Each year, growers contact us in the spring regarding fungicide use on strawberries for botrytis and leather rot control during blossom and the fruiting season.
Here are a variety of suggestions based on our experience as well as information gathered from winter conferences and industry contacts. In addition, consult your local cooperative extension office for specific state recommendations.
1. ALWAYS CHECK THE LABEL regarding annual application limits, resistance management and labeling for your state. Good websites for that information are www.CDMS.net. or agrian.com.
2. RESISTANCE MANAGEMENT IS CRITICAL FOR MAINTAINING CHEMICAL EFFECTIVENESS.
Avoid making sequential applications of the same class fungicides. Information on fungicide class distinctions can be found at http://frac.info and look for 2017 FRAC code list.
3. USE CAPTAN OR THIRAM WITH VARIOUS
FUNGICIDES, whenever possible, for broadspectrum control and resistance management. PLEASE NOTE: Mixing Captan with any oil-based material will cause leaf phytotoxicity. This would include other fungicides or insecticides.
4. OXIDATE HAS PROVEN TO BE AN EFFECTIVE BROAD-SPECTRUM FUNGICIDE control and is labeled for organic growers.
5. A NEW PREVENTATIVE BIOFUNGICIDE from
Bioworks, BotryStop has potential to fit into both organic and conventional spray programs. We have started testing this product at Nourse Farms and initial results are encouraging. For additional information see the Bioworks website at www. bioworks.com.
6. CHECK AND CALIBRATE SPRAYER. Choose tips based on coverage needed, which can change based on growing canopy.
Bloom applications are the critical time to effectively control botrytis, and should begin at 5 - 10% bloom. Because of the importance, a spray schedule of 7 to 10 days is recommended. During excessive wet periods, the schedule might be reduced to a 4 or 5-day schedule. Usually 4 or 5 applications can accomplish the job for the season.
Switch + Captan & Oxidate Merivon + Captan & Oxidate
Elevate + Captan & Oxidate Scala + Captan & Oxidate
Fracture + Oxidate Inspire Super + Captan + Oxidate
LEATHER ROT CONTROL
For leather rot control during extended wet periods, when frost protection is necessary and especially if leather rot occurred last year, add Ridomil Gold as one of the fungicides in your bloom spray program beginning at first bloom. Straw mulch can assist in minimizing water splashing that can spread leather rot. Growers can also consider a phosphorous acid product.
AFTER BLOOM APPLICATIONS – GREEN FRUIT THROUGH HARVEST
After flowering, the threat of botrytis infection decreases. Green fruits are not as susceptible to infection. If spray coverage was poor or lacking (including too long an interval) during bloom, infection could result. Also, Anthracnose and Angular Leaf Spot can be problems during warm, wet conditions. As they are often difficult to control once present, a preventative approach may be best, especially if it was present during prior harvests.
AFTER BLOOM RECOMMENDATIONS
Switch + Captan & Oxidate Cabrio + Captan & Oxidate
Abound + Captan & Oxidate Merivon + Captan & Oxidate Elevate + Captan & Oxidate
If necessary to continue coverage beyond two sprays, alternate the application of the above chemicals with an application of Switch, Elevate,Thiram or Captan.
IMPORTANTREMINDER: Refer to the label and your state’s particular recommendations, as states have varying regulations regarding timing, rates and allowances for any spray program. Organic or ORMI listed fungicides: Copper products, Oxidate, BotryStop, Aremicarb, Serenade/Sonata.