Abstract The corn cropping system can influence the natural enemy identity and the number of Spodoptera frugiperda J.E. Smith, 1797 (Lepidoptera: Noctuidae) individuals infesting the cartridge, ear and stem of this plant. The objectives were to identify the S. frugiperda natural enemies and differences in the number of individuals infesting the cartridge, ear and stem of corn plants under conventional and organic cropping systems, in Brazil after an initial collection of adult males through semiochemical traps. We also evaluated key morphometrical parameters of the larva and factors contributing with the viability of S. frugiperda. A total of 16 and 136 adult males was trapped, and 1,124 and 1,112 larvae was recovered from conventional and organic systems with 4.7 and 6.7% of them parasitized by dipteran and hymenopteran, respectively. Most of the parasitoids recovered had occurrence in both cropping systems, except Cremastinae and Ophion flavidus Brullé, 1846 (Hymenoptera: Ichneumonidae), which were recorded only in organic and Campoletis sp. (Hymenoptera: Ichneumonidae) only in conventional corns. The number of parasitoids recovered was similar in corn plant samples between both cropping systems. A total of 152 and 31 larvae was recovered from corn ears under conventional and organic systems, respectively. Doru luteipes (Scudder, 1876) (Dermaptera: Forficulidae) was recovered from all samples under conventional system. The larva length was overall similar between cropping systems. Parasitism by dipteran and hymenopteran, infection by microorganisms, larva mortality by undetermined causes, and differences in viability of S. frugiperda stages were factors contributing with the supression of this pest. The new associations and parasitoids reported represent possibilities of expanding the biological control strategies to manage S. frugiperda in corn crops.

Aleiodes Wesmael é o gênero mais comum e diverso de Rogadinae, desenvolvendo-se como endoparasitóide cenobionte em larvas de Lepidoptera, resultando na mumificação de seu hospedeiro. Aleiodes japi sp. nov. é descrita e ilustrada. Os espécimes tipo da nova espécie foram obtidos de larvas de Physocleora grosica e Ischnopteris sp. (Lepidoptera, Geometridae, Ennominae). As larvas hospedeiras foram coletadas sobre Alchornea triplinervia (Euphorbiaceae) na Reserva Biológica Municipal da Serra do Japi, Jundiaí, Estado de São Paulo, Brasil. Esta é a segunda espécie do grupo circumscriptus/gastritor descrita para o Brasil.

Aleiodes Wesmael is the most diverse rogadine genus, with koinobiont endoparasitic development in Lepidoptera caterpillars resulting in mummification of the host remains. Aleiodes japi sp. nov. is described and illustrated. Type specimens of the new species were reared from Physocleora grosica and Ischnopteris sp. (Lepidoptera, Geometridae, Ennominae) larvae. Host larvae were collected on Alchornea triplinervia (Euphorbiaceae) at the Reserva Biológica Municipal da Serra do Japi, Jundiaí, São Paulo, Brazil. This is the second species of circumscriptus/gastritror group described from Brazil.