Opennatur

Tomato leaf miner, Tuta absoluta , is a small Lepidoptera belonging to Gelechidae family. This pest has an elevated reproductive potential and can reach 10 to 12 generations per year and has a biological cycle raging from 29 to 38 days.

Native from South America, was probably introduced in Spain on infected vegetal material. As a result of the importance and impact that can have the presence of this pest in tomato fields, and also with a lower impact in eggplant or potato crops, the Ministry of Agriculture and Fisheries, has adopted jointly with the Autonomous Communities, protection actions to eliminate all the risk that suppose the spreading of the pest over the territory.

Adults: Adults can have a wingspan of up to 10 mm in length. Is an insect of nocturnal habits, remaining hidden during the day between the leaves. When being annoyed they start an erratic and short flight. For both sexes the forewings are basically ashen, with shades ranging from dark to gray. The head, thorax and palpi are gray ash with dark overtones. The abdomen of females is creamy brown, and wider and bulkier than males one. The average life of the females reached 10 to 15 days, while that of males is about 6 to 7 days.

Eggs : Eggs are creamy white, sometimes yellow, turning dark when hatching comes. They measure 0.4 mm long and 0.2 mm in diameter. The females lay an average number of 260 eggs throughout their live. The eggs are laid one by one, or sometimes grouped, mainly on the undersides of young leaves, veins, margins of the stalks, etc. can be deposited throughout his life an average number of 260 eggs. Spawning takes place in isolation and sometimes grouped mainly on the undersides of young leaves, veins, margins of the stalks, etc. Laying takes place continuously.

Larva: Larva: it has four well-defined larval stages which can be distinguished thanks to the colour and size. Just after hatching are creamy yellow, and then, as they fed, became greenish, and the dorsal region turns to reddish when they are close to pupate. The size ranges to 1 from 7’5 mm length. The head is brown and the thoracic shield shows a dark brow, but only on the basal part.

Pupae: : during the puping preparation period lava stops feeding and forms the cocoon, on the plant or even on the ground. Pupae has a cylindrical shape, and legs and wings can be differentiated. The size is about 4,5mmm length and 1,1 mm wide. In most cases, it’s usually covered by a silky white cocoon.

The main host is the tomato plant but many Solanaceae species are also affected. Damage is caused by any of the larvae stages, affecting leaf, fruit and stems. The damage caused to the leaves during the early stages are similar to those caused by larvae of Liriomyza spp. Larvae eat the mesophyll tissue, leaving the epidermis intact. Then the mines become necrotic.

The fruits are penetrated in an immature state, mainly trough the stalk ends, leaving galleries that cause deformation and facilitating the attack of pathogens, and enhancing their decay. The larva leaves the fruit to move to another.

The damage is severe if there isn’t an early detection of the pest and if no rational control is applied.

DETECTION AND MONITORING
Delta traps with pheromones should be placed as a range of 2/ha and at 1’80 m high in order to detect the presence of the pest. The pheromone lasts 6 weeks and its necessary to do, at least, a count every week. At the detection of more than 3 captures per week its advisable to perform mass trapping.

Attention should be focused to young shoots and fruits, so as to detect the first symptoms of the attack.

If having infested vegetal material it’s necessary to destroy it, putting on a close bag and not opening it until 30 days had gone by.

MASS TRAPPING
To control the pest using mass trapping, you have to follow these instructions:

Place 20 to 40 water traps "TutaTrap" in each hectare of crop, the exact number varies according to the umber of captures. Put vegetable oil on the water, in order to create a layer, and do the maintenance of the trap refilling the oil and water.

Place traps about 30 cm above the soil evenly distributed in the plot, and strengthen the areas with more captures.

Mass trapping will take place throughout the development of the plant and even when the crop has been removed.