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Septoria leaf spot causes damage similar to early
blight. It affects leaves and occasionally stems. The
spots are small (1/16 - 1/8 inch) and circular, with
light tan or gray centers surrounded by darker margins.
Tiny dark specks occur in the center of the spots.
Leaves are lost the same way as with early blight.
Septoria leaf spot fungus overwinters on decaying
diseased plant material. Temperatures of 60 degrees-80
degrees F and an abundance of rainfall favor the
development of this disease.
To control these diseases, start a protective fungicide
program when leaf diseases usually become evident about
bloom time, or earlier if diseases occur. Continue
throughout the season every 5-10 days. Spray every 5
days if the disease is present. Remember that fungicides
have to be reapplied after a rain. Some materials that
can be used for early blight and Septoria leaf spot are:
chlorothalonil (Bravo or Daconil), mancozeb and Maneb.
BLOSSOM END ROT
Blossom End Rot is a physiological disorder of tomatoes,
peppers, and cucurbits caused by a calcium imbalance
within the plant. Excessively wet or dry soil, too much
nitrogen fertilizer, roots damaged by cultivation, very
high or low pH, or soils high in salts can prevent the
roots from taking up enough calcium. The result is a
water-soaked spot at the blossom end of the plant that
enlarges, turning dark brown and leathery. Rot may set
in at the spot as saprophytic fungi colonize the
decaying tissue. Blossom end rot is common when plants
grow rapidly in the beginning of the season, then set
fruit during dry weather. Fluctuating levels of soil
moisture is usually the culprit. As little as 30 minutes
of water deficiency at any time can cause blossom end
rot. Garden soils should be tested regularly for pH and
nutrient levels. Vegetables do best at a pH of 6.5. Good
mulching practices helps maintain even soil moisture. A
quick fix for blossom end rot is a liquid calcium
supplement applied to the foliage and as a soil drench.
Most garden supply stores carry such products under
names such as “tomato saver,” “end rot” and “stop rot”.
FIREBLIGHT IN APPLE AND PEAR TREES
Fireblight is a bacterial disease. It is the limiting
factor as to what types and what varieties of these
crops are suitable for growing in Arkansas. Fireblight
will also occur on quince, crabapple, hawthorne,
Cotoneaster and Pyracantha.
For the homeowner or hobby grower, the best thing to do
is to use resistant varieties. Commercial growers and
homeowners have the option of using streptomycin, but
anything other than proper rates and proper timing will
result in fireblight developing resistance and making
this control measure ineffective. Streptomycin should be
applied just before blossoms open and continued every
five days till all the flowers are gone.
Fireblight gets its name from the appearance of trees
following infection. The bacterium can infect both
succulent new growth in the spring and flower buds.
Shoot infections can be transmitted by insects, hail,
freeze damage, and splattering rain. When a shoot is
infected it will wilt at the tip and begin to die back
along the shoot. The leaves will remain attached and
have a “burned” look as if a blowtorch had been aimed at
the tree.
If a flower is infected, that flower will turn black and
wilt. It will then move into the shoot and cause that
shoot to wilt. Sometimes, the infection will get into
only one or two shoots, but often it will damage the
whole tree. The amount of damage depends upon the
variety of fruit and the amount of disease spores in the
tree.
Removing the blighted wood is an important control
measure, as it reduces the inoculum for further
infections. Diseased wood should be pruned during an
extended dry period or during the dormant season when
the bacterium is not as active. Wood should be removed
6-10 inches below the last evidence of disease to insure
elimination of the infection.
It is advisable to disinfect pruning tools between each
cut by using a 70% alcohol as a dip or swab. A 10%
solution of laundry bleach can also be used, but is
corrosive to most pruning tools. Tools should be
cleaned, dried, and oiled at the end of the pruning
session.
The best cure is to plant resistant varieties, advises
the Cooperative Extension Service. Pears such as
‘Bartlett’ should not be grown in Arkansas because of
their fireblight susceptibility. For recommended pear
and apple varieties, consult the University of Arkansas
Division of Agriculture Cooperative Extension office at
425-2335 or our website at
www.uaex.edu.
A CASE OF MISTAKEN IDENTITY
(Robert Seay, Benton County
Extension Agent)
At first, you may think you have bumblebees zipping
around near your porch, deck or carport. It’s a simple
case of mistaken identity! Because of other
similarities, as well as their black and yellow
coloring, the carpenter bee is easily mistaken for the
more ill-tempered bumblebee.
