Blight – the greatest threat to potato crops
Potato late blight (Phytophthora infestans) continues to create the greatest challenge for potato growers and agronomists. Blight outbreaks can quickly devastate entire fields, leading to significant yield losses and widespread tuber blight infection.
Favoured by warmer and wetter conditions associated with climate change, issues have been getting progressively more difficult. Blight resistant potato varieties currently offer little or no respite.
New Syngenta R&D for blight protection products and technical support ensures growers and agronomists are best placed to succeed in the fight against blight.
When dealing with blight-affected potato crops,
it’s crucial to act quickly and decisively.
Adapting to the threat of new Blight strains in 2024
The ongoing evolution of new, more aggressive, blight strains poses ever greater threats to blight management strategies.
Independent monitoring by the Fight Against Blight initiative has confirmed the UK’s first isolated case of EU_46_A1 blight sample has been found in Lampeter, Wales.
The James Hutton Institute is conducting a DNA analysis of the sample to investigate whether it will express reduced sensitivity to CAA and OSBPI fungicides. Read the news item in full.
UK growers and agronomists have been successful in tackling previous threats of fungicide resistance. Now, revised strategies, to mix modes of action and alternate chemistry within the Fungicide Resistance Action Committee (FRAC) guidelines, are required to protect crops and prevent the risk of new strains establishing.
Top tips for managing late blight in potatoes:
- Maintain mandipropramid, e.g. REVUS®, efficacy by mixing with a different mode of action* blight fungicide.
- Apply mandipropamid, or other CAA fungicides, preferably in a preventative manner.
- FRAC guidance states not to apply mandipropamid, or other CAA fungicides, in more than two consecutive applications. To further strengthen the CAA anti-resistance strategy, use mandipropamid in alternation with fungicides of a different mode of action.
- Up to six applications of CAA containing fungicides can be applied, making up no more than 50% of the intended total number of sprays.
- Good agricultural practices must be considered to reduce source of inoculum, disease pressure and resistance risk, e.g. consider planting resistant varieties and refer to disease prediction models.
*An effective partner for REVUS® is one that provides satisfactory disease control when used alone at the mixture rate.
Effective active ingredient mix partners for REVUS®
| FRAC Group | FRAC Group number | Active ingredient mix partner | Product example with active ingredient | Comments and restrictions |
|---|---|---|---|---|
| Quinone outside inhibitor (QiI) | 21 | amisulbrom, cyazofamid | Shinkon |
No more than 3 consecutive QiI products to be applied Not more than 50% of intended programme |
| Carboxylic acid amides (CAA) | 40 | mandipropamid | REVUS® | No more than 2 consecutive sprays Not more than 50% of intended programme Resistance to EU_43_A1 (not found in UK) |
| Oxysterol binding protein inhibition (OSBPI) | 49 | oxathiapiprolin | Zorvec Enicade | Up to 3 applications Not more than 20% of intended programme |
| Carbamates | 28 | propamocarb | Raport | Up to 6 applications |
| Benzamides | 43 | fluopicolide | Not applicable | Co-formulated with propamocarb Maximum number of sprays is 4 at full dose No more than three consecutive sprays |
| Quinone outside inhibitor (QoSI) | 45 | ametoctradin | Enervin | Up to 4 applications of any one product containing ametoctradin No more than 3 consecutive sprays |
| Uncouplers of oxidative phosphorylation | 29 | fluazinam | Shirlan | Up to 10 applications Resistance known within UK blight population e.g. EU_33_A2 & EU_37_A2 |
| Cymoxanil | 27 | cymoxanil | Sipcam C50 WG | Up to 4 applications If blight strains resistant to CAA chemistry are discovered in the UK through the Fight Against Blight programme, mixtures containing Cymoxanil must be combined with another effective active ingredient against late blight. Should only be used in mix with another effective active ingredient against late blight. |
| Metalaxyl-M | 4 | metalaxyl-M | FUBOL®Gold | Up to 3 applications Resistance – EU_13_A2 FUBOL®Gold contains mancozeb, see notes on withdrawal period in the box below. |
| Dithiocarbamates | M03 | mancozeb | Manzate | Up to 8 applications. Withdrawal periods have been confirmed by DEFRA and approval of mancozeb expires 31st May 2024:
|
REVUS® IS A TRUSTED LATE BLIGHT FUNGICIDE THAT HAS CONSISTENT PERFORMANCE, NEW GROWTH PROTECTION AND EXCELLENT RAINFASTNESS
Season long protection with REVUS® compared with untreated (Eurofins 2021)
APPLICATION GUIDANCE
- REVUS® is to be applied in mixtures with a fungicide of a different mode of action*.
