Tuta absoluta is a small leafminer belonging to Gelechiidae family (Order: Lepidoptera).
It causes economic damage, especially in tomato, with potential harvest losses up to 50-100% in untreated crops.
The Tuta larva pierces into leaves, stems and fruits. Also, secondary infections can occur at damaged sites.
This leafminer is also found in other ‘nightshade’ crops.
Tuta is native to South America. Since 2006 this species is also found in the Mediterranean, and recently in Western Europe.
This leafminer is 6-7 mm large with a wingspan of approximately 10 mm.
It is gray brown with dark spots on the anterior wings.
The small eggs are cylindrical. They are about 0.36 mm long and 0.22 mm wide and are creamy white to yellow.
The 1st larval stage is cream-coloured and about 0.5 mm long. As the larvae grow, they turn yellowish-green and have a black stripe at the back of their head. Full-grown larvae are greenish pink. Larvae of the 3rd stage are about 4.5 mm long and those of the 4th stage are about 7.5 mm.
Pupae are light brown and approximately 6 mm long.
The larvae pupate in a cocoon.
Tuta absoluta can reproduce extremely fast. The life cycle takes about 76.3 days at 14°C and 23.8 days at 27°C. It can breed 10 to 12 generations a year.
Adult leafminers are mainly active at night and hide between leaves during the daytime.
Over her lifespan, each Tuta-female deposits more than 200 eggs. Eggs are deposited preferentially on the underside of leaves or on young stems and sepals of unripe fruits.
After 3-5 days, the young larvae hatch and penetrate into leaves, young stems and fruits.
After they pass through the 11-19 days of the 4 larval stages, they pupate in the gallery, on the leaf or in the soil. The pupal stage lasts for 6-10 days.
Tuta absoluta can overwinter as an egg, pupa or adult. No overwintering has been observed in the Mediterranean.
Larvae do not enter diapause as long as food is available.
Males live about 6-7 days and females 10-15 days.
Tuta absoluta is considered today as one of the main pests in tomato. All stages can be found at the same time.
Damage manifests itself by the presence of bladder-shaped mines. Larvae feed on mesophyll tissue, hollowing out the leaf and leaving only the transparent epidermis. The larva deposits its excrements at the end of the mine. After some time, mines turn brownish and become necrotic.
Larvae can leave mines to attack other parts of the plant; for instance, they can penetrate in young stems and fruits.
Affected fruits show boreholes under and around the sepal.
Close to a borehole on a stem or fruit, heaps of dark, granular excrements are often found.
Affected fruits are unsuitable for sale and consumption.
If non-chemical and preventive measures result in insufficient control of the pest, support with products compatible with IPM might be necessary. Consult our Biobest website or Biobest advisor to discuss an appropriate approach.