AgriSouthAfrica

An insect pest that wrought havoc in the California fruit industry two decades ago has made its appearance in the Western Cape, a University of Stellenbosch entomologist announced on Tuesday. The Pomegranate or Ash whitefly could severely damage garden shrubs, and apple, pear, olive, citrus and pomegranate trees, Professor Jan Giliomee said in a statement.

Giliomee discovered the insect recently for the first time in South Africa on a wild olive on the Overberg coast, and it was then formally identified by a taxonomist of the National Insect Collection in Pretoria.

The whitefly originates in Mediterranean countries such as Spain, Italy, Israel and Egypt, and has spread to India, Iran, New Zealand and Australia.

Giliomee said a number of pomegranate cuttings had been imported into South Africa from Israel and India in the past few years.

He surmised that the whitefly entered the country with plant material that was not quarantined as required by law.

He said when it arrived in California in 1988, the whitefly affected many shrubs and trees so badly that the plants lost all their leaves and the harvest of fruit trees was reduced.

"Young pear trees even died as a result of repeated exfoliation," he said.

"In cities and towns, the sticky honeydew that is secreted during the sap-sucking early stages, landed on cars and on people and was even carried into houses by the wind to make carpets and furniture sticky too.

"It was intolerable and the pest was only brought under control in California when parasites were imported," he said.

"It must now be established whether wasps that prey on the pest are present here and, if not, they must be imported urgently."

Contrary to what their name suggested, the insects were not flies but were more closely related to scale insects and aphids.

The adults looked like tiny moths and flew around rapidly, while in the younger stages they attached to the underside of leaves.