Within-leaf differences in nutritive value and defence mechanism in chrysanthemum to the two-spotted spider mite (Tetranychus urticae)

Some chrysanthemum leaf characteristics were evaluated to determine their importance as nutrition for, and as factors of resistance to, Tetranychus urticae Koch. These characteristics were: leaf age and chemical composition, content of phenolic substances, total nitrogen, and soluble protein. Mite density was lower on young leaves than on mature ones. Young leaves appear to be protected against T. urticae by a higher concentration of mono- and polyphenols, although they contained higher levels of nutrients than mature ones. After mite infestation, the most valuable young leaves were also the best-protected leaves on their shoots. Content of phenolic compounds increased only in young chrysanthemum leaves after mite feeding.