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These include cypress, willows, sweet gums, green ash
and maples. Other species that are somewhat tolerant of
flooding include some hackberries, oaks, loblolly pines,
birches and elms.
Some trees can tolerate 30 to 80 days of root
submergence. In addition to species, how the tree copes
with the water depends on age, health and how leaved out
the trees are.
The most critical time is just after the leaves have
fully expended. That’s when the most potentially
dangerous flood damage can occur.
Early signs of damage include brown, wilted leaves and
branch die-back. The injuries may leave the trees
susceptible to insects and disease. It could take years
for some of them to die.
Unfortunately, there’s not much people can do to help
their flooded trees.
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SMALL CRITTERS POSE BIG PROBLEMS FOR HOMEOWNERS
For some gardeners, moles can make a mountain out of a
…mole hill. These little critters – moles – are just 4-9
inches long, but their underground tunneling makes them
one of the most destructive mammals that can inhabit a
front yard.
Their digging activities aerate the soil and they eat
invertebrates – like earthworms and grubs – but their
digging often damages roots and bulbs, and the
volcano-like mounds of dirt they leave behind can make a
lawn downright unsightly.
Gophers can also wreak havoc in lawns and gardens. They
range from 3-10 inches, and their mounds are
crescent-shaped rather than circular like those created
by moles. They mainly eat plant material.
Raised earth and ground that sinks beneath your feet are
telltale signs that one of these burrowing pests are on
site. To control the problem, you must figure out which
pest is present.
Moles follow their food source. When the ground is dry,
they burrow deep to find grubs and earthworms; when the
ground is warm and moist, they inhabit the subsurface
tunnels that can be easily detected by property owners.
When we water and fertilize our lawns, we create really
good habitat for earthworms and grubs – and really good
habitat for moles. Moles don’t always leave mounds on
Arkansas property, possibly because of the texture of
the soil.
Dying or vanishing shrubs and plants may be the fault of
gophers.
There are several folk remedies for ridding property of
moles, such as using chewing gum as bait to cause
digestive blockages leading to death, but they simply
don’t work.
Poison baits are available in stores, but are illegal to
use under Arkansas Game and Fish regulations. Plus,
moles don’t eat grain, which is used in many poisons.
Fumigants, too, are illegal, and even if they weren’t,
they don’t typically work. Moles are accustomed to
living in areas with little oxygen, and the fumes don’t
stay trapped under the ground but rather escape through
the coarse dirt.
Some companies market mole repellents, but the
effectiveness of those is questionable.
It’s not really clear whether repellents work. Perhaps
the moles’ food source dries up or they move somewhere
else for another reason. They’re difficult to study
because of their underground habits.
Traps are the most reliable way to deal with moles, and
two of the most popular types of traps available are a
harpoon trap and a scissor trap.
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The harpoon trap is probably the easiest to use and is
available at most farm, hardware and garden stores. The
scissor trap requires some excavation of the tunnel, and
repacking of the soil over the trap’s trigger.
For more information on mole control, stop by the
Cooperative Extension office and pick up “Controlling
the Eastern Mole” factsheet or go to our website,
www.uaex.edu.
DOGWOOD
Dogwood borers, Synanthedon scitula, are pests of
dogwood, pecan, hickory, elm and willow. The damage is
done by the larvae feeding under the bark. An early
symptom of borer damage is leaves turning prematurely
red in the summer. Swollen areas on limbs, peeling bark,
and exit holes are additional symptoms. Heavily infested
limbs and branches can die. Successive seasons of
infestation may kill the tree entirely. Most dogwood
borers emerge in May, but a few continue to emerge until
September. The larvae overwinter in the tree. The best
defense against borers is to maintain good tree health.
Dogwoods grow best in humus rich soil with good drainage
and afternoon shade. Borer sprays may be applied to the
trunk in May. The treatment should be repeated at 6-week
intervals 2-3 times. Bifenthrin and permethrins are
labeled for borer control. A fine wire inserted into the
entry hole will sometimes kill the larvae.
HOSTA
Hosta samples have been arriving at the plant disease
clinic in Lonoke with Hosta Virus X. This is a sap
transmitted virus, and like all viruses is not curable.
The virus comes into a nursery from producer fields.
This is largely due to machine harvesting and bulk
washing to prepare for shipping. At the nursery or the
homeowners, it is spread by trimming or dividing
infected plants. The virus is not spread by insects nor
is it soil borne. To prevent virus transmission, great
care must be taken to dip tools in a 10% bleach solution
before handling another Hosta. Wearing disposable gloves
and changing them between plants is also advisable.
Symptoms are blue or yellow ring spots, mottling,
bleeding along veins, and/or a zipper pattern. The
bleeding along the veins is often blue in color. This
virus seldom kills a plant, but weakens them and often
causes unsightly necrotic spots on the leaves as well as
the mottling. The clinic has a reliable Elisa test to
detect the virus.
MAGNOLIA
Lichenized algal leaf spot is caused by parasitic algae
that cause twig cankers and leaf spots. Southern
Magnolia (Magnolia grandiflora) is susceptible to
infection when hot humid weather provides optimum
conditions for the growth and spread of
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this pathogen. Lesions begin as round, green, somewhat
velvety colonies on leaf surfaces or twigs. On leaves,
the spots eventually turn reddish-brown with age. Algal
leaf spot that has been colonized by fungi take on a
grayish appearance and are called Lichenized algal leaf
spot. The disease is most severe on Magnolias that are
weak and in poor health. Trees that are grown in full
sun and subjected to high temperatures and excessive
leaf wetness are more severely affected. Cultural
practices to minimize disease include a proper water and
fertilization schedule. A soil sample should be taken to
rule out nutritional and pH issues. Irrigation methods
that spray water on the leaves should be avoided. All
fallen leaves and twigs should be raked up and
destroyed. Pruning overhanging branches from surrounding
plants will improve air circulation. Lastly,
applications of copper fungicides (Kocide) every 2 weeks
during wet weather have proven helpful.
