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November 2001. Towards the end of the year (2001) Niue is still fighting with the Bemisia tabaci Type B and has been using so many chemicals recommended by so many companies and experts and notheing seems to work. The white flies are affecting head cabbages, chinese cabbages, capisicum and tomatoes the most. Instead insecticide can anyone suggest an alternative to the controlling of the white flies. Our growers are at the verge of retiring from supplying vegetables to our local market.
The B biotype is almost certainly resistant to organophosphates, pyrethroids, endosulphan, carbamates and possibly imidacloprid. Further, attempting to spray these pesticides will almost certainly eliminate any beneficials. There are effective insecticides which are less harmful, eg the insect growth regulators pyriproxifen, novaluron and buprofezin and the antifeedant pymetrozine. They will help reduce whitefly numbers while at the same time not eliminating natural enemies to the same extent as the broad spectrum chemistries. Petroleum oil sprays can also be effective, but under leaf coverage needs to be very good otherwise PSOs will be ineffective.
Biocontrol using parasitic Hymenoptera,especially Eretmocerus hayati, E mundus and E emiratus are all highly effective. Given the subtropical climate of Niue, I would expect E hayati to be the most effective. Forget about using Encarsia spp.; none have the same efficacy as Eretmocerus.
At the 2nd Pacific Plant Protection Organisation Quarantine Meeting, March 1998 in Fiji, a paper was presented: The sub-regional survey of whiteflies and quarantine implications, plus a report Survey of Bemisia tabaci biotype B whitefly (also known as B argentifolii) and its natural enemies in the South Pacific. The report also listed all the whitefly species found on the various islands surveyed.
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