Binding of several Bacillus thuringiensis delta-endotoxins was studied on histological midgut sections of larvae of coffee leaf miner Perileucoptera coffeella from Brazil and Perileucoptera sp from Madagascar. CryIA(a), CryIA(b), CryIA(c), CryIB, CryIE, and CryllA were tested for binding, and only CrylA(c), CrylB, and CrylE yielded a positive response. The toxins bound to the whole midgut, and the result was identical on both insect populations. The same toxins, to the number of which CrylC was added, were tested on larvae of P. coffeella. CrylA(c) and CrylB were toxic with an LC50 of 1.47 pg/ml and 21.93 pg/ml, respectively. CrylE was not toxic to P. coffeella. CrylA(c) and CrylB were tested for synergistic activity and were shown to act by cumulative effect when delivered to the insect larvae as a mixture.