Tomato leaf miner

Tuta absoluta

Crop: Tomato

Why is it a threat? Although not yet detected in Bhutan, tomato leaf miner is a devastating pest of tomato in Nepal and India. Tomatoes in both open fields and greenhouses are affected. It is proving to be very difficult and costly to control. Control measures currently rely on frequent use of insecticides, but their effectiveness is limited by the nature of the damage, and development of insecticide resistance is a serious risk. The pest has also been reported from potato, eggplant (brinjal) and common beans.

IDENTIFICATION

Identification of the tomato leaf miner

Adult moths are small (5-7 mm long and with a wingspan of 8-10 mm). The most important identifying characters is the filiform (bead like) antennae, silverfish-grey scales and characteristic black spots present on the fore-wing. Eggs are small (0.35 mm long), cylindrical, and creamy white to yellow. Larvae are cream in colour upon hatching, and have a characteristic dark head. They become greenish to light pink in second to fourth instars. Pupae are dark brown initially, becoming dark brown with time.

SYMPTOMS

Tomato leaf miner damage on stems, leaves and fruit

Pest damage can occur on seedlings through to mature plants. Larvae can feed on apical buds, leaves, stems, flowers and fruits, often leaving characteristic black frass (faeces). Larvae mine the leaves producing large, irregular galleries. They also burrow into the tomato fruit. Up to 100% of tomatoes can be damaged, making them unsaleable.

Damage on potato plants is mainly to the aerial parts, although damage to tubers is possible.

Confusion with other pests: The only insect pest currently reported to cause leaf-mining and boring damage to tomatoes and potatoes is the potato tuber moth (PTM). However, if in doubt contact NPPC for confirmation. PTM and a second caterpillar, the eggplant fruit borer (Leucinodes orbonalis), have been reported off eggplant (brinjal).

BIOLOGY

Life cycle of the tomato leaf miner

Lifecycle: The tomato leaf miner can lay up to 260 eggs each and can complete up to 10-12 generations a year under favourable conditions. The total lifecycle is completed within 30-35 days. Adults are nocturnal and hide between leaves during the day time. There are four larval instars (stages). Pupation may take place in the soil, on the leaf surface or within mines. The tomato leaf miner can overwinter as eggs, pupae or adults depending on environmental conditions. Larvae do not enter diapause when food is available.

Dispersal: Movement of infected tomatoes, tomato plants and used containers is known to be a high risk pathway. Outdoor markets that sell infested fruit (potentially sourced from India) would pose a great risk. Adults have been reported to fly up to 100 kilometres, so populations could easily spread once established in Bhutan.

When can damage be expected? The tomato leaf miner can cause serious damage throughout the tomato growing season.

Hosts: It is primarily a pest of tomato, but also attacks potatoes, eggplant (brinjal) and common beans.

MANAGEMENT PRACTICES

This pest has not yet been recorded in Bhutan. Please contact NPPC immediately if its presence is suspected.

Monitoring

Inspect tomato fields regularly for symptoms. Pheromone traps are available and will be used by the NPPC in 2017 to survey for this pest.

 

Version: NPPC 2017. Tomato leaf miner (Pest Alert) V1.0. Bhutan Pest Factsheet. www.PestsofBhutan.nppc.gov.bt. Date produced: 14 April 2017. Contact: nppcsemtokha@gmail.com

Image acknowledgements: http://www.tutaabsoluta.com/tuta-absoluta; An overview on Tuta absoluta, identification, origin, distribution, damage and economic impact. Prepared by Mr. Lalit P. Sah/ Agay P. Giri.

Print Friendly, PDF & Email