| Crops Affected: range of crops (depending on disorder)
Symptoms / Conditions Favouring Development:
Hollow Heart (potatoes)
- Common in oversized or rapidly growing, early tubers
- Very dependent on cultivar
- Most severe under rapid tuber growth conditions
- Uneven moisture (dry followed by wet) or fertility
- Wide plant spacing or missing plants
- No visible external symptoms
- Internal symptoms – tan to brown walled cavities that develop from brown areas at or near the centre of tubers
Hollow Stem (broccoli and cauliflower)
- No visible external symptoms
- Small cracks occur internally, which coalesce to form a hollow central stem
- Cause is suggested to be related to plant nutrient balance, as well as growth conditions after head initiation
Forking (carrots)
- Cause can be a result of disease or pest damage, compacted or heavy soils, excessive plant densities, or other factors that damage the root tips
- Location of the fork can give an indication of when the damage occurred and may suggest probable cause
Growth Cracks (carrots, rutabaga, turnips, potatoes, cabbage, tomatoes, cherries)
- Rapid tissue growth leads to vertical cracking, with cracks varying in size
- Cracks may originate along root or tuber or in neck areas
- Older cracks may have a layer of rougher wound tissue over the inside of the crack
- More typical on larger roots
- Fruit cracking can occur as radial or concentric cracks
- Can occur as “bursting” when very rapid
- Is typically the result of fluctuating soil moisture levels, specifically when abundant moisture follows a dry spell
Jelly End Rot (potatoes)
- Most prevalent in Russet Burbank potatoes
- Stem end tissues of tubers become glassy, jelly-like and shrivels and dries up
- Favoured by high soil temperatures and dry conditions followed by excellent moisture
- Often associated with misshapen tubers
Brown Bead (broccoli)
- Buds of broccoli florets turn tan or brown and can fall off easily
- Associated with rapid growth in high temperatures following abundant moisture
Sunscald (various crops)
Bulb crops
- Soil level tissues shrivel, and the plant withers and dies
- Young, sensitive plants are damaged by hot, sunny conditions in dry springs
Beans / Fruit crops (e.g. tomatoes)
- Small, water-soaked spots on plant parts only on exposed sides of the plant, typically in intense, direct sunlight following cloudy, high humidity and high temperature conditions
- Spots become brown to white and grow together to form large necrotic lesions; may be sunken
Management:
- Maintain adequate (and uniform, if possible) moisture levels throughout the growing season
- This may involve the use of irrigation, improving soil moisture hold capacity, etc.
- Ensure plants are uniformly spaced within the row
- Avoid excess or inadequate fertilization (particularly nitrogen)
- For some disorders (e.g. hollow heart / hollow stem), there are varietal differences in susceptibility
- If possible, adjust planting dates to avoid having susceptible stages present during hot, dry conditions.
- Avoid irrigation to ripe fruit (susceptible to cracking)
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