Building resistance to pests in crops | PHOTOS

Vic workshop focuses on building resistance to pests in crops | PHOTOS


A Victorian training day has explored ways of building in crop pest resistance.


LOOKING after beneficial bugs and identifying pest insects and disease was the subject of a training day in Lindenow, Victoria, recently.

The training, delivered on behalf of VegPro, was attended by agronomists, growers and farm workers from across Victoria, NSW, South Australia and Tasmania.

Landscape, soil type, weather, roadside vegetation and smartphones were all part of the discussion about pests and diseases in crops.

Presenter Stuart Grigg, of Ag-Hort Consulting; and Bulmer Farms, provided the crops at Lindenow for hands-on investigation to support the theory.


Discussion centred on in-crop integrated management programs that included spray timing and application, preparation and monitoring of crops, scarifying, weather monitoring, seasonal experience.

Crop pests and diseases included clubroot, serrated tussock, mites, mildew, slugs and aphids, among others.

Experience and learning, as well as time spent in the crop, were key to identifying a problem in the field. Pheromone traps were encouraged to help identify what insects were in the crop and if they were beneficial or pests.

Lanita Steer insepcting for cabbage aphids.

Lanita Steer insepcting for cabbage aphids.

Integrated crop and pest management methods (ICM and IPM) were becoming increasingly important as customers expected a “perfect” vegetable.

Perfection was based on perceptions of colour, look and taste.

That was where using technology in crop management could improve the end product, according to presenter, Stuart Grigg.

A major issue was identifying what factors, including environmental, were building resistance to pest and disease management in the crop.

Michael Howe, of Busch Organics at Lindenow, said it was important to find a balance between consumer and industry expectations.

“It’s about finding the balance between what the consumer wants and how we can produce that, which determines our management of the crop,” he said.

Stuart Grigg, Ag-Hort Consulting, leading the day’s education.

Stuart Grigg, Ag-Hort Consulting, leading the day’s education.

IPM and organic agriculture relied more on encouraging beneficial insects – discussion centred around native shelter belts and insectaries that encouraged predator insects, spiders and birds to control pests.

“We need to know what is in the crop and how we can use them; but we also need to know what we have to do to attract and protect beneficial insects,” Mr Grigg said.

Monocot and dicot systems were debated.

“Monocrops create opportunities for increased pest insect incursion,” Mr Grigg said.

“When we push the system, it pushes back.”

System influences included influences of environment, nutrition and recent weather events such as drought, rain and frost.

Technology now meant everyone with access to the crop had the means to scan for and identify pests and diseases – with their smartphone.

Noel Jansz, agronomist, Elders Bairnsdale, Vic, with a cabbage leaf with a parasitised wasp on board.

Noel Jansz, agronomist, Elders Bairnsdale, Vic, with a cabbage leaf with a parasitised wasp on board.

“Identifying the problems starts with your phone,” Mr Grigg told participants.

As a cropping tool, it enabled people to take photographs and compare those with identification applications; to keep up-to-date with weather and climate data; and to utilise networks of agronomists and other scientists.

This helped build knowledge that meant better farm management and raised awareness of the disease triangle – host, pathogen, environment – that impacted crop nutrition.

“We should be looking for necrosis, tissue damage, abnormal growth. We can cut lesions and galls longitudinally to determine what’s happening in the vascular system,” Mr Grigg said.

“The important thing is to get dirty. Get into the crop, onto your hands and knees and look at what’s going on.”

Fungi took a particular focus in the training day.

“There are 23,000 species of known fungi. Some of them are beneficial,” Mr Grigg said.

Fungi included downy mildew and rusts and dispersal methods included people, machinery, wind and planting close to infected plants.

A possible springtail.

A possible springtail.

“We’ve got to understand the fungus we have in the crop, to identify our management of it,” Mr Grigg said.

Bridge hosts were also debated.

“Regrowth enables pests to live in crops even during fallow or rest periods,” Mr Grigg said.

Baiting could be assisted by timing it after irrigation or rain.

“Rainfall and watering encourages pests that inhabit the ground several centimetres down, to move to the surface and take up baits,” said Elders agronomist, Pat Feeney.

A challenge across the industry was training workers to understand and comply with market restrictions. In conventional farming, in particular, that included how and when to apply product and how to avoid machinery contamination.

“That might include varying rosters to optimise spraying times,” Stuart Grigg said.

“Know the impact your product is having on the crop.

“It would be the same for the watering roster. The more you’re aware of weather, moisture in the soil and how much water the crop requires, the more effective you can be about applying irrigation.”

Like pests, bacteria and viruses were often spread by how the in-field crop remnants were treated post-harvest. People and machinery could also be viable vectors for transmission.

Scott Botten, Mulgowie Farming Co, Boisdale, Vic, with marshmallow weed showing signs of rust.

Scott Botten, Mulgowie Farming Co, Boisdale, Vic, with marshmallow weed showing signs of rust.

“If we chop the crop in, we infest the ground with pests. We might be better off spraying it, killing the pathogens, then pulling the crop out,” Mr Grigg said.

“Aphids are one of the worst pests for virus infection through vectors.”

Some pests were a global problem – ergo, spinach mites were challenging for the industry in Australia and overseas.

Mr Grigg encouraged growers to negotiate with their neighbours – public and private – to reduce pests in boundary vegetation.

Ideas included spraying, reducing roadside vegetation as a host for pest insects and disease and planting a break crop, if the season and crop rotations allowed it.

There were a number of training days held across the southeast states, including Tasmania.


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