A lighter touch to controlling insects

GIZZY-BASED: A locally based project that looks at better ways of handling insects in citrus orchards could mean intense mowing strips and bare earth under trees could be a thing of the past. File picture

A GISBORNE-based project is exploring a biological method of dealing to pesky insects on citrus orchards by understorey planting to attract beneficial insects.

A Lighter Touch project manager Jeff Smith says leaving bare earth under citrus trees and intensively mowing the grass strips between orchard rows may become a thing of the past.

Mr Smith says they are “revolutionising our approach through strategic planting”.

“We've undertaken trials planting under and beside the trees, ranging from flowering perennials such as clovers and alyssum to annuals like buckwheat and phacelia.

“These plants and others may hold the key to helping us enhance the agro-ecosystem and provide resources for beneficial insects to thrive, which would reduce the need for applications of agrichemicals.”

The two-year project is to be part of a $27 million, seven-year programme backed by the horticultural industry and Government through the Ministry for Primary Industries (MPI) Sustainable Food and Fibre Futures fund.

A Lighter Touch aims to shift the focus from traditional crop protection by carrying out research, understanding crop protection products and integrating biological and ecological processes into food production in New Zealand.

The project has brought in researchers from Lincoln University and Plant and Food Research, who extensively reviewed current literature on how to plant to attract the natural enemies of the country's most persistent pests.

“The researchers are now translating theory into practice,” Mr Smith said.

“We're testing to see what works under New Zealand conditions.

“Seeds were planted late last year on two trial sites alongside two control sites — one in a valley and one on the plains.

“So far we've found that plants on the plains struggled to establish but the valley planting was more successful. This was because there was more rainfall.

“The landowner also had sheep on the land, which trampled seed into the soil. In the future we may look at autumn sowing to see if we can achieve a more consistent establishment.”

Mr Smith said the programme would collect data regularly on the trial and control sites, including fortnightly monitoring for insect presence and species.

“By spring we'll be able to evaluate how effective the planting has been in the first year.”

A workshop held with interested parties in the horticulture sector last October introduced the aims of the project.

“We've found that so many growers want to find a better way of planting with less reliance on chemicals,” he said.

“While citrus was chosen for the model system, our findings should be adaptable for other perennial growing systems.”

MPI director of investment programmes Steve Penno said the project offered a welcome alternative to the traditional method of spraying chemical pesticides on a calendar basis.

“The traditional practice annihilates many of the natural enemies that can help us control pests, whereas this new method helps us work with nature,” he said.

“Being able to transition to this practice would help us tell a more sustainable story to consumers about where our food comes from.

“This project aligns with the intentions behind the Government's Fit for a Better World roadmap for the primary sector, which seeks to find more sustainable ways of producing our world-class products in New Zealand, which in turn will increase consumer demand and generate higher export returns.”