Susceptibility of Nezara viridula (L.) (Hemiptera: Pentatomidae) egg masses of different size to parasitism by Trissolcus basalis (Woll.) (Hymenoptera: Platygastridae) in the field

LILJESTHRÖM, G.G.; CINGOLANI, M.F.; ROGGIERO, M.

NEOTROPICAL ENTOMOLOGY

ENTOMOLOGICAL SOC BRASIL

Lugar: BRASIL; Año: 2013 p. 1 - 26

1519-566X

Nezara viridula (L.) oviposits e 16 ggs in masses which are parasitized by Trissolcus basalis (Woll.). To analyze if larger egg masses had greater susceptibility to parasitism, we exposed sentinel egg masses to parasitism in the field. After 6-7 days egg masses were taken to the laboratory and kept until parasitoid emergence. We registered the number of eggs per egg mass, the number of emerged hosts, and the number of empty and parasitized eggs. We calculated the proportion of attacked host egg masses (DE), the proportion of parasitized eggs per attacked egg mass (PE), and total parasitism (PI). The total number of egg masses exposed to parasitism was 330. The minimum, mean and maximum egg mass sizes were 25, 75.23 and 111, respectively. DE and PE varied widely between different fields, and they were independent of egg mass size. In 14.15% of all parasitized egg masses we found simultaneous emergence of T. basalis and N. viridula independently of host egg mass size. PE exhibited low variability compared to PI and DE, which were linearly related. PI and DE values from other field studies are consistent with the linear relationship, suggesting that total parasitism is mostly related to the proportion of attacked egg masses. This also suggests that total parasitism is independent of egg mass size, of possible differences in plant species, of T. basalis density, and of strains.