In vitro fungicide testing for control of avocado fruit rots
Avocado fruit rots are most commonly caused by five fungi Colletotrichum acutatum C gloeosporioides Botryosphaeria parva B dothidea and Phomopsis sp These rots are controlled by applying copper fungicides in the field on eight occasions during the season Alternatives to standard copper fungicides were screened in the laboratory against these five pathogens for inhibition of spore germination and mycelial growth In total seven fungicides were tested (boscalid boscalid/pyraclostrobin three formulations of copper hydroxide copper hydroxosulphate and dithianon) The effective concentration at which 50 of spore germination or mycelial growth was inhibited (EC50) was calculated for each fungicide The EC50 values for spore germination were lowest for boscalid/pyraclostrobin and dithianon and were le;185 g/ml against all five test fungi For boscalid/pyraclostrobin all EC50 values were le;7 g/ml Copper formulations effectively inhibited spore germination by 50 at concentrations ranging from 01 g/ml to 141 g/ml but were less effective against mycelial growth