18
Jun 2018

Yellow Stems on Tomatoes

Yellow Stems on Tomatoes

Yellow Stems on Tomatoes

Why does this happen? Should we investigate better control solutions?

 

This question was sent to me last week from one of New Zealand’s most experienced tomato growers, “How about some conclusions on yellow stems in old crops at this time of the year?”

It is quite astonishing that yellow stems (as some of us refer to them as), which slowly kill the plants, is still such an issue today.  If this forum cannot figure out the answer I would suggest some serious research needs to be considered and commissioned.

 

What I know:

I had the yellow stem issue when I started growing over twenty years ago.  At that time a consultant described the yellowing and dying back of the stems to me as Dry Stem Bacteriosis.  The photos in this article and what Dry Stem Bacteriosis is could be two different things, only testing and scientific input can confirm.

Yellow stems seem to occur in crops approximately nine months and older, generally in the winter period.  In my early years as a grower I planted on the shortest day, by April or May the following year it was more than likely I would see patches of yellow stem. I assumed these plants were naturally coming to the end of their life cycle.  It was always worse if the old trusses were not removed from the plant.  As the old truss dies back, and goes yellow, it would then travel into the stem towards the root system.  Another observation I made was if these stems came into direct contact with good stems the yellowing would rapidly transfer to the other stems.  It is impossible for stems not to touch and overlap, so it was always important to bite the bullet and remove the plants as soon as the yellowing was visible to prevent it, from the assumption I made, spreading.

When I cut open the stems of infected plants I would see the pith was a brown colour and an obvious sign of some type of tissue decay/dieback.

Contributing Factors:

In my early growing years, I was a very vegetative grower, essentially my stems were fat and my plant had big long leaves. It was suggested that this could have been a contributing factor and when the plant became older the fatness and softness of the stem potentially made it more vulnerable to yellow stem.   When I did start to grow more generative/balanced crops the percentage of yellow stems definitely reduced.  At that time, I had also begun cutting trusses, so the fact I was growing generative might not have been the magic solution but a helping hand.   I say that because even in the strong generative plants I still came across issues with yellow stem from time to time.

If the yellow stems are bacterial, then the only solution is to reduce the risk of contamination.  Therefore, hygiene throughout your entire crop cycle, from start to finish, should be of high importance.  If it is fungal then alternative treatment should be considered.  Unfortunately I cannot give a conclusive answer to the question posed to me, I do believe research has an important role to play in unlocking this mystery.

 

Control possibilities:

1, Grow strong generative crops.

2, Cut old trusses out shortly after picking the fruit of the truss.

3, Always clean your equipment with regular dipping of tools into disinfectant.

4, Irrigation control/reduction.

5, Remove identified infected plants immediately to reduce the risk of potential spread.

 

I appreciate your comments.  Please feel free to comment below or on the grower2grower Facebook page:

https://www.facebook.com/StefanGrower2grower/

Article Written by Stefan Vogrincic, Consultant, Grower2Grower

CLASSIFIED

Subscribe to our E-Zine

Sign up here to subscribe to the Grower2grower Ezine. Every two weeks you will receive new articles, specific to the protected cropping industry, informing you of industry news and events straight to your inbox.

More

From This Category

Grower2Grower annual golf tournament set for Friday the13th of September!
May 6, 2024
Grower2Grower annual golf tournament set for Friday the13th of September!
Sponsorship - we encourage you to enquire early to secure promotion opportunities: contact marie@grower2grower.co.nz today!
Horticentre Charitable Trust Continues as Exclusive Sponsor of Grower2Grower
April 23, 2024
Horticentre Charitable Trust Continues as Exclusive Sponsor of Grower2Grower
"Together we share a goal of offering future growers, and existing growers, a tool set, of credible trusted information, to achieve better outcomes".
Lefroy Valley’s Hydroponic Display Days-showcasing their newest lines
April 23, 2024
Lefroy Valley’s Hydroponic Display Days-showcasing their newest lines
Recently Lefroy Valley hosted a hydroponic field day to display lettuce varieties for the whole head and salad cut market.
What pests and diseases have caused tomato growers issues this past season?
April 9, 2024
What pests and diseases have caused tomato growers issues this past season?
TomatoesNZ asks NZ Commercial Greenhouse Tomato Growers to complete a short survey.
A brewing new industry for the North
March 12, 2024
A brewing new industry for the North
Ngawha Innovation & Enterprise Park progress with Specialty Coffee Project
Ribbon cutting marks the opening of a new JS Ewers Biomass Energy Centre
March 11, 2024
Ribbon cutting marks the opening of a new JS Ewers Biomass Energy Centre
A state-of-the-art biomass plant, which will help reduce on-farm emissions by 98%, has been officially opened at Nelson growing operation, JS Ewers.
CLASSIFIED