Sinfilose crítica no município de Cajuri, Minas Gerais

Resumo

The production of citrus seedlings is the main agricultural crop of Cajuri county. This county ranks first among those producing citrus seedlings in the State of Minas Gerais, with 39. 3% of the citrus orchardists.

Until November 20, 1970, only 33 citrus orchardists sowed rangpur lime seeds (Citrus limonia Osbeck), the others quit the crop as a non-economic undertaking due the attack of the soil pest Hanseniella sp. (Symphyla, Scutigerellidae). Of those sowing rangpur lime, 19 lost their seed-beds, about 124.2 Kg. of seed, as a result of the injuries by this symphylan to the seeds. The economic damages were reported to be about three times the income received from citrus seedling sales during the agricultural year 1969/1970.

The main features of the citrus simphyliasis were reported as follows:

1 - Occurrence of scattered gaps of seedlings, between plantings and between rows, that increase progressively in area, due the continued attack of fitofagous symphylan.

2 - Primarily the leaves became light green or yellowish in color and from the top to the bottom, the lateral margin rolled upward toward the main vein. The plantings were poorlyanchoredinthe soiland could be pushed over easely.

3 - Later on, the wilted leaves and shrunken stems characterized the progressive and irrevocable decline of the seedlings.

The symptoms are atributable towater and mineralde- ficiences, since the seedlings are unable to absort them, as result of the scanty root system.

Keys of family and characteristics of the families and the genus Hanseniella are presented.