO, 2005)).In 2004, T. Absoluta was added by the European and Mediterranean Plant Protection Organization (EPPO) to the A1 List of pests recommended for regulation (pests absent from the EPPO region), and in 2009 was transferred to the A2 list (pests locally present in the EPPO region), 3 years after its arrival in Spain (Urbaneja et al., 2007).During 2006-2012, the pest spread rapidly throughout the Mediterranean basin.Tuta absoluta is considered a typical invasive species, due to its capacity to develop very quickly in suitable agro-ecological conditions, spreading rapidly in new areas and causing economical damage (Desneux et al., 2010).
In India, it was first reported from Pune, Maharashtra during October 2014 (ICAR, 2014) and has rapidly moved across the states and later detected in Karnataka during the rabi (November) season of 2014, where, it has become a serious threat to tomato production in both greenhouse and outdoor crops (Sridhar et al., 2014).Since then alert notice was issued by the Indian Council of Agricultural Research to keep vigil on the incidence of T. absoluta in different states.As a district adjoining to Karnataka, regular surveillance was conducted by scientists of Tamil Nadu Agricultural University in Dharmapuri district particularly in the border blocks.In Dharmapuri district tomato has been cultivated in 4000 hectares in which 40% area is under precision farming.
Tomato plants can be infested from seedlings to mature plants.T. absoluta reduces yield and fruit quality, causing up to 100% yield losses in severely infested crops (Arturo et al., 2012).The main damage is produced on the leaves and fruits, but inflorescences and stems can also be affected.Larvae of T. absoluta feed on the mesophyll of the leaf leaving only the epidermis intact.The galleries produced by young larvae may be confused with those produced by leafminers (Liriomyza spp.), but the gallery produced by T. absoluta subsequently widens and the damaged tissue dries.In the gallery, the larvae of the moth and its black frass can be seen.The economic impact is reflected by an increase in the cost of tomato production (additional costs for crop protection) and yield loss (lower marketable fruits production), as well as potential loss of markets if it were to become established.It is also very challenging to manage and limit the spread of the pest.Hence, there is an urgent need for domestic quarantine measures to curtail the pest from spreading further to other tomato growing regions of Tamil Nadu.The nature of spread, occurrence, damage potential and management options of T. absoluta in Tamil Nadu are discussed in this paper.
Explorative surveys were conducted in the border blocks of Dharmapuri district viz., Karimangalam and Palacode where tomato has been grown throughout the year in the district.Subsequently, during June 2015 a survey was conducted in five major tomato growing districts of Tamil Nadu viz., Dharmapuri, Krishnagiri, Salem, Coimbatore and Dindigul to assess the extent of spread and damage.Varieties viz., Sivam and Sagar, US800, US1036 and Ruchi are widely cultivated.The 25-30 days old portray seedlings from shade net nurseries were procured and planted in the main field.Periodical surveys were conducted to monitor the incidence of SATM damage in the leaves and fruits.After noticing the initial damage in the field, the leaf damage was recorded at weekly intervals in randomly selected 25 plants.The fruit damage was calculated in the selected plants and also during harvest.The pin hole damaged fruits were sorted out during the harvest and percentage of affected fruits calculated to the total harvest during each harvest.To monitor the adult movement sex pheromone lure of T. absoluta from Pest control India Ltd., was installed in the field.Ten traps were installed for 0.4 ha.field.The number of adults collected and counted each day in these traps.
In March 2015, T. absoluta incidence was first noticed in the Kollupatti village of Karimangalam block in 45 days old crop.Followed by the detection of T. absoluta, 100 per cent damage was recorded in Jittandahalli, Palacode (Block), Dharmapuri District (Table 1).The per cent damage was low (43 %) in Velampatti, Nallampalli (Block), Dharmapuri District.As the leaf miner Liriomyza trifolii (Burgess) and T. absoluta incidence occurred simultaneously in the field the farmers were unable to distinguish between the damage symptoms.The coalescing of mines in the T. absoluta damage was different from that of leaf miner L. trifolii damage symptom.Initially T. absoluta larvae mines the leaves, later the mines coalesce to become necrotic lesions.The damage was noticed in 30-40 days old crop.The young and unripened fruits are not infested by T. absoluta.The damage was noticed mostly in the ripened and semi ripened fruits.The adult movement was noticed during the evening hours.In a single fruit a maximum 8 -12 holes were noticed during the survey.In the half ripened fruits the damage was noticed in the inter lobe and soft regions of the fruit.Recent survey on major tomato growing districts of Tamil Nadu also revealed that the pest has spread rapidly into neighbouring districts and the extent of damage ranged from 20-38 and 30-48 per cent on leaf and fruits, respectively.Maximum leaf (38%) and fruit damage (48%) was recorded in Dharmapuri district (Table 2).
the damage was almost equal in all the hybrids (Table 4).As the damage is more than 50% during the survey the further spread of this pest in Tamil Nadu will hamper the tomato cultivation.T. absoluta, originating from South America, has become one of the key pests of tomato in many South American countries since the 1960s (Garcia and Espul, 1982).It has been listed in the A2 quarantine list of the European Plant Protection Organization (EPPO, 2010).Feeding of the pest on other host plants of the Solanaceae family was also recorded (Pereyra and Sanchez, 2006).The moth can develop very quickly under suitable agroecological conditions and can breed 10 to 12 generations a year depending on environmental conditions.Control is extremely difficult once the pest is well established because the larvae are internal feeders.Hence, suitable integrated pest management strategies should be developed to manage T. absoluta effectively.
The pheromone traps kept in the field are able to trap 40 -50 adults on the first day itself with the maximum of 102 adults per trap.The adults are silvery grey to brown with brown to black scales on the forewings.Adults are 6 -7 mm long with a wing span of about 8 -10 mm (Kilic, 2010).Taha et al., (2013) revealed that the pheromone baited traps alone recorded 37.44 per cent incidence of T. absoluta and concluded that the pheromone traps

Table 1 . Incidence of T. absoluta in different villages in two Districts Table 2. Incidence of T. absoluta in five major tomato growing districts of Tamil Nadu
As the insect has several other Solanaceae host plants chances are high for its occurrence on other crops, weeds, and wild plants also.Hence, continuous monitoring/ surveillance are required to contain the spread and timely adoption of management practices can further reduce the yield loss.

Table 4 . Incidence of T. absoluta in different tomato hybrids Tomato hybrids Per cent damage*
* Mean of ten fields P.S. Shanmugam et al.