Belle Glade AREC Research Report EV-1983-6
UNIVERSITY OF FLORIDA
INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES
COOPERATIVE EXTENSION SERVICE
RICE FIELD DAY
BELLE GLADE, FL
JULY 15. 1983
RICE FIELD DAY
AGRICULTURAL RESEARCH AND EDUCATION CENTER
BELLE GLADE, FLORIDA
JULY 15, 1981
Kenneth D. Shuler, Presiding
Palm Beach County Extension Agent
J. M. Good,AREC Center Director
1982 Rice Fertility Trials 1
G. H. Snyder and D. B. Jones
Promising New Rice Varieties for the Everglades 6
D. B. Jones
Weed Control Technology for Rice in the Southern U.S.
Roy J. Smith Jr. 10
Rice Weed Control in the EAA
J. A. Dusky 15
Stinkbugs Attacking Florida Rice
R. H. Cherry and D. B. Jones 20
Sugarcane Production Following Rice:
Four Years of Data
J. Alvarez and G. H. Snyder 23
Pesticides Approved for Use on Rice in Florida
K. D. Shuler 25
Comments from Fellow Rice Growers 27
W. C. Donovan
AREC Rice Field Tour
Dutch Treat Lunch (catered)
Tour of Glades Area Rice Fields
1982 RICE FERTILITY TRIALS
G. H. Snyder and D. B. Jones
NITROGEN. Trails were carried out both at the AREC and at Seminole Sugar
using Lebonnet and Belmont rice varieties to determine the effect of nitrogen
fertilization on rice yield. In all cases nitrogen was applied from urea at
panicle initiation, at rates of 0, 30, 60 or 90 kn N/ha (multiply kg/ha by
0.89 to convert to Ibs/acre), In some cases these rates were split, with one
half being applied at panicle initiation and the second half 7 to 10 days
later. Belmont did not respond to nitrogen fertilization at either location.
However Lebonnet yields were markedly increased by nitrogen fertilization at
both locations (Fig. 1). It is important to notice the nature of this res-
ponse, At the AREC yield increased up to about 42 Ibs N/acre and at Seminole
(Brida) 52 lb N/acre produced maximum yield. At both locations yield de-
creased at fertilization rates greater than that required for maximum pro-
duction. There appears to be no benefit from using split applications or in-
sufficient benefit to warrant the extra cost. Based on data from Seminole
Sugar trials, in which rice was flooded approximately one month after planting
and the flood was maintained essentially uninterrupted until harvest, the
* rate of nitrogen giving maximum economic return can be calculate as:
N = 51.5 1.7 -----
in which N is the optimum nitrogen fertilization rate in Ibs/acre, CN is the
cost of nitrogen in $/lb including application cost, and PR is the price of
Professor and Rice Agronomist respectively, AREC-Belle Glade.
rice in $/lb. Assuming urea costs $320/ton ($0.356/lb N) applied, and the
value of rough rice is $8.00/CWT ($0.08/Ib), the nitrogen fertilization rate
giving maximum economic return calculates out at 44 Ib/acre. Then the follow-
ing economics apply:
N N Rice Income Attributed
Rate Yield* Cost Value To N Fertilization
0 4044 0 323.52 0
44 4795 15.66 383.60 60.08
These results are in line with those of past years in which substantial
increases in rice yield have been obtained for nitrogen fertilization at
approximately 50 Ib/acre at panicle initiation. We believe Everglades rice
growers should experiment with such fertilization on a few fields or on por-
tions of some fields. However, we caution that the effect of this fertil-
ization on such factors as lodging and susceptability to disease has not been
adequately determined. Therefore, we are not encouraging growers to nitrogen
fertilize their entire acreage until they are satisfied that the benefits of
this practice outweigh any risks.
POTASSIUM. A trial was conducted at Seminole Sugar (Brida) using Lebonnet
rice in which potassium (K) was applied at 0, 75, 150 and 225 kg/ha (0, 81,
161 and 242 lb K20/acre, respectively) prior to planting. The AREC-Belle
Glade soil test prior to fertilization was 24 lb K/acre and the recommendation
was 150 Ib/A (170 Kg/ha). All plots received phosphorus at the rate recor-
mended by soil test. The rice was planted on March 19, 1982, flooded appror;xi_-
mately one month later and harvested July 16, 1982. The following results
Yield = 4044 + 29.79 N 0.289 N2
were obtained for the plant crop:
Although there appears to have been an increase in rice production with in-
creasing K fertilization up to about 150 kg/ha (161 lb K20/acre), a statisti-
calanalysis of the data showed no significant effect of K on rice yields.
