May 24 Berry Bulletin

Strawberries

It has been a warm week so far moving berries along, with cooler weather in the forecast. At this point in the season berries seem to be about a week earlier than last year. Early June-bearing strawberries have green fruit, and some berries are beginning to turn colour where row covers were used. Mid and late-season varieties are in bloom. Overwintered day-neutral strawberries are beginning to be harvested.

Make sure new fields are getting enough water for good establishment. Remember to remove spring-planted day-neutral blooms until the plant is well established- about 4-6 leaves present.

• Thrips: are showing up in strawberries. Thrips can cause bronzing under the calyx, on the seeds and fruit, and can cause the entire berry to become bronzed and cracked. Watch for thrips on day-neutrals and June-bearing strawberries. Gently breath on blossoms to encourage thrips to move out of the bloom.  If control is needed Delegate, Exirel, Beleaf or Harvanta are registered for thrips suppression or control.

• Cyclamen mite: Cyclamen mite injury is showing up with crinkled leaves and short, stunted trusses with seedy berries. Look at the youngest, folded leaves to confirm cyclamen mite- it will look like piles of salt.  Agri-mek is registered for cyclamen mite control at 225 mL/ha in a high-volume spray (minimum 375 mL/ha), with a non-ionic surfactant at 0.1-0.5%, where permitted. It is very important to get thorough coverage- slow down and use a high volume. Agri-mek can only be used twice a year. Avoid applying Agri-mek during bloom.

• Aphids:  Stay vigilant with aphid control through the season to manage strawberry viruses. If an aphicide is needed during bloom use Beleaf or Sivanto Prime. Beleaf at the high rate (200 g/ha) will suppress tarnished plant bug. Beleaf is also labelled for thrips at a rate of 200-300 g/ ha if needed.

• Tarnished plant bug: early instar tarnished plant bugnymphs are active, although often below threshold (1 nymph in 4 flower clusters).  If an insecticide is needed Beleaf is a good choice during bloom applied at the high rate (200 g/ha).
• Disease management: See the 2024 Strawberry Disease Decision Support System for the risk of anthracnose and botrytis infection.
• Overwintered day-neutrals often have the highest disease pressure compared to spring-planted day-neutrals. On day-neutral strawberries apply captan up to 6 days before the start of harvest. Once harvest begins use Switch/Button (9+12) or Miravis Prime (7+12) for anthracnose control when there is high disease pressure (hot & humid with rain). Another option is Diplomat (19), however, under high disease pressure Diplomat alone did not provide acceptable control. Note that there is a maximum of 3 applications of fludioxonil-containing products per year, which includes Switch, Button, Miravis Prime, and Scholar. Do not rely on group 11s alone.  
• Use broad spectrum fungicides (group M) during bloom as much as possible for botrytis control (June-bearing and day-neutrals). There are multiple formulations of captan products available- SC (suspension) and WSP (water-soluble pouches). For SC formulations (Captan 480 SC, #34551; Sharda Captan 48 SC, #32300) apply 5.8 L/ha in 1000 L water/ha. For WSP formulations (Maestro 80 WSP, #33488; Supra Captan 80 WSP, #33641) apply 3.5 kg/ha in 1000 L water/ha.
  

Blueberries

Blueberries are in full bloom to petal fall. If applying nitrogen in split applications, plan another application of 6-12 g of N per bush at petal fall. A total of 36-48 g N/bush should be applied each year to established plants.   

Cranberry fruitworm and cherry fruitworm: Petal fall applications of an insecticide can be timed by using pheromone traps or degree day models. Otherwise, plan to apply 1-2 insecticides at petal fall.

Scale: Check bushes that have had scale infestations in the past for scale crawlers by using black sticky tape. Insecticides are most effective at the crawler stage, so it’s important to control when crawlers are active. Wait until after bloom to apply an insecticide. 

Disease: If rainy weather occurs during the bloom period, fungicides will be important for anthracnose and botrytis fruit rot control. This is also a good time to control Phomopsis.

Thrips workshop

Sign up now for a thrips species identification workshop at the greenhouse conference, in Niagara Falls Oct 9 or 10. Go to the events page for the Thrips Identification Workshop and follow the instructions to pre-register.