Discussing whitefly control at a recent tomato seminar hosted by Certis, Kevin Gorman of Rothamsted Research, distinguished two types of whitefly. “Most will be familiar with the glasshouse whitefly, Trialeurodes vaporariorum, but there is also the cotton or tobacco whitefly, Bemisia tabaci. This form is less common and is a notifiable pest, however there were 26 outbreaks in 2003, mostly associated with the poinsettia crop.”
Pointing to the need for fully integrated and responsible control strategies, Gorman urged growers to combine physical, biological and chemical defences. “Physical controls are where most growers can make improvements and should be the primary line of defence,” he said. “Weeds for example, are excellent hosts for whitefly, so should be eliminated as part of a routine hygiene programme.”
Gorman also recommended fitting insect-proof mesh on vents and windows, fitting double doors and ensuring staff follow best practice to keep the pest out of the crop. Monitoring using sticky traps to detect if a population is re-establishing, was also advised.
He said that beneficials should be introduced as early as temperatures will allow and that for chemical control, potential cross-resistance should be avoided by using products with different modes-of-action.
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