The tomato leafminer, Tuta absoluta is an invasive pest that can completely destroy tomato crops. It originates from South America and has spread into several European and African countries. It has recently been detected in traps in Mauritius and represents a potential threat to tomato crops in the country.
Description / Biology
Adult: About 6 mm long with silverfish-grey scales and characteristic black spots present on its anterior wings. The adult female can lay about 260 eggs during her lifetime.
Egg: 0.35 mm long, cylindrical, creamy white to yellow. Eggs are laid underneath leaves and stem
Larva: 0.9 – 8.0 mm long with 4 larval instars, the larva is initially cream in colour but turns greenish to light pink in 2nd to 4th instar. The prothroracic shield is green with a black line; Larval period is completed in 12 – 15 days.
Pupa: Initially greenish, turning brown nearing adult emergence. Pupation takes place in the soil, on the surface or within mines. The pupal period lasts 9 – 11 days.
Damage / Symptoms
Tuta absoluta larvae feed on leaves, stems, buds, flowers, calyces and fruits. On leaves they make distinctive patchy mines. Inside these mines both the larvae and their dark frass can be found. So far damage on tomato plants have not been detected in the country.
Damage on leaves
Damage on stem
Damage on fruits
Other host plants
Potato, eggplant, beans, pepino, brède martin, bringelle marron and datura.
- Practice crop rotation, that is, avoid renewing tomato or having a succession of crops of the Solanaceae family (including potato, tomato, pepper, eggplant).
- Between planting cycles, plough the soil and cover with plastic mulch or perform solarisation.
- Control weeds to prevent multiplication in alternative weed hosts (especially Solanum nigrum, Datura).
- Produce seedlings under protected structures to ensure pest free plants
- Two weeks before transplanting, place pheromone-baited traps sticky traps (1 – 4/ha). The lure septa lasts for 4 weeks. The trap height should be adapted according to the growth stage of the plant .
- Inspect the crop regularly to detect the first signs of damage.
- As soon as more than 3 – 4 moths per trap are captured each week, start mass trapping of moths. Traps are available at the Entomology Division of the Agricultural Services.
- For mass trapping of moths, use sticky traps (20 – 40 traps/ha) baited with pheromone or use pheromone gel at the rate of 100 drops per ha (one drop every 10 metres).
- Keep using pheromone traps for at least 3 weeks after removing the crop; this catches emerging male moths.
- Sanitation (Remove and destroy attacked plant parts). When harvest is over, destroy crop residues to avoid proliferation of Tuta absoluta.
- The following products are recommended for control of larvae in case detected on plants
Synthetic chemical insecticides:
|Product||–||Active ingredient||–||Dosage/L||–||PHI (days)|
|Steward 30 WG||Indoxacarb||0.25g||3|
|Coragen 200 SC||Chlorantraniliprole||0.25 mL||2|
|Tracer 480 SC||Spinosad||0.25 mL||7|
|Radiant 11.7 SC||Spinetoram||0.5 mL||2|
|Runner 240 SC||Methoxyfenozide||1.0 mL||7|
|Belt 480 SC||Flubendiamide||0.1 mL||2|
|Missile 5% WDG||Emamectine benzoate||0.3g||7|
|Product||—||Active ingredient||—||Dosage/L||—||PHI (days)|
|Neem-a-life||Azadirachtin 0.1 %||3.0 mL||1|
|Dipel/BTOne||Bacillus thuringiensis 16,000 IU/mg||2.0 g||1|
|Biocure||Bacillus thuringiensis 32,000 IU/mg||1.0 g||1|
|Fabulous/EB||Empedobacter brevis 1x 10**10 spores/mL||2.5 mL||1|