This makes for easier work at harvest but it also adds an additional concern for jobs like planting oilseed rape or grass seeds and for burning off potatoes.

The use of diquat for burning off potato foliage has long been associated with the risk of vascular browning in the tubers following treatment. This risk is exaggerated when soil conditions are dry at the time of treatment.

Vascular browning is a naturally occurring phenomenon, particularly associated with rapid defoliation (by any method) when the crop is under high soil moisture stress. Split dose Reglone significantly reduces the risk.

To help avoid such problems, Syngenta’s Frank McGauran recently presented an update of how best to use Reglone for haulm desiccation and how to avoid problems where soil moisture levels might be suspect.

While it is still early for the vast majority of burning off, the information is still valid for the weeks ahead, unless there is sufficient rain to remove the potential for moisture stress in all land. The majority of maincrop crops still need to do a lot of bulking up before they will be burned off, so this may be a month or more away.

Some second early crops may be burned off to stop some of the tubers from getting too big for a specific market or to prevent them from becoming misshapen, if they are to experience a burst of regrowth. Burning off will also help skin set.

• LOW RATES ALWAYS SAFE

The first thing to remember is that it is always safe to use Reglone at 1.0 l/ha to ‘open up a crop’, regardless of the soil moisture level. Following this it is still safe to use Reglone a second time to complete crop desiccation as long as the second application is made within five to seven days of the initial application. But if the second spray is delayed beyond this interval or if regrowth has started, then Syngenta recommend that a grower conducts the following SMART decision analysis.

•REGLONE SMART TEST

The Soil Moisture Assessment for Reglone Treatment (SMART) test is a simple practical field test to assess soil moisture and potential crop stress. It should be used to assess the correct application option for Reglone.

Dig down and take soil samples from the centre of the ridge 5cm below the deepest tuber. Gently squeeze the soil sample into a ball with your hands. If it is sufficiently moist to remain as a ball, it passes the SMART test. But if the soil collapses then it has failed the SMART test.

Repeat at several points across the field, especially in the dry areas. If SMART is fail/borderline, the maximum rate for the first part of split dose Reglone should be 1.0 l/ha. This can then be followed withing five to seven days by a second application of 2 l/ha to 3 l/ha.

If the SMART test is a pass (there is adequate moisture in the soil), you can either opt for a single dose or a split dose. The single dose is 3 l/ha to 4 l/ha of Reglone but this can be followed up with a second application (if necessary) to bring the total application to a maximum of 5 l/ha. For a split dose treatment, apply 1 l/ha to 2 l/ha initially followed by 3 l/ha to 4l/ha five to seven days later.

The total dose allowed for Reglone is 5 l/ha with a maximum individual dose of 4 l/ha. There is no restriction as to the number of applications, provided these rates are not exceeded.

If the SMART test is a pass, the grower can choose the rate of Reglone dependent on the haulm condition. This includes a single dose applied to senescing crops. However, if the SMART test is fail/borderline, growers must use split dose Reglone with maximum of 1 l/ha as the initial application.

Only in situations where the second application is delayed, or if regrowth has started, is it necessary to carry out a SMART test to assess safety of use. If the soil is too dry at this stage it is still perfectly safe to apply a second application of Reglone at 1 l/ha to continue crop desiccation.

It is always advisable to include Shirlan with each application of Reglone to aid in the fight against tuber blight. And never include an adjuvant with Reglone at desiccation timing.

APPLICATION

To help cope with the big volume of foliage, growers are advised to use alternate front and rear facing angled nozzles when applying Reglone. This will give improved defoliation and reduced drift. The amount of water can vary from 200 l/ha for senescing crops or split applications but up to 400 l/ha for dense or difficult to clear haulm in the first application. Syngenta recommend using the Orange 05 Potato Nozzle for spraying at 12 km/hour and the Gold 04 Potato Nozzle for spraying at 8 km to 10 km/hour.

KEY POINTS

?One can always use Reglone at 1 l/ha regardless of soil moisture levels. Risk of damage to the tubers is from a combination of low soil moisture levels and high rates of Reglone.

?If you want to burn off with a single spray and a high rate, then it is necessary to conduct the SMART test on your soil to guide the process.

?If soil taken from the centre of the ridge two inches below the deepest tuber is damp enough to form a ball, then the soil is moist enough and the crop can be sprayed with 4 l/ha in a single spray.

?Choose water rate according to the condition of the haulm and use the nozzles advised.

Asulox warning for certain nature conservation sites

While an emergency clearance was awarded to farmers for the use of Asulox to control bracken in grassland and forestry in recent weeks, farmers must also be aware that this clearance requires prior consent for use in certain nature conservation sites.

Landowners are reminded that under the European Communities (Birds and Natural Habitats) Regulations 2011, it is a legal requirement to obtain consent from the Minister for Arts, Heritage and the Gaeltacht prior to applying pesticides, including herbicides, on Special Areas of Conservation (SACs), Special Protection Areas (SPAs) and Natural Heritage Areas (NHAs).

This permission is important because all farmers are subject to cross compliance requirements.

Application on these areas without prior permission constitutes a breach of the regulations which could lead to penalties on farm payments. This is important because a lot of the bracken control is likely to take place in such areas and the permission is needed to avoid the risk of penalties.

Indeed, landowners who apply pesticides in such areas without prior ministerial consent could be liable to prosecution.

CONTACT

If you are uncertain as to whether or not consent is required in a certain area, farmers are advised to contact their local National Parks and Wildlife Service office (see www.npws.ie) or phone 1800-405000.