May 17, 2019
In this update: crop updates, fungicide options, using herbicides in wet conditions.
Strawberries: Crops continue to advance slowly this week. Day-neutral strawberries are beginning to bloom in early areas. June-bearing strawberry buds are emerging from the crown in early areas and where row covers were used. Remove row covers soon after flowers appear.
Planting has been delayed in many areas because of the wet fields. Once spring-planted day-neutrals begin to leaf out remove the first couple flower clusters until there are 5-6 leaves, to allow the plant to establish before fruit production.
Insect activity has been low this last week.
Mites: cyclamen mite activity has been low at this point. Continue to monitor your fields for damage and for mites- look for distorted, shrunken leaves and stunted growth. If cyclamen mites have been a problem in the past or you find them in your field, your options for control are Vegol Crop Oil and Agri-Mek SC. Make sure to include a non-ionic surfactant (0.1%-0.5% v/v) with Agri-mek SC. Avoid using surfactants in close sequence with Bravo, Echo, Captan, Maestro, Folpan or copper fungicides. Cyclamen mites can be protected in the crown so a high volume spray is necessary to ensure thorough coverage.
Natural predators can be effective at controlling two spotted spider mite and cyclamen mite. Avoid using pyrethroid insecticides (group 3), such as Mako and Matador for TPB and clipper weevil, where cyclamen mite is a problem, as these products are hard on natural predators that help manage cyclamen mite.
Strawberry Aphids: Aphid activity has also been low as well. Prepare to manage for aphids before bloom if necessary. Managing aphids is important for virus control.
Tarnished plant bugs (TPB): a few tarnished plant bugs have been found in strawberry fields. Some group 3 insecticides provide control of TPB and clipper weevil, but can be toxic to beneficial insects. Do not spray when bees are active.
Disease: These wet, cool conditions are ideal for botrytis, leather rot, and root rot infections. Phostrol can help manage leather rot. Managing Phytophthora crown rot and red stele can be challenging. There are no fungicides registered for Phytophthora crown rot. Aliette WDG is registered for red stele control and may help reduce Phytophthora crown rot when treating strawberries to manage red stele. Note that Aliette has a 30 day PHI. Check out this article Mike Celetti wrote in 2017 on Phytophthora crown rot and red stele of strawberries for more information and diagnosing these diseases.
If growers are applying Chlorothalonil this spring note that there is a 30 day PHI (correction from Pub 360).
Blueberries: are at pink bud and are approaching bloom in southern Ontario. A bit of winter injury can be found.
Disease: bloom is an important time for disease control. Use fungicides from different groups to control cane diseases such as phomopsis and anthracnose twig blight. Bravo can be used until petal fall.
Mummy berry: Blueberries can be infected with mummy berry shoot blight at the bud burst stage. Control for mummy berry now through early bloom if there is a history of mummy berry on your farm. Mummy berry infections occur after 6 hours of rain or more depending on temperature.
Raspberries: are leafing out and looking good at this point.
Insects: Begin to monitor for raspberry fruitworm and strawberry clipper weevil once fruit buds are present. Diazinon 500 E is registered for control of Raspberry crown borer for one application only, when new canes reach 10 cm.
Herbicides: Soil-applied herbicides can be leached by excessive rains and the rain can affect herbicide performance. Check out Kristen Obeid’s blog post on Herbicides, Weeds and Rain for more information on soil-applied herbicides during this wet spring.
New products and label changes have been registered for berry crops – check out this update on the ONfruit blog for more information.