ABSTRACT
A espécie Sitobion graminis Takahashi, 1950 (Hemiptera, Aphididae) foi detectada no Brasil pela primeira vez em 1998, em Curitiba, PR, associada às gramíneas Erianthus sp., Calamagrotis sp. e Paspalum urvilei. Os espécimes coletados e criados apresentavam uma notável variacão intrapopulacional no comprimento do corpo e apêndices e na esclerotinizacão dorso-abdominal. Esta espécie é reconhecida na Malásia, Nova Guiné, India, Filipinas e Africa, colonizando várias espécies de Poaceae. S. graminis diferencia-se das demais espécies do gênero Sitobion associadas a gramíneas no Brasil, por apresentar a cauda e sifúnculos negros e o último segmento rostral constrito na base. Dados de biologia foram obtidos em laboratório, onde ninfas recém-nascidas criadas sobre as inflorescências das gramíneas hospedeiras, desenvolveram-se em quatro instares. A duracão média do estágio ninfal foi de 11,4 dias, com mortalidade de 36,5por cento. O período médio de pré-larviposicão foi de 1,8 dias; longevidade média das fêmeas de 25,2 dias; fecundidade média de 18,7 ninfas/fêmea, variando de 2 a 41 ninfas/fêmea.
Subject(s)
Animals , Male , Female , Aphids/anatomy & histology , Aphids/classification , Biology , BrazilABSTRACT
Adults and larvae of coccinellids were observed feeding on populations of the giant conifer aphids Cinara spp. on Pinus spp., in Southern Brazil. The objective of this research is to evaluate the consumption capacity of Cycloneda sanguinea (Linnaeus, 1763) and Hippodamia convergens Guérin-Méneville, 1842 (Coleoptera, Coccinellidae) on these aphid species, in order to obtain information for biological control programs. Ten larvae of each predator species were fed with aphids of small size (nymphs of 1st and 2nd instars), and 10 with aphids of medium size (nymphs of 3rd and 4th instars), maintained under 15°C, 20°C and 25°C, 12 h photophase and 70 ± 10 percent relative humidity. The aphids were counted every 24 hours, replacing those that were consumed. The total consumption of Cinara by the larvae of C. sanguinea was not statistically different at the three temperatures: 325.5; 322.2 and 324.8 of small aphids and 121.3; 140.4 and 109.9 of medium ones, respectively at 15°C, 20°C and 25°C. The consumption by H. convergens was higher than by C. sanguinea and increased noticeably with temperature: 444 aphids at 15°C; 491.3 at 20°C and 513.3 at 25°C, considering the small aphids, and 187.1; 205.1 and 216.6 of medium aphids at the three temperatures. The small aphids weigh about half as much as medium ones and were preferred by all larval instars probably because they are easier to manipulate than the large ones. Both predators, especially the 4th instar larvae, showed high consumption capacity on the Cinara nymphs at all temperatures and can be regarded as promising biological control agents.
Subject(s)
Animals , Aphids/physiology , Coleoptera/physiology , Pest Control, Biological , Pinus/parasitology , Host-Parasite InteractionsABSTRACT
The giant conifer aphids Cinara pinivora (Wilson, 1919) and Cinara atlantica (Wilson, 1919) (Hemiptera, Aphididae) have been observed attacking Pinus spp. in Southern and Southeastern Brazil. The coccinellids, on the other hand, were found feeding on these aphids in the field, which can be regarded as potential biological control agents. The biological cycle and mortality rate of larvae of Cycloneda sanguinea (Linnaeus, 1763) and Hippodamia convergens Guérin-Méneville, 1842 (Coleoptera, Coccinellidae) were evaluated using twenty larvae of each predator species fed with nymphs of Cinara. The vials with the insects were kept under 15 ºC, 20 ºC and 25 ºC, with 12h photophase and 70 ± 10 percent relative humidity. The consumption was evaluated every 24 hours and the nymphs replaced. For C. sanguinea, the egg incubation time was 10.5, 5.0 and 4.0 days; the average larval development period was 33.3, 15.8 and 8.6 days and the larval mortality rate 20 percent,0 percent and 15 percent, respectively at 15 ºC, 20 ºC and 25 ºC. For H. convergens, the larval development time was 41.9, 19.3 and 10.9 days at 15 ºC, 20 ºC and 25 ºC, respectively. The larval mortality rate was 35 percent, 15 percent and 0 percent under the three temperatures. Both species developed adequately when fed nymphs of Cinara, however, C. sanguinea performed better than H. convergens, even at 15 ºC, at which temperature the biological cycles of the coccinellids are prolonged, but the temperature is favorable for the development of Cinara populations in the field.
Subject(s)
Aphids , Coleoptera , Pest Control, BiologicalABSTRACT
The lacewings are very voracious predators of aphids. The objective of this research was to evaluate the occurrence of adult chrysopids in areas of Pinus reforestation where the giant conifer aphid Cinara spp. (Hemiptera: Aphididae) is causing severe damages. A total of 47 specimens were collected during one year and identified as: Chrysoperla externa (Hagen, 1861), Leucochrysa (Nodita) intermedia (Scheneir, 1851) and Leucochrysa (Nodita) vieirana (Navás, 1913). The captures in the area where the plants were one year old represented about 75 percent of the adults probably due to the high Cinara infestation on the trees in this area. The chrysopids were recorded mostly during the summer, possibly influenced by temperature.