The next line of defense is regular scouting of the plants
and knowing exactly what the early signs of damage are.
Mites need to be controlled before they get to the stage
when they spin vast quantities of super-fine webbing which
is impervious to spray control compounds and provides an
unsightly home for more rapid population growth.
Early Signs and Symptoms of Mite Infestations
Inexperienced growers often miss the early, and sometimes
even the later stages, of a mite infestation. This is because
the adults are tiny and difficult to see, thus many growers
who are new to mite infestations will miss these signs until
the damage becomes severe. Those who have battled mites
before become well-accustomed to the first signs, which
include small white or yellow flecking, often on older foliage.
This occurs when mites feed on the leaf epidermis, sucking
out cell contents. As the mite population grows, the entire
leaf becomes stippled or light in color and may eventually
develop a bronze appearance under heavy infestations. Mites
then produce the characteristic fine webbing, slung between
leaves, over buds and flowers, or the growing points of plants.
Mites use this webbing as protection from predators. If left
untreated, mites will eventually weaken plants to the point of
defoliation. Even milder infestations will significantly reduce
yields, quality, and overall productivity.
" An integrated
approach
is often required since there is no one
easy fix. Greenhouse growers have had
some success in retarding population
growth via misting, fogging, or damping
down to increase humidity levels.”
Control Options for Mites
The control of mites has become increasingly difficult over
recent years, largely due to the development of pesticide
resistance, which occurs rapidly in these pests. It’s also likely
there have been other genetic changes in mite populations
that have led to their persistence. There is a range of cultural,
environmental, and natural control options for long-term
successful control. An integrated approach is often required
since there is no one easy fix. Greenhouse growers have had
some success in retarding population growth via misting,
fogging, or damping down to increase humidity levels.
However, increasing humidity to levels that deter mites
opens the door for fungal diseases if taken too far.
Weekly scouting for the initial signs of foliage damage and
mites on leaf undersides should become habit. When mites
are found, there are a few different courses of action that may
be taken. These include insecticide sprays,