Endosulfan resistance in the coffee berry borer Hypothenemus hampei (Ferrari) was discovered in New Caledonia after six years of lindane and 12 years of endosulfan biannual applications. The direct spray technique was used to study cross resistance with lindane and to monitor resistance to both pesticides in 15 regions of New Caledonia. An easier monitoring technique was developed for early detection by field laboratories. Results from this simple method, using twice the LC99 of endosulfan to susceptibles (400 ppm) showed a comparable distribution of resistance to the direct spray method in five regions where resistance was detected. The percentage of surveyed fields containing resistant insects in these areas was: Poindimié, 100%, Ponérihouen, 97%; Touho, 63%; Houailou, 10%; Hienghène, 6%. Resistant insects were significantly more frequent in the new sunny fields than in older shady plantations (P<0.05), and fields with endosulfan used in the preceding year (P<0.001). The possible reasons for the observed distribution of resistance are discussed. © 1990, Cambridge University Press. All rights reserved.
