Berry Bulletin 05-20-16 printable PDF
May 20, 2016
Crop conditions: Crop development has been slow, especially in eastern Ontario. Things should move ahead more quickly now that warm weather is here. Early day neutral strawberries from row-covered fields should be ready soon in the earliest areas.
There have been several frosts at ground level this past week and strawberry growers have been using row covers or irrigation to prevent damage. In the absence of frost protection damage has been variable but is easy to find on emerged and developing strawberry buds. There have been no reports of damage to blueberries so far, as this crop tends to be higher off the ground, and growers in southern Ontario were irrigating May 15-16 to prevent damage.
Dry weather is also a concern. Some growers are low on water which impacts the ability to irrigate for frost. On the bright side, planting has been well ahead of schedule this year.
Blueberry pest management workshop: Wed June 1, 2016, in Simcoe (not Woodstock). 4:00 pm – 8:00 pm, includes a light supper, so please RSVP to 1-877- 424-1300. Guest speakers include Dr. Rufus Isaacs, from Michigan (by webinar), and several OMAFRA specialists.
Captan survey: The Ontario Berry Growers Association is asking growers to respond to a survey about use of Captan and Maestro in berry crops. This survey will help the OBGA back up their response to a recent re-evaluation of captan by the Pest Management Regulatory Agency . Captan is a group M fungicide and is an important tool for resistance management. https://www.surveymonkey.com/r/ontarioberrycrops. Please respond to this survey by May 22.
Day-neutral strawberries: Overwintering day neutrals have lots of bloom and green fruit. A few early berries have been spotted. Check for mites and aphids, which may have built up under row covers. It is important to include broad-spectrum group M fungicides (captan, Maestro, Thiram, Granuflo -T) in your disease management program for both botrytis and anthracnose. Anthracnose builds up in warm weather and is spread by splashing rain or irrigation. Risk will increase next week in the warmer weather.
June bearing strawberries: Strawberries are in bloom now, or will be shortly. When bloom is present, it is too late to apply Bravo, Admire soil drench, Venture herbicide, glyphosate spot treatments, or other pesticides with a 30 days to harvest period. It is also too late to apply Agrimek, Cygon, Lagon or other products which are highly toxic to bees.
We expect clipper weevil will become active in the warmer weather this weekend. Scout for damage near the edges of older fields. Where clipper weevil damage is evident, border sprays (outer 10-12 m of crop) should provide adequate control.
THIS IS IMPORTANT– Apply an insecticide for aphids in strawberries, if you have not done so already. During bloom, your options are Beleaf, and if necessary, Sivanto Prime. Apply at night when bees are not working. Beleaf should suppress tarnished plant bug when used at the high rate, and is a good choice now when TPB populations are still fairly low.
In newly planted fields, control aphids with a soil drench of Admire. This will control aphids for several weeks, and will control white grubs as well. Make this application shortly after planting, as new leaves emerge. Or, for other options, see OMAFRA pub #360.
Angular leaf spot is common this year, especially in vigorous fields. The bacterial ooze that can be seen in humid mornings will spread by rain or irrigation. If calyces get infected, they will turn black and make fruit unattractive. Fungicides can be used to suppress angular leaf spot, such as Tivano, or Copper 53W. It helps to start early and make several applications ( note for next year).
Figure 1: angular leaf spot – bacterial ooze is evident in humid conditions
Some June bearing fields are looking slow to get going. If things don’t improve in the warm weather ahead, test the soil in these fields for nematodes and the plants for viruses. Root weevil outbreaks also become apparent at this time of year. Plants in infested areas seem to “grow backwards” as the healthy plants jump ahead. Dig up these plants and take a close look at the soil for root weevil larvae. You can purchase beneficial nematodes for root weevil control – contact me, or a supplier, for details.
Unusual leaf symptoms have caught our attention this week. Here are some photos of things that have unexplained causes but are not something to worry about.
Blueberries – Most growers are reporting lots of fruit buds and blooms, following last year’s light crop. Bloom is an important time for fungicides to control Botrytis and anthracnose fruit rots. The first insecticides are needed at petal fall. You will need 1-2 well timed insecticides for cranberry fruitworm and cherry fruitworm control. The newer products such as Intrepid, Exirel and Altacor work best on eggs and young larvae. Apply these a bit earlier than you would traditionally apply older organophosphates such as Malathion and Sevin.
Raspberries– Developing flower buds on summer-fruiting varieties are susceptible to raspberry fruitworm and strawberry clipper weevil. Scout for these pests by tapping flower clusters over a white trap or dish. Primocanes are slow to emerge in older fields but may be approaching 4-6 inches high in newer fields. Make sure new growth is protected with a fungicide before the next rain. If you are planning to use IGNITE for primocane suppression, the timing is 4-6 inches of primocane growth and actively growing.
Spotted Wing Drosophila: The Ontario Berry Growers Association is working with OMAFRA to coordinate a regional monitoring program in 2016. Traps will be set up next week across Ontario to provide information on SWD activity.
Emergency use registrations for SWD are in place, and are similar to last year. There is one significant change to the malathion label-use of this product is now limited to 2 applications per year.
Happy Victoria Day!