Important Tomato Disease Management Step - Disinfecting Used Stakes
Posted: March 14, 2012
Bacterial spot on tomato is caused by a bacteria that can be transmitted by infected seed or stakes. Photo Dr. Beth Gugino, Penn State Extension.
There are three bacterial diseases of concern on tomato: speck, spot and canker. Bacterial canker is sufficiently destructive that dis-carding stakes is recommended after an outbreak. Before the field season is in full swing often presents an opportunity to find time for disinfecting stakes.
Step one in disinfecting anything is remov-ing as much dirt and debris as possible because this can protect pathogens and de‐activate disinfectant, therefore start by hosing down used tomato stakes.
Clorox or other household chlorine bleach (5.25% sodium hypoclorite) is commonly used as an agricultural disinfectant, but it is not the best choice. Use bleach at a rate of 0.5% (= 1 part bleach + 9 parts water), and use in a well‐ventilated area. Soak stakes for 30 minutes. While bleach is highly effective, it is short‐lived after mix-ing in water, with a half‐life of only 2 hours, and it is especially prone to being inactivated by organic matter, thus pre‐cleaning is critical. A disinfectant contain-ing quaternary ammonium chloride salts like Green‐Shield is more stable than bleach after diluting with water. Use at 1 Tablespoon (= 0.5 fl oz) of Green‐Shield in 1 gallon water. While this disinfecting so-lution will be more stable than bleach, it should not be used more than 24 hours after preparation. Soak stakes for at least 10 minutes. OxiDate is an OMRI‐listed disinfectant containing hydrogen dioxide. Use 0.5‐1.25 fl oz/gal water for disinfect-ing stakes. (Note: Pennsylvania Certified Organic no longer allows bleach for certified organic growers.)