DISTRIBUTION OF THIABENDAZOLE RESISTANT COLLETOTRICHUM-MUSAE ISOLATESFROM GUADELOUPE BANANA PLANTATIONS

In Guadeloupe, anthracnose of bananas, caused by Colletotrichum musae, is commonly controlled by postharvest thiabendazole treatments. A sur vey was conducted in 45 banana packing stations of Guadeloupe to deter mine the proportion of isolates that were resistant to thiabendazole. Isolates resistant to thiabendazole concentrations of 1 mu g/ml (R1), 5 mu g/ml (R5), and 50 mu g/ml (R50) were detected. Most of the resist ant isolates were R1 or R5, and of 1,350 isolates, the proportion of r esistant isolates (R1 + R5 + R50) was 23%, ranging from 0 to 70% depen ding on the location. The presence of resistant isolates was correlate d with the exclusive use of benomyl as foliar aerial sprays from 1972 to 1982 to control Sigatoka disease. Isolates resistant to concentrati ons of 1 and 5 mu g/ml were as pathogenic as the susceptible isolates and were not controlled satisfactorily by postharvest thiabendazole tr eatments. Alternative control measures and the importance of resistanc e in terms of anthracnose control in Guadeloupe are discussed.