Tomato
Tomato Leaf Miner
Tuta Absoluta
Insect
5 mins to read
In a Nutshell
- Irregular grey to white leaf mines on leaflets.
- Later become necrotic.
- Galleries and large burrows into stems.
- Black marks on fruits where they enter or exit.
- Stunted growth.
- Silvery brown adults, 5-7 mm long.
Tomato
Symptoms
Infestation occurs throughout the crop cycle and can affect any crop part. The larvae prefer apical buds, young soft leaflets, and flowers. On leaves, the larvae form irregular, gray to white leaf mines that may later become necrotic. The larvae may drill galleries into stems which affects plant growth. On fruits, black marks can be found at the larvaes entry or exit points. These opening serve as entry points for secondary pathogens, leading to fruit rot.
Recommendations
Organic Control
Several predators feeding on T. absoluta have been found: among other species the parasitoid wasp Trichogramma pretiosum, and the bugs Nesidiocoris tenuis and Macrolophus pygmaeus. Several fungal species including Metarhizium anisopliae and Beauveria bassiana attack the eggs, larvae and adults of the pest. Neem seed extracts or insecticides containing Bacillus thuringiensis or Spinosad also work.
Chemical Control
Always consider an integrated approach with preventive measures together with biological treatments if available. Pesticides recommended for tuta absoluta pest management may not be viable due to the cryptic nature of the larvae, the high reproduction capacity of the insect and the development of resistance. To avoid resistancies, rotate several types of insecticides such as indoxacarb, abamectin, azadirachtin, fenoxycarbe+lufenuron.
What caused it?
Tuta absoluta is a devastating tomato pest because of its high reproduction potential, with up to 12 generations per year. Females may lay up to 300 creamy-colored eggs on the underside of leaves. Eclosion takes place at 26-30ºC and 60-75% RH. The larvae are pale green with a characteristic black band at the back of their heads. Under favorable conditions (temperature, humidity), their development is completed in about 20 days. The adults are silvery brown, 5-7 mm long and hide between leaves during daytime. Tuta absoluta can overwinter as eggs, larvae or adults on leaves or in the soil.
Preventive Measures
- Use pest-free transplants.
- Use sticky traps or pheromone traps to monitor your field and mass-catch the adults.
- Pick up and destroy damaged plants and plant parts.
- Control alternative host plants in and around the field.
- Plow the soil and cover it with plastic mulch or perform solarization.
- Remove and destroy infested plants after harvest.
- To prevent a carryover from previous crops, wait a minimum of 6 weeks before planting the next crop.
- Implement wide crop rotation.
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