Herbicide-resistance threat requires proactive approach

• Resistance reports in some weeds

• Look across entire arable rotation

• Consider costs and ease of use

Proactive weed management is required to help manage the growing threat from ALS-herbicide resistant weeds within sugar beet, say experts.

The advice is especially relevant for farmers planting Conviso Smart herbicide tolerant varieties. Their introduction has been helpful for growers with weed beet issues. But it isn’t entirely risk-free.

The Conviso Smart system allows the use of Conviso One, which contains two ALS-inhibiting active substances in foramsulfuron and thiencarbazone-methyl that would otherwise kill the sugar beet crop.

Up to a quarter of the sugar beet area is likely to be grown using the system this season, says British Sugar weed control expert Pam Chambers. “That will likely include some where it might be grown for a second time in a field.”

Resistance

But resistance is becoming more common to ALS-inhibiting herbicides in broadleaf weeds, such as poppy, chickweed and mayweed – as well as in grass weeds such as blackgrass and Italian ryegrass, says Ms Chambers.

That’s been partly driven by the widespread use of ALS-inhibiting herbicides, such as sulfonylureas, across the rotation, with the mode of action available in virtually all arable crops.

In most crops, using herbicide actives in mix or sequence with ALS-inhibiting herbicides has somewhat masked issues, but growing Conviso sugar beet has potentially exposed weeds to programmes only containing that mode of action, says Ms Chambers.

“We have seen some cases of weeds not being controlled in fields across all arable areas where beet is being grown.”

Alternative modes

A joint British Sugar, BBRO and ADAS study of poppy and chickweed seeds has shown that not all cases of poor control are caused by resistance. But some weeds do survive subsequent Conviso One herbicide application and are capable of setting seed.

Those findings highlight the need to look across the entire rotation when considering ALS-inhibiting herbicide use, says Ms Chambers. Growers should look to use alternative modes of action, she suggests.

In the sugar beet crop, proactive weed management is vital, especially where possible ALS-resistant weeds are suspected, says Stuart Jackson, head of technical services at UPL.

“Don’t leave your weed control until the last minute,” he stresses.

Driving seat

“If there are problems with weed control after a Conviso One application, weeds will already be at least two to four true leaves and competing with the crop for resources. At that size, they will be harder and more expensive to control with other chemistry.”

Instead, Mr Jackson advises growers use either pre-emergence or early post-emergence herbicides containing actives such as metamitron, ethofumesate and the post-emergence only phenmedipham before they apply Conviso One. “Be in the driving seat to manage weed populations at the front end rather than fight a rear-guard action,” says Mr Jackson

Options include products such as Bettix Flo (metamitron), Efeckt (ethofumesate) and Betasana SC (phenmedipham). Combinations of these actives are the bedrock of conventional sugar beet herbicide programmes, he notes.

Poppy control

Another option that could help with poppy control containing quinmerac and dimethenamid-P is likely to be in short supply; only product already in distributor stores or on farm is likely to be available to use.

Using combinations of metamitron, ethofumesate, and phenmedipham will be especially important for controlling poppies while still small, adds Ms Chambers.

Ethofumesate could be useful on any chickweeds that have survived a Conviso One application. “Be mindful of the restriction of a maximum of 1000 g active/ha over a three-year period and check labels for supported rates as they can vary.”

Metamitron and ethofumesate will also provide additional control of grassweeds, such as blackgrass to help boost control from Conviso One. “It’s very unwise to rely solely on Conviso One for grass weed control.”

Earlier spray

Using an earlier spray will also potentially help with the timing of Conviso One follow-up sprays. “The trigger for applying Conviso One is fat hen at four true leaves, but that weed can grow quite fast compared with other weeds, especially weed beet.

“Putting some conventional chemistry on first should make it easier to put Conviso One on at a good time to make sure you catch all the emerging weed beet, assuming that is your main target.”

In the longer term, sugar beet growers should carefully consider the merits of the Conviso Smart system versus conventional beet varieties, Pam adds.

“Where weed beet is the driver, you can easily justify it, and also next year, when there will be a stacked trait variety with tolerance to both Conviso One and beet cyst nematodes. But if you’re using for other reasons, then it is sensible to compare conventional versus Conviso Smart weed control systems.

“Look at costs and ease of use. One way to help you compare is to spray an area of conventional herbicide on Conviso Smart beet to evaluate cost and efficacy against Conviso One treatment.”

Quality accreditation for vegetable handling experts

Vegetable handling equipment manufacturer Tong Engineering has received ISO 9001 accreditation for its quality management systems.

The internationally recognised certification by the British Standards Institution is testament to the hard work and dedication of the entire Tong Engineering team, said the company.

Disease development slowed

Tong conducted a comprehensive review of its operations  under the leadership of process improvement manager Jim Worley, who implemented a structured plan to drive  measurable improvements.

“This accreditation is the result of a tremendous team effort,” said Mr Worley.

“While this is just the beginning of our journey, ISO 9001 certification demonstrates our focus on ensuring every product meets the highest standards –  from initial design to final delivery.”

Tong managing director Edward Tong said ISO 9001 accreditation would help ensure the company continued to improve and provide customers with the best service and post-harvest solutions.

“Quality has always been at the heart of our business,” said Mr Tong. “I’m incredibly proud of our team for their hard work and drive towards this achievement.”

Above: ISO 9001 accreditation is globally recognised – and a milestone  for Tong Engineering