Quick Dips

Native Pesticide

A compound from the native pepper tree, or horopito, may prove useful in the control of agricultural pests. The compound is one of a number of extracts from New Zealand plants being studied by MAF's Plant Extracts Research Unit at Otago University.

Over 50 extracts from New Zealand trees, shrubs, mosses and liverworts have been studied, and the horopito extract is one of three which have proved promising. The extracts team has confirmed that the tree contains a compound known as polygodial, which Canterbury University researchers have found to be anti-fungal [Plant Antibiotics, Dec/Jan 90/91].

The most promising uses for the compound appear to be as an anti-fungal agent or as an insect repellent. Scientists at MAF Ruakura are testing the horopito extracts against a variety of New Zealand agricultural pests. Polygodial is known to be quite volatile, so it may be suitable for use as a short-lived insecticide, replacing synthetic substances.