Efeito da luz transmitida através de coberturas coloridas transparentes sobre a mancha-alvo do tomateiro
Target spot, caused by the fungus Corynesposra cassiicola is the most important disease of the aerial parts of the tomato plants in tropical regions. Aiming to find an alternative management for the target spot disease, with low cost and low impact on the environment and easily adopted by small f...
| Autor principal: | Paixão, Anna Carla de Castro |
|---|---|
| Grau: | Dissertação |
| Idioma: | por |
| Publicado em: |
Instituto Nacional de Pesquisas da Amazônia - INPA
2020
|
| Assuntos: | |
| Acesso em linha: |
https://repositorio.inpa.gov.br/handle/1/5229 http://lattes.cnpq.br/1814774834811362 |
| Resumo: |
|---|
|
Target spot, caused by the fungus Corynesposra cassiicola is the most
important disease of the aerial parts of the tomato plants in tropical regions. Aiming to find an
alternative management for the target spot disease, with low cost and low impact on the
environment and easily adopted by small farmers, was evaluated the effect of light
transmitted through transparent covers in different colors on the pathogen, the disease, and on
the tomato production. This study was conducted at the Instituto Nacional de Pesquisa da
Amazônia, Manaus, AM, Brazil. To evaluated the effect on the colonies diameter, mycelial
mass and sporulation of the C. cassiicola, colony discs (0.5 cm in diameter) grown in PDA
were transferred to the centre of polystyrene Petri dish (90 mm in diameter) containing PDA
medium. The cultures were incubated for 10 days under 12 h photoperiod provided by
fluorescent lamps located 50 cm above the plates, and at 25 ± 2 °C, within red, blue, yellow,
green and colorless cellophane envelopes and under no cover. The conidia germination was
also evaluated under these coverages. The effect of LED illumination (80-100 micromol m-2 s-
1) in red, blue, yellow, green, white and in the dark was evaluated on colony diameter and
mycelial mass. The experiments were performed in randomized block design with three
replications. The diameter, mass of the colonies and sporulation were inhibited under orange,
blue e green and conidial germination was not affected. The colonies under green LED had
significantly small diameter than the other treatments and equal diameter of the colonies
without illumination. No difference in mass of the colonies was observed. To evaluate the
effect of sun light transmitted through the colored plastics on the disease and the tomato
productivity, plants were grown in pots (5 L of soil) and, 45 days after sowing, were
inoculated by spraying the leaves with conidial suspension of C. cassiicola (4.75 x 104
conidium.mL-1) to the runoff point. Plants were transferred to individual greenhouses covered
with transparent plastic in colors: red, blue, green, yellow and colorless. The experimental
design was a randomized block with five replications, each plant in a greenhouse was an
experimental unit. The temperature and relative humidity were recorded daily. The spectrum
of the radiation reaching the plants, under each coverage, was also recorded. With the data of
severity and disease index, measured twice weekly, disease progress curves were prepared
and calculated the areas under the disease progress curves. These data were used in the
statistical analysis. Plants in greenhouses received wavenlength 380 a 620 nm had the
highest rates of photosynthesis, stomatal conductance, transpiration, CO2 uptake. Fruit
production was significantly lower in plants under blue, green and violte roofs. |