UF/IFAS
Okeechobee County Extension Service
458 Highway 98 North
Okeechobee, FL 34972-2578
Phone: (863) 763-6469
E- mail: dfculbert@ifas.ufl.edu
October 10, 2007
| Quick Links: Striped Grass Looper ID Caterpillar monitoring Pesticides References |
Feature Article - for release the week of October 14, 2007
Dan Culbert – Okeechobee Extension Horticulture Agent
Worms in the Grass
Last week’s gardening column on the Yellow-necked caterpillar that is chewing up local oaks has opened up a “can of worms.” Our Master Gardeners have been crawling with all kinds of caterpillar calls in the past week.
Today’s
column will talk about one of these critters that came
from a local lawn. This one is worth worrying about,
as it’s that time of year to be dealing with turf
caterpillars too. Identification is very important,
as we have had a few others creepy crawlies in our local
Florida Yards that are not a problem. And the
decision on what if anything to do depends on whom they
are.
One
of last week’s office visitors brought in a container
filled with a bunch of caterpillars collected from his
lawn. They were generally tan in color, but had some
thin stripes of color running the length of their 2 inch
long bodies. A close look at their eyes showed they
were striped too! Our visitor said they have reduced
a part of his lawn to a pile of frass – the
polite word for what these insects leave behind. The
identification stumped me at first. I’ve seen and
heard of caterpillars that can consume our Florida Lawns,
but had not seen these worms. When disturbed, they
had an inchworm-like habit: “they are kind of
loopy,” I said – and that prompted Angela to suggest
that maybe they are some kind of looper. Boy
was she right! A little searching around and she nailed it
- these crawlies are called Striped
Grass Loopers, one of three common caterpillars
that can chomp down a lawn. Alachua County
Horticulture Agent Wendy
Wilber reports that besides this striped grass looper
(SGL), two other lawn caterpillars active at this time of
year are tropical sod webworms TSW) and fall armyworms
(FA) . These caterpillars all develop into moths, but you
normally don't notice the adults unless you are having a
severe outbreak. Common
Turf caterpillars All photos from Weissling
& Cisar, UF/IFAS This
insect has a wide range, and is known across the southern
tier of the US, throughout the Caribbean and Central
Americas and even South American countries of the Pacific
coast. The species that we deal with is known to
entomologists as Mocis
latipes. Loopers
can be distinguished from fall armyworms by the presence
of many fine lines on its head and two pairs of abdominal
“prolegs”. The
adult moths are an unremarkable tan brown color with very
few markings on their wings. The
adults migrate from south FL to north Florida in midsummer
where the eggs are laid and these larval caterpillars
pupate in spindle-shaped cocoons that are fastened to
grass blades. UF
Turfgrass specialist Eileen Buss has reviewed some
research on caterpillars. She finds that the
application of water-soluble, inorganic nitrogen
fertilizers cause rapid grass leaf growth, and this
increases the chance of caterpillar problems. Female
moths that are ready to lay eggs are attracted to the lush
succulent leaf growth. So its probably best lay off
the high nitrogen fertilizers if you want to reduce the
chances that your lawn becomes lunch for a looper. To
get a sense for how bad an infestation is before your lawn
completely disappears, monitor for the caterpillars.
Look for chewed leaves and follow-up the search with a
soil drench. Drench the soil with a soap solution of
two tablespoons of dishwashing soap in two gallons of
water; pour this solution over a square yard of grass and
watch for pests crawling out of the soil and on to the
grass blades. If
you are able to identify as few as three loopers or
armyworms per square foot, it’s time to take corrective
action. For the tropical sod webworms, the threshold
is much higher – wait to treat until levels are as many
as 10 to 20 tropical sod webworms square foot. There
are many beneficial insects that feed on these
caterpillars. Dr. Ron Cave, a Bio-Control expert at
the UF Research Center in Ft. Pierce, found that in
Honduras there are as many as 31 different kinds of
predators and parasites that can consume this species.
There are not as many as that here, but ants, ground
beetles, rove beetles and wasps can all eat these
lawn-munching caterpillars. Bottom-line: try to use
pesticides as a last resort, and use the least
toxic method first. If
you catch the caterpillars when they are still young, a
product containing Bacillus
thuringiensis
or “Bt” will work. Some trade names for products
with this material are Dipel, Thuricide or Safer’s
Caterpillar killer. If the problem is ongoing,
you will need to spot treat with an insecticide like
Scott’s MaxGard or Sevin.
