PPDL Picture of the Week
April 25, 2016
Fusarium Crown and Root Rot of Tomato
Dan Egel, Extension Plant Pathologist, Southwest Purdue
While many of us wait for the first frost-free date to place
our tomato plants outside, some folks are already producing tomatoes in
greenhouses to get a jump on the season.
The photos shown here, however, are of a greenhouse tomato plant that
will not produce any tomatoes this season.
Figure 1 shows a wilted tomato plant in a greenhouse. The reason the plant is wilting can be understood
by looking at Figure 2. There is a
lesion at the base of the stem that is girdling the tomato plant. If the stem of the plant is cut open, the
water conducting or vascular tissue inside the stem has been discolored brown an
inch or two (Figure 3). These are all
symptoms of the disease Fusarium crown rot and root rot of tomato (FCR). I was able to confirm this disease by
isolations conducted in the laboratory.
The fungus that causes FCR survives well in the soil in the
absence of a host plant. Therefore,
tomatoes planted in soil infested with the FCR fungus may become diseased even
after several years of a rotation to crops unrelated to tomato. Some tomato varieties have resistance to
FCR. However, most of the tomato
varieties with resistance to FCR are the indeterminate type often grown in
greenhouses as opposed to the staked determinate types that are often grown in
gardens. Tomatoes may be grafted onto
rootstocks resistant to FCR as discussed here.
There may be many reasons why tomato plants may wilt. Use the photos here to help determine if
your wilted tomato plants are affected by FCR.
Plants may be submitted to the Purdue Plant and Pest
Diagnostic Laboratory for identification of plant problems.