Thus in this experiment the AREC soil test recommendation for K on rice was
conservative and no increase in applied K was warranted.
CALCIUM SILICATE SLAG. A trial was conducted at Seminole Sugar (Brida) using
Lebonnet rice in which calcium silicate slag was applied at 0, 2500, 5000,
10,000 and 20,000 kg/ha (0, 2232, 4464, 8929 and 17,857 Ib/acre, respectively)
prior to planting. All plots received P and K according to the AREC soil tet
recommendations. The rice was planted on March 19, 1982, flooded approximately
one month later and harvested July 16, 1982. The following results were ob-
tained for the plant crop:
Slag Application Silicon Content
Rate Yield of Straw
--------- kg/ha---------- %
0 5329 1.02
2500 6285 2.78
5000 6614 4.34
10000 7190 6.25
20000 7675 6.30
The trend for increasing yield with increasing rates of calcium silicate slag
was statistically significant (linear and quadratic terms). The theoretical
optimum rate of slag was 17,320 kg/ha. The yield response appeared to result
from the silicon (Si) contained in the slag. Plots that received amounts of
P, Ca, or Fe equivalent to that in the slag did not have higher yields than
the check. Silicon in the straw at harvest increased considerably as rates of
calcium silicate slag were increased (above). Although yield was increased
over 40% by the application of slag, it is doubtful whether slag applications
are economically justified.
BIOSTIMULANTS. Three commercially available "biostimulants" were evaluated
in the Everglades Agricultural Area during the summer of 1982. Field trials
with ERGOSTIM were conducted on rice growing on organic soils at Seminole
Sugar (Brida Ranch) in the eastern part of the Everglades, at the AREC in the
north-central Everglades, and at Gulf & Western, Okeelanta Division, in the
western Everglades. The materials BURST and KEYPLEX were evaluated only at
Gulf & Western. Most trials utilized the variety Lebonnet, but some used
Labelle or Belmont. Foliar applications were accomplished by diluting the
required amount of material with tap water and spraying at the rate of 20
gallons per acre with a CO2 pressurized hand sprayer. Field plots generally
were 1 to 2 meters in width by 6 to 10 meters in length. Harvest generally
were made by hand collecting the panicles from 4-meter portions of two ad-
Over the course of 6 trials, ERGOSTIM was applied either as a seed
treatment, or as a foliar spray at an early tillering stage, at a late til-
lering stage, and at a heading stage. BURST and KEYPLEX were applied cnly :t
an early tillering stage. In all foliar application trials rates greater than
recommended(5X -10X) were included along with the recommended rates to assure
adequate opportunity for plant absorption. The use of these "biostimulants"
did not result in statistically significant increases in rice yield in any of
II-I- --- r I
0 20 40 60 80 100
Fig. 1. Yield of Lebonnet rice at two locations as affected by ni tr' ,
fertilization at panicle initiation.
Promising New Rice Varieties for the Everglades
Five new rice varieties adapted to southern rice growing conditions were
released for production on a limited basis in 1983. Four of the varieties are
long grained and the fifth, Pecos, is medium grained. Since Pecos has not
been tested in the Everglades yet, it will not be discussed here. The other
four varieties, Bond,Newbonnet, Skybonnet and Lemont were tested last year at
AREC and all showed some promise, Table 1.
BOND- Bond is a very-short-season, short statured,long grain variety having
the same maturity as Labelle, but has the larger seed size of Lebonnet. Com-
pared to Labelle. Bond hac averaged 10% higher grain yields in tests in
Arkansas over the past 6 years. Ityielded 15% higher than Labelle when tested
at ARFC in 1982.
Plants of Bond average about 5 inches shorter than thoro of Labelle,
have a more upright growth habit and are more resistant to lodging; also they
tiller more profusely and react similarly to common diseases. As might bl ex-
pected with its larger grain size, the whole (head) rice milling yields of
Bond average 3 to 4 percentage points less than those of Labelle,but the added
grain yield from Bond results in an average of 5% greater per-acre value of
milled rice than from Labelle in Arkansas tests.
NEWBONNET- Newbonnet is a high yielding, short-statured, long-grain variety,
Compared to Starbonnet, a full seasoned variety (140 days from seedinq to
harvest) Newbonnet is approximately 9 days earlier in maturity ('rka c d-T-a)
At AREC Newbonnet was three days later in maturity than Lebonnet, the -it
Assistant Professor, Rice Agronomist, AREC-Bee Glade.
Assistant Professor, Rice Agronomist, AREC-Belle Glade.
should be about a 125 to 130 day variety here in the Everglades.
