Why Did My Pinto Bean Plants Die in Just Two Days?
Question: I’ve been a customer of yours for 3 years now, if memory serves, as a foundation. I am writing because I’ve just experienced a situation where bean plants die suddenly, and exclusively so far in my pinto bean patch. Two days ago, when I last inspected my bean garden, which includes a patch each of your black beans, pinto’s, Vermont cranberry, and Great Northerns, they all looked absolutely beautiful. After planting the seeds, I laid straw down over the entire garden which greatly helped in weed control and moisture retention. The beans have been watered consistently 3 days/week, and were growing exceptionally well.
Today when I went into the patch, the pinto bean plants were essentially dead and partially desiccated, appearing as though they alone had been sprayed with glyphosate, for instance. I’ve been gardening for many years and currently manage 7–8,000 square feet. We live out in the country without visible neighbors. We’re in the northwestern lower peninsula, about 35 miles south of Traverse City.
I’ve never seen anything like this happen before. There has been zero insect pressure and minimal weed pressure, with utterly robust plants, until today. The pinto bean section is right between the black beans and the Vermont cranberries, literally abutting each other.
Answer: Thank you for your email. We are sorry to hear of this issue. The first thing that came to mind was cutworms, as they will make their way through a patch and cause such destruction when bean plants die suddenly. Did you look at the base of the plants, possibly? There would be a partial, or full cut/chew through base of plants, and they appear as you mentioned. You’ll often find one of the worms buried by the base of the plant taking a nap after their destruction.
Otherwise, here is a list of possibilities, below. We hope this helps. We haven’t had reports of anything similar with other customers. Please let us know what you come up with. Thank you for your dedicated patronage. God bless and keep you!
Here’s a breakdown of the most likely causes when bean plants die suddenly and how they fit the symptoms:
1. Cutworms or Soil-Borne Chewers
Signs: Cutworms typically chew through stems at or near soil level, causing plants to wilt and collapse quickly.
Fit with Symptoms: If the pinto bean plants die and are partially desiccated, but the other bean varieties nearby are untouched, cutworms could be possible. However, cutworms usually affect scattered plants rather than wiping out an entire patch overnight. You’d often see the stems severed cleanly or partially chewed just above the soil. Checking around the base of several dead plants for chewed stems or curled cutworms in the soil would confirm or rule this out.
2. Herbicide Drift or Residue
Signs: Sudden, uniform wilting, yellowing, and death, similar to glyphosate injury, often across the whole section.
Fit with Symptoms: You specifically said the damage “appeared as though they alone had been sprayed with glyphosate,” and the damage was isolated to the pinto patch. Even without visible neighbors, herbicide drift can travel from farm fields nearby in the right wind, or contaminated mulch/straw can introduce residues.
If straw was sourced from a sprayed field (common with persistent herbicides like aminopyralid or picloram), symptoms could appear later, affecting only certain plants that are more sensitive. Pinto beans could possibly be more sensitive than the other varieties planted, which might explain why only the pinto bean plants die while others remain unaffected.
3. Disease – Possible Root Rot or Anthracnose
Signs: Root rots (Pythium, Rhizoctonia, Fusarium) can cause sudden collapse, often following periods of excess moisture. Anthracnose can cause rapid blighting of foliage and pods.
Fit with Symptoms: Pinto beans may have specific susceptibility compared to the black beans or Great Northerns. The sudden collapse of the entire patch could happen if soil-borne pathogens built up in that specific area. Digging up several plants and inspecting roots for browning, rotting, or lesions would help confirm. These diseases can make bean plants die very quickly in favorable conditions.
4. Environmental or Soil-Specific Stress
Signs: Sudden change in soil moisture, a fertilizer burn, or anaerobic conditions from waterlogging can stress or kill plants.
Fit with Symptoms: Your watering schedule sounds regular, and the straw mulch should help prevent extremes. However, if the pinto section is in a slightly lower area, excess water could cause localized stress and death. That being said, this doesn’t really seem to fit with the rapid onset seen when bean plants die in just two days.
