Integrated pest management consultant Dr Rob Jacobson told growers at last week's tomato pest and disease seminar that while Spinosad — commercially available as Tracer or Conserve — is okay to use on organic crops, it appears to be harmful to predatory bugs such as Macrolophus.
"This is counterproductive," he said. Fortunately, when researchers irrigated Spinosad as a possible solution to this problem, the results from just one trial were 'quite spectacular' with Tuta levels "immediately reducing.
"Not all of our experience has been so good, but this does look to be a promising way forward. The studies are continuing," reported Jacobson.
He added that while pheromone traps have so far been "extremely successful" at monitoring early stages of infestation, they are an expensive control method.
"You can catch an awful lot of male moths with the traps — very large numbers — and it does slow the population growth by disrupting mating.
"But what we are trying to work out at the moment is whether it's going to be cost-effective. The lures are expensive and it does become a significant cost."