1. Trans-boundary Plant Pests and Diseases in the SADC region
Tomato leafminer:
ScientificName: Tuta absoluta (Meyrick)

2. Taxonomic Tree
Domain: Eukaryota
    Kingdom: Metazoa
        Phylum: Arthropoda
            Subphylum: Uniramia
                Class: Insecta
                    Order: Lepidoptera
                        Family: Gelechiidae
                            Genus: Tuta
                                Species: Tuta absoluta

3. Scouting Guide: Description
Egg: The eggs are elliptical, and their colour varies from oyster-white to bright yellow, darkening in the embryonic phase and becoming almost black near eclosion.
Larva: The first-instar larvae are whitish soon after eclosion, becoming greenish or light pink in the second to fourth instars according to food (leaflet or ripe fruit, respectively). There are usually four instars.

4. Pre-pupa
The pre-pupae are lighter than the feeding larvae (first to fourth instars) and develop a distinguishing pink colouration on the dorsal surface.
They leave the mines and build silk cocoons on the leaflets or in the soil, according to habitat.
When pupation occurs inside mines or fruit the pre-pupae do not build cocoons. Pupa
Pupae are obtecta with greenish coloration at first, turning chestnut brown and dark brown near adult emergence. Adult
Adult moths are about 10 mm long, with silverish-grey scales, filiformantenae, alternating light or dark segments and recurved labial palps which are well developed.

5. Hosts/Species Affected
T. absoluta feeds almost exclusively on tomato (Solanum lycopersicum) and there is also some reports that it feeds on potato (Solanum tuberosum).
Other Solanaceae reported as hosts for T. absoluta, besides tomato, include the wild species Solanum nigrum, S. elaeagnifolium, Lycopersi conpuberulum, Datura stramonium, D. ferox and Nicotia naglauca
Growth Stages
Flowering stage, Fruiting stage, Post-harvest, Seedling stage, Vegetative growing stage

6. Detection and Inspection
T. absoluta is easily found on tomato apical buds, flowers or new fruits.
When there is a severe attack it colonizes the leaves on the other parts of the plant.
Mines are evident on attacked leaves.

7. Symptoms
Fruit: abnormal shape, visible frass, internal feeding, exit hole premature drop nd reduced size
Growing point: dead heart, distortion, visible frass, internal feeding,and lesions
Inflorescence: external feeding, fall of shedding, visible frass and internal feeding

8. Leaves: abnormal forms, external feeding, visible frass, internal feeding and rolled od folded leaves
Stems: dead heart, die back, witches broom, distortion, internal feeding, visible frass and wilting
Whole plant: dead heart, distortion, visible frass, internal feeding, dieback and dead plant

9. Prevention and Control
Cultural Control
Ploughing, manuring, irrigation, crop rotation, solarisation, and the elimination of symptomatic leaves and destruction of infested tomato plants have all been used to control this pest.
The removal of alternative reservoir hosts is strongly recommended before and during the cropping cycle.
In greenhouses, one of the management tactics used to reduce the initial level of populations is to keep infested greenhouses closed after harvest to prevent the migration of adults to open-field crops.

10. Semiochemicals
Pheromone traps are considered as the first line of defence against this moth both in open fields and in greenhouses as they are used for monitoring and male annihilation, mating disruption.
Inherited sterility (sterile males)
Inherited sterility programs which involve releasing irradiated sterile males was recently proposed as a possible method for control of this moth..

11. Chemical Control
The most common method of controlling T. absoluta is the application of insecticides, usually pyrethroids and carbamates and organophosphates.
However, these insecticides are of low to moderate effectiveness.
In addition, several cases of insecticide resistance have been reported including resistance to organophosphates, pyrethroids, abamectin.

12. Biological Control
Several bio-control agents are used to control the tomato leaf miner in open field and greenhouse tomato cultivation.
The most common predators are the mirid bugs Nesidiocoris tenuis and Macrolophus pygmaeus.
Bacillus thuringiensis(Bt)-based insecticide formulations have been used to control T. absoluta.
Entomopathogenic nematodes Steinerne mafeltiae have been tested for the management of T. absoluta.
Several fungal species including Metarhizium anisopliae and Beauveria bassiana are reported to attack the eggs, larvae and adults of the pest.

13. Host-Plant Resistance
Host-plant resistance is being explored by developing tomato accessions with high zingiberene and/or acylsugar contents that result in low ovipostion rates and larval feeding of T. absoluta.