Does native bromeliads represent important breeding sites for Aedes aegypti (L.) (Diptera: Culicidae) in urbanized areas?

This study evaluates the importance of native bromeliads growing on rocky outcrops interspersed with urbanized areas as breeding sites for the Aedes aegypti (L.) in Vitória, state of Espírito Santo, Brazil. Oviposition traps were installed in backyards of houses in two separate zones. In the first zone houses were up to 50 m away from the rocky outcrops, while in the second zone they were at least at 200 m from the rocky outcrops. Aedes aegypti was significantly more abundant in the latter zone. The finding was that rocky outcrops with native bromeliads, even with the greater availability of potential breeding sites, do not play an important role as breeding sites for A. aegypti. This conclusion supports the hypothesis that the macrobiota of native bromeliads plays an important role in the natural control of A. aegypti. Besides, the interspecific competition between species of mosquitoes and the attractiveness of bromeliads could also be important factors.

Alternativas para el control de hongos postcosecha en naranjas valencia (Citrus sinensis) / Alternatives for postharvest fungi control of valencia oranges (Citrus sinensis)

La finalidad de este estudio fue conocer la efectividad del hongo Trichoderma harzianum, el quitosano y el bicarbonato de sodio en el control de hongos postcosecha en naranjas valencia. Se utilizaron 120 naranjas valencia, usando 24 naranjas por grupo. Cada uno de estos grupos fue sumergido en uno de los siguientes tratamientos: cultivo del hongo T. harzianum (1x10(9) esporas/mL.), quitosano (2%), bicarbonato de sodio (1%) y agua común (testigo); las 24 naranjas restantes no recibieron tratamiento y fueron consideradas como grupo control. Las naranjas fueron posteriormente almacenadas en envases de plástico con papel absorbente durante 14 días, a 27ºC, para determinar el crecimiento de hongos u otra alteración. Se desarrollaron 4 especies de hongos en el grupo control: Penicillium digitatum (80%), Penicillium italicum (10%), Colletotrichum gloeosporioides (5%) y Cladosporium herbarum (5%), con diferencias significativas entre hongos (p<0,05). En el testigo, sólo se encontró P. digitatum en un 29,1% y en los tratamientos con quitosano y bicarbonato de sodio sólo se presentaron pudriciones no fúngicas en un 20,8% y 41,6% respectivamente. Las tratadas con T. harzianum no presentaron hongos, ni ninguna alteración en 14 días de tratamiento, existiendo diferencias significativas (p<0,05) en cuanto a la presencia de hongo o alteración por tratamiento. Esto sugiere que es posible controlar hongos postcosecha de las naranjas con el hongo T. harzianum.

The purpose of this study was to establish the effectiveness of the fungus Trichoderma harzianum, chitosane and sodium bicarbonate for postharvest fungus control of valencia oranges. We used 120 valencia oranges using 24 oranges per group. Each of the groups was immersed in one of the following treatments: T. harzianum cultures (1x10(9) spores/mL), chitosane (2%), sodium bicarbonate (1%) and running water (witness); the remaining 24 oranges did not receive any treatment, and were considered as the control group. The oranges were later stored in plastic containers with absorbent paper during 14 days at 27ºC to determine fungus growth or any other alteration. Four fungi species developed in the control group: Penicillium digitatum (80%), Penicillium italicum (10%), Colletotrichum gloeosporioides (5%) and Cladosporium herbarum (5%) with significant differences among fungi (p<0.05). In the witness group there was only P. digitatum (29.1%), and in the groups treated with chitosane and sodium bicarbonate there was only non-fungal rotting in 20.8% and 41.6%, respectively. The oranges treated with T. harzianum did not present fungi or any other alteration during the 14 treatment days, and there were significant differences (p<0.05) as to presence of fungi or alterations during treatment. This suggests that it is possible to perform a post harvest control of oranges with the T. harzianum fungus.