Plants of Newbonnet are relatively short, averaging about 34 inches when
properly fertilized and they tiller profusely. Leaves are relatively erect
and narrow and retain a dark green color after heading, Newbonnet shows very
good lodging resistance and somewhat more resistance to the prevalent races of
blast in the Gulf States.
Newbonnet has about 11% heavier kernel weight than Starbonnet (a very
small kernelled variety), is equally high in milling yields and has exceeded
Starbonnet by 12% in grain (rough rice) yields in 23 replicated tests in
Arkansas over the past 5 years. The estimated per-acre value of milled rice
of Newbonnet is about 12% above that for Starbonnet. Newbonnet was one of
the highest yielding varieties tested at AREC last year. It yielded the same
as Mars ( a high yielding medium-grain variety) and 28 and 31% more than
Lebonnet and Labelle. Although Newbonnet has only been tested one year in the
Everglades, it looks very promising. Its only possible drawback at this time
is its slightly longer growing season than other varieties that are currently
being grown in the EAA.
SKYBONNET- Skybonnet was developed from the same cross as Lebonnet. The
average plant height of Skybonnet is about 38 inches, approximately 1-2 inches
less than Labelle and Lebonnet. In the reproductive stage, Skybonnet closely
resembles Lebonnet but the top three leaves are slightly smaller than those of
Lebonnet so that, overall, Skybonnet appears less leafy than Lebonnet. In
tests in the Gulf States, Skybonnet matured about 3 days later than La!el i
and 3 days earlier than Lebonnet. When tested at AREC last year, SkyL :~rnt
was slightly later in maturity than Lebonnet. A major advantage of S'L .: t
over Labelle and Lebonnet is that it is more lodging resistant than either of
Whole-grain milling yields of Skybonnet have been consistently higher
than those of Lebonnet and the superior milling of Skybonnet relative to that
of Lebonnet was a primary factor in its release. Skybonnet has yielding
ability equal to that of Lebonnet and superior to that of Labelle and Star-
bonnet. The ratoon crop yielding ability of Skybonnet appears to be about
equal to that of Labelle and superior to that of Lebonnet.
LEMONT- Lemont was developed from the same cross from which Bellemont was
developed. Lemont possesses a semidwarf plant type and in all morphological
characteristics closely resembles Bellemont. Lemont is about 2 inches taller
than Bellemont and 12 inches shorter than Labelle.
Milled kernels of Lemont are approximately the same length as, but wider
and heavier than,those of Lebonnet. They are distinctly larger in all di-
mensions than those of Labelle, Bellemont, and Starbonnet. Lemont has
milling.quality markedly superior-to .that of.Leah and.equal or superior
to.that:.of other long-grain cultivars. ;
Lemont has demonstrated the ability to produce yields superior to those
of current U.S. long-grain cultivars in numerous tests across the Southern
rice-growing area of the United States. Lemont is extremely resistant to
lodging and it can be fertilized for maximum economic yield with no fear of
Seedling vigor of Lemont is somewhat better than that of Bellemont but
it should be drilled shallow (less than 1 inch and preferably 0.5 inch) he-
cause the seedlings may not emerge from the soil as well as stan~dir ~ight
cultivars, particularly under cool wet conditions. Therefore, if this va-
riety is to be used, proper.spedbed preparation.is very important.
Table 1. Performance of some promising new rice varieties tested.at AREC
Yield Days to 50% 'Stand
Variety Ibs/A1/ Headin/ Establishment3-
Lebonnet 3670 90 3.1
Labelle 3580 79 4.0
Bond 4110 79 4.0
Newbonnet 4700 93 3.7
Skybonnet 3770 92 2.2
Lemont 3900 95 3.1
I' Rough rice at 12% moisture
- Days from planting (4/15/82) to head emergence of 50% of the plants in
the stand. Most varieties are ready to harvest approximately 30 to 35
days after this time.
3/ A visual rating of stand density from 0 (no plants) to 5 (100 % stand)
taken on 6/1/82.
WEED CONTROL TECHNOLOGY FOR RICE IN THE SOUTHERN U.S.1
Roy J. Smith, Jr.2
Weeds reduce the yield and quality of rice. Annual losses due to weeds
in U. S. rice have been estimated 17% of potential production or 22 million
cwt. valued at $205 million,
More than 50 weed species infest rice in the U. S. The seven plants or
groups of plants most frequently reported as weeds of rice fields are barn-
yardgrass, broadleaf signalgrass, sprangletop, red rice, ducksalad, hemp ses-
bania, and sedges (bulrush spikerush and umbrellaplant). Of the seven, four
are grasses, two are broadleaf weeds and one is a sedge. Two are single
species (broadleaf signalgrass and hemp sesbania) while the other five are
weed groups containing two or more species and/or genera.
