How to control Tuta absoluta in tomatoes

Tuta absoluta is an insect pest that attacks tomato plants. Left unchecked, they can destroy your tomato crop within days. Since they were discovered not too long ago, they have caused major losses for tomato farmers. Farmers struggled to contain them until these techniques were developed.

You have these techniques to get rid of them:

Insect Traps

Plowing and solarization

Burning infected plant parts

Insect nets around the greenhouses

Biological control

Chemical control

Techniques for Tuta absoluta control

tuta absoluta in tomatoes
Tuta absoluta

Insect traps like the one used against Tuta absoluta come in various forms. The sex pheromone trap which can be tailored to target the Tuta pests is preferred over other insect traps. When it comes to getting rid of Tuta absoluta, the first option should always be organic or integrated.

Sex pheromone traps

The sex pheromone trap is one of the most effective non-chemical techniques for Tuta absoluta control. You are probably wondering what this is.

 The pheromone trap is a technique for catching and killing male Tuta absoluta flies. It borrows its name from the type of hormone called pheromone. Pheromones are released by female Tuta absoluta to attract the males when they are ready to start reproducing.

When the males detect the scent, they move towards it in the hope of finding a partner to mate with. It is their instinct for survival. The trap takes advantage of this response using that pheromone produced by the female Tuta absoluta to attract the males.

The pheromone is extracted from the female and placed inside a slow-release capsule. This capsule releases small doses into the air as the wind passes over it until it is empty.

Sticky sex pheromone trap

The capsule is placed on a sticky piece of paper which is then folded to form a hollow paper prism. You suspend the trap on a tick anywhere on the farm. The male species will be attracted by the pheromone.

tuta absoluta in tomatoes pheromone trap
Pheromone trap for tuta absoluta

Tuta absoluta control sex pheromone trap

When they get to the trap they will land on the surfaces around the trap which are sticky. They will starve and then die. You can actually make some of these sticky traps on your own with some sugar water and yellow or white plastic bags.

You then smear wrap a piece of plastic with the plastic bag and smear its surface with the sugar water. Fold the paper into the triangular prism shape I described above and voila. I have seen this work.

Soapy water technique

Another way of using the pheromone is with a water trap instead of sticky paper. You fill a trough with water and add a little soap.

The soap breaks the thin layer that forms on water which allows insects to walk on water. After you add soap, any insect that lands on that water will drown.

You then take your pheromone capsule and suspend it over the trough near the water surface using a wire or a stick attached to the ground. It will attract the male species and when they come and land on the water where they will drown.

tuta absoluta in tomatoes soapy water trap
Tuta absoluta in tomatoes soapy water trap

The goal is to kill the males so that the females have no mates. If they have no mates, no reproduction will take place and the population will slowly decrease until they die.

You have to maintain the traps to ensure no resurgence occurs.

Also, keep checking the traps to see if you need to change the water on the sticky paper.

Make sure the glue is still sticky and there is more room for other males to stick to it.

Plowing, solarisation, and burning of plants

There are various mechanical methods for Tuta absoluta control which when used together are very effective against the Tuta absoluta moth.

ploughing and solarisation
Solarization

These are plowing, harrowing, solarization and burning. They work well before during and after the planting season has ended.

As you prepare your land, it is good practice to plow early and expose the lower soil to the sun. This practice is called solarisation.

Getting exposed to the sun kills many pathogens, insect larvae, and eggs in the soil. This includes the eggs of the Tuta absoluta moth.

During the season and when the season ends, you can walk around the farm or greenhouse and prune out the infected plant or plant part. You can tell the leaves are infected when you see tunnels in the leaf fruits infected with Tuta absoluta are deformed and have black spots on their surfaces.

Prepare a hole far from the farm and burn them. This will destroy any chance the eggs had of hatching.

You might also like: Pruning Time: When To Start Pruning Tomato Plants

Insect nets around the greenhouse openings

tomato plants in an insect net
Tomatoes in an insect net

If you are growing your tomatoes in a greenhouse, invest in an insect net to cover the vents and any open spaces. Make sure that any tears are repaired so the insect has no way to get into your greenhouse.

Biological control of Tuta absoluta

Biocontrol refers to setting other harmful microorganisms and predator pests against Tuta absoluta. There are bacteria and nematodes that will kill Tuta absoluta.

Bacteria like Bacillus thurigensis target the Tuta larvae while the nematode called Nesidiocorus tenuis targets the eggs.

Organisms can be bought from specialized companies that make them. You can find one that delivers with a quick search on the internet

Chemical control of Tuta absoluta

This is the most commonly used method out in the field for Tuta absoluta control. It works best when used as a control measure. When I say control I mean you have to spray it regularly on the farm to keep the pest at bay.

If you have to wait till you see symptoms, you might be too late or might require more invasive and expensive intervention.

You can use any insecticide in recommended doses at regular intervals. Ask your local specialist about what is available in your region.

Get any insecticide with abamectin, indoxacarb, chlorantraniliprole will do.

Ask for local advice because of regulations, some of these components may be available in different formulations or there may alternatives that work where live.

How to identify Tuta absoluta symptoms from their damage

White spots (eggs) on leaves

They lay their eggs on tomato leaves and tomato flowers before they fully develop. You can see the eggs like tiny white spots, especially on the lower leaves.

The fruit matures with the eggs inside it. When the eggs hatch, they begin feeding on the fruit and boreholes through it making it unfit for the market.

Tunnels or cavities on the tomato plant leaves

leaf eaten by tuta absoluta
Leaf eaten by tuta absoluta

While on the leaves, their eggs hatch and make tunnels inside the leaves. Unlike the whitefly which forms continuous tunnels, Tuta absoluta concentrates their tunnels around where they hatched till they form a cavity.

The insects later mature turn into flies and lay more eggs. These eggs hatch and the larvae do the same thing.

Scars on fruits where larvae emerge and tiny fruits

tomato fruit ravaged by Tuta absoluta
Tomato fruit ravaged by Tuta absoluta

When they do this over a long period, the leaves will no longer have the capacity to produce food because most of them have been eaten off by the insect.

Moths flying around on the farm

tuta absoluta in tomatoes
Tuta absoluta

You may notice moths flying from plants when you touch the leaves exposing their undersides. They are very active in the morning and later in the evening because they like to avoid the sun.

Leaves are drying up

In the advanced stages, the plant leaves begin drying up and turning brown as shown in the feature image. The fruits form black spots where the larvae used to leave the fruit after they had hatched.

The end result is a plant with dead leaves that cannot produce fruit or has deformed fruits, till it eventually dies.

Read More

How to treat blossom end rot in tomatoes (black rot at the base of the fruit)

How to identify tomato bacterial wilt symptoms fast

How to identify tomato early blight symptoms

How to identify late tomato blight in the farm

Can Tomato Grafting Make Your Tomatoes Stronger?

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