Plantwise Factsheets for Farmers
Sprays against Tuta tomato leaf miner
Recognize the problem
Tomato leaf miner is a
devastating pest of tomatoes. It is also known as Tuta absoluta, Tomato
moth, or kidomozi wa nyanya in Kiswahili.
Tomato leaf miner adults are small silver-grey moths with black spots on
their inner wings. They are about ½ cm long and have wings of about 1 cm if
spread. They hide under leaves in the daytime. Young larvae in the tunnels
are creamy-greenish with a dark head but later turn pinkish-green. They are
tiny and feed in tunnels (galleries) through young leaves and into young
fruits. The larvae destroy leaves and fruits. Note that single ½ cm holes on
upper part of tomato fruits are caused by bollworms not by Tuta.
The life cycle of Tuta only takes about 1 month so they can multiply 10 to 12 times
per year. The moth lays more than 200 eggs from which the damaging larvae hatch.
The larvae must be controlled because they are so destructive. Foliar sprays
of biological or synthetic pesticides might help. Sprays may only help
against young larvae so act when you first see symptoms. Pupation of larvae
happens in the soil below the plants so pupae are hidden from treatment.
- Spray early in the morning
when the larvae of leaf miners are not active and are still on the leaves
- Preferably, use
biopesticides like the microbial sprays of Bacillus thuringiensis var. kurstaki over synthetic pesticides
like Imidacloprid because
they are less dangerous to you and to tomato consumers
are several products based on Bacillus
thuringiensis such as BN3 WP, Ascopel WP and others. They are also called
Bt products. Follow
instructions on the product label for dosages.
needed, spray twice per season but with at least 1 week interval between
sprays. Do not enter the field for a day after spraying.
not spray the day before a harvest
- If you still experience
infestation, then use products with the active ingredient Imidacloprid such as Hotshot 70WG
and Imax 700WDG
are often mixed at 10ml product per 20 litres water sprayed per acre but
double-check with product labels, because products have different concentrations
only once per season
not spray later than 3 days before harvest, and do not enter the field for 1
day after spraying, as the product is toxic
of bio or synthetic pesticide, you must wear gloves, mask, googles, overcoat, gumboots
during mixing, spraying and cleaning
When using a pesticide, always wear protective clothing and follow the instructions on the product label, such as dosage, timing of application, and pre-harvest interval.
The recommendations in this factsheet are relevant to:
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