The New Missouri Summer Brings with It — Anthracnose Fruit Rot??

Dear Friends,

Have you noticed a trend in the last few years? If you live here in the Midwest I’m sure you’ve caught on to a change…once upon a time it rained in April and early May. Then it dried out, warmed up, and was beautiful until the summer heat of July hit. That no longer seems to be the case. Climate change is becoming more noticeable all the time…especially in a Midwestern summer.

This is the third out of the last four summers that the rain has come down in buckets for weeks longer than normal. By this time of year the mowing should be down to once every week or two because it isn’t raining enough for the grass to grow. Instead, we were having regular storms up until the end of June, and we’ve been having pop-up showers and rain events every couple of days since then, even in spite of the July heat.

The Mississippi River has been flooded since early March, and the water level has finally just receded enough for the flood gates downtown to open back up earlier this week, although it is still two-to-three feet above flood stage. The ground has also been consistently wet, preventing me from finishing a landscaping project I started in early April that requires digging down several inches into soil that has basically been clay all summer. The grass also won’t stop growing, making mowing season a little extra aggravating.

The worst part, however, is the gardening. I struggle already with not having enough sunlight in my back yard, but the excessive amount of moisture has created a new problem — fungus and bacteria. When I first started harvesting tomatoes a couple of weeks ago I noticed a couple of them had some dark spots. At the time I didn’t think much of it, but now every single red or ripening tomato on every plant has dark spots on them.

I haven’t experienced this before in all of my years of gardening, so I really didn’t know what it was. I did some research, fearing that it may be blight, but the spots on the tomatoes don’t seem to be consistent with blight (thank goodness!), especially since blight seems to effect the leaves more than the fruit. They looked a lot like bacterial spots, but from what I’ve found bacterial spots tend to be tiny, just a few millimeters across. These spots are larger than that, so that didn’t quite fit either.

Finally I found a photo of something that looked just like my tomatoes. I followed the photo to the linked webpage and found something called anthracnose fruit rot. I looked up images of this disease, and it definitely fits what my tomatoes currently look like. What also fits is the explanation of causes. Tomatoes planted in soil that has inadequate drainage, for example. I have my tomatoes in a raised bed, but I lined the raised bed with landscape fabric to prevent weed growth.

I honestly didn’t think drainage would be a problem in an 8×4 raised bed, because typically in a Missouri tomato growing season we are hard-pressed to get enough rain and have to keep tomatoes watered daily. We are much more likely to have problems with drying soil than soaked soil…except, evidently, this year. I actually thought lining the raised bed and not creating drainage holes would help keep the tomatoes watered enough to thrive. You know what they say about the best laid plans…

So basically, insects carry this fungus from one plant to another, and it thrives in damp environments. Just like a lined tomato bed with the plants crowded closer together than they really should be (I decided to shove four plants in instead of three), where they don’t get quite enough sunlight and the soil is constantly wet from rain water. The good news is, unlike with blight, I may be able to salvage my plants without pulling them up.

I’ve read a lot about washing the fruit with a baking soda mixture, which I plan to try this weekend. I’ve also been reading a lot of good things about copper-based sprays, and I’ve ordered some to treat the plants. I will be sure to share an update as to how well this works in a later blog post. For now, I will share some photos of what this looks like on my tomatoes. I am no botanist, but based on my research, this is anthracnose fruit rot on my tomatoes: