Effect of commercial proteinase inhibitors on the life cycle of the coffee berry borer, Hypothenemus hampei (Ferrari), in artificial diet

Abstract

Three trypsin inhibitors (T9003, T9253, T9378), two Chitinases (C1650, C6137), and a chymotrypsin-trypsin inhibitor (T9777) in two doses (1.0 and 0.1%) were evaluated on a random design with a factorial arrangement of 6x2+2. Each treatment consists of 200 eggs of Hypothenemus hampei. The experimental unit was four eggs placed in 1 cm' of an artificial diet with 50 repetitions per treatment. The evaluations were made from the eggs hatch until adult emergence (T=28 °C and R.H.= 75%). With the T9003, T9253 and T9378 (1.0 %), the insect life cycle had a mean half-life ± SD) of 20.81 ± 1.64, 21.71 ± 1.93 and 22.57 ± 1.35 days and the mean mortality was 47.69, 57.66 and 60.66%, respectively; for the con­centration 0.1% was 21.75 ± 2.11, 23.60 ± 2.59 and 22.23 ± 1.85 days, and the mean mortality was 37.50, 43.0 and 39.33%, respec­tively. The control allowed the complete life cycle duration, 22.08 ± 1.55 days, and mean mortality of 10.50%. With the chitinases (1.0%), the mean half-life was 20.36 ± 2.51 and 20.37 ± 2.98 days, the mean mortality was 43.25 and 51.40%; for 0.1% the mean half-life was 20.62 ± 2.03 and 20.25 ± 2.33 days, and the mortality was 42.57 and 44.84%, respec­tively. With the chymotrypsin-trypsin inhibi­tor in 1.0%, the mean half-life was 20.92 ± 2.44 days and the mean mortality was 33.29%; for 0.1% the mean half-life was 20.89 ± 3.07 days and the mean mortality was 25.61%. The control for the two latter treatments exhibited a complete life cycle duration of 22.21 ± 1.47 days and the mean mortality was 15.43%. In relation to the insect life cycle, there were not significant differences among treatments and the control; in contrast, the mean mortal­ity showed differences, however, this mortal­ity was less than 65%. It is important to con­tinue testing other commercial inhibitors.