The integration of weed control technologies into systems for rice is im-
portant. Effective weed control for rice in the U.S. combine preventive, cul-
tural, mechanical, biological and chemical methods. The system that omits
any one of these components is often inadequate.
Crop rotation, seedbed preparation, seeding method, water and fertilizer
management and cultivar selection are important components of integrated weed
control systems for rice.
Rotations of upland crops with rice is the only means of controlling many
hard-to-kill weeds such as red rice. Because red rice is the samo species as
lCooperative investigations of the Agric. Res. Serv., U.S. Dep. Agric. and the
Arkansas Agric. Exp. Sta.
Res. Agron., Agric. Res. Serv., U.S. Dep. Agric., Stuttgart, AR 72160.
white rice, it is difficult to control in the rice crop. Rotating upland
crops with rice permits the use of herbicides that control red rice in soy-
beans. If red rice iscontrolled for 2 years in soybeans, rice can be grown
in the third year without severe competition from red rice.
Thorough seedbed preparation helps to control weeds that infest rice
fields. The goal is to eliminate all weed growth up to the time of seeding
rice. Weeds that germinate and emerge with the rice crop are easier to con-
trol with herbicides.
Seeding method influences weed population shifts in rice. -Barnyardgrass
is more prevalent in dry-seeded than in water-seeded rice. However, aquatic
weeds, such as ducksalad, redstem, waterhyssop, spikerush, and annual umbrella-
plant are more troublesome in water-seeded rice.
Water management influences weed growth in rice fields. Floodwater ap-
plied 1 to 2 days after treatment with propanil prevents barnyardgrass from
reinfesting rice fields. Maintenance of the floodwater on rice fields for 2
to 3 weeks after applying molinate is essential to obtaining control of til-
Although cultural-mechanical methods of weed control for rice are ben-
eficial, nonchemical methods alone seldom control weeds adequately. They
control weeds more effectively when combined with herbicide treatments.
Use of herbicides for control of weeds in rice in the U.S. is an important
component of weed control systems. Herbicides used in the US. are propanil,
.molinate, phenoxys (2,4-D, MCPA, 2,4,5-T and silvex), bentazon, thiobe:-rb,
pendimethalin and acifluorfen.
Propanil is applied at 3 to 5 Ib/A postemernence when grass weeds are
in the 1- to 4-leaf stages of growth. It is usually applied aerially to un-
flooded rice fields. Sequential applications are frequently made to about
70% of the rice in the Southern U.S. The activity of propanil is influenced
by rainfall. At least 8 hours without rainfall after propanil treatment are
required for effective weed control. Best control of weeds by propanil occurs
when daily maximum air temperatures range from 700 to 900F and daily minimums
are above 600F. When temperatures are above 900F, rice may be burned severely
especially if the rice plants are succulent from high levels of residual ni-
trogen in the soil. Irrigation water must be managed properly to obtain sa-
tisfactory weed control with propanil. If the soil is dry, irrigating the
rice field 2 to 5 days before propanil treatment increases weed control.
Flooding rice 3 to 4 inches deep within 1 to 5 days after treatment prevents
germination of more grass weeds. Propanil controls or suppresses weeds other
than grasses -- broadleaf weeds, including seedlings of eclipta, hemp ses-
bania and northern jointvetch, and sedges and aquatics including spikerush,
ducksalad, false pimpernel, redstem, smartweed and waterhyssop.
Molinate is applied at 3 to 5 lb/A postemergence into the floodwater wh'
barnyardgrass ranges from the 4-leaf to jointing stages of growth. Rice is
tolerant to molinate if the plants have grown above the floodwater. Water
management is critical for effective weed control when using molinate. As
grass weeds get larger, longer flood periods are required to kill or c!ppres-
them. Granular molinate is applied aerially to large commercial rice fields
Molinate also controls or suppresses broadleaf signalgrass, fall panicum,
bearded and Amazon sprangletop, eclipta, spikerush and spreading dayflower.
Phenoxy herbicides are applied as postemergence treatments. The stage
of growth greatly influences the response of rice plants to phenoxy herbi-
cides. Rice in the late-tillering to early-jointing stages is not injured
by phenoxy herbicides. The tolerant stage can be positively identified when
the basal internodes begin to elongate from 0.25 to 0.5 inch. Rice cultivars
vary in the length of time required to reach this tolerant growth stage.
Also, environmental and cultural practices influence the period required for
rice to reach the tolerant stage.
