The current population of Tuta absoluta present in Dutch greenhouses is still a threat to organic cultivation of tomatoes. From 2014, damage caused by the larvae has greatly increased. The measures and resources that organic greenhouse growers can use, are limited. The intervention possibilities are:
- To reduce the population (1) by trapping the moths for example with lamps with sticky traps, water traps and Delta traps; (2) to confuse males by pheromones (no admission yet); (3) by removing of by Tuta affected leaves (requires additional labor);
- Natural control by introduction of mainly Macrolophus, the population increase of Macrolophus is promoted by banker plants (zucchini, squash and others);
- Control through the use of natural resources: (1) Bacillus thuringiensis (several strains and brands; (2) Spinosad (Tracer brand).
Corrective Means
Given the damage that was caused last year, the attendees are of the opinion that additional corrective measures are required. A candidate is the product Neem, or more specifically NeemAzal; this ecological insecticide has been approved for ornamentals under glass, but not for tomatoes. Meanwhile, approval for NeemAzal has been applied for, but whether the insecticide becomes available, remains to be seen. Until then organic tomato growers will have to do with the measures and means as mentioned above.
Source: BioKennis.org