- Apply REVUS®, or other CAA fungicides, preferably in a preventative manner.
- FRAC guidance states not to apply REVUS®, or other CAA fungicides, in more than 2 consecutive applications. To further strengthen the CAA anti-resistance strategy, Syngenta UK would advocate the use of REVUS® in alternation with fungicides of adifferent mode of action.
- Up to 6 applications of CAA fungicides, making up no more than 50% of the intended total number of sprays.
- Good agricultural practices must be considered to reduce source of inoculum, disease pressure and resistance risk, e.g. consider planting resistant varieties and refer to disease prediction models.
- An effective partner for REVUS® is one that provides satisfactory disease control when used alone at the mixture rate.
- The drift retardants Crusade, Sterling, LOK-IT and Vigilant are supported with the use of REVUS®.
REVUS® IS A TRUSTED LATE BLIGHT FUNGICIDE THAT HAS CONSISTENT PERFORMANCE, NEW GROWTH PROTECTION AND EXCELLENT RAINFASTNESS
REVUS® SUMMARY ON POTATOES
| Active | mandipropamid 250 g/l |
| Formulation | suspension concentrate (SC) |
| Maximum individual dose | 0.6 l/ha |
| Maximum no. of treatments | 4 per crop |
| Latest time of application | 3 days before harvest |
| Varieties | REVUS® can be used on all varieties, including seed crops |
| Resistance management | FRAC guidelines must be followed |
EVAGIO® FORTE, THE NEW MANDIPROPAMID AND AMISULBROM FORMULATION PROVIDING EXCELLENT LEAF AND TUBER BLIGHT CONTROL
BOTH REVUS® AND EVAGIO® FORTE GIVE EXCELLENT FOLIAR BLIGHT CONTROL!
APPLICATION GUIDANCE
- Mandipropamid is to be applied in mixtures with a fungicide of a different mode of action.
- Apply mandipropamid, or other CAA fungicides, preferably in a preventative manner.
- FRAC guidance states not to apply mandipropamid, or other CAA fungicides, in more than 2 consecutive applications. To further strengthen the CAA anti-resistance strategy, Syngenta UK would advocate the use of mandipropamid in alternation with fungicides of a different mode of action.
- Up to 6 applications of CAA containing fungicides can be applied, making up no more than 50% of the intended total number of sprays.
- Good agricultural practices must be considered to reduce source of inoculum, disease pressure and resistance risk, e.g. consider planting resistant varieties and refer to disease prediction models.
- The drift retardants Crusade, Sterling, LOK-IT and Vigilant are supported with the use of EVAGIO® Forte.
EVAGIO® FORTE – SUPERIOR PROTECTION FROM TIP TO TUBER
The potency of mandipropamid against foliar blight helps to limit the sources of tuber blight infection. However, in combination with amisulbrom, which directly inhibits both the mobility and germination of zoospores, it stops the sources of tuber blight.
EVAGIO® FORTE SUMMARY ON POTATOES
| Actives | amisulbrom 100 g/l + mandipropamid 200 g/l |
|---|---|
| Formulation | Suspension concentrate (SC) |
| Maximum individual dose | 0.6 l/ha |
| Maximum number of treatments | 3 per crop |
| Latest time of application | 7 days before harvest |
| Varieties | EVAGIO®Forte can be used on all varieties, including seed crops |
| Resistance management | FRAC guidelines must be followed FRAC Recommendations |
Blight forecasting
Syngenta’s industry leading BlightCast gives growers and agronomists up to 15 days advanced warning of conditions conducive to blight disease infection and development - PLUS NEW 15 days of previous blight risks that will be impacting crops now. This invaluable time window allows for proactive measures to fine tune blight protection strategies.
Access BlightCast for free as part of the Syngenta MyField app, with a section specifically dedicated to potato and sugar beet growers.
Download the free myFIELD app
Stay informed, stay prepared, and stay ahead with BlightCast, Syngenta's industry-leading forecasting tool!
FAQ
Strengthen Blight Protection With ICM
Application On Target Every Time
We recommend the Syngenta 3D ninety nozzle for blight sprays. The engineered droplet spectrum and specific angle of delivery enables spray throughout the dense crop of potatoes, effectively protecting lower leaves and stems against potato late blight infection. The larger droplets penetrate crop canopy with greater momentum, while fine droplets are more prone to drift. Read more...