New dose rates for Dow Shield 400 in sugar beet

Sugar beet growers who have used Dow Shield for a number of years to control difficult and competitive weeds such as volunteer potatoes and creeping thistle are reminded that the new more concentrated formulation contains twice as much clopyralid and so should be applied at half the dose rate per hectare.

David Roberts of Dow AgroSciences says that sugar beet growers are, quite rightly, focusing on high yields in order to keep profits up and to do so they need to make sure that they rid their crop from thistles and volunteer potatoes as they are particularly competitive weeds. "Just one creeping thistle plant per square metre can cause yield losses in sugar beet of as much as 1 tonne per hectare. Volunteer potatoes are even more competitive, with one weed plant per square metre causing losses of 3 t/ha and the benefits of control will continue into following crops. To achieve effective levels of control of these highly competitive weeds, both of which are increasing in incidence in sugar beet, post-em applications of Dow Shield 400 will be required, but make sure you remember the new dose rates for this year."

"Starting when the smallest sugar beet plants have expanded cotyledons, the use of Dow Shield 400 also improves activity on many weeds, such as corn marigold, groundsel, mayweeds, smooth sow-thistle and black bindweed. However, where crops have struggled through stressful weather and where Dow Shield 400 is applied in a programme with other herbicides, applications should start when the first true leaves on the crop are at least 10mm long," he says.

David Roberts points out that particular strengths of clopyralid are the control of creeping thistles and volunteer potatoes. "The use of Dow Shield 400 in sugar beet crops for the control of these difficult weeds is flexible, allowing its inclusion in differing management approaches, even when volunteer potato emergence occurs over an extended period. To keep on top of volunteer potatoes, start as soon as possible with the first treatment of the new dose rate of 0.25 l/ha of Dow Shield 400 when the potato haulm is 5 to 10cms high, followed by a second application at the same rate at 10-14 day intervals later when the volunteers are 10-20 cms in height. For creeping thistles, the first treatment of Dow Shield 400 should be at 0.25 l/ha when thistles are at the rosette stage of growth, followed 3 to 4 weeks later by an application at 0.5 l/ha. In traditional low-dose programmes, Dow Shield 400 can be included with applications of ethofumesate and phenmedipham. In all cases, applications of Dow Shield 400 to sugar beet should be completed by the end of June."

He explains that the new soluble concentrate formulation performs just as effectively and as consistently as the previous product. "In sugar beet trials, Dow Shield 400 gave the same 93% plus control of creeping thistle. Dow Shield 400 is translocated through the rhizomes and roots of perennial weeds and offers excellent levels of control in a programme."

David points out that the new concentrated formulation of Dow Shield 400 also has the same excellent crop selectivity and the same compatibility. "But by applying half the dose rate, having fewer packs to open, rinse and clean and no fiddly induction foil to open and get rid of, the whole spraying process and pack disposal is more streamlined and much easier, which is helpful at a busy time of year or when trying to get sprayed up."

Dow Shield 400 has label recommendations for a wide range of crops including sugar beet, red beet, fodder beet, mangels, oilseed rape, grassland, forage maize, ornamentals, wheat, barley, oats, swede and turnips and Brussels sprouts.

It also has a number of Extensions of Authorisation (were SOLA’s) including asparagus, apple, crab apple, pear, chard, spinach, spinach beet, poppy for morphine, broad-leaved trees, coniferous trees, grassland seed crops, durum wheat, rye, triticale, borage, canary flower, evening primrose, honesty, mustard and outdoor herbs.

Dow Shield 400 contains 400 g/litre of clopyralid, formulated as a soluble concentrate and packed in a 2 litre pack. In sugar beet it is recommended at a maximum individual dose rate of 0.5 l/ha with a maximum total dose of 0.75 l/ha. It can be applied post-emergence up to when crops meet between the rows (BBCH 39).