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Future-proofing horticultural growing practices through the use of biologicals and softer chemistries

Future-proofing horticultural growing practices through the use of biologicals and softer chemistries

Future-proofing horticultural growing practices through the use of biologicals and softer chemistries

The use of traditional broad-spectrum pesticides and insecticides as a first choice of control within a horticultural or viticultural crop protection programme is now in the past. Increasingly growers are utilising softer chemistries and biopesticides within their integrated pest management (IPM) programmes to control pests and diseases and to meet strict export requirements.

“Broad spectrum pesticides and insecticides impact beneficial insects and pollinators,” explains Elaine Gould, Fruitfed Supplies’ Technical Specialist – Subtropicals. “People understand the effects these products have on the local ecology; if you’re spraying to control one insect species, a broad-spectrum product can harm pollinators and impact the insects that feed on the target species. For an ecological balance, it is better to use softer chemistry within an IPM programme.”

Horticultural industry bodies prefer the use of softer chemistries as they provide sustainable options for growers and this is increasing in importance as the number of organic growers continues to grow. Elaine offers the example of AVOCO, New Zealand avocado growers’ governing body, which sets out the preferred products for use on crops - softer chemistries - while broad-spectrum pesticides and insecticides, and chemistries shown to have resistance developing, falling into the non-preferred category.  

Biologicals is an umbrella term used to describe products derived from naturally occurring materials such as plants or beneficial organisms. Falling under this umbrella term are biopesticides, biological control agents and biostimulants. Biopesticides, Elaine says, are sprayed onto the crop, the same as traditional agri chemicals. They can be a fungus, virus, yeast, or bacteria that are used to control other microorganisms or insects. Biological control agents are insect predators or parasitoids used to control insects or other plants by either eating or laying their eggs within the target organisms. Biostimulants are used to promote the growth of the plant and improve plant recovery.

Elaine says biologicals are often less harmful to the plant and the surrounding environment as they are generally target specific. She shares the example of the bacteria Bacillus thuringiensis, or BT, which is used to control leaf roller caterpillars across multiple crops and forms a part of an IPM programme.

With a greater emphasis on registering softer chemistries and biologicals for use in New Zealand, the Fruitfed Supplies Research and Development (R&D) team conducts trials measuring their efficacy in local conditions.

A recent trial held in Pukekohe, led by Catherine James Fruitfed Supplies R&D Technical Advisor, measured the effectiveness of biopesticides at controlling green looper and tomato fruit worm caterpillars in lettuces. Catherine says the caterpillars are a long-time pest in this crop, and with old chemistries now being phased out, it is vital for new products to be developed and registered for use.

As R&D trial data becomes available to share with the wider Fruitfed Supplies team and growers, the Fruitfed Supplies’ Technical Extension Team, including Elaine, takes on this role.

“I keep abreast of the latest research and findings from both our trials and others within the industry, so I can recommend to growers the most effective way of using a biological product. This includes application timings, the product’s fit within a crop protection programme, and its compatibility within a tank mix. These are the technical aspects growers want to understand.”

“By sharing this information with our Technical Horticultural Representatives, they can then advise growers on the most effective way to apply a biological product. This is particularly important as these products often need to be applied when disease or pest pressure is low. If left too late, they may not establish in time,” says Elaine.