Mary Helen Ferguson – Louisiana State University Agricultural Center
Botrytis spp. fungi cause diseases that affect several small fruit crops, including strawberries, bunch grapes, blackberries, raspberries, and blueberries. Some populations of Botrytis spp. have developed resistance to a number of fungicides formerly effective against them. It is important for growers and Extension faculty members to know what fungicides are likely to remain effective so that gray mold is managed effectively and money is not wasted on ineffective pesticide applications.
The Southern Region Small Fruit Consortium (SRSFC) allocated $5000 for fungicide resistance testing in Botrytis spp. through Clemson’s Molecular Plant Pathogen Detection (MPPD) Lab (864-646-2133). This laboratory tests Botrytis isolates for resistance to the following active ingredients: thiophanate methyl (FRAC 1); iprodione (FRAC 2); boscalid, fluopyram, isofetamid, and penthiopyrad (FRAC 7); cyprodinil (FRAC 9); pyraclostrobin (FRAC 11); fludioxonil (FRAC 12); and fenhexamid (FRAC 17).
To submit samples and have the cost covered, each SRSFC member state must request funds and set up an account with the MPPD. Extension agents and growers interested in submitting samples should contact a SRSFC steering committee member (administrator or faculty member) from their state for the account number to use when submitting a sample. Once the funds for a state are used up, samples can be submitted at the normal cost ($80 for SC, $100 for other states).
Botrytis Fungicide Resistance Testing Form and Collection Guidelines are available on Clemson’s MPPD Lab website.