Seed harvest on the Yorkshire Wolds is in full swing in ideal lifting conditions; so far quality looks pretty good, with yields around average. Earlies and second earlies in the west finally caught up in terms of yield, although the exceptionally dry spring and early summer resulted in some crops struggling throughout, particularly those without irrigation.

Desiccation of main crop potatoes is well underway; generally crops seem to be maturing well and senescing nicely. Yield and quality is extremely variable. Common scab is the most common skin blemish disease noticeable at present, although I am seeing a lot of black dot on stem bases, which no doubt will create problems in store on susceptible varieties.

Getting the crop into store safely is the next priority. Making sure that the crop is suitable to store in the first place and that skins are thoroughly set is a good start. Ideally fill stores as quickly as possible, aiming to ventilate as soon as possible to remove field heat and moisture. Remember that if using CIPC (chlorpropham), the maximum dose is being reduced annually and for the 2015/16 storage season, the statutory maximum rate of CIPC that can be applied is 50g/t for processing potatoes and 30g/t for fresh market crops. Best practice permits just one application in cold stores (<5°C), early in storage, before temperature is decreased below 7°C.

It is worthy of note that by 2017, all CIPC product labels will be limited to a maximum total dose of 36g/t. Some clients are already being proactive by making changes to stores to enable CIPC to be applied more effectively and efficiently. If you haven’t already done so, just think what life would be like without CIPC and make those changes sooner rather than later, just a little thought about how boxes are stacked and how air moves around the store could make all the difference.

Finally, and most worryingly, the news from DuPont regarding the availability of Vydate (oxamyl) hit the headlines last week. It seems highly unlikely that there will be any product available for growers next spring. For those growing main crop varieties on potato cyst nematode (PCN) infected land where harvest interval is not an issue, then of course the product of choice will be Nemathorin (fozthiazate). For growers of earlies and second earlies looking for loose skin, off the field harvest there is more of a problem, as there will be for those growers who are just looking for free living nematode and spraing control. The alternative here is to use Mocap (ethoprophos) which has a similar harvest interval to Vydate, however supplies of this seem to be limited in most years.

The other issue is that of application. Vydate can be applied in furrow at planting for free-living nematode (FLN) and spraing control at rates between 15kg/ha and 23 kg/ha, (140g/100m row – 210g/100m row) costing in the region of £120-180/ha. Nemathorin and Mocap must both be applied as an overall application and in my opinion only full rate will offer any decent protection against FLN and Spraing which will increase the cost of control to over £400 per hectare. Field and variety selection will be crucial in order to minimise the risks, weed control in order to reduce the disease reservoir is vital. More to come in the next few weeks…