Dry Edible Beans: Other Problems

Excerpt from Agronomy Guide for Field Crops (Chapter 7)

Order OMAFRA Publication 811: Agronomy Guide for Field Crops

Table of Contents

1. Frost and Hail Damage
2. Bronzing
3. Seed Quality Problems
4. Herbicide Injury
5. Updates on Dry Edible Beans: Other Problems
6. Related Links

Frost and Hail Damage

Both frost and hail can be devastating to a bean crop. The extent of early-season frost damage will depend upon where the plants were damaged. If the plant is damaged below the cotyledons, it will not recover. If the growing point is damaged, but the lower stem remains intact, the plant will send out new shoots from the base of the leaves or cotyledons. Wait a few days before replanting to see if these shoots appear.

When evaluating hail damage, check for bruising on the plant stem. Damage to the stem will make it more difficult for the plant to recover. It can also lead to increased stem disease. When the pods are damaged by hail, the seeds or entire pods will often rot.

If frost occurs close to maturity, pods that are yellow-to-brown are often sufficiently mature to escape damage. Green beans will shrivel, retain their off-green colour and increase pick. Delaying harvest until the beans dry down sufficiently will help prevent staining and will improve separation.

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Bronzing

Bronzing is not caused by a living organism or pathogen but instead is the result of ozone damage to the leaf surface. A reddish-brown flecking or "bronzing" occurs on the upper leaf surface.

Plate 135. Ozone (bronzing) injury. High levels of ozone can injure the leaves and cause bronzing of the upper leaf surface.

Affected leaves are often the highest leaves on the plant; bronzing often occurs shortly following an ozone event. The number of leaves affected varies depending on exposure duration. Symptoms may be more severe on plants under moist conditions. Under dry conditions, plants are more tolerant to ozone. The amount of damage found on the plant or in an area often corresponds to air pollution alerts or heavy thunderstorms. These conditions can result in atmospheric ozone being forced down onto the crop. Ozone is also produced when lightning strikes. The higher the concentration of ozone and the longer the duration, the greater the impact on the crop. Use tolerant varieties in areas that have a history of ozone events.

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Seed Quality Problems

Poor seed quality reduces germination and vigour of seedlings. Mechanically damaged seed may cause bald-headed beans (beans that emerge, but have no growing point). This injury should not be confused with symptoms of seed corn maggots, which will leave the seedlings ragged in appearance. Poor-quality seed can also cause seedlings to have broken or cracked cotyledons, or hypocotyl. Damaged seedling is more prone to diseases and insect damage. Plant only high-quality certified seed. Treat seed with a fungicide at planting to protect against seedlings. Handle seed gently to minimize mechanical damage.

Herbicide Injury

Edible beans are very sensitive to certain herbicides. To reduce carry-over injury, select herbicide for fields where beans will be rotated into the following year carefully. Consult herbicide labels for crop sensitivity and rotation information.

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Updates on Dry Edible Beans: Other Problems

No updates available at this time.

Related Links

• Dry Edible Beans

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