RESUMO
The impact of commonly used organophosphate (chlorpyrifos, methamidophos), carbamate (carbaryl), and pyrethroid (cypermethrin) insecticides on insect natural enemies was compared with that of a nucleopolyhedrovirus (Baculoviridae) of Spodoptera frugiperda (J. E. Smith) (Lepidoptera Noctuidae) in maize grown in southern Mexico. Analyses of the SELECTV and Koppert Side Effects (IOBC) databases on the impact of synthetic insecticides on arthropod natural enemies were used to predict approximately 75-90% natural enemy mortality after application, whereas the bioinsecticide was predicted to have no effect. Three field trails were performed in mid- and late-whorl stage maize planted during the growing season in Chiapas State, Mexico. Synthetic insecticides were applied at product label recommended rates using a manual knapsack sprayer fitted with a cone nozzle. The biological pesticide was applied at a rate of 3 x 10(12) occlusion bodies (OBs)/ha using identical equipment. Pesticide impacts on arthropods on maize plants were quantified at intervals between 1 and 22 d postapplication. The biological insecticide based on S. frugiperda nucleopolyhedrovirus had no adverse effect on insect natural enemies or other nontarget insect populations. Applications of the carbamate, pyrethroid, and organophosphate insecticides all resulted in reduced abundance of insect natural enemies, but for a relatively short period (8-15 d). Pesticide applications made to late-whorl stage maize resulted in lesser reductions in natural enemy populations than applications made at the mid-whorl stage, probably because of a greater abundance of physical refuges and reduced spray penetration of late-whorl maize.
Assuntos
Baculoviridae/fisiologia , Controle de Insetos/métodos , Insetos/efeitos dos fármacos , Insetos/virologia , Inseticidas/farmacologia , Controle Biológico de Vetores , Zea mays/parasitologia , Animais , Bases de Dados Factuais , Interações Hospedeiro-Parasita , Insetos/crescimento & desenvolvimento , México , Fatores de TempoRESUMO
In the last 10 years, we operated on 231 patients with hemorrhagic portal hypertension. Most of these patients had some form of liver disease. We performed various surgical procedures: 47 conventional shunts with H grafts and terminolateral portacaval shunts with arterialization of the portal stump, 139 selective Warren shunts, and in those patients in whom a selective portasystemic shunt could not be performed for technical reasons, esophagogastric devascularization in the form of the Sugiura procedure. Forty-five patients were treated with the Sugiura procedure as a one stage or two stage procedure. A total of 68 emergency and elective operations were performed. The operative mortality rate for the emergency thoracic operation was 41 percent and for the abdominal operation, 42 percent. The overall operative mortality rate in the emergency group was 41 percent. The incidence of recurrent variceal bleeding and encephalopathy was 0 in the surviving patients. The survival rate at 3 year follow-up was 40 percent. The elective group was made up of 24 patients. Eighteen patients had a two stage procedure and 6 patients had a one stage procedure. The operative mortality rate for the abdominal operation was 11 percent, whereas that for the thoracic operation was 7 percent. The operative mortality rate for the one stage procedure was 16 percent. The overall operative mortality rate in the elective group was 10.8 percent. None of these patients had recurrent variceal bleeding and encephalopathy developed in only one (5 percent). The encephalopathy was easily controlled with medical treatment. The 3 year survival rate was 83 percent. We conclude that the Sugiura procedure is an effective procedure to treat hemorrhagic portal hypertension when a selective shunt cannot be performed.