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Bacterial Soft Rot

Bacterial Soft Rot

Pectobacterium and Dickeya species

Bacterialalso: Soft rot, Bacterial rot, Rhizome rot, Calla lily soft rot, Corm rot of calla

A bacterial disease that turns the fleshy parts of plants into a soft, wet, foul-smelling mush, in the garden and especially in storage. Bacterial soft rot hits a huge range of crops, potatoes, carrots, onions, cabbage, cucurbits, peppers, and more, and rots the rhizomes and corms of ornamentals such as calla lily, iris, and gladiolus. It enters through wounds and spreads fast in warm, wet conditions, and there is no cure once it starts.

🔎 How to spot it

Look for a soft, watery, mushy rot that begins as a small water-soaked spot and spreads, turning the tissue into a slimy, cream-to-tan mass that often collapses. A foul, putrid odor is the giveaway and separates it from the drier, moldy rots of fungi. It strikes fleshy roots, tubers, bulbs, rhizomes, corms, stems, and fruit, frequently starting at a wound or bruise and rotting outward. On calla lily the rhizome goes soft and slimy with a fishy odor and the leaf bases and flower stalks rot and collapse.

🥀 Damage it causes

Soft rot dissolves the fleshy, edible parts of the plant into slime, destroying roots, tubers, bulbs, rhizomes, heads, and fruit in the garden and, very commonly, in storage where it spreads from one rotting vegetable to its neighbors. It is one of the most important causes of post-harvest loss, and a wet season can rot a crop in the field as well. In rhizome and corm ornamentals it is the main cause of plants failing to come up or collapsing in the bed.

🔬 What causes it

Bacterial soft rot is caused by several bacteria, most often Pectobacterium (formerly Erwinia) and Dickeya species, that live in soil, water, and debris. They cannot break through intact skin, so they enter through wounds from tools, insects, cracks, and weather, and through natural openings. Warm, wet conditions, poor air circulation, low-calcium tissue, and waterlogged or overfertilized soil all favor a fast, spreading rot.

🛡️ Prevent it

Avoid wounding produce and rhizomes: handle gently at harvest and planting, control the insects that chew openings, and keep tools clean. Harvest in dry weather, cure roots, bulbs, and tubers properly, and store only sound, unblemished, dry stock in a cool, dry, well-ventilated place. For calla and other rhizome plants, plant in well-drained soil, use drip rather than overhead watering, avoid excess nitrogen, and dry incoming rhizomes so abrasions heal before planting. Rotate crops, improve drainage and airflow, and do not work among wet plants.

🧯 If it is already here

There is no cure once tissue is rotting, so remove and discard affected plants, rhizomes, and produce promptly and do not compost them, since the bacteria spread readily. In storage, sort out and remove any rotting item immediately so it does not infect the rest, and lower the humidity and temperature. Prevention through gentle handling, curing, and dry, cool storage is the only real control.

💡 Good to know

The foul smell and slimy texture are the signature that separates bacterial soft rot from the firmer, fuzzy rots caused by fungi. Because the bacteria need a wound to get in, the most effective single step is avoiding cuts and bruises and keeping stored produce and rhizomes dry, since a single rotting unit can spoil a whole bin or bed.

🌱 Plants it affects

290 plants in the library can be affected by this problem

Acorn SquashAdirondack Blue PotatoAdzuki BeanAji Amarillo Pepper🥔All Blue PotatoAmbrosia CornAmish Paste TomatoAnaheim PepperAngelique TulipAnjou PearApeldoorn TulipArmenian CucumberArugulaAsian PearAtlantic Giant Pumpkin🥕Atomic Red CarrotBanana PepperBartlett PearBeauregard Sweet Potato🍅Beefmaster TomatoBetter Boy Tomato🥬Bibb Lettuce🍅Big Beef TomatoBig Boy TomatoBitter MelonBlack BeanBlack Beauty EggplantBlack Beauty ZucchiniBlack Beluga LentilBlack Cherry TomatoBlack Kabouli ChickpeaBlack Krim Tomato🥬Black Seeded Simpson Lettuce🥕Black Spanish RadishBlack-Eyed PeaBloomsdale SpinachBlue Lake Green BeanBok Choy🥕Bolero CarrotBosc Pear🥒Boston Pickling CucumberBottle Gourd🍅Box Car Willie TomatoBrandywine TomatoBroad Windsor Fava BeanBroccoli RabeBrussels SproutsBull's Blood BeetBurdockBurgundy OkraButtercrunch LettuceButtercup SquashButternut SquashCalabrese BroccoliCannellini BeanCardoonCarolina Reaper PepperCasaba MelonCassavaCayenne PepperCelebrity TomatoCeleriacCeltuce🥬Champion CollardsChantenay CarrotChayoteCheddar CauliflowerCherokee Purple TomatoCherry Belle RadishChicoryChinese BroccoliChioggia BeetChoy SumCinderella PumpkinCipollini OnionClemson Spineless OkraCollard GreensCosmic Purple CarrotCostata Romanesco ZucchiniCranberry BeanCrenshaw MelonCrimson Cherry RhubarbCubanelle PepperCupani Sweet PeaCylindra BeetDaikon RadishDandelionDanvers CarrotDe Cicco BroccoliDelft Blue HyacinthDelicata SquashDetroit Dark Red Beet🥒Diva CucumberDragon CarrotDwarf Blue Curled Vates Kale🥬Dwarf Siberian KaleEarly Girl Tomato🌸Easter Egg RadishEdamameEgyptian Walking Onion

For educational and informational purposes only. Disease management advice is general guidance drawn from university cooperative extension sources; always identify a problem positively and read and follow the label on any product before use, especially around food crops, children, and pets.