Most likely based on the description:
If the damage is uniform across the pinto patch and appeared suddenly, herbicide injury or contaminated straw remains the prime suspect when bean plants die quickly. This type of damage often presents as an even, across-the-board collapse with no chewing marks or gradual decline, and it can happen almost overnight.
Cutworms and other chewing pests can certainly make bean plants die, but they usually leave scattered damage on individual plants rather than wiping out an entire section at once. They are still worth investigating by checking stems at soil level for clean cuts or chewing. A fast-spreading disease is also possible, especially under warm and damp conditions, but it is less likely to completely kill a whole variety patch so quickly without visible early warning signs such as leaf spots, stem lesions, or yellowing before death.
Diagnostic Checklist for the Customer:
- Inspect several dead and dying plants at soil level for cleanly chewed stems or partially severed stalks (cutworms).
- Dig up a few plants and examine roots for browning, mushiness, or lesions (root rot or other soilborne disease).
- Smell and inspect straw mulch; if it has a chemical odor or came from an unknown source, consider possible herbicide contamination.
- Check nearby vegetation outside the garden for similar symptoms, which could indicate herbicide drift.
- Note whether the pinto section sits in a lower, wetter spot compared to the other bean varieties.
- Look for any signs of leaf spotting, streaking, or fungal growth that might indicate anthracnose or another foliar disease.
- Review recent weather for high winds that could have carried spray from distant fields.
- If suspecting herbicide residue, test by planting a few bean seeds in pots with the garden soil and compare growth to beans in fresh, clean soil.
- Keep detailed notes and, if possible, photograph affected plants for future reference and possible lab diagnosis.
Conclusion:
When bean plants die suddenly, especially in just a couple of days, it can be both alarming and frustrating. While the exact cause can vary—from herbicide drift and contaminated straw to pest damage or disease—pinpointing the problem quickly is key to preventing further loss. Careful inspection of stems, roots, surrounding plants, and recent environmental factors will help narrow down the culprit. By documenting symptoms, testing soil if needed, and adjusting your gardening practices, you can protect future plantings and avoid another sudden, complete loss of your crop.
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FAQ:
Why would my pinto bean plants die in just two days?
Sudden death in pinto beans can be caused by herbicide drift, contaminated straw mulch, cutworm damage, or certain diseases. Identifying the specific signs will help narrow the cause.
Can cutworms really make an entire section of bean plants die overnight?
Cutworms typically damage scattered plants, but a heavy infestation can take out a large area quickly. Look for cleanly chewed stems at soil level to confirm.
Could herbicide drift make only my pinto bean plants die while others remain fine?
Yes. Certain bean varieties are more sensitive to herbicides. Drift or contaminated mulch can selectively damage one variety without affecting others.
How can I tell if herbicide contamination caused my bean plants to die?
Look for sudden, uniform wilting, yellowing, and death, often without chewing damage. Test by planting beans in the same soil and comparing them to beans in clean soil.
What diseases can make bean plants die so quickly?
Root rots like Fusarium, Pythium, and Rhizoctonia, as well as anthracnose, can rapidly collapse plants. Check roots for rot and stems for lesions to confirm.
Could contaminated straw mulch make bean plants die?
Yes. Straw from fields sprayed with persistent herbicides can kill beans weeks after planting, especially if the variety is sensitive.
Why would bean plants die in one section but not others?
Differences in soil moisture, drainage, disease presence, or variety sensitivity can cause localized death in one patch while others thrive.
What should I check first when bean plants die suddenly?
Inspect stems for chewing damage, roots for rot, nearby plants for similar symptoms, and review recent weather or spraying events in your area.
Can environmental stress make bean plants die overnight?
Severe waterlogging, fertilizer burn, or sudden temperature extremes can cause rapid death, but these usually affect more than one variety.
How can I prevent my bean plants from dying like this again?
Source clean mulch, monitor for pests regularly, rotate crops to reduce disease, and be aware of herbicide spraying nearby to protect future plantings.
