ABSTRACT
Bioactivity of the latex from Parahancornia amapa (Apocynaceae) on the development of Rhodnius nasutus (Hemiptera, Reduviidae, Triatominae) under laboratory conditions. The aim of this study was to verify the effects of the methanolic fraction of the latex from Parahancornia amapa (Apocynaceae) (PALAM) on individuals of the species Rhodnius nasutus Stål (Hemiptera, Triatominae). Many of the insects treated with the substance presented deformities and these may interfere in the feeding and possibly hinder the reproductive capacity. They also presented significant mortality during the molt when compared to the control group, noting a gradual increase in mortality. The treated insects also presented delayed nymphal development (5th instar) and higher adult longevity.
ABSTRACT
Chemical insecticides have been the main way to control synanthropic flies of medical and veterinary importance; however, residuals of these products have become a factor impacting on the environment, as well as the potential toxicological that they may cause damage to humans and domestic animals. Phytochemical screening carried out with the aqueous crude extract of Pouteria sapota (Jacq.) H.E. Moore & Stearn, Sapotaceae, leaves showed that coumarins, reducing sugars, flavonoids and cyanogenic glycosides were its most abundant metabolites. This study evaluated the activity of the crude aqueous extract of this plant on the post-embryonic development of Chrysomya putoria. Larvae treated with 5, 10 and 25% extract showed a decrease in the pupal period and in the newly-hatched larvae to adult period when compared to the control groups. Larvae from the 25% extract group were the lightest (45.8 mg) when compared with the control group (46.5 mg). The larval and newly-hatched larvae to adult stages were more sensitive to the leaf extract from P. sapota (5%) and the treated flies showed the low viability (47.5 and 45.5% respectively). The results demonstrated that topic treatment with P. sapota could alter C. putoria post embryonic development.
ABSTRACT
The aim of this study was to evaluate the effect of the latex from Euphorbia splendens var. hislopii (N.E. Br.) Ursch & Leandri, Euphorbiaceae, on the eggs and engorged larvae of Rhipicephalus (B.) sanguineus (Latreille, 1806) (Acari: Ixodidae). Six aqueous concentrations: 25, 50, 100, 125, 250 and 500 μL/L of the latex of this plant were tested. The control group was tested only with distilled water. The latex of E. splendens var. hislopii presented an LD50 of 18.031 μL/L and LD90 of 84.610 μL/L against the eggs of R. (B.) sanguineus. The larvae of all the groups treated with the latex presented a low survival rate of 0 percent at 25 μL/L, 1 percent at 50 μL/L, 2 percent at 100 μL/L, 3 percent at 125 μL/L, 9 percent at 250 μL/L, 5 percent at 500 μL/L when compared with the control group (91 percent). On day 7 and 14 after the application the latex killed more efficiently the treated groups (25, 50, 100, 125, 250 and 500 μL/L). As from day 21 the latex became less effective for all treatments. Our results clearly show that the aqueous concentration of the latex have a strong effect on tick eggs and larvae suggesting that it could become an important acaricide.
ABSTRACT
Different strains of Bacillus thuringiensis Berliner were proved to be a powerful biologic insecticide against larvae of several insect orders. Due to the epidemiological importance of blowflies of the Chrysomya Robineau-Desvoidy genus in the production of secondary cutaneous myiasis and mechanic transmission of pathogenic agents, the performance of two strains of B. thuringiensis (LFB-FIOCRUZ 907 and LFB-FIOCRUZ 856) was tested against larvae of Chrysomya putoria (Wiedemann). The LFB-FIOCRUZ 907 strain was tested in four different concentrations, added to the diet; the LFB-FIOCRUZ 856 strain was tested in three concentrations. C. putoria larvae showed sensibility to the treatment with the LFB-FIOCRUZ 907 strain at the tested concentrations. The higher concentration presented the best efficiency, causing higher mortality and reducing larval weight and adult emergence more intensely. The LFB-FIOCRUZ 856 strain showed low toxicity, sliglity reducing emergence time of adults at 326 mg/ 25 g concentration and larval weight at 326 mg/ 25 g and 86 mg/ 25 g concentrations.
Diferentes linhagens de Bacillus thuringiensis Berliner têm provado ser poderoso inseticida biológico contra larvas de várias ordens de insetos. Dada a importância epidemiológica das moscas do gênero Chrysomya Robineau-Desvoidy na produção de miíases cutâneas secundárias e transmissão mecânica de agentes patogênicos, avaliou-se a atividade de duas linhagens de B. thuringiensis (LFB-FIOCRUZ 907 e LFB-FIOCRUZ 856) sobre larvas de Chrysomya putoria (Wiedemann). A linhagem LFB-FIOCRUZ 907 foi testada em quatro diferentes concentrações misturadas à dieta e a linhagem LFB-FIOCRUZ 856 em três concentrações. As larvas de C. putoria apresentaram sensibilidade ao tratamento com a linhagem LFB-FIOCRUZ 907, nas concentrações testadas, sendo a concentração mais alta a de maior eficiência, causando maior mortalidade e reduzindo mais intensamente o peso larval e a taxa de emergência dos adultos. A linhagem LFB-FIOCRUZ 856 apresentou toxicidade muito baixa, redizindo ligeiramente a emergência dos adultos na concentração de 326 mg/ 25 g e o peso larval nas concentrações de 326 mg/ 25 g e 86 mg/ 25 g.