Gloxinia (Sinningia)
Plant Health Problems
Diseases caused by Viruses:
Spotted wilt, virus, Impatiens Necrotic Spot Virus (INSV).
Symptoms can appear as a yellow line pattern on the leaves, as yellow ringspots
or blotches, or as necrotic brown spots. Young plants may turn brown from the
center out. This disease is transmitted by the western flower thrips.
Control of this disease is focused on prevention since once plants are
infected, they cannot be cured. It is important to eliminate and remove
infected plants as soon as they are recognized and to eliminate other
symptomatic plants since this virus has a very broad host range. It is also
critical to manage the thrips population.
Diseases caused by Nematodes:
Foliar nematodes, Aphelenchoides spp.
Black to brown V-shaped areas appear in the lower leaves, showing first at the
bottom of the plant and working their way up the plant. These spots are bounded
by veins at first but eventually may involve the entire leaf. The trouble is
caused by microscopic eelworms which live in and destroy the leaf tissue. They
come out of the leaf when the leaf surface and stems are wet with rain, dew, or
syringing, and swim up the stem to infect the leaves above. The nematodes
overwinter in plant debris in the soil.
This disease can be minimized by reducing leaf moisture and removal of infected
tissues, debris, or plants.
Insect Problems:
Aphids, Myzus persicae and Neomyzus circumflexus.
The green peach and crescent-marked lily aphids attack gloxinia. Insecticidal
soap or ultrafine horticultural oil, which are among the compounds registered
for use against this pest in Connecticut, can be used for control if it is
needed. Imidacloprid, applied as a soil drench, will provide season-long
systemic control. Consult the labels for dosage rates and safety precautions.
Cyclamen mite, Phytonemus pallidus.
This translucent, microscopic mite often infests the new leaf and blossom buds,
and can proliferate on spent blossoms. Characteristic injury includes dwarfed,
thickened and wrinkled leaves. Infested plants do not bloom, or blossoms may be
misshapen. Cyclamen mite is not easily controlled when mature plants are badly
infested: effective miticides are not available to homeowners, so a commercial
applicator may be required for effective miticide applications. Effective
restricted use products include abamectin, dicofol, and endosulfan. Consult the
labels for dosage rates and safety precautions.
Thrips, Frankliniella spp.
These small whitish insects feed on pollen and flower petals. The adults may
have wings equal or greater than the body length. The four wings are veinless
with long hairs on the leading and trailing edge. Plants are damaged when
thrips pierce plant tissue and suck plant sap. They quickly scurry into hiding
when the plant is touched or they sense changes in the environment. Thrips are
readily detected by exhaling on a blossom held over your hand, or tapping the
blossom onto a white sheet of paper. The carbon dioxide in the breath will
cause the thrips to exit the bloom and fall into your hand. A sign of their
presence is pollen spread downward from the anthers, spoiling the blooms. This
is more noticeable on the darker-colored flower forms. Control in the home
begins with buying clean plants and if needed, handpicking of infested
blossoms. Spinosad is an effective product for controlling thrips. Consult the
labels for dosage rates and safety precautions.