Environment and nitrogen fertilization may influence the activity of
phenoxy herbicides on rice and weeds. Phenoxy herbicides control weeds ef-
fectively if rain occurs no sooner than 6 hours after treatment. Even when
rice is treated during the tolerant stage, high temperatures (above 900F)
may increase rice injury by phenoxy herbicides. Temperatures below 600F
during the week before treatment may slow weed growth and reduce control.
Because phenoxy herbicides may cause some injury to the crop even when ap-
plied in the tolerant stage of growth, nitrogen applied within 5 days after
treatment helps the rice to recover from the herbicide injury.
Pendimethalin and thiobencarb
These two herbicides give residual control of grass weeds in rice. Pen-
dimethalin at 0.75 to 1 lb/A is tank mixed with propanil at 3 to 4 1;:/:.
This mixture is applied after rice emerges and when grasses range f'ro: to
4-leaf stages of growth. Thiobencarb alone at 4 Ib/A may be applied from
just before or after rice emergence; grass weeds should be no larger than the
1- to 3-leaf stages of growth. Thiobencarb at 3 Ib/A may also be tank mixed
with propanil at 3 Ib/A and applied early postemergence when grass weeds
range fron the 1- to 4-leaf stages of growth. Pendimethalin gives residual
control of grasses and other susceptible weeds for 1 to 2 weeks. Thiobencarb
gives residual control of weeds for 3 to 4 weeks. Pendimethalin controls or
suppresses barnyardgrass, bearded and Amazon sprangletop, broadleaf signal-
grass, fall panicum, ducksalad, redstem, spikerush and waterhyssop. Thio-
bencarb controls or suppresses all of these weeds except broadleaf signal-
Bentazon and acifluorfen
Both of these herbicides may be applied alone or in a tank mixture with
propanil as a postemergence treatment. Bentazon at 0.75 to 1 Ib/A alone ap-
plied early postemergence controls flatsedges, nutsedge, spikerush, redstem,
cocklebur, dayflower, smartweed and waterhyssop. Tank mixtures of bentazon
+ propanil (0.75+3-5 Ib/A) applied early postemergence control weed species
susceptible to both herbicides.
Acifluorfen at 0.125 to 0.25 Ib/A alone applied at midseason controls
hemp sesbania. Tank mixtures of acifluorfen + propanil (0.2+2-3 Ib/A)
applied at midseason control hemp sesbania, eclipta, morningglory and water-
hyssop. Rice in the late-jointing stage of growth is tolerant to bentazon or
acifluorfen, but not to propanil.
RICE WEED CONTROL IN THE EAA
J. A. Dusky*
Since 1980, evaluations of various herbicides for weed control in rice
have been made. Results indicated a number of compounds provided acceptable
weed control. During 1982, trials were conducted at two locations to further
evaluate these compounds as well as combinations of these compounds,
Emphasis was placed on early postemergence treatments.
Trial 1: Rice (Lebonnet) was planted April 4, 1982 at the Seminole Sugar
Brida Ranch. A preemergence application of Prowl (pendimethalin) was made on
April, 6 using a CO2 charged back sprayer, 28.4 gpa and 26 psi. Early post-
emergence applications were made on April, 22 with a ground rig sprayer, 37.5
gpa and 30 psi. Compounds evaluated were Stam (propanil), Prowl (pendimetha-
lin), Bolero (thiobencarb), Machete (butachlor) Modown (bifenox), Basagran
(bentazon) and Blazer (acifluorfen). Evaluations were made 2 and 6 weeks
after application. Plots were 600 ft.2 and there were 3 replications of each
treatment in a randomized complete block design.
Trial 2: Rice (Mars) was planted on April 18 at Roth Farms. No preemergence
application of Prowl was made, Postemergence applications were made on April
20 in the same manner as above. Evaluations were made 2 and 6 weeks after
application. Yields at the time of harvest were also recorded. The experi-
mental design was the same as above except the plots were 450 ft.2
Weed Scientist AREC-Belle Glade.
Results: Results for trials 1 and 2 are given in Tables 1 and 2, respective-
ly. The primary weed species at location 1 were goosegrass, Panicum sp.,
Amaranthus sp., Eclipta alba, and taro. No yield results were obtained from
Preemergence applications of Prowl (2.0 3.0 lb ai/A) provided accept-
able grass and broadleaf weed control for six weeks with little or no crop
injury. Bolero (4.0 6.0 Ib ai/A) used as an early postemergence treatment
provided acceptable (>72%) broadleaf and grass weed control for six weeks
with little or no crop injury. However, treatment with Bolero (4.0 lb ai/A)
in combination with Stam (1.5-3.0 lb ai/A) enhanced weed control. Machete
(4.0-8.0 lb ai/A) and Modown (2.0-3.0 lb ai/A) did not provide acceptable
broadleaf and grass control when used alone. However, thesecompounds in com-
bination with Stam did result in acceptable control. Basagran (0.75 15
lb ai/A) did not provide acceptable weed control either. Some crop injury
was also evident. A combination early postemergence treatment of Basagran and
Stam (1.5+3.0 lb ai/A) did, however, result in good weed control. Blazer
(0.5 lb ai/A) provided excellent grass and broadleaf control for two weeks
but six weeks after treatment the weed control was no longer acceptable.
