BY DAVID DANIELS
NATIONAL AGRICHEMICAL MANAGER, AUSVEG

The APVMA’s recent decision on paraquat and diquat represents one of the most significant regulatory changes affecting vegetable, potato, and onion growers for many years. For most growers, these herbicides have been trusted tools for decades, playing an important role in bed preparation, knockdown weed control and desiccation among other applications. While neither active constituent has been completely withdrawn from the Australian market, the changes will have a severe impact for many horticulture businesses.

What do the new restrictions mean in practice?

Shortly after publishing its final decision, the APVMA updated approved labels for paraquat and diquat products to reflect new usage conditions. Below provides a simplified overview of what we understand to be the only remaining approved uses relevant to vegetable, onion and potato growers. It is intended as a general guide only. Growers and users should always refer to the approved product label for definitive directions, restraints and conditions of use. Trade names are provided as examples only because many growers are more familiar with trade names than active constituents. The inclusion of a trade name does not imply endorsement or exclude other registered products containing the same active constituent.

Diquat products (e.g. Reglone®)

• blanket spray at 1.4 L/ha for certain brassicas, bulb onions, certain fruiting vegetables, cucumbers, leafy vegetables, legume vegetables, root and tube vegetables.

Paraquat plus diquat co-formulations (e.g. Spray.Seed®)

• pre-crop emergent spot spraying only in vegetable crops (240 – 320 mL per 100L)
• spot spraying in market gardens and nurseries (240 – 320 mL per 100L)
• spot spraying in potatoes (240 mL per 100L).

Paraquat products (e.g. Gramoxone®)

The review has removed almost all vegetable uses from the label, leaving only:

• fallow establishment or to prepare a clean bed for sowing
• non-Agricultural situations, around sheds, roadways, paths
• firebreaks.

Transition period

The regulatory decision includes transitional arrangements that allow existing stock in existing containers with existing labels to continue moving through the supply chain for two years from the date of the final decision, though the provision applies only to products that were manufactured and packaged before 23 June 2026. Any product manufactured or packaged after that date must carry the revised label and be used in accordance with the new directions. It is likely that existing stocks will be exhausted well before the transition period expires.

Why has this happened?

Many products being reviewed today are legacy products. Some were originally approved more than 30 years ago under Australia’s former state-based registration systems, before the APVMA existed. For that reason, the APVMA is legally required to periodically review existing registrations against modern scientific standards. While we don’t always like the outcomes of reviews, they do ensure crop protectants are scientifically evaluated, and provide strong evidence that they are safe for people and the environment. Independent government assessment is the price to pay to maintain public confidence and our social licence.

It might seem unusual for someone in my position to defend Australia’s regulator, but Australian agriculture does benefit significantly from a competent regulator that bases decisions on robust scientific evidence. While the outcome of the recent paraquat and diquat decision will have a significant impact for our industry, it does provide an example of the APVMA’s thoroughness. Before reaching its decision, the APVMA examined an enormous body of scientific evidence accumulated over many years. Taking nearly three decades to complete its review, the regulator did not rush to a conclusion, and was not swayed by unscientific, activist views which have seen crop protection products under increasing attack in recent years. While many use patterns were removed, several important uses remain available under strengthened label directions.

The APVMA concluded that paraquat and diquat can continue to be used safely in Australia, in accordance with new risk management measures. Even following its final decision, the APVMA continued to face criticism from stakeholders who argued that the review had not gone far enough in not banning the products entirely. The Authority has stood by its decision, supported by the available scientific evidence it comprehensively considered.

What do we use now?

Since the APVMA decision, many growers rightly wonder: What do we use now? There is no simple answer.

Paraquat and diquat performed several different roles within vegetable production systems. These included rapid knockdown before planting and after planting (prior to crop emergence), stale seedbed techniques, weed control around infrastructure and fence lines, and, in the case of diquat, potato haulm desiccation and crop synchronisation. No single herbicide can replace all of these functions.

It has only been a few weeks since the revised labels were published, and the vegetable industry is still coming to terms with the new restrictions. As we continue engaging with growers across many vegetable crops, a better understanding of both the practical challenges and the potential solutions are emerging, as limited as they may be.

Many businesses we work with are leveraging international networks to understand how overseas growers have adapted to similar regulatory changes. We have also had extensive discussions with the major agrichemical registrants. Candidly, there is no overwhelming pipeline of alternative products waiting to fill the gap. While there are replacement options for particular situations, no single product offers the same combination of versatility, speed, and reliability.

It is therefore likely that growers will increasingly adopt a more integrated approach to weed management. Greater reliance on improved application timing, integrated weed management, cultivation practices and other non-chemical control measures will become increasingly important. Precision application technologies may also play an increasingly valuable role by targeting weeds more accurately, reducing herbicide use and improving overall application efficiency.

Alternative herbicides will undoubtedly form part of the solution, but likely not the entire solution. Successfully adapting will require a tailored combination of chemical and non-chemical strategies.

Why new herbicides don’t come along very often

Unlike insecticides and fungicides, very few (if any) genuinely new herbicides have been introduced to the Australian vegetable industry in the last 20 years. Unlike insecticides and fungicides, herbicides must selectively kill one plant while leaving another unharmed, making them the most technically challenging products to discover, develop, and register.

In addition to effective weed control, developers must also demonstrate crop safety across multiple crops and varieties, acceptable residue outcomes, minimal environmental impacts, and that the herbicide will not persist in the soil and impact subsequent rotational crops. These challenges help explain why new herbicide registrations are relatively rare, particularly in Australia’s diverse horticultural industries.

While we are working hard with growers, registrants, researchers and other stakeholders, identification and implementation of solutions will be gradual. Adapting to the loss of such versatile chemistry will take time, and meaningful progress is likely to come through a combination of incremental improvements in herbicide technology and ongoing research, rather than the emergence of a single replacement.

The real lesson

For me, the biggest lesson from the paraquat and diquat review is about preparedness. By the time a chemical review reaches its conclusion, there is usually very little opportunity left to generate the necessary supporting data for alternatives. Residue trials cannot be completed overnight. Efficacy trials take time. Crop safety work requires multiple seasons. Registrants need sufficient commercial confidence before committing significant investment.

In other words, if industry waits until a product has been lost before beginning to investigate alternatives, we are already five years behind.

Much of our work involves trying to identify potential problems well before they become crises. Sometimes that means pursuing minor use permits. Sometimes it means encouraging registrants to expand existing labels. Sometimes it means working with Hort Innovation to develop the data needed to support future registrations. Not every project succeeds. Not every chemistry has a suitable replacement. But doing nothing is not an option.

This is only the beginning

The review of paraquat and diquat will not be the last major challenge facing Australian horticulture.

Over the coming years, the APVMA is expected to complete or commence reviews of several other important actives used across Australian horticulture. Some of these decisions are likely to have relatively modest impacts, while others will be significant.

FIND OUT MORE
For more information or to get involved, contact david.daniels@ausveg.com.au