Resumo
The subfamily Pentatominae, which includes Euschistus nicaraguensis Rolston, 1972, presents 116 genera and aproximately more than 667 species, reported for the Neotropical region (Grazia et al., 2015). The geographical distribution of this species comprehends diverse countries in Central America, between Panama and Honduras (Rolston, 1974), reporting species of weeds in rice crops (Rolston, 1974; Maes, 1994). In spite of the occurrence reports of E. nicaraguensis, of rice crops in Panama (Rolston, 1974; Maes, 1994; Arismendi, 2002), the presence of this species of Pentatomidae is sporadic and its population reduced. Nevertheless, the colonization, adaptation, and biological development of E. nicaraguensis with the species complex of weeds associated with the agricultural ecosystem of rice, have been least studied. In a similar manner, the interaction between the natural control of this insect species with the population of biological control agents and specifically the eggs parasitoids, is considered as a new association between E. nicaraguensis and Telenomus podisi Ashmead, 1893, defined as a fundamental component in the integral management of the agricultural ecosystem of rice. The present report evidences the importance of this species, as a potential insect-pest, to the extent in which the biotic and abiotic factors, among other variables, promote the increase of E. nicaraguensis population. The identification of the species E. nicaraguensis, was performed by Dr. Jocelia Grazia, from the Department of Zoology, of the Universidade Federal de Rio Grande do Sul, Porto Alegre, Brazil. The samplings were performed in June 2016, in extensive areas of rice production from the IDIAP-38 variety, between the floration and milky stage, in the location of Juan Hombron, province of Cocle, Panama (08°2383N; 08°1390O). The average temperature and relative humidity, in the sampled plots, was 32.8 °C and 82%, respectively. It is highlighted that the average temperature and relative humidity, in this productive region of rice was of 30.0 °C and 80%, for the last five year period (2010-2015). The total number of samples collected randomly was 15, in a crop area of 8 hectares, free from insecticide application. The recollection of eggs and adults of E. nicaraguensis, was performed by means of sweep net and by visual methods. The samples in the complex of host weeds of E. nicaraguensis was performed in areas next to the experimental plot, visually examining and collecting egg masses by square meter m2, totaling 20 samples, in the experimental plots. The collected egg masses were individually placed in glass Petri dishes (9.0 × 1.5 cm), maintaining the internal humidity by the moistened filter paper with distilled water, placed at the base. Later, the egg masses were transferred to controlled climate chambers regulated at 28±1 °C of temperature, 85±3% of relative humidity and 12 hours of photophase, with the purpose of waiting for the emergence of parasitoids. The parasitism rate of eggs, was determined by the formula P [(% = number of eggs parasitized /total number of eggs submitted to parasitism) 100]. The nymphs that hatched were maintained under controlled abiotic conditions, until the adult stage was reached and confirmed that the parasitized eggs belong to E. nicaraguensis.(AU)
Resumo
The dispersion capacity of Trichogramma pretiosum, Riley 1879 in relation to eggs of Anticarsia gemmatalis, Hübner 1818, was studied in soybean, in Piracicaba, State of São Paulo, Brazil. The dispersion capacity of T. pretiosum 24 hours after release, was 8m and 77 m2. The results obtained indicate that the release for controling A. gemmatalis should be performed at 130 points/ha.
Avaliou-se a capacidade de dispersão de Trichogramma pretiosum, Riley 1879, em relação a ovos de Anticarsia gemmatalis, Hübner 1818, na cultura da soja, em Piracicaba, São Paulo. Após 24 horas da liberação dos parasitóides, determinou-se a distância média e a área de dispersão para T. pretiosum, atingindo 8 m e 77 m2, respectivamente. Desta forma, a liberação do parasitóide deve ser feita em 130 pontos/ha, para que toda a àrea seja atingida pelo parasitóide.
Resumo
The dispersion capacity of Trichogramma pretiosum, Riley 1879 in relation to eggs of Anticarsia gemmatalis, Hübner 1818, was studied in soybean, in Piracicaba, State of São Paulo, Brazil. The dispersion capacity of T. pretiosum 24 hours after release, was 8m and 77 m2. The results obtained indicate that the release for controling A. gemmatalis should be performed at 130 points/ha.
Avaliou-se a capacidade de dispersão de Trichogramma pretiosum, Riley 1879, em relação a ovos de Anticarsia gemmatalis, Hübner 1818, na cultura da soja, em Piracicaba, São Paulo. Após 24 horas da liberação dos parasitóides, determinou-se a distância média e a área de dispersão para T. pretiosum, atingindo 8 m e 77 m2, respectivamente. Desta forma, a liberação do parasitóide deve ser feita em 130 pontos/ha, para que toda a àrea seja atingida pelo parasitóide.