With artificially lit tomato crops now underway, the timely introduction of Biobest's confusion pheromone, Isonet T, will help prevent Tuta absoluta from becoming a pest. "To be successful, it is important to use this mating disruption product preventatively and to start the crop clean," says Biobest advisor Bart Elseviers.
Isonet T is a filament-shaped dispenser loaded with scents from female moths. Bart: "by using it preventively, hanging 800 to 1,000 strips per hectare, males cannot find the females. As a result, mating does not take place. Although quite a costly solution, it works very well in practice. The number of moths must be limited. Otherwise, they will still find each other."
To be successful, it is very important there is no tomato leafminer moth pressure at the outset, carried over from a previous crop or from other greenhouses or the plant propagator. "If larvae and/or adults are present at the start, we recommend applying a chemical spray to start clean," says Bart. "Once growers have built up the biology in the greenhouse, these chemical interventions are no longer an option."
Every three months
Bart advises growers to hang the Isonet T dispensers as low as possible as the pupae fall to the ground to hatch. "Place the strips between the plants or on the gutters below a height of 1.5 meters," he says.
"The strips work for around three months, although in high temperatures, the fragrance can evaporate a little faster. By weighing the strip, growers can see if it still contains pheromone."
"Most growers introduce Isonet T three times per crop. Those who consistently follow this advice have very few issues with Tuta absoluta," he concludes.