At location 2 the primary weed species were goosegrass and barnyard grass
with very few broadleaf weeds present. The infestation of the grass species
was also considered relatively low.
Weed control ratings at six weeks were similar to those at two weeks and
are not included in the report. Bolero and Prowl alone and in combination
with Stam provided excellent weed control when used as early postemergence
Early postemergence treatments with Machete, Modown, or Basagran provided
less weed control than Prowl and Bolero. However treatment with these com-
pounds in combination with Stam provided excellent control.
The relatively light weed infestation is documented by the high yield
(4676 cwt) of the check plots. Because the weed infestation was so low,
little or no weed competition occurred. None of the yields were significant-
ly different from each other.
Future Weed Control Practices
From the experiments conducted many potential weed control practices
exist. The use of Bolero, Prowl, Machete and Modown as preemergence herbi-
cide applications have provided four to six weeks residual weed control.
Bolero and Prowl also have some contact activity whereas Machete and Modown
do not. Consequently, the use of Bolero and Prowl with a contact herbicide
such as Stam as early postemergence treatments would extend the residual
control of these compounds past six weeks. Results have indicated that early
postemergencetreatments of Bolero, Prowl, Machete, and lodown with Stam pro-
vided good season lonr weed control if the permanent flood is applied four
to six weeks after planting.
From previous work the effectivines of Prowl and Bolero seems to be de-
pendent upon soil moisture and the exact constraints must be determined. At
the present time, work is being conducted to support the registration of
Table 1. Weed control and vigor ratings of herbicide trials conducted at
Seminole Sugar, 1982.
2 Wat 6 Wat
* PreEmer-eJnce Arplicaticns ;
Weed Control Ratings; 0=no control,
Bl= Broadleaf; Gr= Grass
Vigor Ratings; 0= Dead ,10=no injury
10=100%; Wat=Weeks after treatment;
Table 2. Weed Control and
Roth Farms 1982,
Vigor Ratings of Herbicide Trials conducted at
two weeks after treatment and yields at harvest.
Rate (Ib ai/A)
Grass Weed Control*
Weed Control Ratings; 0=no control ,10= 100%;
Vigor Ratings; =Dead =no injury
Vigor Ratings; 0=Dead ,10=no injury
Stink Bugs Attacking Florida Rice
R. H. Cherry and D. B. Jones*
Stink bugs (Family Pentatomidae) are one of the most important insect
pests of rice in Florida. These pests occur annually in Florida and rice
growers frequently treat for them.
Often these practices have given unsatisfactory control. Thus it is of
importance to the successful establishment of rice in Florida to gain a better
understanding of these pests so that effective control procedures can be de-
Five different species of stink bugs are found in Florida rice fields.
Of these, the rice stink bug (0 laebus pugnax) and the southern green stink
bug (Nezara viridula) are the most important. The rice stink bug is found in
rice growing areas of Cuba, Dominican Republic, and the U.S.A. while the
southern green stink bug is found wherever rice is grown although it does not
always attack rice.
Both the adult and nymphal stages of stink bugs feed on individual grai::s
of rice as the panicle develops. The insect uses its long stylets to puncture
and extract the fluid from the developing grain. Grains of rice fed upon in
the early milk stage fail to continue normal development, and the result is a-
empty glume or shriveled grain. Grains fed upon in the dough stage may be
weakened structurally, or if infected with certain fungi, may develop a blTck
spot which is commonly known as pecky rice. Such damage leads to lower r'l-
ling yields and inferior grades of rice.
Entomologist and Rice Agronomist, respectively, AREC-Belle nlde.
General economic thresholds for the rice stink bug were set at 15 stink
bugs/10 sweeps of a 15 inch diameter net: These recommendations were later
reduced to 10 bugs/10 sweeps. Yet, even at a population of 3.7 insects/10
sweeps, Bowling reported the per acre loss in Texas based on value factors and
harvested yields was $90.44 in 1982.
