18 April 1986 Research awarded to Lincoln College to investigate fruit pests

Potatoes and pumpkins will be used to establish colonies of scale-insect pests in joint Government-private industry-funded research at Lincoln College intended to maintain the quality of export fruit while keeping insecticide residues in the fruit below acceptable levels.

The Lincoln College Council was told today (Tuesday April 22) research contracts from the D.S.I.R. and Ivon Watkins-Dow, Ltd, of New Plymouth were providing funds for the work.

Both contracts are over three years, with $24,000 coming from D.S.I.R., and $10,050 from Ivon Watkins-Dow.

The research will be headed by the Professor of Entomology at Lincoln College, Professor David Penman.

Three significant scale insects are found on export fruit: greedy scale, oyster shell scale and San Jose scale.

Greedy scale, found on many woody plants and a major pest of kiwifruit in most North Island regions, needs strict chemical control.

Oystershell scale, a major pest of pip-fruit in Central Otago and dominant in Canterbury, can contaminate fruit with emerging crawlers.

San Jose scale, a world-wide pest of pip-fruit, is important in New Zealand from Nelson northwards.

All three scale pests present major quarantine problems on export fruit colonies establishing on woody tissues can debilitate fruit trees.

The potatoes and pumpkins will be used to rear the three pests so that breeding conditions can be investigated.

Insecticides are used to control scale-insect pests, but there is the possibility of resistance to these developing.

Knowledge gained from the research will allow new insecticides and control methods to be developed.

Efficient and cost-effective control depends on careful selection of pesticides, and when and how these
are applied.

Chemicals presently being used and those likely to be used will be investigated.

Laboratory work should provide some recommendations on using insecticides in the field during the research.

The intention is to find more efficient and effective ways of using sprays while keeping levels of residue in the fruit as low as possible.

Further information from Professor David Penman, Professor of Entomology, Lincoln College 8150, Canterbury, New Zealand; phone (03) 252-811 extension 715.