In this bulletin:
- Crop & Pest Update
- North American Strawberry Growers Association Summer Tour
Strawberries: June-bearing strawberries began to bloom in many areas over the last week and we are starting to see green fruit in early varieties and where row covers were used. There is lots of bloom and green fruit on overwintering day-neutrals and some early harvest is beginning.
In new day-neutral plantings, remove flower buds and bloom until the plant is well established – generally 4-6 new leaves present.
Disease:
Bloom is an important time for disease management. In June-bearing strawberries include a broad-spectrum fungicide for both botrytis and anthracnose control. Rotate between Switch and a group M for anthracnose control and resistance management during bloom. Spraying after bloom for anthracnose is only needed if there are warm & wet conditions.
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 (9+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 pre year, which includes Switch, Miravis Prime, and Scholar. Do not rely on group 11s alone.
Insects: In strawberries monitor for aphids, tarnished plant bug, clipper weevil, and cyclamen mite. In new fields watch for flea beetles.
- Aphids: Many June-bearing fields have had an aphid product applied- if you have not been monitoring for aphids a spray is likely needed at this point. Aphids need to be managed approximately every 3-4 weeks. Beleaf or Sivanto Prime can be applied during bloom if needed.
- Tarnished plant bug: TPB activity has been fairly low. More nymphs are starting to be found, although often below threshold. The threshold for TPB is approximately 1 nymph in 4 clusters. If an insecticide is needed Beleaf is a good choice during bloom at the early instar stages. Apply Beleaf at the high rate for TPB suppression.
- Flea beetles: Some of the insecticides applied for aphids will also provide some control of flea beetles, including Assail, Cygon or Lagon. Malathion may also provide some efficacy when applied for leafhoppers.
- Clipper weevil: Damage from clipper weevil can occur until all flower buds are open.
- Cyclamen mite: Mites and damage can now be found in both June-bearing and day-neutral strawberry fields. Look for damage in all fields, especially the oldest fields. Damage will look like stunted plants and crinkled, crispy, tough leaves (Below). Pinch out the youngest leaves to look for mites inside the folded leaves:
- Agri-mek and Vegol Crop Oil can be applied to control these mites. If Agri-mek is needed:
- Apply Agri-mek at 225 mL/ha in 750-1000L water /ha, with a non-ionic surfactant at .1-.5%
- Watch the pH of your spray tank.
- Slow down and get thorough coverage of the plants and crowns.
- Apply Agri-mek under slow-drying conditions to improve uptake into the leaves.
- Do not apply Agri-mek within 10-14 days of chlorothalonil (Bravo or Echo) or captan applications.
- Avoid applying Agri-mek during bloom.
- Agri-mek can only be used twice a year.
Blueberries: are at bloom to petal fall across the province.
Disease: After today the forecast looks fairly dry for the next week, however 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.
Cranberry fruitworm and cherry fruitworm: begin to fly at bloom. Petal fall applications of an insecticide can be timed by using pheromone traps or degree day models. In the absence of this information, make two applications of an insecticide beginning at petal fall.
Spongy moth: continue to watch for spongy moth (formerly gypsy moth), especially in young fields. Young blueberry fields can tolerate less damage than established fields.Bt products (Dipel, Bioprotec) applied for cranberry and cherry fruitworm will also have some activity on gypsy moth larvae. See last week’s bulletin for more information on spongy moth forecast this year.
Raspberries: raspberries have a lot of fruit buds present. Insect pressure has been fairly low in raspberries but monitor for raspberry fruitworm and strawberry clipper weevil with a tapping tray of dish. If there are no signs of beetles or leaf shredding an insecticide isn’t needed until after bloom.
Protect growing primocanes and developing laterals with fungicides before and during bloom.
North American Strawberry Growers Association Summer Tour- coming to a farm near you! The NASGA summer tour is in Ontario this year August 16-17th, and will visit 8 farms in southern Ontario. For more information visit: Summer Farm Tours, North American Strawberry Growers Association (nasga.org)
Follow our ONfruit blog for regular updates and berry information.