Walnut Blogletter 29 – April 2017

This blogletter is a quick appeal for information from you lot. We have just had the absolutely worst season weather-wise that any of us imagined. A problem, yes. But it is also a once in a lifetime opportunity to learn about growing these walnut things. So please get on your computer and give us a quick description of how this season has treated you. If everyone does it we will learn answers to questions none of us ever thought of. So, if you are reading this, give us a quick note of how this season treated you. It only has to be a few lines.

To get you started here are a couple of email exchanges. Kate Carter has lost a big part of her crop, can you help her? Valda Muller in Otago was confronted with all her crop on the ground in one day, on a soggy boggy ground. Is this the weak link in machine harvesting?

Hi Nick,

We are new to being members of the Tree Crops Assn & joined as we are interested in seeing how other peoples season has gone. We have a 300 tree walnut orchard in the Pohangina Valley, Manawatu. “Konewa Walnuts”.  We have only owned the property 3.5yrs so have just experienced our third season. The trees range from 8-13yrs old now & we have predominantly Shannon & also some Rex & Meyric. Our last two seasons went very well but this season was a different story & we didn’t know where to turn for help so I am hoping you have some answers for us 🙂

We don’t spray our trees for the fact they are too big to make it effective using our quad sprayer with short wand & we have not yet had any blight problems. We had a bumper crop this season & good harvest, we thought all was going well until we started opening some nuts to find there was white fuzzy mould surrounding the inside walls of the shell. The Kernel itself is still normal looking, nice colour (I was game enough to do a taste test & they also tasted good, no rancid taste) The more nuts we opened the worse the problem seemed. We thought maybe collecting every second day wasn’t enough in the poor weather so we ventured out again & hand collected a few nuts directly off every tree only to find they are mouldy even when in the tree. The only variety that seems unaffected are the Rex’s.

We abandoned the majority of the crop & let our pigs in to clean up. We were devastated & left looking for answers. Being reasonably new to the Walnut business we couldn’t find any helpful info. It does not appear to look anything like blight as the shells are nice & so is the kernel. We have continued to dry the nuts already collected & plan to open them to see how many are unaffected & if those ones can be sold as pieces. So far of the nuts we have opened, we have been striking on average 70% bad.

Is this just because it has been a very wet season & the Shannons have a somewhat loose seal which has let moisture in? Is there anything we could be doing to help the situation for future crops? Do you have any info if other people have struck the same issue?

 Thanks, Kate & Reuben

Kate and Reuben,

I am sorry to hear of your plight.

This is nothing like I have ever seen in 40 years of growing walnuts. Hopefully someone else on the blogletter circuit can shed some light on what is happening. We did not spray and did not get anything like you are describing even though it was a horrible cold wet season. I must admit I had not opened any Shannon, but have just grabbed a torch and gathered a handful; nothing that fits your description. Can you take some photos to give us a better idea of what this lurgy looks like?

All the best


Hi Nick,


Thanks for your reply. If you haven’t seen or heard of this in your years of experience I hope it isn’t something really bad or new.

The ones I have opened tonight are more of a grey coloured mould. It does range from white to grey. I have also tonight found some of it is on the kernel.


Something else we have found this season is this black discolouration around the join line on the inside of the shell (pic 6) . I think it looks like a black mould but it isn’t fuzzy. The picture I have added of that is quite bad but a lot of the nuts have one or two small spots of this.

Cheers, Kate

OK Kate,

Those photos are very helpful. I have seen the odd nut like that. When I have been a bit slack in getting them off the ground promptly, you get the odd one with mould. I notice that the kernels have got the characteristic orange colouration when moisture has been getting into the shell. So, your diagnosis seems spot on to me. That black line around the joint line is also characteristic of a poor seal with moisture getting in. All the best


Can anyone else shed some more light on this for Kate?

Then, when the power came back on amid the chaos left behind by Cyclone Cook, in the queue of emails was this one from Valda Muller.


…. well that was one way to get walnuts on the ground ….. but !!!  I hope there is not too much damage at your place


Thanks Valda,

Our power has just come back on, so completely unaware what has been happening in the rest of the country. Did you get hit by cyclone Cook?

We did get a bit of damage in terms of trees blown over, a couple of our favourite walnut trees among them. We haven’t ventured far because we don’t want to drive over the carpet of nuts, so don’t know what the rest of the property is like. Now the power has come back on we can put the nuts back in the driers again. We had to spread them out in the sun the old fashioned way because they were sweating confined in the driers.

A handy gate was pressed into service!

Apart from having your whole crop dumped on the ground on the same day, how has this season been for you?

 All the best



It did not get down this far ….. but I was very much aware of what was happening in your area as I have a brother in Tauranga

Sorry to hear about the loss of some trees (especially the favourite ones) and feel for you with so many walnuts on the ground which will be sodden and strewn with torn off branches etc – could not have come at a worse time for you and will be a major task trying to rescue what walnuts you can and tidying up the property ….. would that we were closer so I could help.

It has been a really mixed season for us – a wet and cold November and a summer which really did not eventuate – 700 tomato plants (Black Krim) in the hot house ….. and I am still harvesting from the bottom truss of many plants!!?!  I still have at least 70% of the crop as green tomatoes on the plant ……. and that is in a hothouse in Central Otago!!!

The nut harvest has been “interesting” with a really heavy frost (wind machines going in the vineyards from 8pm right through to 9am the following morning – a really noisy night about 10 days ago) then all cultivars ripening at the same time coinciding with the leaves all falling  (Smile!) …….. really appreciate the staggered harvest that we normally enjoy.  I have NOTHING to complain about – there will be so many with nuts blown off trees all at once and landing in sodden grounds – I am sure this season will go down as the most challenging harvest season ever!

Hope you are getting lots of community support to get immediate tasks in hand

 Best wishes


Thanks for your kind thoughts Valda,

There are lots of people all around us who are much worse off. (We are not far from Edgecumbe.) I feel guilty about not being one of those giving community support.

I did get to the back of our place 5 days later, chainsaw in hand. Less damage up there than I expected. The NZTCA variety trial is on a very exposed ridge, and it is fine.

One comment you made got me thinking; I had never really considered the implications of a frost 10 days before harvest. What would happen if one struck?  It is all just a hypothetical question, fortunately, up here in BOP. I am very familiar with late spring frosts from my younger days on the volcanic plateau, but I was dealing with little seedlings at that stage.

My thoughts are with you guys operating machinery in this wet weather. The picture of mud comes to mind. As you can see (doesn’t look too bad in the photo actually)our nets were all covered with leaves and branches, but still seemed to work O.K. We are calling it the pneumatic autumn.

All the best

nick nelson parker

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