Well over 40 specialist crops for a classic herbicide in its 40th year

Dilwyn Harris

Dilwyn Harris

Vegetable, allium and nursery crop growers have suffered in the last few years through the loss of crop protection actives, either as more products are revoked or go through re-registration and lose crops and uses. One manufacturer however has been busy adding to their recommendations and supporting and encouraging Extension of Authorisation for Minor Uses (EAMU’s) for their chemistry. “We receive a lot of queries from growers on our Hotline about what they can use on their vegetables and onion crops. One of our classic active ingredients clopyralid that has been on the market for 40 years this year continues to be an important herbicide for these specialist growers and each year additional crops are added or recommendations altered to make them even better,” says Dilwyn Harris, Principal Biologist for Dow AgroSciences.

“Having been available for 4 decades doesn’t mean that there have been no improvements on its journey. In that time all registration hurdles have been exceeded and four years ago Dow invested in and launched a new and improved double strength Dow Shield 400 formulation. Through this process it held onto its key crop recommendations and has become an even more important active ingredient for the control of difficult perennial and annual weeds such as creeping thistles, volunteer potatoes, corn marigold, groundsel, mayweed and smooth sow-thistle. The more concentrated formulation comes in advanced packaging with self-seal cap technology with no foil to dispose of, making it easy to handle, making spraying more streamlined and minimising the risk of point source contamination. So vegetable growers benefit from this advanced formulation as well as the broad-acre crop growers,” says Dilwyn.

“Dow Shield 400 has full label recommendations for 19 different crops, including swedes, turnips, mangels, bulb onions, broccoli/calabrese, cabbage, cauliflower, fodder beet, forage maize, linseed and Brussels sprouts as well as most cereals and rape and 19 EAMUs, including asparagus, garlic, shallots, chard, spinach, spinach beet, Chinese cabbage, kale, collard, outdoor leafy herbs, outdoor leeks and salad onions. Adding together its label recommendations and EAMU’s, well over 50 crops can be treated with Dow Shield 400 now and the list is always growing and evolving,” says Dilwyn.

onionsAllium growers have fewer and fewer chemicals that they can use but Dow Shield 400 has recommendations for most allium crops including bulb onions, salad onions, outdoor leeks, garlic and shallots. Dow Shield 400 should be used from 1st March and when these crops have at least 2 true leaves but before 6 weeks prior to harvest.

Cabbage, cauliflowers and broccoli can also be treated from the 2 true leaf stage up to 6 weeks before harvest and Brussels sprouts between the 2 true leaf stage up to 9 true leaves. It’s 0.25L/ha for annual weeds, for perennials it’s 0.5L/ha in a single application or up to 0.75L/ha total maximum dose from two applications in a programmed approach.

No peas or beans should be planted in the same year as the treatment with Dow Shield 400 however. For any EAMU, growers should obtain a copy of the notice of approval via the Chemicals Regulation Directorate (CRD) web site, ADAS offices or NFU.