Summer season spud report

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By Gemma Carroll, PNZ Comms & Engagement Officer. 

It’s been a mixed bag of weather across the country this Spring and Summer, much as the rest of the world has seen, with unusual changes in weather and increased occurrences of extremes. 

NZ agronomists and growers in our main growing regions had the following to say about the 2019-2020 potato season: 

In Pukekohe the report in from agronomist Shane Smith indicates a most challenging season, ‘the most difficult in 10-15 years’. Erratic weather has affected yields.  

Initially in Spring the new season potatoes showed good results, but then late wet weather in Spring, a cool Summer mixed with sudden hot, dry spells and unseasonably strong and drying winds have resulted in lower yields over Summer and also cracking in the soil has meant easy breeding for tuber moth, from which the effects are being observed in both foliage and potato. 

There has been a definite lower yield in main crops in Pukekohe and seed has also shown more stem numbers. Shane is predicting it will be a shorter season for harvesting this Summer. 

Otherwise there has been no sign of disease, including crops apparently free of psyllid and no PMTV. 

In Manawatu a fair season has been had, with a bit of wind recently but nothing they haven’t seen before. There’s been no weather extremes and no late frosts. It may be getting a bit dry now and was dryer than normal after planting in October. This has meant there has been more irrigation in the last 2 weeks. 

The region is expecting average yields and not expecting crop failures.  

There’s some psyllid around and has been for at least a month, but not huge numbers.  

Manawatu at this time of year is mostly into main crops and these are still in full foliage. Calendar spraying takes care of most pests. 

In Canterbury agronomist Roger Blyth indicated a quiet confidence despite some occasional extreme weather earlier in the season. 

Planting time saw good, dry conditions and all seed was in the ground in a timely manner. 

Emergence took longer than usual with cool days and nights and very little rainfall early to mid-Spring. Overall it has been a dry time right through. 

At times the wind has been ‘horrific’ with hot dry nor’ westers. This has seen some crop damage and for farmers a tough season overall. Also a significant hail event early on was detrimental to a number of crops. In early December a heavy rainfall event on the Western side of the Southern Alps meant rivers were running full stream which shut irrigation systems off and so a number of crops were blown around in wind as well as flooded by burst riverbanks. Russet Burbank have shown some signs of secondary  growth, so setting tubers at the time may have been lost. 

Psyllid has been non-existent with control strategies around a week or 2 earlier than usual, which may have helped. There are plenty of incentives in contracts for psyllid controls to be in place. 

Potato Mop Top virus symptoms have not been seen, which may be due to good management plans but also the dry Spring will have reduced the occurrence of it’s vector powdery scab. 

Canterbury’s season is a little later than the North Island and so they are still harvesting early potatoes. The main crops in late January will begin with McCain crops such as Innovator. Full stream digging of Canterbury main crops will begin early to middle of March and then move into storage systems. 

The cooler than usual Summer nights may actually mean a longer growing season, which could be a good thing. If January and February bring good weather then there should be good results.