Abstract The study was conducted throughout two
seasons (2013 and 2014) at Xmatkuil farm at Merida,
Yucatan, Mexico, to determine the relationships and
the interactions between chemical compositions of
condensed tannins and mimosine and their effects on
the susceptibility of four Leucaena genotypes: Cunningham
and K636 (L. leucocephala), and Nativa and
KX2 (L. leucocephala 9 L. pallida) to the infestation
of the most destructive insect pests; Leucaena Psyllids,
Heteropsylla cubana Crawford, 1914 (Homoptera:
Psyllidae), and Onion thrips, Thrips tabaci Lindeman,
1889 (Thysanoptera: Thripidae). Mimosine showed
insignificant effect on the population of both pests.
However, tannins exhibited a significant effect for
Psyllid population on Nativa and K636, and highly
significant effect on thrips for the same respective
genotypes. The insignificant relationships of tannin effect were found for Cunningham and KX2 to the
population fluctuations of Psyllid and Thrips.