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Meetings OBGA Annual Twilight Meeting 2009 *Please confirm your attendance by contacting the OBGA office at 613-258-4587 or info@ontarioberries.com Strawberries: Weed pressure is high and control continues to be difficult. The only herbicide options for emerged weeds are to spot treat them with a glyphosate product and avoid contact with strawberry plants. Fall is an excellent time to control quackgrass with glyphosate. See sources of spot treatment equipment: http://www.omafra.gov.on.ca/english/crops/resource/spot_treatment.htm Weeds between the strawberry rows can be treated with gramoxone using hooded nozzles or shields to prevent damage to the row. Winter annuals such as chickweed, mustards, field pansy traditionally germinate about this time, when soil conditions are moist and temperatures are cooler. Winter annuals should be controlled now with a pre-emergent herbicide such as Sinbar, Dacthal or Devrinol. Apply Sinbar @ 0.18 to 0.28 kg/ha (for sensitive cultivars or sandy soils use the low rate) in a high volume of water, rinsing the solution off of the leaves with irrigation immediately after application. Sinbar has been associated with increased incidence of black root rot in some fields, likely because it can burn strawberry roots near the soil surface. Where groundsel or grasses are a problem, apply Devrinol as well. Devrinol may only be applied once per season, and rain or irrigation is essential right after application. Mow weeds on field edges to prevent seed shed. Weeds on the edge produce more seeds, so frequent mowing is important. Avoid all use of 2,4D or Lontrel in strawberries at this time, because these herbicides could interfere with fruit bud initiation in strawberries. Plan to follow up the Labour Day application of herbicide with a dormant application of Goal, Devrinol, Sinbar or Chateau, just before mulch is applied. Cyclamen mite: apparently there is more cyclamen mite out there than usual. Scout fields for roughened, crinkled or stunted growth. Pinch out the newest leaves and examine with a high power handlens for tiny amber coloured oval mites. If damage is not too bad, simply flag infested areas for treatment with endosulfan or Thiodan next spring. If plants are definitely stunted, you could try to treat with Thiodan now, but remember that high volumes are needed to get coverage of the crown of the plant (Figure 1.).
Figure 1. Cyclamen mite on strawberry causes crinkled, roughened leaves and stunted growth. Note the healthy leaf in the bottom left and compare it to the crinkled leaves in the center of this picture. Leaf diseases: Mid August to early September is the traditional time for leaf disease control. Try to identify the disease which is causing the problem and use the best fungicide to control the biggest problem. (See attached info sheet with photos of leaf diseases) , Many growers mistake powdery mildew for leaf scorch, because both cause reddish purple blotching on the upper leaf surface. Powdery mildew is also associated with a reddish or pinkish discolouration on the lower leaf surface, and curling up of the leaf edges. If powdery mildew is predominant, consider Pristine or Nova for control. Otherwise Captan or Maestro are good broad spectrum fungicides for leaf diseases. Raspberries: Botrytis grey mould is a common problem on fall-bearing raspberries. Pre-pick fungicides such as Switch (1 day to harvest) and Pristine (0 days to harvest, but 24 hour re-entry) are quite good when disease pressure is high. Leaf rust and fire blight are also showing up in fall fruiting raspberries. Fire blight is showing up on varieties like Polana, Joan J and Himbo Top. Rust is more serious on Heritage and Caroline (Figure 2.).
Figure 2. Fire blight causes dried up fruit on fall-bearing raspberries. Photo credit Andre Carrier MAP. In summer red raspberries, I believe it is too late to prune out old fruiting canes now. If this job was not done immediately after harvest, leave it alone till next spring. Yellow jackets and wasps: There have been several calls this week about wasps in fall-bearing raspberries and day-neutral strawberries. This is a serious problem if it gets out of hand. Insecticides are not practical or effective. Keep all sources of ripe fruit harvested on a regular basis. Consider using traps to attract the wasps away from the crop. It is important to identify if the pest is paper wasps or yellow jackets because they are attracted to different baits. Let me know if you need more info on bait traps for these pests. Link to an article on identification and trapping wasps: http://www.upr.org/media/access_utah/wasptrap.pdf Great link: Is it insects, mice or another problem? Diagnosing and Avoiding Damage to Drip Tape http://www.dripirrigation.org/troubleshooting.html Other news: Farewell and thank-you to summer students Erin Styles (funded by the Ontario Berry Growers Association through a project with the Pest Management Centre) and Melissa Klitzke (funded by the Summer Experience Program) . Both students were involved in a variety of projects including:
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