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—Lancaster Farming, Saturday, Oct. 23, 1976
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Johnsongrass usually towers above corn and can one and a half feet long with reddish-brown oval
grow to eight feet high or more. It has a seed head seeds.
‘Bankruptcy grass 9
LANCASTER, Pa. - Com production on thousands of
acres in Pennsylvania is reduced annually due to heavy
infestations of johnsongrass Furthermore, the problem is an
increasing one as the weed continues to spread here.
According to Pennsylvania State University agronomists,
johnsongrass is now widely scattered across the state
causing yield losses wherever it occurs. Heaviest infestations
are in the so-called South Mountain region - the southeast
comer of the state - with Lebanon, Dauphin, Lancaster, York
and Cumberland counties bearing the brunt of the attack.
However, University specialists agree that growers in all
parts of the state should be on the lookout for the weed. It no
longer restricts itself to the damper lowlands and river
bottoms, but has moved on to the well-drained mineral soils
of the uplands In addition, johnsongrass is reaching further
north than ever before Weed watchers speculate this may be
due to milder winters that allow the rhizomes to get through
the season Others suggest the weed has evolved a hardier
strain that can take the cold
One major reason for the proliferation of the weed is its
tremendous reproductive potential Johnsongrass
reproduces by seeds and underground rhizomes The
rhizomes spread easily through the soil In fact, a single
plant has the potential of producing 200 to 300 feet of rhizomes
and each f’ode (joints, approximately four inches apart) is
capabl ? of sprouting to produce a new plant These plants in
turn make new rhizomes and seed In one recent field study,
over four million viable johnsongrass seeds were measured
in the top inches of soil in a single heavily infested acre.
Furthermore, these seeds are viable in the soil at least five
years, making the effective control of johnsongrass all the
more difficult
If proper control measures aren’t used against john
songrass, it can take over a crop within three years, causing
sufficient damage to reduce yields up to 50 per cent and
more. In some severe infestations, growers find the corn is
invading fields
Bankruptcy Grass
v.
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not worth harvesting. It’s commonly believed that there are
more com fields abandoned because of johnsongrass than
any other single weed. Older growers used to call it
‘bankruptcy grass’ for obvious reasons.
Several Pennsylvania growers recently put the problem
into field perspective. According to Jesse Copenhaver of
Lebanon, “I was ready to quit farming one farm because of
the johnsongrass. I had a real mess - used to lose 50 acres of
com, and I mean a total loss.”
One of Copenhagen’s neighbors, John Landis, faced similar
problems: “My one regret is that I didn’t start a control
program soon enough,” says Landis. “I only had small
patches of johnsongrass four years ago when I first noticed it.
Unfortunately, I didn’t do anything special to control it and
last year I had the weed in over 80 acres of corn. In fact, it
was so bad in some areas - about two acres worth -1 had to go
in and cut down the com along with the johnsongrass.”
It is not difficult to identify johnsongrass since it usually
towers above corn. It grows more than eight feet high, has a
seed head one and one-half feet high, and its root-like
rhizomes are about the size of a man’s thumb in diameter.
The reddish-brown seeds are about one-eighth of an inch long
and oval shaped.
The jungle-like growth of this grass has been compared to
that of sugarcane It is a fierce competitor to cultivated crops
such as com and alfalfa
In addition to competing for light, soil nutrients, and
moisture, it also serves as a host for the corn disease called
Maize dwarf mosiac. The virus over-winters in johnsongrass
rhizomes and is spread from johnsongrass to corn by aphids.
This disease causes stunting of the com plant and dwarfing of
the ears in some of the more sensitive, non-resistant
varieties.
“Although johnsongrass may be new to some areas of the
state, we have been plagued by it for more than a dozen years
now,” explains Dennis Hoke, Lebanon Extension agent. “It
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A continual problem in Lebanon County
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Johnsongrass roots and rhizomes. Having the
plant on the farm can be a costly consequence,
hence the nickname ‘bankruptcy grass.’ Getting rid
of the weed can be tricky and is not cheap.
John Landis, Lebanon County farmer, examines
johnsongrass rhizomes. Lebanon County repor
tedly has the worst infestation of the weed in
Pennsylvania, although it is found in many other
parts of the state and also in neighboring states. At
a recent meeting of the Lebanon County Farmers'
Association, it was voted to have the state classify
the plant as a noxious weed.
seemed to be a continual problem since we didn’t know how
to handle it, until recently. Now we have the chemicals to
control it, and know what cultural practices to employ to
help.”
“One practice I find that helps is fall plowing,” says
Copenhaver, “this brings the rhizomes to the surface for a
good winter kill. However, fall plowing alone won’t get it; you
need the appropriate herbicides.”
“You must disc the soil enough times to break up clods and-,
cut the rhizomes into small pieces before applying herSsJ
bicides,” Hoke adds. “This weakens rhizomes and enables
the herbicide to make contact with rhizomes and seedlings.”
For example, in the spring, Jesse Copenhaver first field
cultivates, then discs at least once before applying her
bicides, and after application, cross-discs.
I Continued on Page 18)