Tomato diseases part 2

By Rennie Phillips

A week ago we looked at some of the common diseases and problems which tomato growers face every year. If it isn't one of them it's another. Usually my problems start or appear about the time my tomatoes are putting on fruit. But the truth of the matter is most problems are starting long before this. Some sources recommend that you begin treating for fungal diseases soon after planting. This would probably be a good idea.

Here in Missouri where we live the most common problems are early blight, septoria leaf spot, late blight and blossom end rot. Early blight is characterized by spots on the lower leaves which are dark brown in color. Slowly the lower leaves will die and gradually this losing of leaves works up the plant. The fungus is found in the soil, so whenever soil or mud or dust gets on the leaves at the bottom of the plant, the fungus has a start on your plant. Any barrier you can put down around the ground level of your plant will help. Drip watering will help. Try to be extremely careful when planting the tomato not to get dust or dirt up on the leaves of the transplant. I also trim the bottom branches off my tomato plants when transplanting them.

Septoria leaf spot is real similar to early blight. It begins on the older lower leaves as a small spot. Little by little the lower leaves die and the disease gradually goes right up the plant. Fungicide sprays will help with a spraying program starting at planting of your transplants.

Late blight occurs after the plant has blossomed. It appears on the top of the plant as small lesions and these can be on the leaves or stalk or even the tomato the way it sounds. Two of the varieties I grow, Plum Regal and Mountain Merit, both have a disease package making them resistant to late blight. What I have found is that both deal with early blight pretty good as well.

The most common problem with many gardeners is blossom end rot. Blossom end rot occurs after the tomato is formed and growing. I normally don't notice it until the tomato has started to turn red. A hard, dark-colored spot will form on the bottom of the tomato causing the tomato to be almost worthless. Once the spot has formed there is no cure for that tomato. The best prevention is to water only as needed and never overwater. Overwatering leaches the calcium from the soil which in turn causes blossom end rot. You can spray with blossom set which will help. You can water in this blossom set in a water mix as well. I simply add calcium nitrate to my irrigation system when tomatoes are first forming and then again when they are fair sized.

One problem that most tomato growers face is cracks in the skin of their tomatoes. These cracks are formed when the tomato outgrows the skin on the tomato thus making cracks in the skin. Usually these cracks are caused when the tomato receives too much rain or irrigation on an irregular basis. Here in Missouri we may have a couple weeks of dry weather followed by several inches of rain. One can water their tomatoes on a regular basis when the weather is dry but one can't undo all the rainfall at the wrong time and too much as well. A great variety that tends to not have cracks is Jet Star tomatoes. Consistent watering is about the only way to prevent cracking.

Cat facing is caused when the tomato develops an odd shaped or weird top. This is caused when the female parts of the reproductive system in the flower doesn't develop right. It doesn't affect the tomato as far as taste or it being safe to eat. It just looks weird. The only way to prevent this issue is to be diligent in regards to soil preparation, fertilization, irrigation, weeding, etc. We never water our tomatoes using an overhead sprinkler system. All our watering on all our garden is using a drip water system on a four inch drip system. We lay down a low pressure line right by the plants and then water them when it's needed. The entire water system runs on about 10 lbs. of pressure. We attach an injection type of waterer in the line where we can add fertilizer or added nutrients. A lot of the problems associated with fungus and such is because one is using an overhead sprinkler system.

One great practice is to walk your garden on a regular basis looking for problem areas. For example in June watch for tomato worms that will eat the leaves right off your tomato vine. In several days if left unchecked your tomato plants won't have any leaves. At the first sign of worms whether it be branches with no leaves or black poop spots on lower branches or fruit we need to take care of the problem. Walk and watch for problems.

Look for spots on the leaves especially those at ground level. These spots could be the start of a fungal problem. Watch your tomatoes right where the stem attaches to them. There is a small worm that likes to bore into the tomato right there. These worms are about the size of the lead in a #2 lead pencil. They are tiny. Tomatoes require enough water when first planted but not too much. Water every three or four days depending on your soil. Watch the leaves. They will show if the tomato is too dry. But when the tomato is growing fruit the plant may need ½ to ¾ a gallon of water per plant per day. They also need fertilizer but also at the same time be careful of putting on too much nitrogen. I like Miracle grow or a no name brand imitation. Happy gardening this summer.