The situation can actually be worse since the carpenter
bee, as the name implies, will bore into exposed,
unpainted wood structures, resulting in a greater
problem than a mere bumblebee sting. Their one-half inch
diameter tunnels are then partitioned into individual
brood chambers.
Carpenter bees are solitary, which means they don’t nest
as a colony or hive. But once they hang out their
shingle, a resident population of individual bees boring
individual holes will gradually develop. This
repetitious boring can create 12-inch tunnels in the
lumber, resulting in a weakened post, rafter or joist.
Their best trait is one of non-aggression since the male
bee can’t sting, and you would probably have to catch
and hold a female bee before experiencing a sting. When
a nesting site is approached, the male has a habit of
hovering around, zipping back and forth trying to repel
the intruder, which is as much aggression as they
express.
As kids, my brothers and I would take wood slats, stand
around an abundantly bee populated barn and take batting
practice. The bees seemed to get caught up in the game
and would continue to buzz back and forth, daring us to
swing away. The only risk was in getting smacked by a
wild swing from another wood slat.
Control is actually simple since a coat of paint on
exposed wood members seems to deter their boring. By
exposed, I mean any structure that is open to partial
light. I’ve never seen carpenter bees bore into wood
members inside an enclosed structure. Treated lumber may
not provide much advantage either since I’ve noted
carpenter bee tunnels in this product.
Another option is to remember that carpenter bees go to
roost, so to speak. Once a hole is located, wait until
the late evening and stuff it with an insecticide
treated cotton ball and seal with a dab of putty. It
would be great if all nuisance insects could be handled
this easily!
WHAT DOES
‘CERTIFIED ORGANIC’ REALLY MEAN?
Buying
organic is becoming more and more popular as some worry
about the health and safety of the foods they eat. But
what does it mean for a food to be organic?
According
to the National Organic Program of the USDA, organic
meat, poultry, eggs and dairy products come from animals
that are given no antibiotics or growth hormones.
Organic
food is produced without using most conventional
pesticides, fertilizers made with synthetic ingredients
or sewer sludge, bioengineering or ionizing radiation.
For a food
to be certified as organic, the produce must come from a
farm and processing plant that is certified as organic.
This means
they go through an inspection process from certified
government officials that ensure organic farms are up to
the USDA organic standards.
It’s the
responsibility of the inspectors to assure that only
organic methods are used and that there is no impact on
the environment, such as contamination from pesticides,
synthetic fertilizers or other non-organic compounds.
Just as
food labels must meet standards to say that they are
“heart healthy,” organic foods must meet standards to
make the claim that they are organic. The labeling
requirements are based on the percentage of organic
ingredients in a product.
The
following definitions and facts can help you understand
organic food labels better:
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Agricultural
products labeled “100 percent organic” must contain
all organically grown ingredients and processing
aids.
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Products labeled
“organic” must contain at least 95 percent
organically produced ingredients, except for added
water and salt.
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The USDA seal and
the seal or mark of approval involved in certifying
agents may appear on product packages and in
advertisements.
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Agricultural
products labeled “100 percent organic” and “organic”
can’t be produced using excluded methods, sewage
sludge or ionizing radiation.
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If buying processed
products labeled “Made with Organic Ingredients,”
these products need to contain at least 70 percent
organic ingredients, and list up to three organic
ingredients or food groups on the principal display
panel.
-
Processed products
that “contain less than 70 percent organic
ingredients,” can’t use the term organic anywhere on
the principal display panel. However, they may
identify specific ingredients that are organically
produced in the ingredients statement.
Are organic foods
better for you than non-organic foods?
The verdict
is still out on that. Some will say yes; others will say
no. One point to consider is that organic products
aren’t more nutritious than conventionally grown foods.
If you compare an organic apple versus a conventional
apple, you would receive the same vitamins in the same
amounts.
The
drawback for many with organic products is cost. They’re
more expensive to grow than conventionally grown foods
and that cost shows up in higher prices at the grocery
store.
UNIVERSITY OF
ARKANSAS DIVISION OF AGRICULTURE
RELEASES NEW
BUTTERFLY BUSHES
The
University of Arkansas System’s Division of Agriculture
has released two new varieties of Buddleja, also
known as butterfly bushes because their blooms and
nectar attract butterflies.
