Nature of Damage

Tuta absoluta is a devastating pest of tomato. The Larva feeds voraciously upon tomato plants, producing large galleries in leaves, burrowing in stalks, and consuming apical buds and green and ripe fruits. It is capable of causing a yield loss of 100%. Tomato is the main host plant, but Tuta absuluta also attacks other crop plants of the solanaceae family, including potato, brinjal, chilli, capsicum and tobacco. The infestation of Tuta absoluta is very challenging to control. Effectiveness of chemical control is limited due to insect’s nature of damage as well as its rapid capability of development of insecticide resistant strains.

Life Cycle

Tuta absoluta is a micro lepidopteron moth with high reproductive potential. The life cycle of a leaf miner includes some distinct stages; egg, larva, pupa, and adult. The total life cycle is completed within 30 – 35 days. Egg stage lasts for 7 days.

The eggs tend to be laid on the underside of the leaves of the host plant. Eggs are small cylindrical, creamy white to yellow 0.35 mm long. Egg hatching takes place 4-6 days after egg lying.

The larva is cream in colour with characteristic dark head. Four larval instars develop. Larvae do not enter diapause when food is available. The larvae becoming greenish to light pink in second to fourth instars. Larval period is most damaging period which completes within 12 – 15 days. After 4 larval instars, the larvae will fall to the ground in a silken thread, ready to begin pupation in the soil.

The pupal stage is of 5 days. Development of pupa takes place in the soil and occasionally on plant parts such as the stem or within mines. Tuta absoluta can overwinter as eggs, pupae or adults depending on environmental conditions.

Adult moths of Tuta absoluta are relatively small with a body length of 5 – 7 mm. The body is brown in colour with darker flecks of colour on each wing. The most important identifying characters are the filiform antennae (bead like antennae), silverfish-grey scales and characteristic black sports present in anterior wing. Adults are nocturnal and hide between leaves during the day time. Adult females lay eggs on host plants and mature female could lay up to 260 eggs before completing life cycle. The stage lasts for 9 days. The adult month has a wingspan around one centimetre. In favourable weather conditions eight to ten generations can occur in a single year.