Washing in seed potatoes causes concerns

Overgrowth in the seed potatoes is not permitted by the NAK inspection service. Glassy primary and secondary tubers have poor shelf life and cause problems with emergence. The NAK inspectors only visually check glass. If there are germs on the tubers, the problem is less serious. However, the potatoes remain germinable. Is there one? heavy damage, then letting it grow out is the only option.

racial differences
In Flevoland, overgrowth is found in all places. There is no fixed picture to be formed. Agria is susceptible, but growth is also found in the relatively insensitive Fontane variety. Advisors and traders call the situation unique. Wash-out normally does not manifest itself to this extent. Delphy advisor Johnny Remijn does not see much growth in the province of Zeeland. It is especially noticeable in the Agria and Bintje varieties, although the acreage of the latter variety is very small.

Remijn also saw it last year plots with full growth: "The old and new tuber had a measured underwater weight of 300 grams. They held up well in storage, but this spring the emergence of both tubers was poor. The glass heads rotted and bacteria and fusarium struck. Is the underwater weight high enough, then the seed potatoes can be used."

Virus attack
Potato plots are blooming again along the Wadden coast. There is no serious damage (yet), an insider said. The late varieties in particular have to deal with sprouts on the tubers. Plots that have already been collapsed also grow again and are therefore attractive for a late aphid flight. Just like last year, there are fears of a late virus attack.

Since many crops died prematurely due to the warm weather, the NAK has hardly carried out a third inspection round. The selectors could no longer look for plants that were sick with bacteria and viruses. The latest figures from the NAK (6 August) level off at a reduction of 15,8% and an additional 2,3% has been rejected. The trading houses expect that the follow-up inspection may be disappointing.

(Text continues below the image)Regrowth in seed potatoes raises concerns about late virus contamination.

complacency
Trading house De Nijs Potatoes from Warmenhuizen notes that growers sometimes think about the problem somewhat lazily. The yield is low, so we waited a long time before spraying to grow as many kilos as possible. It calls the situation in North Holland worrying. The early varieties suffer less from regrowth than the late ones. Most plots are now dead, but plants are starting to sprout again. Sometimes side shoots of mature tubers grow from the ridge to form new leaves.

The trading companies also mention scab as a problem. During the test harvesting the damage was minor, but this picture appears to have changed during the harvesting. This is also registered by the NAK. Mother tubers are not seen as a problem. Due to the drought they have often been drained and sufficiently digested; especially when the crop has been dead for some time.

Ideal harvesting conditions
The grubbing up has mainly started in Flevoland. In many other areas it was too dry. Sufficient rain has now also fallen in the north, North Holland and southwest. The underwater weight is very high, so extra care must be taken when harvesting. Ton Stolte, operations manager at the NAK, advises growers to submit grubbing-up notifications to the NAK in a timely manner so that their laboratory can get started. This is advisable for early exports.

De Nijs notes that the lots that were harvested in very warm weather are already showing signs of germination in storage. In the Frieslander variety, the tubers are already sprouting. It expects many problems with germination during the storage season. The quality is otherwise averagely good.

Low yields
The yields are very disappointing everywhere. In dry Zeeland, Remijn registers yields between 15 and 40 tons per hectare. The sebum is relatively high. De Nijs also mentions similar figures in North Holland. On average, the company has a lower yield of 30%. In Friesland, where there is no irrigation, the net amount is 25 tonnes, after deduction of the undersize.

There is plenty of rain in the province of Flevoland, but the situation is also nothing to write home about. The regional differences can already be large in the Noordoostpolder. A reduction in yield of between 25% and 30% is expected. This also applies to Eastern Flevoland.

Does the price compensate for less yield?
As with consumption potatoes, the question remains: does the price make up for a significant reduction in yield? It is striking that opinions differ. Trading houses react soberly. They often have multi-year (price) agreements with customers. The slight stretch in prices is insufficient to compensate the grower's losses.

The consumer grower must be able to pay for the expensive seed potatoes again next year, even though nothing has been earned. In other parts of Europe, the danger of non-certified seed potatoes lurks. If the price is too high, more potatoes will simply be planted.

In previous years (2016), sales of oversized seed potatoes were sometimes a nest egg. However, many varieties hardly have any large tubers this year, so little can be achieved here. Those who have allowed their crops to grow for a long time are now experiencing the greatest problems with washing through.Flowering potato plots are observed everywhere in the Netherlands.