Tomato plants strangled at base

Question: I have several tomato plants in one area of the garden that have fallen over. Looking at the base, the stem is strangled, thinned, and brown. The otherwise healthy looking tomato plant falls over due to the weakened stem base. What is causing this? Note the rest of the tomato plants in other areas of the garden are all fine. They are receiving adequate water and have straw mulch.

responder: An Ask Extension Expert Replied June 08, 2023, 9:25 AM EDT
response: Hi Allison, thanks for the question. This looks like it could be a stem rot issue; however, I noticed that the plant did not look like it was supported.  If you recently had some winds this could explain the problem.  There are also fungal issues that could be at play.  Fusarium crown rot is a good candidate.  Other diseases like Sclerotinia could also cause this condition.  Take a look at the following links and get back to me.  Fusarium crown and root rot | UMN Extension Fusarium Wilts and Rots (missouribotanicalgarden.org) Fusarium Crown and Root Rot of Tomato | Purdue University Vegetable Crops Hotline (vegcropshotline.org) I look forward to your response.

responder: The Question Asker Replied June 08, 2023, 2:53 PM EDT
response: My tomato plants are supported by wooden stakes and tomato cages. There has been no wind. The tomato plant was fully healthy looking the day before - no wilting. We did an inspection at night and found numerous small caterpillars at this spot, which makes us think it could be a cutworm. On Jun 7, 2023, at 4:08 PM, Ask Extension <<personal data hidden>> wrote: ﻿  Dear Alison, Thank you for using Ask Extension. A request for support has been created and a representative will follow-up with you as soon as possible. Questions are usually answered within two business days. You can view this question's progress online. YOUR QUESTION #0104328: Tomato plants strangled at base I have several tomato plants in one area of the garden that have fallen over. Looking at the base, the stem is strangled, thinned, and brown. The otherwise healthy looking tomato plant falls over due to the weakened stem base. What is causing this? Note the rest of the tomato plants in other areas of the garden are all fine. They are receiving adequate water and have straw mulch. Ask Extension offers one-to-one expert answers from Cooperative Extension/University staff and volunteers within participating Land-Grant institutions across the United States. If you wish to provide additional comments or information regarding the issue, please login to your account for a complete archive of your prior questions and answers.  This message for informational purposes only. It is not intended to be a substitute for personalized professional advice. For specific local information, contact your local county Cooperative Extension office or other qualified professionals. eXtension Foundation does not recommend or endorse any specific tests, professional services, products, procedures, opinions, or other information that may be mentioned. Reliance on any information provided by eXtension Foundation, employees, suppliers, member universities, or other third parties through eXtension is solely at the user's own risk. All eXtension content and communication is subject to the Terms of Use which may be revised at any time.

responder: An Ask Extension Expert Replied June 08, 2023, 9:23 PM EDT
response: Hi Allison, You could be correct about the cutworms.  Usually, they completely sever the stem of seedlings.  The plants looked older those commonly attacked but it can happen. The damage looks like it had healed somewhat.  Many of these problems can look similar.  Check out the following link: Cutworms in the vegetable garden - MSU Extension Cutworms in home gardens | UMN Extension