Plant
breeder Jon Lindstrom said the new plants, named Orange
Sceptre and Winter Waterfall, are suitable for
greenhouses and conservatories. Orange Sceptre survives
outdoors over winter in Arkansas but, if planted
outside, Lindstrom recommends growing the plant in a
container. Because Buddleja is a prolific non-native
plant, the complete flower heads should be removed after
blooming to prevent seed production.
Lindstrom,
associate professor of horticulture, bred a sterile
Buddleja, called Asian Moon that was released by the
Division of Agriculture in 2006. Because it produces no
seed, it’s more suitable to outdoor gardens, he said.
Orange
Sceptre and Winter Waterfall resulted from a breeding
program begun in 1999.
Lindstrom
said the most striking characteristic of Orange Sceptre
is its unique orange blooms. “This is a new color in
Buddleja,” he said. “It attracts hummingbirds as well as
butterflies.”
Orange
Sceptre flowers well and has a long bloom time. In a
greenhouse, Lindstrom said, it flowers year-round.
Outdoors, flowering on new growth begins in late spring
and, because it can tolerate temperatures that dip into
the mid- to high-20s, it flowers well into late fall. An
herbaceous perennial, it dies back to the ground in
winter and grows back in the spring.
The plant
has an upright and open growth habit, grows about 6 feet
per year and can reach heights of more than 8 feet at
maturity. Each cyme, or flower cluster, produces 15 to
24 flowers that are orange when open.
Winter
Waterfall has a spreading, open growth habit and mature
plants reach a height of about 10 feet. It produces
clusters of white flowers in drooping panicles. It
blooms from November through March.
Both Orange
Sceptre and Winter Waterfall should be pruned
immediately after flowering. Pruning on Winter Waterfall
should cease in mid-summer to allow proper development
of flower heads during the short days in fall.
The plants
tolerate dry soils but grow best on moist, well-drained
soil and prefer neutral pH. They grow best in full-sun
and, in greenhouses, adapt readily to cool winter night
temperatures down to around 50 degrees Fahrenheit.
Lindstrom
said several nurseries have expressed interest in the
plants, especially Orange Sceptre because of its unique
color. He expects them to be available in nurseries in
2009.
CLOVER MITES
Baxter
County Cooperative Extension Service is receiving
reports from around the county of tiny (smaller than a
pinhead) reddish-brown creatures that appear around
homes by the hundreds, crawling around windows and other
areas of the house. They are known as clover mites and
are usually most abundant in the Spring in Arkansas.
Sometimes, noticeable infestations also occur in the
Fall. They can be distinguished from other mites by
their extra long front legs.
Clover
mites are plant feeders that occasionally invade homes;
however, they will not reproduce under indoor conditions
and will perish shortly of their own accord. They do not
bite humans or pets nor cause damage but are extremely
annoying both by their presence and the red stain that
they leave when crushed.
Since the
conclusion of World War II, the mite has become more
common as a household pest. This increase in activity
may be related in some way to an increased use of lawn
fertilizers. The soil nutrient level or plant vigor and
the proximity of the lawn to the house are factors that
appear to govern the incidence of infestation.
Clover
mites are most numerous in newly established lawns and
in old lawns where there is a heavy growth of succulent,
well-fertilized grass. They enter homes wherever they
find tiny openings and seem to enter homes in largest
numbers on the sunny south side.
Extensive
use of a vacuum cleaner will remove many of the mites
from inside the house. Chemical control inside the house
may be difficult but household insecticide aerosols
containing pyrethrins, pyrethrum, allethrin, permethrin,
tralomethrin, prallethrin, cyfluthrin, cypermethrin,
eugenol, or imoprothrin may reduce the number of mites
in the house.
The best
answer to the problem is to prevent the mites from
entering the home by spraying the outside walls and
border areas of the lawn with effective miticides and to
use a twelve-inch barrier of cultivated soil next to the
foundation.
Spray
outside walls and foundations with bifenthrin,
cyfluthrin, esfenvalerate, lambda-cyhalothrin,
permethrin, tetramethrin or tralomethrin. The house
should be sprayed from the lower window sill down to the
ground. Be sure to test insecticide in an inconspicuous
place on the house to be sure it doesn’t stain the
house.
Be sure to
read and follow label directions on the pesticide used.
For more information on
any of the above topics, contact the University of
Arkansas Division of Agriculture Cooperative Extension
office at 425-2335.
Sincerely,
Mark D. Keaton,
County Extension Agent-
Staff Chair
MDK/sa
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