Parasitism of Diatraea saccharalis (Lepidoptera: Pyralidae) eggs by Trichogramma exiguum (Hymenoptera:Trichogrammatidae): Influence of Zea mays leaf pubescence

The effect of maize foliar pubescence on the oviposition of D. saccharalis and egg parasitism by T. exiguum was assessed. Sixty-eight maize cultivars were classified by hair density on the upper leaf face into “high pubescent “ (HP) and “low pubescent” (LP) classes. No differences in total egg masses/ plant and total eggs/plant were found between HP and LP cultivars. More egg masses/plant and eggs/ plant were found in the lower face of leaves of HP cultivars, but no differences were found between leaf faces in LP cultivars. The percentages of parasitised egg masses and eggs were higher on LP cultivars, and the egg masses and eggs on the lower leaf face showed a higher level of parasitism than the ones on the upper face. The results suggest the advantage of incorporating low hair density as a trait for the development of resistant maize cultivars, since this character would increase the oviposition activity of T. exiguum.