Incidence of verticillium and plant development in pepper as affected by the bioactivator harpin

Abstract

There is a group of compounds containing proteins that activate responses to stress in plants. One of these proteins is harpin, used for an alternative control of insects and fungi, as well as to increase yield and quality for vegetable production. Harpin was applied to foliage to study effects on induced resistance in pepper (Capsicum annuum L.), cvs. Demre and Yalova Charleston, inoculated with Verticillium dahliae Kleb., a pathogen of pepper. Plants grown in a greenhouse were treated with three applications of harpin at 50 g/100 L in water. Changes in stem dry weight, root dry weight, leaf water content and leaves/plant, total chlorophyll content in leaves, leaf color, and leaf defoliation were determined. Reduction in total leaf chlorophyll content was caused by V. dahliae. Values of total leaf chlorophyll content (cv. Demre 13.10 mg/100 L, cv. Yalova Charleston 12.96 mg/100 L) in plants subjected to +harpin +V. dahliae were higher than for those treated with -harpin +V. dahliae (cv. Demre, 6.76 mg/100 L; cv. Yalova Charleston, 7.05 mg/100 L). Leaves/plant and plant height values were lower for V. dahliae inoculated plants. The results indicate that harpin may induce resistance to V. dahliae in peppers.