This week’s berry bulletin includes:
-cyclamen mite management
-strawberry disease management
-blueberry and raspberry update
June 1, 2018
Strawberries: Day neutral harvest has started in the earliest areas! Green fruit is present in early June bearing varieties and harvest will likely begin in two weeks. In other parts of the province there is full bloom and the crop is looking promising.
Some of the low vigour we’ve been seeing in overwintered June bearing fields may be due to late straw removal. Keep this in mind for next year. It is important to remove straw early in the spring following snow melt. Keeping the straw on for too long can reduce the fields’ vigour and reduce yields.
In new day-neutral plantings remove flower buds and bloom until the plant is well established (4-6 leaves present).
With the heat this week pest activity has increased, and disease management will be very important, especially if you are expecting rain this weekend.
Mites: cyclamen mites have been found in fields across the province, and damage is evident (Figure 1). We are finding more cyclamen mites this spring than we have the past few years. It is a good idea to look for cyclamen mites in the new, unexpanded foliage even if you don’t have a history of cyclamen mite or see damage this year. Keep an eye on all your fruiting fields. If your plants do not have the vigour you would expect at this time check for cyclamen mites.
- Your options for control at this time are Vegol Crop Oil and Agri-Mek SC. Do not apply Agri-mek once bloom is present, or Vegol Crop Oil in high temperatures.
- Make sure to apply Agri-mek with a surfactant. Refer to the 2018 Pub 360, Adjuvants used in Ontario, page 221 for a list of available surfactants.
- Apply in a high-volume spray to get coverage of the plant, as cyclamen mites are usually protected in the crown or young leaves.
- Sanitation is very important throughout the season. Cyclamen mites can move easily from field to field on equipment, workers clothes, and shoes. Make sure to work in older fields before moving to the new or younger fields, to protect the new crop.
Figure 1. Cyclamen mite damage. Note distorted, crinkled leaves compact around the crown.
Two spotted spider mites (TSSM): TSSM damage can be seen in a few fields. Populations can rise quickly in hot temperatures. Avoid using pyrethroids for TPB and clipper weevil to avoid mite flare ups.
- There are a number of products registered for control of TSSM. Similar to cyclamen mite management, it is important to apply these miticides in a high-volume spray.
Tarnished plant bugs (TPB): larger nymphs can be found in strawberry fields. Remember the threshold for TPB is approximately 1 nymph per 4 flower clusters.
- Beleaf will suppress TPB and control aphids at the high rate.
- Rimon and groups 3s are other options for control during bloom.
- Growers are limited to 2 applications of group 4As per season (including Assail, Admire, Clutch, Actara and Alias).
- Do not spray when bees are active.
Strawberry Aphids: Aphids populations are increasing. Once you begin to see aphid numbers increase it is time to apply an insecticide. We want to stop aphid numbers from rising and them from flying to new, healthy fields and spreading viruses.
- Beleaf can be used once bloom has started and will have some activity on tarnished plant bug at the high rate. Do not spray when bees are active
- In newly planted fields control aphids with a soil drench of Admire. Do not use a soil and foliar application of group 4A insecticides in one season (ex. Admire and Assail). Maximum two applications of group 4A insecticides a year.
- Check table 3-12, Activity of Insecticides and Miticides on strawberry pests in the 2018 Pub 360, Guide to fruit protection, to see what activity these products have on other pests.
Clipper weevil: check for clipper weevil damage, especially in older fields. . Only spray for clipper weevil when necessary, or spray border rows, to avoid harming beneficial populations with the pyrethroids. These beneficial populations can help keep cyclamen mite populations in check.
Anthracnose and botrytis: This week’s hot and humid weather + potential rain are optimal for anthracnose disease development. Anthracnose builds up in warm weather and is spread by splashing rain. With the unusual heat this spring June bearing fields need to be protected from anthracnose infection. Make sure your strawberries are protected with a fungicide before rain.
- For anthracnose management use Pristine (7+11), Cabrio (11), or Switch (9+12), and rotate with Captan or Maestro for botrytis control and resistance management. .
- Avoid working in fields when they are wet.
Angular leaf spot: check older leaves for angular leaf spot. The bacterial ooze can spread by rain or irrigation. The calyces can turn black if they get infected and leave the fruit unmarketable.
Blueberries: Crop stage ranges from bloom to petal fall. The crop is looking promising.
Disease: during bloom growers will need to apply a fungicide if you expect rain for anthracnose and botrytis fruit rot. Use fungicides that control both botrytis and anthracnose fruit rots during bloom. Look for mummy berry trumpets on the ground under debris and leaf litter.
Insects: Cranberry fruitworm and cherry fruitworm begin to fly at bloom. Prepare to apply a spray at petal fall, or use pheromone traps or degree day models to time sprays. Without traps or models spray at petal fall, and again 7-14 days later. There are multiple products available for control of cranberry and cherry fruitworm. Check the 2018 Pub 360.
Raspberries: fruit buds are present in southern and central Ontario. Bloom has begun in south western Ontario, and will begin in the next week in other parts of the province.
Disease: Make sure new growth is protected before the next rain. Apply Tanos and Ferbam when there is 25-30 cm of new growth.
Insects: Insect activity has been low in raspberry fields but continue to monitor for raspberry fruitworm and clipper weevil. Raspberry fruitworm beetles are now active. Check Pub 360, Fruit Crop Protection Guide, table 3-8 Activity of Insecticides on Raspberry Pests for insecticides for these different pests.
Haskaps: berries are forming and the crop is looking promising.
Spotted Wing Drosophila (SWD): We have a small monitoring network set up this year at a few sites across the province. We have not found any SWD so far. Stay tuned to the blog and the berry bulletin for updates on what we are finding and different management practices. Check out this blog post on managing SWD for the different management tools.
Prepare now to manage for SWD. Prune your blueberries and raspberries to improve insecticide coverage and remove the shaded, protected areas in canopy SWD prefer. Once you have ripe berries you can evaluate your fruit yourself with a salt water test or a plastic baggie test.