Blossom Frost Injury

Frost-damaged blossoms have black centres and dry-up or drop before forming fruit, or form misshapen fruit. Frost injury is more common in low areas of the field. Damage can be reduced by sprinkler irrigation during the low temperature periods, use of row covers or wind machines. Late blooming varieties such as Rainier are less prone to blossom frost injury.

Misshapen Berries

Berry size and shape is largely due to the number of seeds that develop on the surface of the berry. If a seed, or a group of seeds, does not develop, the portion of the berry under the seed will not enlarge or ripen. This results in a misshapen berry. Misshapen berries are usually pinched-in (called “monkeyfaced” or “catfaced”), multiple-tipped or fan-shaped (fasciated).

Anything that prevents seed development can result in misshapen berries. Causes include:

Poor pollination: cold, wet conditions or lack of bees during bloom,

Frost injury to blossoms,

High temperatures and drying winds during bloom,

Botrytis (grey mould) disease: can cause misshapen fruit when flowers are attacked,

Frost or hail during early fruit development,

Other environmental conditions: short day length in fall can result in fasciation. Cold, dry fall weather can cause multiple-tipped berries,

Insect feeding on flower parts or developing fruit: many insects (strawberry mites, aphids, spittlebugs) when present in high populations can lead to misshapen fruit. Lygus bugs are the most serious pest. Lygus injury can look slightly different than weather-related injuries. Seeds damaged by lygus are hollow inside and about the same size as those in the undamaged areas of the fruit. Seeds damaged by weather-related injuries tend to be smaller than undamaged seeds. Also, lygus injury is usually seen later in the season after the risk of cold-weather injury is reduced. For further information on this problem, see “Lygus Bugs”.

Nutrient imbalances: boron or calcium deficiencies, or excessive nitrogen,

Herbicides: Some herbicides can cause fasciated fruit.

Genetic factors: Some varieties tend to produce fasciated fruit.

Soil Problems

In the western end of the Fraser Valley (especially Richmond and Delta), poor soil conditions are a common cause of poor growth and plant death during the establishment year. Typically, a newly planted field can look good to the end of July. Plants then begin to wilt and die. Further losses occur over the winter leading to a poor stand in the first cropping year. This type of injury is often caused by a combination of very acid soil (low soil pH), inadequate winter drainage and high levels of soil salts.

Management

Check the acidity of the soil before planting a new field. Add lime, if needed, to raise the pH to a suitable level (pH 5.5 to 6.5).

Improve winter drainage to help leach the salts from the soil.

Avoid fields known to have a high salt level at least until the winter drainage is improved.

Apply sprinkler irrigation during the dry summer months to keep the salts below the root zone.