THE EFFECT OF WATER STRESS AND LEAFLET SIZE ON THE DENSITY OF TRICHOMES AND THE RESISTANCE TO COLORADO POTATO BEETLE LARVAE (LEPTINOTARSA DECEMLINEATA[SAY]) INSOLANUM BERTHAULTIIHAWKES

Abstract Solanum berthaultiiHawkes bears trichomes reportedly providing resistance to insects. Results indicated that the density of types A and B trichomes was linearly related to the inverse of the leaflet area. The number of trichomes on the adaxial and on the abaxial surface of terminal leaflets was not affected by two levels of water stress or by growing conditions in the greenhouse or the field. The leaflets of the water-stressed plants were generally smaller and, consequently, the density of trichomes higher. The survival of first-instar Colorado potato beetle larvae was similar onS.berthaultiigrown under varying drought conditions and on leaves from field-grown plants bearing different densities of trichomes.