is a Plant Pathologist and President of Chase Research Gardens, Inc.
C.R.G. is a private research and consulting corporation specializing in
Both hourly and contract services are available.
You can reach C.R.G. at P.O. Box 168, Mt. Aukum, CA 95656 Phone and Fax:
916-620-1624 - E-mail: MTAUKUM@AOL.COM
BLIGHT OF LIPSTICK VINE
Pathogen - Botrytis cinerea
Symptoms - Botrytis blight usually appears on lower leaves
of cuttings in contact with the potting medium. The water-soaked
area may enlarge rapidly to encompass a large portion of the leaf
blade or even the entire cutting. The area turns necrotic and dark
brown to black with age. When night temperatures are cool, day temperatures
warm, and moisture conditions high, the pathogen readily sporulates
on both leaves and flowers, covering them with grayish-green, dusty
masses of spores. Cuttings rooted during the winter are especially
susceptible to Botrytis blight since the environment is ideal for
the disease and very poor for rapid growth of the plant. Episcia,
Sinningia, and African violets are also commonly affected by Botrytis
Control - Controlling Botrytis blight is particularly important
during the winter months. Cultural methods which improve foliage
drying and reduce moisture condensation on foliage during the night
reduce Botrytis blight. Iprodione (Chipco 26019) reduces the severity
of this disease and is labeled for lipstick vine.
WATER SPOTS IN NEMATANTHUS
Pathogen-Cold irrigation water
Symptoms-Round spots which are light yellow or green appear
on the upper surfaces of leaves. Spots can appear on margins or
blades and are sometimes irregular or donut-shaped and white.
Control - Water that is colder than the leaf surface will
cause spotting and is most common in Florida during winter. Deep
well water is usually near 70°F and rarely causes problems, except
when it is stored in outdoor tanks. Be sure temperatures of overhead
water applications are near leaf-surface temperatures.
LEAF SPOT OF LIPSTICK VINE
Symptoms-Spots on lipstick vine appear first as tiny sunken
areas which are slightly brown. These areas enlarge to about 1/2
inch in diameter and darken with age. A bright purple or red margin
and a yellow halo about 1/16 inch wide are usually present on lipstick
vine but not other gesneriads. Leaf drop may also occur. Similar
symptoms are seen on other gesneriads such as Episcias, Streptocarpus,
Nematanthus, Columnea, and Saintpaulia ionantha (African violet).
Control - Use the same cultural controls as mentioned for
Botrytis blight. Chemical control trials have indicated that both
mancozeb (Protect T & O) and chlorothalonil (Daconil 2787) provided
excellent disease control.
STEM ROT OF EPISCIA
Pathogen - Fusarium spp.
Symptoms - Fusarium stem rot and blight typically appears
as a soft, mushy rot at the base of a cutting or rooted plant. The
pathogen sometimes forms tiny, bright red, fruiting bodies or dusty
tan masses of spores at the stem bases of severely infected plants.
Control - Remove infected plants from stock areas as soon
as they are detected. Since Fusarium stem rot appears similar to
other diseases, accurate disease diagnosis is very important prior
to fungicide application. Always use pathogen-free cuttings and
new or sterilized pots and potting media, and grow plants on raised
benches with adequate spacing to allow rapid leaf drying following
irrigation. The fungicides listed for Rhizoctonia control should
be effective for Fusarium control as well. Be sure to check labels
for legal uses.
LEAF SPOT OF LIPSTICK VINE
Pathogen - Myrothecium roridum
Symptoms - Spots appear at edges, tips, and broken leaf veins.
Dead areas are dark brown and initially appear water-soaked. Examination
of the bottom leaf surface generally reveals black sporodochia (fruiting
bodies) which are irregularly shaped and have a white fringe of
mycelium. Sporodochia form in concentric rings within the necrotic
areas. Most gesneriads are susceptible to M. roridum.
Control - Using fungicides when temperatures are between
70 and 85° F, minimizing wounding, and fertilizing at recommended
levels contribute to the control of Myrothecium leaf spot. Chlorothalonil
(Daconil 2787) and iprodione (Chipco 26019) have been effective
for Myrothecium control on other foliage plants.
AERIAL BLIGHT ON LIPSTICK VINE AND EPISCIA
Pathogen - Rhizoctonia solani
Symptoms - Rooting cuttings may be completely covered by
a mass of brownish mycelia (spider-web consistency). Growth of mycelia
from the potting medium onto stems and leaves can escape notice
and give the appearance that plants have been infected from an aerial
source of inoculum. Close examination, however, generally reveals
the presence of mycelia on stems prior to the development of obvious
foliar symptoms. This disease is most common during the hottest
times of the year when the plant foliage remains wet for long periods
of time or when the relative humidity is high. Most gesneriads can
be attacked by Rhizoctonia spp.
Control - Use pathogen-free cuttings, new pots and potting
media, and avoid extremes in soil moisture. Chemical control of
diseases Pathogend by Rhizoctonia has been investigated on
many plants using a variety of fungicides. The fungicide most widely
used for soil-drench control of Rhizoctonia diseases is thiophanate
methyl (Domain or Cleary 3336). Foliar applications of chlorothalonil
(Daconil 2787) may be effective in protecting leaves from Rhizoctonia
infection, but remember that the potting medium or soil is the most
common source of this soil-borne plant pathogen.
SEEDS ON LIPSTICK VINE
- Sticky weed seeds such as those of Oxalis
Symptoms - Small black bodies can be found on leaves, stems,
and pots. These bodies are easily scraped away with a fingernail
leaving no apparent damage to the plant surface. Sometimes weed
seeds can be confused with scale insects.
Control - Control weeds both within pots and under benches.