Disease and Diagnostic Update

Published: June 1, 2012

Tomato bacterial canker was a problem in 4 areas of Missouri last year. We believe it originated with Scarlet Red seed of the 2010 seed increase year (sold in spring of 2011). Once in a production region it can reoccur, which it has in two areas from last year- North and Central Missouri. It's been found in greenhouses and high tunnels.

It sometimes causes fruit damage, but affects a great deal of the foliage and can eventually kill the entire plant. Leaf margins get a scorched black look. Good photos and a description are in the Penn State Vegetable Disease Booklet. There is no treatment/'cure'. Strict hygiene and good cultural practices are about the only control. Last year we distributed a Rutgers University fact sheet on the disease. Contact an Extension Specialist if you think you have the disease. We want to understand how extensive it is again this year.

Herbicide contamination in soil (or compost) has caused a problem in north Missouri for a third year in a row. In 2010 and 2011 it was traced to the herbicide Grazon®, It is a mix of two active ingredients (picloram and 2,4-D). While 2,4-D is notorious for drifting or volatilizing and moving off site, picloram is a serious risk for soil contamination. This herbicide is applied to pastures and the label clearly says to never move any soil from where it was applied for growing food crops. Growers who have done so did this accidentally, but that doesn't make the problem any less or go away. The product can also be carried over into the manure of cattle or buffalo feeding on pasture where it has been applied. In 2011 it showed up in compost which had manure as a component. Again the label clearly provides a warning- "Do not use manure from animals grazing treated areas of land or feeding on hay from those areas, for growing broadleaf crops, ornamentals, orchards or other susceptible desirable plants. Manure may contain enough picloram to cause injury to susceptible plants."

Tomatoes are VERY susceptible! Know the source of your soil or manure.