The Missouri Disease Beat

Published: August 1, 2011

Onion
Xanthamonas leaf blight from Barton County. This is a somewhat uncommon disease in the Midwest. It is described in a Colorado fact sheet. It can cause the plant to mature early but is not reported as damaging the bulb (in Colorado).

Summer Squash
Choanephora wet rot from Barton County (but was seen statewide this late spring/early summer). This disease is prevalent during periods of continued damp weather. Wet rot affects both blossoms and fruits. In squash, the fungus usually enters through the blossom end, but can enter through wounds. There is no chemical control. Cultural methods to hasten the drying of foliage will help. Picking off blossoms before they rot, but after fruit is set, may also help. It was seen in 2010 as well.

Tomato
Bacterial canker has been confirmed in Morgan County. It is also suspected around Jamesport. This disease is usually introduced by infected seed and then spreads. 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.

Fusarium Crown Rot - Audrain County. While both Fusarium Crown Rot and Fusarium Root Rot are mentioned in the Midwest Vegetable Production Guide, 'root rot' is more commonly seen.

Southern Blight - Barton County, in a high tunnel.

Author's opinion: Growers seem to be struggling less with Bacterial Speck and/or Bacterial Spot this year.