Research conducted on stink bugs outside of the U.S. has indicated the
pest can cause severe damage to rice. In the Dominican Republic, where the
climate is more similar to Florida than that of Texas, another species, Oebalus
(Solubea) ornata, has been reported to cause serious losses to rice. It fre-
quently occurs in large numbers and crop loss as high as 50 percent has been
recorded often. In Japan, the southern green stink bug (N viridula), is be-
coming increasingly serious (Feakin, 1976). Growers have been using earlier
maturing varieties in recent years which have provided the pest with a pre-
ferred host early in the season. Therefore, large populations of bugs are able
to build up on later crops.
Information is badly needed on the population dynamics of the stink bug
complex in Florida rice in an effort to achieve better control of these pests.
General observations are that currently used control measures are insufficient
since shortly after spraying stink bugs reappear in the rice fields. Currently
we simply do not know when or how to control stink bugs in Florida rice.
Therefore, the need exists for information on population dynamics of this pest
under our local conditions.
Sampling for stink bug populations in rice began in spring, 1983 rcd
continue for two years during the 1983 and 1984 rice growing seasons. E.t
commercial rice fields planted at four different dates are being sampled.
Each week, 100 sweeps are being taken in each of the rice fields to collect
insects. Sweeps are being made with 15 inch diameter sweep nets. These are
standard and inexpensive sampling tools which can easily be used by rice
growers to evaluate their own insect problems. After collection, all insects
are being stored for later counting. Date and stage of rice development are
S being noted to correlate stink bun populations with these factors.
Since this project has only started this spring 1983, results and con-
clusions will be given at a future date. At the termination of this study,
the data gathered will give the following information.
1) The relative abundance of major stink bug species will be known. This will
allow identification of major species so that literature on the subject can be
examined for control techniques, etc.
2) Variability of stink bug populations between fields will be known. This
will identify how well synchronized stink bug populations are over a wide aros.
3) Seasonal abundance of stink bugs in rice will be known. This will allow
for more appropriate timing of pesticide application when necessary.
4) Since this will be the first intensive survey of rice insects in Florida,
any unplanned data such as other pest insects, beneficial insects, etc. will
also be noted.
5) The effect of planting rice at different times (i. e., early planted vs
late-planted) on stink bug populations will also be known.
In summary, this study should aid growers in deciding if, when, art !~- to
control stink bugs in Florida rice fields.
SUGARCANE PRODUCTION FOLLOWING RICE:
FOUR YEARS OF DATA
Jose Alvarez and George H, Snyder*
At the 1980 Rice Field Day the authors reported the results of a preliminary
attempt at investigating the effect of rice culture on subsequent yields of
sugarcane. The conclusion that rice production increased sugarcane yields
was based on two years of data and was stated tentatively until more data
Today we are presenting the results of a similar analysis which included
sugarcane yield data from the first rice fields planted in 1977 to rice fields
where cane was harvested in the 1980-81 season. The total number of obser-
vations amounted to 130. The "rice fields" (fields in which rice immediately
preceded the sugarcane crop) included 90, and the "nearby fields" (fields
located near the-above fields that were followed during the summer prior to
sugarcane planting) were 40. The information collected included yield (gr s
tons and-% sucrose in normal juice), cane variety, planting and harvestifn
dates, and method of harvesting, Four firms were included in the s-anmp';
To-test the-validity of the assumption that equivalent fields were
chosen to compare with the fields in which rice was grown prior to.sugarcar:f
(i, e., that both sets of fields would have produced approximately equal
sugarcane yields-in the absence of rice production in one set),.data from "the
same fields for-the plant cane crop of the previous cycle were collected,-.
The results of-the regression analysis supported the hypothesis that w-
lent fields had been chosen.
*Area Economist and Professor, respectively, AREC-Belle Glades
The "rice effect" (the difference in cane yields between "rice fields"
and "nearby fields") was then estimated using repgression analysis. Equations
were developed in terms of net tons/acre, % sucrose in normal juice ard stan-
dard tons per acre. The three models were statistically sound. Results
showed an increase of 7.2 net tons/acre, 0.30 % sucrose in normal juice, and
8.5 standard tons/acre for sugarcane following rice. The benefit of rice
cultivation to the subsequent sugarcane crop was computed using economic
figures for the 1981-82 season. The average season price was approximately
$22.25 per standard ton. Harvesting, loading and hauling costs were $9,50
per ton. Therefore, the rice effect amounted to a net return of $108/acre.
While a determination of the factors responsible for the rice effect is
beyond the scope of this study, the extended period of flooding associated
with rice production is likely a major contributing factor. Clearly, t1e
bonus in sugarcane profits that can be obtained by including rice in t`6-
sugarcane production cycle makes consideration of rice production worthy -;
all Everglades sugarcane growers.
