IPM strategy for Tuta absoluta in conventional season tomato crops

When Tuta absoluta first arrived in the UK in 2009 there were no effective control measures approved for use by our tomato growers. Within just four years, AHDB-funded projects led by the Tomato Growers’ Association (TGA) had introduced a new IPM-compatible control strategy, which you can read about below.

For the purpose of the Tuta absoluta IPM strategy, the conventional growing season has been divided into four time periods:

• Monitor to detect the arrival of Tuta absoluta adult moths and the development of the first generation of caterpillars in the plants
• Release the primary biological control agent, Macrolophus pygmaeus and provide supplementary food to aid establishment
• Use one of the following two approaches:
  • Implement the mating disruption technique at first sight of adult moths
  • If the Tuta absoluta population is still susceptible to spinosad, apply this insecticide via the irrigation system before the first caterpillars pupate

• Despite the measures taken during the first period to delay Tuta absoluta population growth, at least one ‘second line of defence’ (SLoD) treatment may be required before the predatory bugs begin to have a significant impact
• Additional physical control measures may be employed to further retard the pest’s population growth

• Macrolophus pygmaeus should now be more numerous and capable of suppressing the pest’s population growth by feeding on their eggs and larvae
• Further SLoD treatments may become necessary to correct the pest-predator balance if any external factors provide an advantage to the pest
• The choice of SLoD product will depend on the type of crop, type of damage and the insecticide resistance status of the pest

• The main objective is to reduce the number of pests that survive to infest the following crop
• The options for a ‘clean-up’ treatment can include insecticides with a broader spectrum of activity if the biological control programme and pollination by bumblebees have ended
• Indoxacarb (as Steward^®) is useful in this situation because it brings different chemistry to the programme and thus contributes to resistance management

Crops grown through the winter, using supplementary lighting when natural light is limiting, present some additional challenges. These crops may be planted at any time of the year and overlap with other more mature crops. The overall approach to IPM is similar but it is likely to be more intensive during the early plant growth stages due to greater pest invasion pressure. 

AHDB is grateful to all the TGA members who contributed to the trials that developed the current IPM strategies. Particular thanks to Peter Bell, Richard Bezemer, Colin Bridges, Roly Holt, Paul Howlett, Brian Moralee and Phil Morley, as well as our overseas colleagues at Horticilha, Portugal.

The content on this page was authored for AHDB by Dr Rob Jacobson (Rob Jacobson Consultancy Ltd).