Beware mixing and matching two potato blight fungicides

Combining the individual components of a co-formulated pesticide product by mixing “straights” can save money and add rate flexibility to a spray programme.

However, in the case of potato blight fungicide Curzate, this can result in a number of pitfalls that might land a grower in hot water through breaches of label restrictions.

Containing the actives cymoxanil and mancozeb, many potato growers will be familiar with market-leading co-formulation Curzate and its label conditions of use.

See also: 5 easy steps to tackling bruchid beetle damage

It would be easy to assume that combining these two “straights”, or using one or the other to top-up that particular component, would adopt the same conditions of use.

But this month’s Pesticide Watch highlights significant variation between approvals of a range of cymoxanil and/or mancozeb-containing products.

The tables show examples of these differences and in the case of the one can options, there is variability in maximum concentration, maximum rates, maximum applications, harvest intervals and product Local Environmental Risk Assessment for Pesticides.

Looking at straight cymoxanil products the variants are similar, but there are also products available with maximum quantity limits and no spray interval limit.

With mancozeb straights, the majority of products have similar approvals, but there are differences in maximum dose rate, which could trip growers up.

It should be noted that not all available approvals are included in the tables, but it highlights the necessity to check individual labels when mixing and matching products that contain these actives.

Failure to do so may result in unknowing breaches of cross-compliance and processor protocols, ending with heavy fines or unsaleable potatoes.

Cymoxanil-mancozeb co-formulations

Product

Active(s)

Max concentration

Max rate (kg/ha)

Max applications

Harvest interval

Mapp

Lerap

Curzate M WG

cymoxanil + mancozeb

2

0

0

11901

Globe

cymoxanil + mancozeb

1.5

6

7

17,175

B

Master Cyman

cymoxanil + mancozeb

2kg in 300 litres

2

8

0

16,686

Nautile WP

cymoxanil + mancozeb

2.2kg in 300 litres

2.25

8

21

16,468

B

Profilux

cymoxanil + mancozeb

2.5

6

7

16,125

B

Zetanil

cymoxanil + mancozeb

1.5

6

7

17,285

B

Zetanil WG

cymoxanil + mancozeb

2.4

8

7

15,488

B

 

Cymoxanil products

Product

Active(s)

Max Rate (kg/ha)

Max applictions

Max quantity

Harvest interval

Interval

Mapp

Lerap

Cymbal 45

cymoxanil

0.25

10

7

7

16,647

Cymostraight 45

cymoxanil

0.2

14

7

14,615

Dauphin 45

cymoxanil

0.22

8

14

7

16,434

B

Drum

cymoxanil

0.25

10

7

7

16,750

Option

cymoxanil

0.15

8

1

7

16,959

Option

cymoxanil

0.15

7

11,834

Sacron WG

cymoxanil

0.22

8

14

16,433

B

Sipcam C50 WG

cymoxanil

0.24

0.96

7

7

16,743

Mancozeb products 

Product

Active (s)

Max rate (kg/ha)

Mapp

Dithane 945

mancozeb

2

17,269

Laminator 75 WG

mancozeb

2.13

15,667

Manzate 75 WG

mancozeb

1.7

15,052

Quell Flo

mancozeb

3.3

15,237

Pesticide Watch

Gatekeeper logoCrops is working with Gatekeeper agronomists to highlight key pesticide rule changes and the potential implications, keeping you on the right side of the law and aiding on-farm record-keeping.

Sentinel is a decision support tool linked to Gatekeeper crop management software, a programme that helps arable farmers with record-keeping and legislation issues.

For more details visit www.farmplan.co.uk or call 01594 545 011.

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