Pesticides Approved for Use on Rics in !-'E:i
K. D, Sluler-1
Most of the pesticides listed below have federal labels which do not restrict their application to any specific area
of rice production and are therefore approved for use on rice grown in Florida. Several pesticides still only have
registrations for the traditional production areas of California and the Mississippi Delta states. Some of the herbi-
cides listed below which may be used in Florida are approved for use on weeds and/or soil types which are not common
to Florida. Therefore, this is a list of pesticides which may be used in Florida, but are not necessarily recommen-
ded for Florida conditions.
Rohm and Haas
BASF, Mobah, DuPont
blast and stem rot
Blast, stem rot, sheath
2-4 oz./100 Ibs.
3-4 oz./100 Ibs.
2.25 oz./100 lbs.
4. oz./100 lbs.
4-8 oz./100 Ibs.
1.5 oz./100 lbs.
/Palm Beach County Extension Agent, Florida Cooperative Extension Service, located in Belle Glade, Fl.
parathion 4E methyl
Methoxychlor 50 WP
NOTE: Several fumigants
Bolero 8 EC
D. Harvest Aid
are available for use in
Rohm and Haas
chinch bug, fall armyworm
chinch bug, fall armyworm
storage bin treatment
starage bin insects
gas tight storage bins.
selected aquatics and
selected aquatics and
broadleaf, bulrush, and
13.3 Ibs./A .100 days
0.5-0.75 pt/A 2 days
1 lb./1,000 sq. ft.
1 pt./1,000 bu.
COMMENTS FROM FELLOW RICE GROWERS
In talking with different rice growers in the Everglades Agricultural
Area (E.A.A.) several points were made:
One comment was the need to find rice varieties better suited for our
organic soils. The easiest method to accomplish this is to adapt existing
varieties from other locations to our conditions.
Related to the need for better varieties is the problem with lodging.
Lodging is directly related to the level of fertility, especially nitrogen.
Short stature rice varieties are resistant to lodging and respond readily to
nitrogen fertilizer. Using short stature varieties would enable moderate
amounts of nitrogen to be used to increase yields. One method of nitrogen
fertilization, would be to broadcast the fertilizer by airplane. Another way
would be to drain the fields at midseason and let the soil release the nitro-
gen. Researchiscurrently being done at AREC-Belle Glade on short stature rice
Another problem occurring in the E.A.A. is a sterility problem, in that
the grains of rice in the head do no fill. The cause for this condition is
not known, and it has occurred under both drought and normal wet conditions.
Possibly severe winds from storm conditions during booting and early heading,
thirty to forty days before harvest, affect sterility.
A general comment was that flooding the rice fields early resulted in a
good rice stand. For a manganese deficiency, for example, putting the water
William C. Donovan is Extension Agronomist Specialist, Sugar Cane at AREC-
on fifteen days after planting corrected the problem. Flooding the rice
field early does not solve all problems. A seedling yellowing problem in
some locations, for example, can be only corrected through iron sulfate ap-
Another observation was that if the rice field was to be flooded early,
the cane stubble in the field should be plowed to cover it to prevent it from
drifting to the windward side of the field and killing the rice. Disking will
not prevent the stubble from drifting. If the rice is up and well establish-
ed, the stubble will not kill the plant and the field can be disked as usual.
Several different approaches were used for weed control when the field
was flooded early. One grower used 3 pints of propanil/acre (1 Ibs. of
active ingredients) when the rice plant was at the 1 to 2 leave stage with a
second application of 4 to 5 pints/acre of propanil applied when the rice
plant was at the 3rd or 4th leaf stage. The rice field was then flooded the
next day after the second application. Another rice grower flooded his fields
15 days after planting, then allowed the water to receed for 3 to 4 days.
Propanil was then sprayed on the 20th day after planting, resulting in a 90%
reduction in weeds. The field was then reflooded.
The management of herbicide application is a function of cultural
practices; if the grower does not flood early, his management practices will
Different rice growers had fertility conditions that were specific for
their locations and these were not mentioned except as examples. The above
comments were the result of interviews with different rice growers in the EAA,
Your additional comments are welcome.
RICE RESEARCH PROGRAM SUPPORT
The University of Florida Agricultural Research and Education Center Belle Glade rice
research program received support in 1982 in the form of financial aid and/or equipment donations.
With limited availability of public funds, outside support significantly enhances the rice research
program. Contributions from the following organizations are gratefully acknowledged: The
Florida Rice Council, Busch Agricultural Resources Anheuser Bush and Montedison USA, Inc.
Research Plot Seeder
Busch Agricultural Resources
Research Plot Combine
The Florida Rice Council