Growers can use Captan for Emperor brown spot
Growers can now use Captan to control Emperor brown spot (EBS) on mandarins, after the Australian Pesticides and Veterinary Medicines Authority released a permit on October 5 for its use.
The permit can be viewed here.
Plant pathologist Andrew Miles said Captan controls EBS very effectively – it is up to twice as effective as mancozeb – but it does not control citrus black spot.
“Therefore, Captan and the permit use pattern was developed with autumn/winter use in mind, when fruit need protecting from EBS, but no longer need protecting from citrus black spot.
“The same is the case for iprodione – iprodione controls EBS – but does not control citrus black spot,” Andrew said.
Fungicides effective against citrus black spot are copper, mancozeb and azoxystrobin.
“A combination of these products will be needed to be used during spring/summer to ensure protection against citrus black spot. These fungicides also have efficacy against EBS,” Andrew said.
“I would not suggest trying to use Captan as a spring/summer replacement for mancozeb for the reasons above, but also because spring/summer is not typically the highest EBS infection period. “Rather, save the Captan for autumn/winter when EBS is most commonly a serious problem.”
Andrew said to read the actual permit carefully regarding rates of Captan.
“The rates and volumes in the permit are what have been determined to be optimal for EBS control.”
Andrew said the APVMA has established a temporary MRL of 3 mg/kg for mandarins.
Importing country MRLs are established in China for mandarins only (5 mg/kg), Japan (5 mg/kg) for all citrus fruit, Singapore (15 mg/kg) for all citrus fruit, Taiwan (0.01 mg/kg) for all citrus, and the European Union (0.02 mg/kg) for all citrus fruit.
No MRLs are set in Codex, USA, Hong Kong, Indonesia, Malaysia, Thailand or Canada.
“My understanding is that there is a shortage of Captan in Australia. I would suggest growers place orders now if they wish to have captan available for use in autumn/winter 2017.”
Growers may contact Andrew Miles at firstname.lastname@example.org for any technical advice.