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Bacterial Soft Rot Prevention – The Ultimate Grower’s Guide

Bacterial soft rot is a common disease in greenhouse cultivation. Fortunately, growers can use various climate control measures to prevent bacterial soft rot breakouts.

Bacterial soft rot is a very common disease associated with food production. In fact, it’s said to cause the most crop loss of any bacterial disease, worldwide.

It affects greenhouse and indoor grows, as well as outdoor cultivation. It also infects a wide variety of crops, including carrots, onions, tomatoes, cucumbers, potatoes, and more.

What Is Bacterial Soft Rot?

Bacterial soft rot is a general name for a group of bacteria-related diseases. The bacteria responsible for the disease is Pectobacterium carotovorum (formerly known as Erwinia carotovora).

Soft rot bacteria damage the plants’ succulent parts, such as fruit, stems and bulbs. It damages the molecules that bind plant cells, ultimately causing the plants to fall apart.

Bacterial soft rot refers to several diseases. Some of which are specific to a type of crop, such as ‘beet vascular necrosis’ and ‘blackleg’ of potatoes.

How to Identify Bacterial Soft Rot Symptoms

Soft rot infections appear as soft, sunken spots on the plant’s flesh. In time, the spots grow, and turn anywhere from cream-colored to black.

Soft rot begins odorless. However, it develops a foul smell over time, as the bacteria breaks down and decays the plant’s tissue.

What Causes Soft Rot?

P. carotovorum (or Erwinia carotovora) bacteria exist almost everywhere. They can be found in soil and water around the world.

There are several ways these bacteria can reach your plants. They can enter through wounds in the plants’ tissue, infiltrate using insects, or reach through the soil. Some growers may even suffer from infected seeds.

Bacterial soft rot can develop in almost any temperature. But it’s much more prevalent in wet conditions. In fact, the presence of free water is one of the leading causes of soft rot infections.

How to Prevent Bacterial Soft Rot

It’s incredibly difficult to avoid this bacterium’s presence. However, using the following methods, you can prevent it from infecting, developing, and spreading in your crops.

There are two main methods to prevent soft rot – physical plant protection and climate control.

Limiting Free Water Presence

One of the leading factors for soft rot development is free water. Avoiding water presence in a greenhouse or grow room can be tricky, but it’s completely possible.

First, you can improve the way you irrigate crops. Watering from above will cause splashing, so water can reach the leaves or other parts of the plant.

So, it’s best to irrigate straight to the soil, avoid over-watering, and ensure that your soil is well-draining. These simple methods can prevent a large portion of soft rot infections.

Using Dehumidification

The second most common way water reaches the greenhouse is humidity.

Air that’s saturated with moisture eventually needs to release some of it. This leads to condensation occurring on various surfaces, including equipment, machinery, railings, or even on the plants themselves.

The only way to completely avoid dew point condensation is to keep humidity low using dehumidifiers.

A dedicated piece of machinery that extracts water from the air will ensure comfortable climate conditions and prevent condensation.

Using Clean Tools and Avoiding Plant Damage

The final method to prevent bacterial soft rot is fairly simple. But it requires attention and careful work practices.

First, you should always avoid damaging plants. Bacteria can enter through wounds, so the more intact your plants are, the harder it will be for soft rot to infect them.

Second, you should always work with clean equipment. One of the ways P. carotovorum travels in a greenhouse is by hitching a ride on your equipment. Routine sterilization and cleaning will help prevent the transport of bacteria and reduce infections.

Third, if you encounter infected plants, you should dispose of them immediately. The same is true for debris, such as fallen leaves. Bacterial soft rot bacteria can survive in the soil, so make sure not to bury infected plants!

Preventing bacterial soft rot, like other humidity-related diseases, is all about controlling conditions and maintaining proper greenhouse protocol.

DryGair provides the leading solution for disease and mold prevention in commercial horticulture. For more information on preventing greenhouse diseases, please feel free to contact us.