organic fungicide for tomatoes

[noopin2014]

Hello,

 

I try to grow some beefsteak tomatoes in Isaan. What kind of product can i use as a fungicide please ?

 

Cheers

 

 

[grollies]

Hi. Neem extract has antifungal properties and will help with pests.

[noopin2014]

7 hours ago, grollies said:

Hi. Neem extract has antifungal properties and will help with pests.

Thanks, where can i buy it please ?

[drtreelove]

15 hours ago, grollies said:

Hi. Neem extract has antifungal properties and will help with pests.

If your suggestion is from hard experience and you have found a neem product that is effective for fungal pathogens, then please post that product information and source.

 

But I suspect that the suggestion is theoretical based on wide spread mis-information that all neem products are insecticial and fungicidal.  

 

If you could get neem oil or 70% neem oil that would be true.  But the neem extract products that I have found available in Thailand do not have significant anti fungal properties.  

 

The products available from Thai Neem and other distributors are primarily Azadirachtin concentrates, which are excellent for insect and mite prevention/suppression.  But in the process of extracting and isolating the potent Aza ingredient, many of the other properties of the complex neem seed oil chemistry are lost. 

 

Raw neem seed oil, or the commercial 70% clarified hydrophobic extract product widely used in some countries like the US, has some mild fungicidal properties that are effective for superficial (ectotrophic) plant pathogens like powdery mildew and rust. But it is not systemic and not effective for deeper vascular fungal pathogens.

 

This information is from my own experience using neem products and according to an email discussion I have had recently with the leading neem product researcher in India,  a PhD researcher at a major Ag university in Bangalore.  He told me that he trialed Azadirachtin products and found no significant fungicidal effectiveness.  

 

Regarding the original post, I thought that experienced tomato growers here would respond.  I have limited experience with tomatoes in Thailand, but in my California garden and for customers,  I was able to avoid any serious pest and disease issues with a 100% organic program, primarily focused on soil fertility and soil test based mineral balancing, and secondarily with proactive/preventive applications of a sprayer tank mix including azadirachtin, pyrethrins, and a biological fungicide, once every two weeks. I also used a soil drench monthly with a bio-fungicide, in a tank mix with hydrolyzed fish fertilizer and kelp solution. 

 

I have not used this Trichoderma product, but it's along the same lines as other biofungicides that I know. The key is to recognize that biofungicides are usually not curative. They are effective only as preventive. They are bacterial or fungal organisms that colonize (grow on the leaf or root surface) and prevent disease causing organisms from getting started.  Don't wait until the plants are diseased before starting treatment. 

 

 

 

 

[grollies]

I had bad gummosis on my lime trees this rainy season. I scraped back the infected bark, sprayed with neem extract and painted with the red paint we use on the rubber tree panels. Worked for me, but you are probably right and I'm no PhD grad. Thanks for the info.

[drtreelove]

On 11/24/2018 at 12:49 PM, grollies said:

I had bad gummosis on my lime trees this rainy season. I scraped back the infected bark, sprayed with neem extract and painted with the red paint we use on the rubber tree panels. Worked for me, but you are probably right and I'm no PhD grad. Thanks for the info.

Citrus gummosis is usually due to a Phytophthora infection (fungus-like organism called a "water mold").  Excision of the bark and underlying infected tissue is a recommended method of of control, and this may have been the primary reason that you noticed positive results.  

 

It would be natural to assume that the substances you applied were responsible for the suppression of the disease, and maybe they helped, especially the coating that may prevent side effects, secondary infections from open wounds.  But I wouldn't assume from that procedure that the neem product is an effective fungicide. 

 

http://ipm.ucanr.edu/PMG/r107100411.html

 

https://www.apsnet.org/publications/imageresources/Pages/FI000301.aspx