In this bulletin:
- Crop & Pest Update
- North American Strawberry Growers Association Summer Tour
Strawberries: After a couple days of hot weather last week we’re having great weather for strawberries. Harvest began last week on row-covered June-bearing strawberries, and strawberries that weren’t row covered will start to be picked this week. Malwina is beginning to bloom- don’t forget this late variety. A separate spray is likely needed for disease and tarnished plant bug control.
Overwintered day-neutral strawberries are being picked and the fruit is looking good. Make sure to pinch off the bloom on new day-neutrals until there are well established- approximately 4-6 leaves present
Disease: For June-bearing strawberries rotate between Switch and a group M for anthracnose and botrytis control during bloom. Spraying after bloom for anthracnose and botrytis is only needed if there are warm & wet conditions. Do not rely on group 11s alone.
For day-neutral growers use a group M when possible- there is a 6-day REI for captan and maestro. During harvest rotate between Switch (group 12+9), Diplomat (19) and Quadris Top (11+3)- use Switch when there is high pressure. Miravis Prime (7+12) is a new product registered for botrytis control on strawberries, and also has some efficacy on anthracnose. Do not make more than three applications of fludioxonil-containing products (eg Switch, Miravis Prime, Scholar) on strawberries per year.
- Tarnished plant bug: TPB activity has increased a lot in the last week, especially in day-neutral fields. Rimon, Assail, Cormoran or Beleaf can be applied at this time to control TPB.
- Thrips: have been found in some fields- Monitor for thrips in June-bearing and day-neutral fields. If your tapping trays are collecting a lot of thrips blow gently on the bloom to see if thrips crawl out. If control is needed consider using Delegate, Exirel or Harvanta- these products only provide suppression.
- Cyclamen mite: If you are seeing cyclamen mite damage in your fields prepare to apply a miticide after bloom if needed. Keep in mind the 10-14 day interval between captan and Agri-mek. To confirm it is cyclamen mite look at the youngest leaves. They will look tough, crinkled and crispy and the mite eggs will look like piles of salt inside the folded leaves. Your options are Agri-mek or Vegol Crop Oil. Spray the entire block or the entire variety where you are finding mites and damage. If you are not spraying after bloom plan to spray after renovation.
- New plantings: Watch for flea beetles in new fields. 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.
Blueberries: are at bloom to petal fall across the province.
Cranberry fruitworm and cherry fruitworm: spray for these fruitworms at petal fall. You will need 1-2 well timed insecticides for cranberry fruitworm and cherry fruitworm control. Watch for spongy moth larvae as well- the larvae I’ve seen are approaching the period when they are too big for a Bt product now. Once larvae reach 2.5 cm or more and develop distinctive yellow markings on their head capsule they are no longer susceptible to a Bt. product. Insecticides applied for leafrollers will also have some activity on gypsy moth larvae.
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.
Raspberries: Raspberries are starting to bloom. Flower buds are susceptible to raspberry fruitworm and strawberry clipper weevil. If there are no signs of beetles or leaf shredding an insecticide isn’t needed until after bloom. Do not apply an insecticide 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)