Gardeners Concerns About Tomatoes

Carol Pinnell-Alison  |  6/25/2015 9:33:36 PM

blossom end rot

Leaf footed bug

Tomatoes are a favorite vegetable in a home garden.  It is very common to get visits or calls from distressed gardeners with tomato plants or fruit that have something wrong with them.  Cloudy and rainy days late winter and early spring are  perfect conditions for problems with growing plants of any kind.  The first calls are about having a large healthy plant but no fruit. This is usually due to over fertilizing the plant especially with nitrogen.  The over fertilization keeps the plant in its growth stage and delays the plant from converting to its reproductive stage of flowering and setting fruit.  Once the plant begins to fruit, the first cluster of fruit may have blossom end rot.  This is a physiological disorder caused by the plant roots not being able to take up enough calcium.  Calcium is not a highly mobile element in the soil.  Factors limiting root growth like cold wet soils or a fluctuation in water supply can cause the condition.  Other factors are rapidly growing plants due to over fertilization with ammonium nitrogen, insufficient calcium in the soil and high relative humidity.  Taking a soil sample for analysis is an inexpensive way to check on the fertility needs of your garden site.  The LSU AgCenter has a soil testing lab on main campus in Baton Rouge.  The cost to analyze a soil sample is $10.  As the plant grows there are many diseases and insects that can damage the plant and fruit.  It is important to select tomato varieties that have resistance to diseases for planting.  Fungicides can be applied to control fungal diseases but there are no pesticides that will control virus diseases like the tomato spotted wilt virus.  Common insect problems are stink bugs, leaf footed bugs and tomato hornworms.  It seems that tomato hornworms can defoliate a plant overnight.  Insecticides can be used to control insects.  Make sure to identify the disease or insect correctly and apply the correct pesticide for their control. Read and follow the pesticide label for all mixing, application timings and fruit harvest intervals after an application.  As the weather gets hotter our spring planted tomato plants begin to produce less fruit.  High nighttime temperatures reduce the viability of the pollen. It is best to plant a second crop of heat tolerant tomato plants if you want to continue harvesting fruit through the summer and early fall.  Some heat tolerant varieties are Florida 91, Solar set, Sunmaster and Phoenix.  The LSU AgCenter has several publications available for gardeners.  Some of these are free and can be picked up at our office in the Franklin Parish Courthouse or printed off our web site at  We have several publications for purchase and they are found on our web site through our on-line store.  If you have any questions call our office at 318-435-7551 or come in person to our office in the Franklin Parish Courthouse.
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