ACAROS TARSONEMUS - RESISTENCIA A LA CONGELACION

Resumen

Penicillium glaucum y ácaros del género Tarsonemus fueron
colocados en 20 tubos de 100 x 13 mm cerrados con tapones
de algodón, contenientes 5 ml- cada uno de terreno laetrimei.
A la semana, toda la superficie estaba ocupada por el moho y
multitud de ácaros se desplazaban sobre éste. Los 20 tubos
fueron entonces pasados a un congelador a -12° C. Sendos
pares de tubos fueron retirados del congelador a los 30, 60,
120, 180, 240, 300, 360, 420, 480 y 540 minutos y posteriormente
examinados por microscopio con 100 aumentos cada
día por una semana. Sólo se encontraron ác aros vivos en los
tubos congelados por 3 horas o menos. Todos los huevos
congelados por más de 1 hora resultaron muertos. Los ácaros
sobrevivientes de la congelación por 2 ó 3 horas murieron sin
reproducirse en los 3 días siguientes. Ninguna merma se notó
en la vitalidad de P. glaucum. Se comenta el uso de
temperaturas bajas y altas en la lucha contra invasiones de
cultivos fúngicos por ácaros.

SUMMARY
A Penicillium glaucum strain and mites of the genus
Tarsonemus were transferred to 20 cotton plugged tubes, 100
x 13 mm in size, containing each 5 mL of the lactritmel
medium, and were incubated at 2224° C. After a week, the
whole surface of the medium was found occupied by the mold
that was actively foraged by a lot of mites, The 20 tubes were
then put into a freezer at -12° C. Pairs of tubes were retrieved
after 30, 60, 120, 180, 240, 300, 360, 420, 480 and 540
minutes and kept at 22-24° C. Microscopic controls through
the tube walls were repeatedly made on the same' day and '
on every following day for a week. No motile mite was seen in
tubes refrigerated during more than 3 hours. A few mites
survived in tubes refrigerated during 2 or 3 hours, but died
within a week. Several mites survived in tubes refri crated for
an hour or less, that thrived and began o reproduce at the end
of the week. Apparently, no egg resisted a 60' congelation.
The use of temperature variation in the struggle against
fungus-invading mites is discussed..