(Non)Resistance to fungus

jk · September 6, 2006

Every few years I try to grow tomatoes, and then vow never to try to grow them again. “Try” is the operant word here because usually I usually don’t get any fruit or the fruits don't mature because the plants are consumed by fungus. The only exception is cherry tomatoes. Well, the cycle has started again, and this time I have been slightly more successful than before. I live in Hawaii (translation: “Good weather, but not for tomatoes. Fungus everywhere”). This time I’m using a commercial potting mix in containers rather than planting in the ground, and I’m spraying with compost tea. So far the plants are growing slightly faster than the fungus is killing the leaves. And I actually have a few tomatoes, though they are still green.

I wonder what it is about the structure of the tomato plant that makes it so susceptible to fungus. And is it due to the hundreds of years of breeding? I might be wrong on this, but I think it’s likely that tomato species originated in the tropical jungles of South America where there was fungus was all over the place, so he original species must have been quite resistant to fungus. However, as the tomato was bred for European climates, resistance to fungus was not so important (not as much of it around in the Old World due to colder winters), and resistance may have been largely bred out. Furthermore, I wonder, what makes cherry tomatoes more resistant to fungus. Are they genetically more like the original species, so the resistance has not been bred out?

I ask the people on this forum who are much more informed than I to share their wisdom on this subject.

feldon30 · September 6, 2006

Maybe build a high bed that drains extremely well and use a soil that dries out quickly. Then switch to drip irrigation so the plants and foliage never get wet.

Just ideas.

**carolyn137** · September 7, 2006

jk,

The nine species of tomato originated in the highlands of Chile and Peru, not in the tropical jungles, so there wasn't any fungus pressure to deal with.

You're suggesting that your plants have a foliage disease. Both bacteria and fungi of certain kinds can cause foliage diseases and there are NO varieties, hybrid or OP that have significant tolerance ( better word than resistance) to foliage diseases save three with minimal tolerance and of no use to the home gardener.

So can we assume that you have typical foliage infections? If so have you tried to ID exactly which diseases you have re bacteria or fungi?

What have you used as a preventative spray to combat these infections?

honu · September 7, 2006

jk, Did you mulch the area? Where in Hawaii are you growing tomatoes?

Quote:

Furthermore, I wonder, what makes cherry tomatoes more resistant to fungus.

I have not noticed less fungal problems on my cherries.
What varieties did you grow?

kimpossible · September 7, 2006

Other questions that come to mind are the basic - How many hours of sun? ... Early a.m. sun to help plants dry out from overnight humidity/dew/rainfall? ... Air circulation? ... Humid, wet climate?

michael johnson · September 7, 2006

Try Kewalo or very simular name, as I read that it is specialy bred for Hawaiian conditions- I think TGS used to keep it, but I am not sure if they still do

In the past I have read several articles relating to special breeding programs conducted by the university of Hawaii, or one of the universities there,that is specialising in producing varieties of tomatoes suitable for the hawaiian islands.

September 6, 2006	#1
jk Tomatovillian™ Join Date: Sep 2006 Location: Hawaii Posts: 5	(Non)Resistance to fungus Every few years I try to grow tomatoes, and then vow never to try to grow them again. “Try” is the operant word here because usually I usually don’t get any fruit or the fruits don't mature because the plants are consumed by fungus. The only exception is cherry tomatoes. Well, the cycle has started again, and this time I have been slightly more successful than before. I live in Hawaii (translation: “Good weather, but not for tomatoes. Fungus everywhere”). This time I’m using a commercial potting mix in containers rather than planting in the ground, and I’m spraying with compost tea. So far the plants are growing slightly faster than the fungus is killing the leaves. And I actually have a few tomatoes, though they are still green. I wonder what it is about the structure of the tomato plant that makes it so susceptible to fungus. And is it due to the hundreds of years of breeding? I might be wrong on this, but I think it’s likely that tomato species originated in the tropical jungles of South America where there was fungus was all over the place, so he original species must have been quite resistant to fungus. However, as the tomato was bred for European climates, resistance to fungus was not so important (not as much of it around in the Old World due to colder winters), and resistance may have been largely bred out. Furthermore, I wonder, what makes cherry tomatoes more resistant to fungus. Are they genetically more like the original species, so the resistance has not been bred out? I ask the people on this forum who are much more informed than I to share their wisdom on this subject.

September 6, 2006	#2
feldon30 Tomatovillian™ Join Date: May 2006 Location: Rock Hill, SC Posts: 5,346	Maybe build a high bed that drains extremely well and use a soil that dries out quickly. Then switch to drip irrigation so the plants and foliage never get wet. Just ideas. __________________ [SIZE="3"]I've relaunched my gardening website -- [B]TheUnconventionalTomato.com[/B][/SIZE] * [I][SIZE="1"]*I'm not allowed to post weblinks so you'll have to copy-paste it manually.[/SIZE][/I]

September 7, 2006	#3
carolyn137 Moderator Emeritus Join Date: Jan 2006 Location: Upstate NY, zone 4b/5a Posts: 21,169	jk, The nine species of tomato originated in the highlands of Chile and Peru, not in the tropical jungles, so there wasn't any fungus pressure to deal with. You're suggesting that your plants have a foliage disease. Both bacteria and fungi of certain kinds can cause foliage diseases and there are NO varieties, hybrid or OP that have significant tolerance ( better word than resistance) to foliage diseases save three with minimal tolerance and of no use to the home gardener. So can we assume that you have typical foliage infections? If so have you tried to ID exactly which diseases you have re bacteria or fungi? What have you used as a preventative spray to combat these infections? __________________ Carolyn

September 7, 2006	#5
kimpossible Tomatovillian™ Join Date: Mar 2006 Location: Z5b SW Ont Canada Posts: 767	Other questions that come to mind are the basic - How many hours of sun? ... Early a.m. sun to help plants dry out from overnight humidity/dew/rainfall? ... Air circulation? ... Humid, wet climate? __________________ *So Many Tomatoes ... So Little Time*

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September 7, 2006	#6
michael johnson Tomatovillian™ Join Date: Jan 2006 Location: UK. Posts: 960	Try Kewalo or very simular name, as I read that it is specialy bred for Hawaiian conditions- I think TGS used to keep it, but I am not sure if they still do In the past I have read several articles relating to special breeding programs conducted by the university of Hawaii, or one of the universities there,that is specialising in producing varieties of tomatoes suitable for the hawaiian islands.