During spring tomato growers see whitefly infestation pressure increase slowly, but surely. At this time of year, predatory mirid bugs - such as Macrolophus pygmaeus - are often not yet at full strength. However, Biobest’s biological insecticide Preferal can be a valuable addition to the control strategy.
Containing spores of the Isaria umosorosea fungus, Preferal works best at high relative humidity. That is why it is important to choose the right moment to apply the product – for example, at the end of the day. At sufficiently high humidity, the spores germinate well and the fungus infects various lifecycle stages of the whitefly, killing it.
Local treatments or full field applications
Preferal controls various whitefly types including greenhouse whitefly (Trialeurodes vaporariorum) and tobacco whitefly (Bemisia tabaci). In recent years, we have seen pest levels in tomato crops increase. Once the greenhouse whitefly is under control, Bemisia populations can increase again. This whitefly can transmit many harmful viruses.
Growers who applied Preferal several times previous years noticed that it worked well against Bemisia. Meanwhile the biology in the greenhouse remains intact, because it is a biological insecticide. Growers have the option to apply it locally, or to the entire greenhouse, depending on the infestation level.