24 research outputs found
Selectivity of Pesticides used in Integrated Apple Production to the Lacewing, Chrysoperla externa
This research aimed to assess the toxicity of the pesticides abamectin 18 CE (0.02 g a.i. L-1), carbaryl 480 SC (1.73 g a.i. L-1), sulfur 800 GrDA (4.8 g a.i. L-1), fenitrothion 500 CE (0.75 g a.i. L-1), methidathion 400 CE (0.4 g a.i. L-1), and trichlorfon 500 SC (1.5 g a.i. L-1) as applied in integrated apple production in Brazil on the survival, oviposition capacity, and egg viability of the lacewing, Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) from Bento Gonçalves and Vacaria, Rio Grande do Sul State, Brazil. An attempt was made to study morphological changes caused by some of these chemicals, by means of ultrastructural analysis, using a scanning electronic microscope. Carbaryl, fenitrothion, and methidathion caused 100% adult mortality for both populations, avoiding evaluation of pesticides' effects on predator reproductive parameters. Abamectin and sulfur also affected the survival of these individuals with mortality rates of 10% and 6.7%, respectively, for adults from Bento Gonçalves, and were harmless to those from Vacaria at the end of evaluation. Trichlorfon was also harmless to adults from both populations. No compound reduced oviposition capacity. C. externa from Vacaria presented higher reproductive potential than those from Bento Gonçalves. In relation to egg viability, sulfur was the most damaging compound to both populations of C. externa. Ultrastructural analyses showed morphological changes in the micropyle and the chorion of eggs laid by C. externa treated with either abamectin or sulfur. The treatment may have influenced the fertilization of C. externa eggs and embryonic development. Sulfur was responsible for malformations in the end region of the abdomen and genitals of treated females. When applied to adults, abamectin, sulfur, and trichlorfon were harmless, while carbaryl, fenitrothion, and methidathion were harmful, according to the IOBC classification
An update of the Worldwide Integrated Assessment (WIA) on systemic insecticides. Part 2: impacts on organisms and ecosystems
New information on the lethal and sublethal effects of neonicotinoids and fipronil on organisms is presented in this review, complementing the previous WIA in 2015. The high toxicity of these systemic insecticides to invertebrates has been confirmed and expanded to include more species and compounds. Most of the recent research has focused on bees and the sublethal and ecological impacts these insecticides have on pollinators. Toxic effects on other invertebrate taxa also covered predatory and parasitoid natural enemies and aquatic arthropods. Little, while not much new information has been gathered on soil organisms. The impact on marine coastal ecosystems is still largely uncharted. The chronic lethality of neonicotinoids to insects and crustaceans, and the strengthened evidence that these chemicals also impair the immune system and reproduction, highlights the dangers of this particular insecticidal classneonicotinoids and fipronil. , withContinued large scale – mostly prophylactic – use of these persistent organochlorine pesticides has the potential to greatly decreasecompletely eliminate populations of arthropods in both terrestrial and aquatic environments. Sublethal effects on fish, reptiles, frogs, birds and mammals are also reported, showing a better understanding of the mechanisms of toxicity of these insecticides in vertebrates, and their deleterious impacts on growth, reproduction and neurobehaviour of most of the species tested. This review concludes with a summary of impacts on the ecosystem services and functioning, particularly on pollination, soil biota and aquatic invertebrate communities, thus reinforcing the previous WIA conclusions (van der Sluijs et al. 2015)
<it>Parasitylenchus bifurcatus</it> n. sp. (Tylenchida: Allantonematidae) parasitizing <it>Harmonia axyridis</it> (Coleoptera: Coccinellidae)
<p>Abstract</p> <p>Background</p> <p>The harlequin ladybird, <it>Harmonia axyridis</it> Pallas (Coleoptera: Coccinellidae) is native to central and eastern Asia and was purposely introduced into Europe to control aphids. While it proved to be a good biological control agent, its rapid spread and buildup of large populations made it a nuisance, since it overwinters in homes, emits unpleasant odors, stains fabrics, occasionally bites humans and feeds on apples, pears and grapes. Aside from the above, the ravenous appetite of <it>H. axyridis</it> results in their consumption of harmless native insects, including even other ladybird beetles. A study of the natural enemies of <it>H. axyridis</it> in Denmark revealed the presence of nematodes. The present study describes this nematode parasite and discusses aspects of its development and ecology.</p> <p>Methods</p> <p>Adult harlequin ladybird beetles were collected from March to November from four localities in Copenhagen on different plant species. In addition, groups of last-instar larvae and pupae (n = 50) were examined for the presence of nematodes. Living and recently dead nematodes were removed from adult <it>H. axyridis</it> in 0.5% saline solution, the nematodes were then heat killed (at 75C), fixed in 5% formalin and transferred to glycerin on slides for further examination and measurements.</p> <p>Results</p> <p>A new species of Allantonematidae (Tylenchida), <it>Parasitylenchus bifurcatus</it> n. sp., is described from adults of the harlequin ladybird, <it>Harmonia axyridis</it> in Denmark. The new species is characterized by a straight stylet lacking basal thickenings, a bursa and a forked tail tip in the vermiform (infective) females and juvenile males. The new species is compared with <it>P. coccinellinae</it> previously described from ladybird beetles in France. Parasitism resulted in depletion of the fat body and partial or complete atrophy of the reproductive organs of the beetles. Infections occurred throughout the year with rates of parasitism reaching up to 35%. The rate increased to 60% when field-collected ladybirds were incubated for 30 days in the laboratory.</p> <p>Conclusions</p> <p>The production of subsequent generations within the host with only the fertilized females (not the males) leaving the hosts and the absence of parasitism of the larvae and pupae is an impressive developmental modification of <it>P. bifurcatus</it>. It is proposed that the vermiform (infective) females pass from one adult host to another when the beetles are hibernating or in assemblage groups. Rates of parasitism show that <it>P. bifurcatus</it> could be a significant biological control agent of <it>H. axyridis</it>.</p
Influence of seasonality and climate on captures of wood-boring Coleoptera (Bostrichidae and Curculionidae (Scolytinae and Platypodinae)) using ethanol-baited traps in a seasonal tropical forest of northern Thailand
The impact of aphicide drenches on Micromus tasmaniae (Walker) (Neuroptera: Hemerobiidae) and the implications for pest control in lettuce crops
Curativos para tratamento de feridas operatórias abdominais: uma revisão sistemática
O objetivo deste estudo foi identificar o curativo prevalente para o tratamento das feridas operatórias abdominaiscom complicações, visando buscar evidências que possam subsidiar o desenvolvimento de um protocolo institucionalpara o tratamento das mesmas. Metodologia: desenvolveu-se uma Revisão Sistemática, que teve como perguntanorteadora “Qual é o curativo prevalente no tratamento dos pacientes com complicações de feridas operatórias(FOs) abdominais?” Foram utilizados MeSH para buscar o maior número de estudos possíveis em sete base dedados eletrônicas. Resultados: a busca nas bases de dados resultou em 6.107 artigos que, após serem submetidos aostestes de relevância, resultaram em 33 estudos que compuseram a amostra. O curativo a VAC foi o mais indicadopara tratar FOs abdominais que tiveram complicações. Conclusão: sugerem-se novas pesquisas para que se possaavaliar a efetividade e viabilidade da terapia VAC na nossa realidade