Tuta Absoluta – the tomato ‘Ebola’

•The pest, which has earned itself an infamous nickname – the Ebola of tomato – is considered to be one of the most devastating tomato pests.

By MOSES KABAILA jr –

RECENTLY, local media in Nigeria reported that a state of emergency had been declared in the tomato sector of Nigeria’s Kaduna State. A moth called the Tomato Leaf Miner or Tuta Absoluta had ravaged about 80 per cent of tomato farms.
The ravaging of the tomato farm by the Leaf Miner triggered the basket price of tomatoes from US1.20 to US$40 as of last week.
According to an item on BBC news, renowned business executives of Nigeria like Aliko Dangote, who owns a tomato paste manufacturing business, stopped production temporarily.
While this desolation was happening in Nigeria and other parts of Africa, Zambia has not been an exception from the Leaf Miner, especially this year.
The moth has silently been wreaking havoc in most small-scale tomato farms in the country.
The challenge for the Zambian local farmer has understood what exactly has hit them and their tomato fields as the spraying of insecticides, pesticides and fungicides have in most cases proved to be ineffective.
Even the time when local tomato prices sky rocketted to a record K300-K350 per box, it was unclear what had pushed up the cost of the red vegetable.
One local prominent farmer in Chisamba area last month had four hectares of his seven-hectare tomato field ravaged by the pests.
The advice to the farmer by local agronomists was to get rid of the entire infected area of four hectares so as to protect the other three hectares that was not infected.
The tomato crop was already at its flowering and fruit stage.
Another farm on the Ndola-Mufulira Road was recently ransacked by the tomato borer (Tuta Absoluta), leaving two hectares of tomatoes with a short harvesting lifespan than projected.
To date, a number of local farms have been attacked by the Leaf Miner and farmers are desperately
trying to understand what is causing them not to yield desired results from their tomato farms.
With a loss of hundreds of tomato hectares around the country, it was inevitable that the vegetable would fetch more on the local market.
Tuta Absoluta – the tomato Leaf Miner or tomato borer – is a South American tomato pest, a micro lepidopteran (insect) moth that recently originated from Europe.
It has a high reproductive potential.
Its main host is tomato, but it also infests other solanaceae crops like egg plants and potatoes.
The pest, which has earned itself an infamous nickname – the Ebola of tomato – is considered to be one of the most devastating tomato pests.
It was detected for the first time in Europe, particularly in Spain in 2006 and since then, it has continued to spread very quickly along the Mediterranean Basin and to other central, northern European and African countries.
From Spain in 2006, other countries subsequently followed, with Morocco recording the presence of the Leaf Miner in 2007, Tunisia in 2008.
France was next the same year, in 2008, and so was Italy, the Cannary Islands and Algeria.
Other places, like the United Kingdom (UK), were hit later in 2009 and in 2010, one of the great nations in terms of agriculture, Israel,  was struck with the Tuta Absoluta moth.
A research conducted by the Office of International Research, Education and Development, showed that African countries, like Sudan, Niger, Senegal and Ethiopia had their tomato fields ravaged in 2012 by the same moth.
The successive year in 2013, Ethiopia, one of the most affected countries with the Tuta Absoluta pest at the time, organised an international workshop to meet the challenge of the tomato Leaf Miner.
The research also predicted that Tuta Absoluta would continue spreading through west and central Africa downwards in the coming years.
When the pest was detected in Spain in the first year of introduction, pesticides were applied 15 times per season and the cost went up by 450 Euros per hectare.
It is also estimated that when Tuta Absoluta invades the rest of the world, the tomato pest management cost will go up by US$500 million per year.
By the year 2009, the world’s production of tomatoes was about 152 million tonnes with a production area of 4.4 million hectares.
The top 10 tomato producing countries at the time were China, USA, India, Turkey, Egypt, Italy, Iran, Spain, Brazil, and Mexico.
In 2011, Tuta Absoluta infested 1.0m hectares of tomato cultivated area (22 per cent of cultivated surface).
Again today, the pest is a threat to Asia and Africa (south of Sahara) including Nigeria, which has 5 per cent of tomato cultivated in the world.
As stated by a training paper by the Institute of Agrifood Research and Technology (IRTA), tomato plants can be attacked from seedlings through to mature plants and in severely infested tomato crops, the Leaf Miner may cause yield losses of up to 100 per cent.
The main damage is produced on the leaves and on the fruits.
The larvae of Tuta Absoluta feed on the inner tissue called mesophyll of the leaf producing galleries and can also penetrate the fruit and stems.
Research has revealed that the moth has a high reproductive potential and a life cycle that can take from 24 to 76 days, depending on environmental conditions.
Adults are silvery gray with black spots on the forewings and a wingspan reaching 10mm.
Their activity is concentrated in the early morning and dusk. During the rest of the day, they remain hidden among the leaves.
Adult lifespan ranges between 10 and 15 days for females and 6–7 days for males.
The female lay eggs mainly on the leaves, although they can also be found on stems and sepals.
Eggs are laid in isolated places thus facilitating their distribution on the crop.
The number of eggs per female is usually between 40 and 50 and may reach 260.
Eggs are small, 0.35mm long, cylindrical and creamy white to yellow.
Egg hatching takes 4-6 days.
Young larvae are cream in colour with a dark head. As they develop, the larvae become greener and slightly pink in the last development stage known as instar.
Larval development goes through four stages and pupation may take place in the soil, on the leaves and even within the galleries or other parts of the plant.
The pupa is cylindrical and greenish when recently formed, later turning brown.
It may be protected by a silky white cocoon.
To control the pest effectively, it is critical to combine all available control measures, including cultural methods, biological control agents and the correct use of registered pesticides.
However, because, Tuta Absoluta has high reproduction capacity and short generation cycle, the pest is at a higher risk of developing resistance to insecticides.
This risk increases significantly when management of the pest relies exclusively on chemical control with a limited number of effective insecticides available.
This situation usually leads to an increase in the frequency of use and thus, increased selection pressure for resistance.
To avoid potential crop damage, it is very important to detect symptoms early and especially the eggs or small galleries.
Chemical control of the pest is especially difficult because the larvae live inside leaves, fruits and stems.
Therefore, it is crucial to avoid systematic applications and only apply treatments according to pest population density and crop damage following the recommendations of professional advisers.
It is also essential to alternate the use of active substances with different modes of actions.
So what can a nation like Zambia, which is trying to find its feet in the world of modern agriculture breakthrough for economic recovery and future agriculture dependence do in order to control this pest as reversing the spread has already been pronounced to be difficult?
Experts advise that though a silver bullet for Tuta Absoluta has not been found yet, it is possible to control the pest effectively.
First of all, it is critical to combine all the control measures available and not to rely only on insecticide sprays.
It is very important to pay attention to the side effects of pesticides on natural enemies, especially predatory bugs which help in the controlling of bad bugs.
The insecticide should be selected carefully, especially in the early growth stages of the tomato crop.
Farmers should use tomato transplants free of pests.
When the pest damage is low, it is important to remove any leaves, stems and fruits affected by the presence of larvae or pupae and place them in plastic bags.
Remove weeds that may be host to the pest.
Do not leave infested plant material (from pruning or weeding) on the ground, as the larvae will quickly leave them and colonise new plants.
Keep this material in closed containers until destroyed.
After harvesting, destroy crop residues as soon as possible. Residues should be buried or covered with transparent plastic film to ferment them.
Soil exposure may be useful in warm climates to kill pupa that remain in the soil.
Leave a minimum of six weeks between successive susceptible crops.
At national level, a Tuta Absoluta monitoring programme should be established.
More research on the pest should be carried out so as to find ways of effective prevention of the pest to avoid losing thousands of tomato hectares to the bug.