ARKANSAS FRUIT VARIETIES IN DEMAND WORLDWIDE
(Howell Medders, University of Arkansas)
“Just a bunch of briars, but some sophisticated ones at
that,” John R. Clark likes to say about the blackberry
varieties developed in the breeding program he directs
for the University of Arkansas System’s Division of
Agriculture. But these briars have pedigrees and are in
demand around the globe, which has led to partnerships
between the Arkansas breeding program and companies in
Chile and England, with more to come.
A horticulture professor based on the university’s
Fayetteville campus, Clark inherited in 1997 a unique
collection of blackberry germplasm and continues to
improve it in a fruit breeding program that also
includes grapes, peaches, nectarines and blueberries.
His predecessor, Distinguished Professor Emeritus James
N. Moore, started the collection in 1964.
Moore started patenting UA varieties with the Reliance
grape in the early 1980s and Clark has continued to do
so. Royalties for the propagation of plants are paid to
the university.
Clark says he realized that, while the germplasm
collection exists to benefit Arkansas fruit growers, “we
couldn’t keep it to ourselves if we wanted to.”
Protecting a plant worldwide with plant breeders’ rights
available in over 60 countries and strictly enforcing
this protection is difficult, he says. Others can
legally use patented varieties for breeding with no
return to the university.
“Our testing of Arkansas breeding lines and varieties in
other states and countries revealed opportunities to
maximize genotype by environment interactions,” Clark
says. “Some of our germplasm that doesn’t do well in the
heat and humidity of our summer does great in a more
moderate climate.” Clark recognized that there were
lines in the program – also in the grape, blueberry,
peach and nectarine breeding programs – that likely
would be discarded in Arkansas but might have use in
other locations.
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So, starting about 2002, Clark began broadened testing
and breeding relationships with partners in various
locations such as South America, Australia and South
Africa in the southern hemisphere, where the growing
season occurs during Arkansas’ winter, and the United
Kingdom, where fresh fruit is not likely to be produced
and marketed in competition with Arkansas producers.
The partnerships were developed to strengthen the
program on behalf of Arkansas growers by generating
royalty income for research, Clark says.
One partner is Hortifrut, one of the world’s largest
fruit growing and marketing companies based in Santiago,
Chile. Another is Hargreaves Plants, a nursery company
in Spalding, Lincolnshire, United Kingdom.
“Our partners pay for access to our material for us in
the cooperative improvement programs, and if a variety
is developed that is commercialized the university
receives royalties,” Clark says.
Other partners are interested in simply growing already
patented Arkansas varieties of blackberries, grapes,
peaches, nectarines and blueberries. One of these is
Eurafruit, which is testing Arkansas varieties on its
farms in South Africa for production and shipment of
fruit to Europe. Ozeki Nursery in Japan is licensed to
propagate and market a variety of Arkansas blackberry
plants.
“Blackberries are hot, right now,” Clark says, “and
fortunately, for our purposes, it is mainly a fresh
market crop with limited storage time compared to frozen
berried.” However, he adds, Arkansas growers could
benefit from an expanded “market presence” over a longer
period of time to strengthen consumer demand for
blackberries if berries from other areas find their way
into local stores.
Come June, Clark says, the deal-making goes on hold
while he attends to his main chore of tasting berries
and evaluating plants from this year’s almost nine miles
of seedlings at the Division of Agriculture’s Fruit
Research Station on Red Lick Mountain near Clarksville.
He’ll select plants for further crossbreeding and maybe
one or two from advanced lines for consideration as new,
patented varieties.
The Arkansas breeding program has produced some of the
world’s most widely planted blackberry varieties,
including several that are thornless, and planting is on
the increase in the U.S. and other countries. Unlike the
wild blackberry briars, the Arkansas varieties have
erect canes rather than vines and are easier to manage.
Named for Native American tribes, the most popular are
Navaho and Ouachita.
The program achieved a major breakthrough in the late
1990s when the first “primocane fruiting” types were
selected. Primocanes are first-year canes that normally
don’t bear fruit. Blackberries normally are borne only
on second-year canes. Thus, only about half of the canes
on each plant produce berries. This new type of plant
can provide options for growers in time of ripening and
management of plantings, Clark says.
Primocane-fruiting raspberries became commercially
important about 25 years ago. They produce high-quality
berries on plants that can be managed for production for
longer periods, particularly into the fall season, Clark
says.
The Division of Agriculture has released two primocane
varieties, “PrimeJim”® and “PrimeJan”®, named for James
Moore and his wife. But they are not well adapted to
Arkansas conditions, Clark says. He sees potential to
license the primocane fruiting material to other
breeding cooperators to help generate funding for
research to combine primocane fruiting with other traits
needed for Arkansas growing conditions.
“Science works best when scientists share information,”
Clark says. Hybrid seedlings grown in Chile or England,
for example, might generate a primocane fruiting plant
that would be perfect for those locations or for
Arkansas, he says.
If you have questions regarding any of the above topics,
please feel free to contact me at the University of
Arkansas Division of Agriculture Baxter County Extension
office at 425-2335.
Sincerely,
Mark D. Keaton,
County Extension Agent-
Staff Chair
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