Death Valley

Ok that may be a bit of an exaggeration – but my garden is in a valley and there has been death – three so far and by the end of the season I suspect there will have been twenty with a complete tomato population wipe out.  The only advantage I can see is I will still get some tomatoes although from what I have read, they won’t be as “tasty”.

Young tomato plants
I started my growing season with such hope and each plant held so much potential.

I have a disease.  To give it its full name:  Pith Necrosis.  And to be honest I’d never heard of it until today and it isn’t one of the big three problems that strike tomatoes in their prime.  You normally think of Blight, Blossom End Rot (which isn’t a disease but a nutrient availability issue) and the dreaded TTP Tomato Potato Psyllid.  I have a problem solver book that lists 22 things that could possibly go wrong with tomatoes, and Pith Necrosis isn’t there!  It wouldn’t surprise me if it was rare, we’re always getting some kind of rare problem around here – nothing that will kill us mind you.

Tomato Potato Psyllid eggs
And I thought my troubles began and ended with the Tomato Potato Psyllid which is why I was so quick to treat their eggs, however treating them the way I did only made my other problem worse. Sorry not sorry.

I discovered the problem yesterday, unintentionally, but in doing so may have made it a whole lot worse.  I have been diligently spraying my tomatoes for the Psyllid every two weeks ever since I discovered those first tiny eggs clinging to the edge of a leaf.  I have been taking care of the needs of the tomatoes on a Monday as they are in sector one and doing the spraying then.  But last time I wasn’t able to do it on a Monday and couldn’t remember for the life of me if I had done it on a Tuesday or a Thursday and decided to wait until the next Monday to get back into routine.  But my goodness, those horrid little bugs didn’t wait for me…  there was quite the infestation, and plenty of green vegetable bugs to boot.

poorly tomato plants
I have been a bit ashamed of my tomatoes as I have felt something wasn’t quite right so I avoided showing them off too much. They are all a bit scrappy.

So, I grabbed the nearest secateurs and removed infested foliage and tied in wayward branches, making it easier to penetrate the tops and bottoms of the leaves with spray.   Before spraying I did a hard pick of anything that may come ripe in the next 7 days for the withholding period, which will probably save them from the ravages of the green vegetable bug.  There weren’t many but I thought that was because of the Psyllid.  Oh, how I was mistaken.

Dirty Secateurs
This is terrible. These dirty secateurs are completely disease laden and ready to inoculate the next tomato plant I touch.

While I was at it, I decided to remove the plants that were clearly dead.  I knew it wasn’t the Psyllid but thought it was a stem borer as it looked a little munted at ground level.  Not only did I pull them out, but I chopped them up to make it easier to fit in my weed bucket.  Little did I realise what harm I was doing.  I was spreading disease!

Clean Secateurs
Much better. Keep your tools clean and sanitise between plants. This isn’t a suggestion or recommendation, it is actually very important. The dirty world of gardening requires good hygiene practices.

You see – Pith Necrosis is a bacterial disease and Pseudomonas corrugata is responsible.  If I remember back to the days of my microbiological training, many moons ago, Pseudomonas was one of those ubiquitous bacteria that are found everywhere and if you didn’t know the answer to a question in a test or exam – if you wrote Pseudomonas down there was a high chance you’d get a point for getting the genus right.

pith necrosis
This is what pith necrosis looks like when you pull up the plant.

This particular species lives in the soil and takes advantage of weak tomatoes in the perfect storm of weather conditions, with a little bit of help from an unwary gardener.

Firstly, as a bacterial disease, it is spread easily through contact and if you remove the lateral from one plant and then move on to the next plant without washing hands or sanitising tools, then you are spreading disease.  I should have known better.  It is microbiology basics drummed into students from day one.  I will no longer do or recommend pinching out laterals.  It is best to do it with clean, sharp secateurs and sanitised in between with a small spray bottle of meths.

pith necrosis
When you split the stem you can see the destroyed tissue up the middle. You can see how I would have mistaken it for a stem borer.

The main reason my tomatoes were weak is my fault…  I wanted them to grow fast as they went into the garden late and so when they shot up, I thought nothing of it.  It turned out they shot up because there was too much nitrogen in the soil.  This causes fast but weak growth and makes them a target for all sort of pest and disease that can sense weakness.  But all that lush green growth looked healthy.

