Mango stem-end rot (Botryosphaeria dothidea) disease control by partial-pressure infiltration of fungicides

The in vitro efficacy of several fungicides against Botryosphaeria dothidea (syn. Dothiorella dominicana) and their in vivo efficacy in controlling mango cv. Kensington Pride stem-end rot on partial-pressure infiltration v. dip treatment of green mature fruit was evaluated. In vitro sensitivity of B. dothidea to Benlate (benomyl), Sportak (prochloraz) and Scala (pyrimethanil) at 10 dilutions of the manufacturer's recommended rate was first determined at typical cold (13degreesC) and shelf (23degreesC) storage temperatures. The effectiveness of partial-pressure infiltration and conventional hot (52degreesC) or cold (26degreesC) dipping of fruit after harvest was then evaluated using the commercially recommended rate for each fungicide. In vitro, Benlate and Sportak prevented the growth of B. dothidea at both storage temperatures and at all concentrations, while Scala partially controlled growth of the pathogen. Benlate was the most effective fungicide for stem-end rot control. Sportak and Scala resulted in stem-end rot control when applied by partial-pressure infiltration, but not as dips. Partial-pressure infiltration holds promise for enhancing the efficacy of otherwise less effective but alternative fungicides for control of stem-end rot diseases.

First report of Tubercularia lateritia as the causal agent of canker on macadamia

Tubercularia lateritia was recorded for the first time as causing canker, characterised by a sunken centre surrounded by galls or callus, on macadamia. The fungus was isolated and inoculated on young macadamia trees in the glasshouse and produced characteristic disease symptoms from which the fungus was successfully reisolated.