In this bulletin

• Crop Update:
  • Strawberries
• • Blueberries
  • Raspberries

Crop Update:

Growers have been protecting against frost for the last couple weeks with a few serious frost events in different regions. The long weekend provided a nice period of heat, before we went back into thinking about frost protection again this week. Hopefully the worst of the frost is behind us now. However, as flowers and fruit develop, it is important to remain vigilant and protect the plants when needed. Temperatures can be colder at ground level compared to the forecast. Check out Irrigation for frost protection for more information on frost and protection methods.

Strawberries:

Plants under row covers are at green fruit stage, and there are plenty of flowers in uncovered fields.

Disease: The Strawberry Disease Decision Support System is now running for the 2026 season. These disease production models can be used to time fungicide applications to protect against anthracnose and botrytis. The model is updated 3 days a week and provides a risk of disease at 50 locations across the province. The risk of botrytis and anthracnose infection throughout most of the province has been low over the past week (Fig. 1). Should the model predict an increase in risk, make sure to protect your strawberries with effective fungicides during bloom. Bravo or Echo can be applied before bloom for botrytis control to reduce disease inoculum and help with disease management later in the season. Apply two applications if possible, 10 days apart. Make sure to get these applications on before bloom with the 30-day PHI. Use broad spectrum, group M products like Captan during bloom. Do not rely on group 11 products.

Figure 1: Strawberry disease prediction map.

The Strawberry Diseases Decision Support System can be found on the ONfruit blog under the ‘Berries’ tab, or you can bookmark this page:  2026 Strawberry Disease Decision Support System. The Strawberry Diseases Decision Support System includes a map indicating fruit infection risk across the province and a graph tracking risk through the season.

Insect activity is increasing:

• Tarnished plant bug (TPB) nymphs are beginning to be found in fields with bloom- the threshold for TPB is roughly 1 nymph in 4 flower clusters. Some fields may be over this threshold already. Beleaf will provide TPB suppression at the high rate (200 g/ha) and also control aphids.
• Aphids populations are increasing and can be found in high numbers in some fields. Cygon, Lagon, Exirel, Beleaf and group 4s (such as Sivanto Prime) can be applied before bloom to control aphids. Once bloom is present choose Sivanto Prime or Beleaf. Do not use Admire at this timing; Admire cannot be used pre-bloom or during bloom. Apply post-bloom only.
• Clipper weevils are active and can be found in June-bearing strawberries (clipped buds and round holes on bloom (Fig. 2). Pay close attention to older fields, and monitor field edges for clipped buds. Group 3s or Cormoran can be used for clipper weevil control before bloom if needed.  Border sprays may be sufficient at minimizing clipper weevil damage.

Figure 2: Clipper weevil adult and round holes in blooms from clipper weevil feeding (photo credit Erica Pate).

• Potato leafhoppers have been found this spring. For strawberries, they are typically only an issue in new plantings.
• Keep an eye out for cyclamen mite as the canopy fills in. Plants infested with cyclamen mite will have crinkled, toughened young leaves, and small, stunted plants. Pinch out a young, folded leaf where symptoms are found and look along the mid-vein to confirm cyclamen mite. There is no established threshold for cyclamen mite; once cyclamen mite is identified plan to treat the entire field or block. If cyclamen mite is identified or injury is present, apply a miticide before bloom, if possible, before damage to the bloom can occur, and when miticides can reach the mites in the crown.  

Agri-mek and Magister are registered for cyclamen mite control:

Agri-mek® SC (abamectin, group 6):

• Apply Agri-mek® SC at 225 mL/ha in a high-volume spray, with a non-ionic surfactant at 0.1-0.5%.
• Slow down and use sufficient water volume to get thorough coverage of the plants and crowns. Do not apply in less than 375 L water/ha.
• Agri-mek® SC is locally systemic or translaminar (absorbed into leaves), and is absorbed best by new, expanding leaves.
• Agri-mek® SC will be rainfast after 2 hours or once dry
• Agri-mek® SC can be applied twice per year, with a 3-day PHI
• This product is toxic to bees exposed to direct treatment or residues on blooming crops and weeds. Avoid application during crop blooming period.
• Timing can be challenging: Do not tank-mix Agri-mek® SC with chlorothalonil (Bravo or Echo), or captan. Make sure to keep a 5 day gap between Agri-mek® SC or oil applications and chlorothalonil (Bravo or Echo) or captan applications. Do not apply sinbar after applying Agri-mek® SC. Wait 5-7 days after Agri-mek® SC before applying sinbar.

Magister® SC (fenazaquin, IRAC group 21A):

• Apply Magister® SC at 2.63 L/ha in a minimum of 1000 L water/ha. 1000 L water/ha is the optimal volume; lower water volumes may reduce efficacy. Do not use less than 500 L water/ha.
• Apply with a non-ionic surfactant at 0.25% v/v.
• Magister® SC can be applied once per year, with a 1 day PHI.
• Magister® SC provides rapid knockdown, is non-systemic and requires thorough coverage of the plants and crowns.
• Magister® SC is rainfast after 3-4 hours
• This product is toxic to bees. Avoid application during bloom or when bees are active. See label for specific bee toxicity statements.
• Magister® SC targets nymphs and adults, is less effective on overwintering eggs but is more effective on new eggs.

Blueberries:

Blueberries are near the end of the bloom period in southern Ontario, and not far away in other parts of the province.

• For cultivars where the bloom period is done, the window to control mummy berry is over.
• Bloom is also an important time for anthracnose, Phomopsis, and botrytis grey mould, especially with wet weather during bloom. Fungicide options are listed on the Ontario Crop Protection Hub.  
• Cranberry and cherry fruitworm begin to fly at bloom. Use pheromone traps to time insecticide applications or plan to apply insecticides at petal fall.

Raspberries:

Raspberry fruit buds can be found and new primocanes are 6-8’’ tall.

• Begin to monitor for raspberry fruitworm (Fig. 3) and strawberry clipper weevil once buds are present using a tapping tray or dish.
• Protect growing primocanes and developing laterals with fungicides before and during bloom. Tanos is registered for cane diseases, but Pristine and Switch also do a great job on cane diseases when they are used to control Botrytis grey mould. Good coverage is important.

Figure 3: Raspberry fruitworm adults feeding around raspberry fruit buds (Photo credit: Erica Pate).