Green tomatoes
Tomatoes in healthier days…. so much potential… sigh….

The first mistake I made was I thought I was doing a good thing following the tomatoes with the peas – a nitrogen rich soil must be good – right?!  Then I grew a cover crop to return organic material to the soil – only the best for my plants.  Once that had been dug in and allowed to rot down, I added compost, blood and bone, sheep pellets and Dynamic Lifter – all according to the instructions.  However, there should be instructions that says “when used in conjunction with…  then use this much…”

burn or trash diseased material
I would show you what a fully diseased plant looks like, but I’d already chopped it up. Remember burn or trash diseased material. Don’t put it on the compost or send it out with the green waste.

For the home garden it is difficult to know what state the soil is actually in as soil testing in a laboratory is cost prohibitive.  To test each of my beds individually would be well over two thousand dollars.  And there aren’t any effective home test kits readily available here – although under the circumstances I may need to investigate this further.  So, what is left is trial and error.  You know you need to replace the nutrients taken by the plant and tomato plants are big there for it makes sense to give the soil lots of love.  However not all plants have the same needs.  Corn is a big tall hungry plant and would love the preparation I prepared for the tomatoes.  Carrots on the other hand don’t like too much nitrogen and would split at the thought of it.

Pith Necrosis
The new growth is quite spindly and the small leaves can begin to look like they have a nutrient deficiency, which would make sense when the stem is being destroyed from the inside.

So, I will ease up on the additional material going into the garden and rearrange my crop rotation – again – to put the corn before the tomatoes instead of the peas.  I was going to move the corn into that cycle anyway to benefit from the shelter provided by the wind break along the fence.  I just need to make sure where I put them fits in with the timing of the early starters and the slow pokes who languish in the beds too long.  It is a bit of a puzzle.

If only you could tell if your soil was good by looking at it. This looks like good soil…

The last part is out of my control – the weather.  Cool night time temperatures, high humidity and wet conditions are the final factors that encourage this disease.  And that dodgy spring and early summer we had would have been perfect conditions for a bunch of rampaging Pseudomonas to go off looking for a nice juicy stem to climb into.  If only I could control the weather…

tomato harvest
This is the result of a hard pick from 17 plants. Not exactly abundant. I look on with envy at the bountiful harvest people are getting from just a few plants. The fruit is ok to eat but it isn’t advisable to save seeds.

So next season – I will have a gentle hand when preparing the soil, I’ll pop them into the bed where the corn once was, which will mean the corn will be where the tomatoes have been and before the peas.  This arrangement should suit everyone.  I will be slow to grow my tomatoes – there is no hurry and hope they respond by growing slowly.  I will take garden hygiene more seriously and I will pray the weather is better suited to avoiding this problem.

As a gardener you are always learning and boy have I just had a major lesson.

Come again soon – I’ll come up with something less gloomy.

Sarah the Gardener  : o)

NB:  Thanks to the experts at Yates NZ who diagnosed the problem for me.

11 thoughts on “Death Valley

  1. That’s sad about your Tomatoes. Mine are doing really well. 1 Heirloom and 6 Money Maker though I did notice some blight today so out with the ‘sterilisied’ secateurs tomorrow and trim them off.

  2. Very informative post. We’re a long way from setting out tomatoes, but I’m sure I’ll be more watchful, and maybe know what I’m seeing thanks to you! Better luck as your season progresses.

    1. It can be so easy to become complacent, doing what you’ve always done and never running into problems, until conditions changed and become ideal for some kind of disaster. Everyday is a learning day in the garden. : o)

  3. I feel for you. I gave up on tomatoes after many blighted harvests until I was given a packet of seeds that just grew and grew like a fairytale. I decided they were genetically modified and so I never planted them again – you cant win with tomatoes!

    1. From what I understand, there are no genetically modified seeds available to home gardeners and so it was probably a variety that was cross bred and selected by growers to become blight resistant, so if they grew well in your garden, it is worth a shot having another go. All the best with your garden this season. : o)

    1. It hasn’t been an easy season in the garden this year, I’ve had so many problems! But I’d never heard of this one either, but I’m glad I found out so I can try and avoid it in the future. : o)

Leave a Reply