'Phytophthora remedies vary in importance'

"Phytophthora is a very dynamic fungus that always finds new ways to control us. The only thing we can do is to defend ourselves as best we can with a smart use of resources." So says Simon Jensma, potato specialist at Bayer.

With a strong expansion of the new race EU 43, it is, according to him, 'all hands on deck' in combating phytophthora. "Alternating agents from different active groups is now more important than ever."

EU-43, that's the name of the new culprit. Simon Jensma points to the annual overview of EuroBlight, the independent European network of scientists that charts the relationships between the various phytophthora isolates every year. Whereas in 2021 the EU-36 was by far the most important isolate (physio) in the Netherlands with a share of around 50%, last season the EU-43 was by far the largest with almost 50%. According to Jensma, the shift is remarkable, but it does not come completely out of the blue. "Last year this isolate was already well represented in the Scandinavian countries", the consultant knows. 

Means from the so-called CAA group (Carbonic Acid Amides) seem to be less able to combat the EU-43. Although Jensma is careful not to 'handle off' substances in this group, he does indicate that intensive use entails risks. The adviser shows that the agents in the CAA group – mandipropamid, benthiavalicarb and dimethomorph – fall under FRAC code 40. In practice, this group of agents is amply represented in the spray schedules. Often at the beginning of the season (block 1), but also just before and in the middle block (blocks 2 and 3). With the strong rise of the EU 43 isolate, it has become even more important to (also) use products from other active groups, says Jensma. In that respect, the Infinito remedy 'fits' very well into this picture. "Infinito contains the active substances propamocarb and fluopicolide, both of which are in different active groups, namely FRAC 28 and FRAC 43. That is why Infinito is a very good partner in the field of resistance management," the consultant summarizes.

Best protection against leaf and tuber infections
Although Infinito is a very well-known and appreciated product among potato growers, Jensma would like to point out a (sometimes underexposed) quality of the product: its effect on an outdated crop. According to him, Infinito – and in particular the active ingredient fluopicolide – offers excellent protection against phytophthora later in the season, both against leaf and tuber infections. "A large series of flushing tests carried out throughout Northwest Europe have shown that Infinito offers the best protection against late foliar infections. The product also has an excellent effect against tuber infections. is not inferior to resources that are now often used at the end of the season."

Robbester boosts Infinito
As a tip for next season, Jensma says that the addition of 1 l/ha of Robbester can give Infinito a boost – especially the active ingredient fluopicolide. "With Robbester, the absorption of fluopicolide is better, as we have seen in tests."

The advice for using Infinito remains broadly the same. For seed potatoes, this is: starting from the start of tuber formation until the haulm killing, with a maximum quantity of 6,4 liters per hectare in a maximum of five applications. 

For consumption and starch potatoes, the advice remains: apply from the start of tuber formation until spraying. Depending on the phytophthora pressure, the dosage of Infinito can be adjusted. That is to say: 1,2 l/ha at normal pressure to 1,6 l/ha at high pressure. When damage is already present in the crop or in situations with very high pressure in the environment, 0,2 kg/ha of Curzate® Partner is added. Optionally, a remedy against Alternaria can be added, such as Propulse.

^{Curzate ® partner is a registered trademark of Corteva Agriscience}

This business case is powered by: