Agriculture Reference
In-Depth Information
one larval and two nymphal stages to adult)
takes from 2 to 4 weeks, depending upon tem-
perature. Infestations in straw bales and manure
in cucumber beds often spread to the plants; the
mites often hide within the shelter of the unfurl-
ing leaves, and feeding on cucumber plants is
usually restricted to the young foliage and grow-
ing points. Although the mites may deposit eggs
on infested cucumber plants, such sites appear to
be unfavourable for breeding success and, in the
absence of straw within which to overwinter,
mite numbers decline.
common, the mites appear better adapted to sur-
vival as plant feeders than various other related
species.
Tyrophagus putrescentiae
(Schrank)
Mould mite
This small (0.3-0.5mm long), translucent, rela-
tively slender-bodied mite is often reported
infesting mouldy plant material, including
laboratory plant tissue cultures on agar plates.
The mites, along with other species of
Tyrophagus
(and certain related genera: e.g.
Caloglyphus)
also occur in mushroom beds.
They often form pits in the mushroom stipes and
caps, and may also hollow-out the tissue within
the developing buttons; damaged areas usually
become further broken down and moist, follow-
ing associated bacterial decomposition (cf. pits
formed by gunpowder-mites,
Hypogastrura
spp.,
p. 87).
DESCRIPTION
Adult
0.3-0.7 mm long, shiny, whitish, with
very long bristle-like setae on the body (see Fig.
176);
legs
pale brown.
Egg
0.1mm long, oval,
hyaline-whitish, with a sculptured surface.
Tyrophagus neiswanderi
Johnston
&
Bruce
Cucumber mite
This species may also infest cucumber plants;
attacks have also been noted on damaged tissue
of other glasshouse-grown plants, including
chrysanthemum. The mites are similar in appear-
ance to
Tyrophagus longior
(above) but slightly
smaller; also, they possess a characteristic pair
of pigmented, eye-like patches on the
propodosomal shield. Populations of this species
are capable of overwintering in glasshouses in
the absence of straw and, although generally less
Tyrophagus similis
Volgin
Grassland mite
The grassland mite is very similar in both appear-
ance and habits to
Tyrophagus longior
(p. 269),
and is also reported damaging cucumber and cer-
tain other glasshouse-grown plants. The two spe-
cies are frequently confused and detailed
microscopic examination is necessary to distin-
guish between them.
ORDER CRYPTOSTIGMATA (BEETLE MITES)
Family MYCOBATIDAE
Humerobates rostrolamellatus
Grandjean
Cherry beetle mite
algae, lichens and mosses. The mites will also
congregate on split, ripening cherries and plums,
but they do not attack sound fruits. The adult
mites are globular, about 1 mm long, shiny, dark
reddish or blackish (see Fig. 177). When clus-
tered on the bark, they are often thought to be
eggs of some kind of pest; they may also be mis-
taken for bryobia mites, especially the apple &
pear bryobia mite,
Bryobia rubrioculus
(p. 266).
This generally common mite is often recorded
in considerable numbers on the trunks and
branches of trees, including unsprayed fruit trees
and ornamentals, where they feed mainly on
