Information from our September 2009 newsletter regarding the late blight that devastated many tomato fields last year.  A reader requested that we post it here on the blog. A Boss’s Corner column is included every week in our newsletter.

The Boss’s Corner

Hi,

So far this September, the sun has sent its warm rays and bathed Magicland Farms with its photosynthesis inducing electromagnetic energy from sunup to sunset. Clouds have been scant and fleeting and liquid sunshine has been absent replaced with the genuine stuff. This sunny, dry weather has really helped our tomatoes and it hurt the Phytophthora infestans fungus/mold, more commonly referred to as late blight.

Canning Tomatoes

Tomatoes are usually canned using the hot water method, which is well known by most of our customers. It is also known that while tomatoes can be successfully canned with this method beans can’t be. Why? It has to do with the acidity and the problem of botulism and other bacteria. While it is impossible to get a jar of tomatoes hot enough using a hot water bath to kill the botulism organism, the botulism bacteria can’t survive in an acid environment. How to you measure acidity? Using the pH number. A pH of 7, like distilled water, is neutral, vinegar is an acid and has a pH below 3 while baking soda is an alkaline with a pH above 9. In order to can tomatoes safely, the tomatoes must have a pH BELOW 4.5. Every tomato of ours we tested tested below 3.8 which means they are plenty acid enough. (By the way our beans test around pH 5 which means they must be canned with a pressure canner.) We looked up about the USDA’s recommendations concerning blight infected tomatoes and they say it is OK to eat them fresh BUT THEY SHOULDN’T BE CANNED!!! Why? The USDA never said in the bulletin although we think it is because tomatoes picked from dead vines aren’t as tangy (less acid) than those from healthy vines. WE NEVER PICK TOMATOES FROM DEAD VINES!!! If you have a question about the acidity of your tomatoes, our tomatoes or any other vegetable or fruit, stop by our market and we can give you, free of charge, a little paper test strip that will let you know if the acidity of the fruit or vegetable is below or above pH 4.5. We also can show you how to use it-this takes about 20 seconds to show how. In short, there is a tiny sensitive area in its center where you put a drop of juice. This sensitive area turns color and you can then tell what pH the juice is-the color coding is right on the strip so you don’t need another color chart. Nice little thing…

Late Blight

First off, late blight generally infects only tomatoes and potatoes. This is the same disease that caused the horrific Irish potato famine of the 1840s. It is caused by the Phytophthora infestans organism and loves mild (60 to 80F) temperatures and lots of wetness. It is the same thing that killed Martha Stewart’s tomatoes in Connecticut and did the same to millions of other tomatoes across the eastern part of the country this year. I have never seen it before on our farm and a 85 year old woman who grew tomatoes all her life in Newaygo County never saw it before either. What happened? Well, Lowe’s, Home Depot, Kmart and Wal-Mart all sold tomato seedlings with late blight in their garden centers from April to June this year. They obtained their plants form several southern growers who grew them outdoors and apparently didn’t take care of them right so they got full of late blight. This explains how the blight got started but not how it spread to people who grew the tomatoes themselves and didn’t plant infected tomatoes (like us). The other culprit here is the weather-the lack of sun and the cool, rainy and wind. The two working together-the diseased plants all over the place in home gardens and the weather-did many, many tomatoes in this year.

Late Blight and Magicland Farms

My middle daughter, Rebekah, called my attention on August 6th to something funny on a couple of tomato plants in our #1 patch. It was late blight. That same day we removed and buried hundreds of plants, in all three patches, that had any sign of blight on them The next day I put on a fungicide on most tomato plants. Apparently, the blight had already spread and a week later it was visible on many, many more plants in all three patches. However, the fungicide and the warmer, dry weather worked together to stop the blight in its tracks and about 2 weeks later the tomatoes grew on and now look healthy with delicious blight-free tomatoes-however, we lost about 2/3rds of our potential crop since the blight really set the plants back and while they are growing well now it’s very late for tomatoes since the days are growing shorter and our usual frost is just a little over 2 weeks away (October 1). (By the way, while at the farm the average killing frost is in early October, next to inland lakes it is the end of October.)

Just to reassure you: we never knowingly picked a blighted tomato except to toss it and we don’t pick tomatoes from dead plants!

Liking the sunny dry weather for now but have a secret hope for some rain soon.

Nashle!
Tom

Things get really busy around here from about May/June until November. I mean crazy busy where we don’t know if we are coming or going.  One of the casualties of this craziness is going to be this blog. I like blogging but don’t have the amount of time needed to do it justice.

Luckily, we also publish a newsletter (at least one issue per week) during the farm season. It includes recipes, crop information, notes from the boss and whatever else strikes our fancy. You can subscribe to the newsletter by clicking on the button on the right sidebar that says  ”Email Newsletter Signup”. I think you will enjoy the newsletter and find it full of some great information.

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