Insecticide use should be ideally timed for
about two weeks after peak moth activity noted, and is
most effective in the early evening when larvae begin
feeding. Baker
County CED Mike Sweat also says these are a problem in
pastures. The striped grass looper damage is similar
to the chewing on forages done by fall armyworm. And
like the fall armyworm, female moths prefer to lay their
eggs on tender new growth. Population studies have
found that some kinds of pasture grasses are favored by
the loopers, so get with us for the research results if
these insects are affecting your business of growing
pasture grasses. I’ve
placed more information on our Okeechobee web page, http://okeechobee.ifas.ufl.edu.
If you need additional information on the Striped Grass
Looper or other turf caterpillars, please email us at okeechobee@ifas.ufl.edu
or call us at 863-763-6469. Local residents can stop
by our office at 458 Hwy 98 North in Okeechobee, and visit
our Okeechobee County Master Gardeners from 1 to 3 PM on
Tuesday afternoons. GO
GATORS! -30-
Buss, E.A. and
Meagher, R. Lawn Caterpillars (ENY-352). Gainesville:
UF/IFAS Extension Service, April 2006. http://edis.ifas.ufl.edu/IN608 ibid.
"Nibbling
and notching caterpillars in Florida turfgrass" .
Florida
Pest Pro. p. 14-17. 2005.
http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=185226
Cave,
Ronald D. Inventory of Parasitic Organisms of
the Striped Grass Looper, Mocis
latipes (Lepidoptera: Noctuidae), in Honduras. Gentry,
Grant. Mocis latipes [Guenee]
Small Mocis (Louisiana Lepidoptera website). http://www.tulane.edu/~ggentry/LAleps05/species/Noctuidae/Mocis/Mlatipes.htm Sprenkel, R. Insect
Management in Pasture. Gainesville: UF/IFAS Extension
Service, 10/2007. http://edis.ifas.ufl.edu/IG061 Sweat, Mike. "Insect
Management in Pastures & Hayfields". In: Northeast
Florida Beef and Forage Group (Newsletter). MacClenny,
FL: UF/IFAS Baker County Extension Service,
4/4/2007. http://nfbfg.ifas.ufl.edu/newsletter/April%202007.pdf Weissling,
T. & Cisar, J. Caterpillars (Sod
Webworms, Loopers & Armyworms) Fort
Lauderdale: UF/IFAS Fort Lauderdale REC, http://flrec.ifas.ufl.edu/pdfs/Caterpillars.pdf Wilber,
Wendy. "Tropical sod webworms feast on
lawns." Gainesville: Gainesville Sun,
September 5, 2007. http://www.gainesvillesun.com/article/20070906/COLUMNISTS/709060304/1023/COLUMNISTS
These
were the caterpillars recently found chewing
up a small pasture in Okeechobee. The Striped
Grass Looper can also consume lawns. Photo:
Dan Culbert, UF/IFAS.
Striped Grass Looper (SGL)
Tropical Sod webworm (TSW)
Fall Armyworm (FA)
The "loopy"
inchworm habit of the Grass looper is seen in this
picture. Photo (c): Grant
Gentry, Tulane University.
The adult moth of the
Striped Grass Looper. Photo: Lyle
Buss, UF/IFAS
This shows how to
use as soap solution to help look for caterpillars in
turf . Count the number of caterpillars that come up
from within a 1 square foot area to measure the
severity of the infestation. If more than 3 SGL worms
(or 10-20 TSW) are found, its time to apply an
insecticide. Photo:
UF/IFAS
Trade
names, where used, are given for the purpose of providing
specific information. They do not constitute an
endorsement or guarantee of products named, nor does it
imply criticism of products not named. The Florida
Cooperative Extension Service - Institute of
Food and Agricultural Sciences is an equal
opportunity/affirmative action employer authorized to
provide research, educational information, and other
services to individuals and institutions that function
without regard to race, color, sex, age, handicap, or
national origin. Florida
Cooperative
Extension Service / IFAS /
University
of
Florida.
Larry
A. Arrington, Dean.
Last
update: 10/12/2007. This page is maintained by Dan
Culbert
The Florida Entomologist, Vol. 75, No. 4 (Dec.,
1992), pp. 592-598. http://arsserv0.tamu.edu/research/publications/publications.htm?seq_no_115=194681