Phytophthora pressure has been extremely high lately and has spread quite a bit. Now that the aphids are also on the rise again, the concerns about the plots for the seed potato growers are increasing considerably. The growers do not differ much in the time of haulm destruction compared to other years, although that can also be a challenge.
Infestations of phytophthora have been frequently found on seed potato plants for several weeks now and several plots have now fallen prey to the fungal disease. Although it has been mainly dry last week, the leaf wet periods were still very long due to the dew-wet nights and because the mercury rose only to a limited extent during the day. And once phytophthora lurks around a bit, it can strike thoroughly at any chance of infection. That seems to have happened, because since last weekend the infections in the potatoes have increased considerably again. Advisors and growers indicate that the fungus is quite aggressive and, despite a strict spray schedule, still manages to settle in the leaves and stems.
Limited free riding on consumer prices
Despite the late planting dates, it appears that the foliage has already been destroyed from a considerable area of seed potatoes. There is no official data, but it seems that more than half of the foliage has already been taken care of. The lower tuber number, together with the favorable weather, ensured that seed potatoes quickly grew to size. According to insiders, growers leave the seed potatoes for only a little longer than normal and potatoes up to size 60 will also be labeled as seed potatoes. They don't seem to do much free riding on consumer prices. The volume of potatoes that becomes additionally available for consumption appears to be very small compared to the total volume.
Aphid pressure
Some varieties still have to continue growing until they reach size. The phytophthora pressure and the weather forecast are causing concern for the seed potato grower. The past period is here a lot of primary virus was detected in various plots, but aphid pressure had decreased significantly due to precipitation and moderate temperatures. As a result, growers dared to leave the plots for a while with some selection rounds until they were slightly on the coarse side. Now that lice pressure is increasing again due to the warmer weather, a rapid spread of the mosaic virus is lurking. Therefore, consideration must be made for certain plots. With the (thunder) showers planned for this weekend, we are not yet rid of phytophthora.
Foliage destruction is slow
Getting seed potatoes dead at the right time is still a challenge in some cases. A round of growers and advisors shows that foliage destruction via full-field spraying is not going so smoothly this season. It has often been cloudy and rainy lately and the current foliage destroyers such as Quickdown and Spotlight need a lot of sunlight to work properly. Don't forget the particularly vital crop for this time of year and you see that the products are only effective to a limited extent. In the meantime, the potatoes continue to grow at a rapid pace. This means that a lot of growth is still possible in a week when the crop dies.