The summer of 2014, at least in our area of the Shenandoah Valley, has been cooler than normal and fairly dry. The rain we’ve had has mostly come as heavy downpours, not nice steady, soaking rains. Heavy rains, which are often associated with thunderstorms, are usually more destructive than helpful because most of the water runs off without soaking in and takes a lot of topsoil with it.
So far this summer, we’ve only had 15 days over 90° – the normal is 25 days by this point. Many days in July and August were in the 70’s and nights were often cool – in the 50’s and even several nights when the temperatures dipped into the mid to upper 40’s. Very unusual to say the least. It's nice for us but it has caused some issues in the vegetable garden.
Tomatoes don’t do well in cool weather – especially when the nights are cool. Temperature extremes (daytime temps above 90° or nighttime temps below 55°) can cause poor fruit set.
The tomatoes started the season growing well; producing loads of flowers and setting lots of fruit. After this initial burst in June, everything slowed way down in July and August. We noticed fewer flowers and didn’t see many young tomatoes forming. The tomatoes that formed in June continued to grow and eventually ripened but production has certainly tapered off. I have heard the same complaint from other gardeners. This summer just hasn’t been favorable for growing tomatoes.
I have noticed several different problems on our tomato fruit this year but most of these are issues that I have seen in other years as well. They are fairly common tomato problems.
Growth cracks develop in tomatoes when they undergo a spurt of rapid growth during ripening. This often occurs when extended dry conditions are followed by sudden heavy rain or irrigation. This isn’t an unusual situation and has occurred several times in our garden this season. As a result, many of our ripe tomatoes are showing varying degrees of cracking. Growth cracks frequently appear on the top of the tomato near the stem but sometimes when a tomato is fully ripe or overripe, cracks will develop on the bottom of the fruit. Shallow cracks will normally heal over but deeper cracks that develop can become easy pathways for disease and insects to enter and cause secondary problems.
Try to keep your garden soil evenly moist. Mulching definitely helps with this.
Anthracnose of tomatoes is a disease caused by the fungus Colletotrichum coccodes. It appears as sunken, circular lesions on ripe tomatoes. Often these lesions have concentric rings of black fruiting bodies in the center. Green tomatoes can become infected with anthracnose but the symptoms do not appear until the tomato ripens.
The fungal spores are found in the soil and on plant debris left in the garden. Tomatoes are infected when soil containing spores is splashed up onto the fruit and foliage.
Anthracnose does little damage to the leaves but can cause major damage to mature, ripe tomatoes. This disease is more common during warm, wet weather but spores can also be transmitted to the plants from splashing during overhead irrigation.
Mulching around your tomato plants and trellising or staking them to keep them off the ground will help to prevent this fungal disease. Avoid working among the plants when they are wet and harvest the tomatoes as they ripen and use them promptly.
Infected fruit should be removed to prevent the spread of the disease. Crop rotation and careful clean up of all plant debris in the fall is important for controlling anthracnose.
Ever find tomatoes that have funky-shaped, puckered bottoms? This is called cat facing and it is thought to result from the abnormal development of the flower bud or flower – before the fruit is even formed! The factors that lead to cat facing in tomatoes are normally environmental, including cool temperatures before and during flower formation. Hmmmm, that sounds familiar!
Other causes of cat facing in tomatoes are any type of physical damage to the flowers, herbicide damage (such as drift from nearby 2,4-D spraying), and sometimes excessive pruning of tomato plants.
Varieties that produce large tomatoes, such as beefsteaks and the large-fruited heirloom tomatoes, are more prone to cat facing than small-fruited varieties.
Normally, tomatoes that are disfigured from cat facing are still edible however they may ripen unevenly and they can be difficult to slice – I just chunk them up instead! Still delicious!
Black mold is caused by various fungi (including Alternaria alternata) that attack tomato tissue that has been injured in some way. It is rarely found on healthy, unblemished tomatoes. The fungal spores usually enter the tomato where the skin has cracked or where insects have caused injury to the fruit. As the fungus grows, it creates brown or black sunken lesions which expand and eventually cause the whole tomato to rot.
If you catch it early, you can just cut out the bad patches but it’s important to remove all the soft tissue or the tomato will taste bad.
All of these problems have developed on at least some of my tomatoes this season. Fungicide sprays listed for use in vegetable gardens can help but, unless you are having major problems with your tomato crop, their use is often not warrented. We usually just harvest the blemished fruit, cut out the diseased parts, and eat them.
You should NEVER can or freeze tomatoes that show signs of disease.
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