Post Details

The heavy rains have facilitated an increase in the cost and demand of tomatoes. This is because the rains have damaged the roads and resulted in an increase in the diseases that have affected tomatoes, especially on open field farms. In the process, this has disrupted the supply of tomatoes.
Growing tomatoes can be disastrous if your crops get infested by Tuta absoluta. Over the past few years, a large number of farmers have suffered huge losses after their precious crops were infested and destroyed by the dangerous pest. If effective control measures are not employed early enough, the pest can destroy an entire tomato farm.

Detection

For effective management, proper diagnosis is important. The input dealers, service providers, and farmers need to correctly identify the possible symptoms of Tuta absoluta such as coalesced lesions.

Damage caused

The pest mainly spreads through seedlings, tomato fruits, and containers. Tuta absoluta can also come from production greenhouses or through the soil. It feeds on all parts of the tomato plant such as the stem, leaves, inflorescences, and the fruits. Symptoms of the tomato leaf miners include leaf mines, rolled leaves, lesions, abnormal shape, necrotic areas, and exit holes. If these symptoms are detected, corrective measures should be taken. Leaf mines are found on the upper and lower parts of the leaf lamina. With keep observation, one can see white or cream tunnel marks on the leaves and sometimes green caterpillars inside the tunnel. The caterpillars produce silk-like substance at an advanced stage which partially webs and folds the leaves to protect the developing larva until it matures. At times, the leaves completely die off and the fruits reduce in size and fall off before reaching maturity. When the fruits are damaged, fungal diseases enter resulting in rotting of the tomato fruits before harvesting. The yield of tomatoes can reduce by even more than 60% if the tomato fruits are severely infested by Tuta absoluta.

Control

Controlling Tuta absoluta is a challenging process. This is because it has a short life cycle, a fast reproductive rate, a concealed larvae stage inside the tomato plant parts and nocturnal adults. The life cycle of the tomato leaf miner is completed within 35 days. The effectiveness of chemical control depends on the nature of damage of the pest. Integrated Pest Management should be adopted to ensure that sustainable management measures are employed in the control of Tuta absoluta. Chemical, cultural or biological measures can be employed to control the destructive pest.

Chemical control

Spraying the same product frequently results in pest resistance, therefore, the insecticides should be alternated after two sprays. Regular crop monitoring and scouting help farmers to make the right decision on when to spray and the insecticide to prevent severe infestation of pesticides.  Due to the trans-laminar damage of Tuta absoluta and the fast development of resistance, insecticide use has become challenging. However, the pest can be controlled with insecticides such as Radiant, Tracer, Belt, Tihan, Escort, and Coragen. Farmers should also sterilize the soil before planting to ensure that they kill any eggs present in the soil.

Cultural control

Cultural control involves measures such as plowing, irrigation, and crop rotation with non-solanaceous crops such as capsicum, beans, and maize. Plants such as potato, Pepino, eggplant, tobacco, and nightshade should not be grown on tomato fields since they host the pest. The tomato farms should be kept weed-free since some weeds such as Datura spp. and managu act as alternative hosts of Tuta absoluta. Solarization and elimination of symptomatic leaves can also help in controlling the pest. Infested tomato fruits and debris should not be dumped in markets, collection points, and at farm edges. They should be instead be buried in deep holes.

Biological control

Biologically, Tuta absoluta can be controlled using predatory bug ‘Macrolophus pygnaeus’, Trichogramma spp, and  Entomopathogenic fungi

Sustainability

Integrated pest management measures help in promoting sustainability in tomato farming. The methods employed should enable farmers to produce high-quality tomatoes hence more returns. Extensive application of cultural and biological control has a positive impact on biodiversity and the ecosystem.