Evaluation of the mango anthracnose prediction models for the control of anthracnose and soft-brown rot in mango.
Oosthuyse S. A.
Author Affiliation: HortResearch SA, P.O. Box 3849, Tzaneen 0850, South Africa.
: 40-47
Abstract : Spray prediction models of Fitzell et al (1984), Dood et al (1991) and Oosthuyse and Schutte (1998) were evaluated for their ability to indicate appropriate dates on which to spray fungicides to control anthracnose (Colletotrichum gloeosporioides [Glomerella cingulata]) and soft brown rot (Nattrassia mangiferae) of mango. Experiments were conducted in 'Kent' and 'Keitt' orchards in Letsitele Valley, South Africa. Prochloraz followed by copper hydroxide was applied when spraying was advocated by the models. Certain trees were not sprayed (controls) and certain trees were sprayed every three weeks with copper hydroxide (standard programme). At harvest, the sampled fruits were washed, waxed and packed in 4 kg cartons. The commercial packline fungicidal treatments (hydro-heating and prochloraz) were either included or excluded. Following packing, the fruits were placed in cold storage at 9.5°C for 28 days and allowed to ripen at 20°C. Best control of anthracnose was achieved following spraying in accordance with the model of Fitzell et al. Best control of soft brown rot was achieved by regular copper spraying. The packline fungicidal treatments had a pronounced effect in reducing the manifestation of both anthracnose and soft brown rot shortly after cold storage. The effects of these treatments were less clear at the time of full ripening. It is concluded that the model of Fitzell et al can be used to schedule spraying for the control of anthracnose, while a model for soft brown rot requires developing.