Rice Varieties andManagement Tips

2003

Decisions on variety selection are some of theearliest and most critical you will make. This informa-tion will help you decide which rice varieties are bestsuited to your particular growing conditions.

The varieties are grouped on the basis of graintype (long or medium). After each variety name areletters in parentheses to indicate the state of origin ofthe variety. The long-grains are divided into twogroups based on relative maturity. A brief descriptionof the agronomic characteristics of each of the recom-mended varieties is provided. In addition to recom-mended varieties, descriptions of other varieties maybe included for the various maturity groups. These arevarieties which are not recommended but may begrown on limited acreage.

This publication is available through the LSUAgCenter’s rice Web page at:

www.lsuagcenter.com/subjects/rice/ricehome.htm

Data were generated at six research locations.These include the Rice Research Station at Crowleyand off-station locations in Acadia, East Carroll,Jefferson Davis, Morehouse and Vermilion parishes.The following information is included:

Yield: Dry weight, lb/A

Milling:a) Head - % of whole kernels after millingb) Total - % of all kernels (whole and broken)

after milling

Seedling Vigor: Vigor ratings are based onsubjective estimates made during variety testing.

Days to 50% Heading: Average number of daysfrom emergence to 50 percent heading - includesboth drill- and water-seeded experiments. 50percent heading is when half of the flag leafsheaths have panicles emerging from them. Mostvarieties will reach harvest maturity (20 percentgrain moisture) within 30-40 days after headingunder normal conditions. Medium grains normallyrequire five to seven days longer after heading toreach harvest maturity than do long-grains undersimilar environmental conditions.

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Recommended Long-grainRice Varieties

CL121, CL141 and CL161 are Newpath-resistant rice varieties that have been developed foruse in the Clearfield system for the control of redrice. This system is discussed in the Weed Controlsection of this publication.

CL121: (LA) – CL121 is a very early, semidwarf,long-grain rice variety. It has averaged four to fivedays earlier than Cocodrie in days to 50 percentheading, making it similar to Jefferson. The variety hasdisplayed good milling yield and milling quality. It ishighly resistant to lodging. CL121 has shown goodsecond crop potential in limited testing. The varietyis rated moderately susceptible to blast and suscep-tible to sheath blight.

CL141: (LA) – CL141 is a tall, early long-grainrice variety. It is similar in height to Drew and ratedas moderately susceptible to lodging. It is similar toCocodrie in maturity and has shown good secondcrop potential in limited testing. Grain yield is good,and grain quality and appearance are very good.CL141 is rated susceptible to sheath blight andsusceptible to blast.

CL161: (LA) – CL161 is a high yielding, highquality, long-grain rice variety. It is very similar toCypress in appearance and maturity but averagestwo to three days later in days to 50 percent head-ing. The variety is also very similar to Cypress inyield and milling potential, but grain size is smaller.The variety is rated susceptible to sheath blight andmoderately susceptible to blast.

Cocodrie: (LA) – Cocodrie is a very early,semidwarf long-grain variety that has displayedexcellent yield potential. It is about the same heightas Cypress but has displayed somewhat betterresistance to lodging. Cocodrie averages four to fivefewer days to 50 percent heading than Cypress. Thenew variety has displayed good second crop poten-tial. It has displayed good milling characteristics andgood seedling vigor. Cocodrie is susceptible to sheath

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blight and straighthead and moderately susceptible toblast.

Cypress: (LA) – Cypress is a semidwarf, long-grain variety. It is slightly taller than Lemont and maybe slightly more susceptible to lodging. Cypress hasdisplayed excellent first crop yield potential and hasalso exhibited good second crop yield potential. Ithas displayed excellent milling characteristics andextremely good seedling vigor. Cypress is susceptibleto sheath blight and susceptible to blast. This varietyis also susceptible to panicle blight, a physiologicaldisorder that causes abortion of the developing grain.

Francis: (AR) – Francis is a high yielding, con-ventional height variety released by Arkansas in 2002.This line has consistently been one of the highestyielding in most Louisiana yield tests over the previ-ous two years. Francis has fair to good milling quality,but should be harvested at optimum grain moisture.The variety is moderately susceptible to lodging.Francis is moderately susceptible to sheathblight and susceptible to blast. The varietyis normally one to two days later inmaturity than Cocodrie. Francis hasdemonstrated good ratoon potential.

Jefferson: (TX) – Jefferson is asemidwarf long-grain that is approximatelythree to four days earlier than Cocodrie. Itis about the same height as Lemont and ishighly resistant to lodging. Milling yields aregood, but seedling vigor is poor. Shallowseeding and/or gibberellic acid seed treat-ment will enhance establishment. Jeffersonis susceptible to sheath blight and moder-ately susceptible to blast. Because of the larger seedsize and lower seedling vigor of this variety, theplanting rate should be increased by 15 percent.(See the section on seeding rates for more informa-tion.)

Wells: (AR) – Wells is a newly released shortstature long-grain variety. It has displayed excellentyield potential in tests throughout the rice-growingareas of Louisiana. Milling yields are normally good,but Wells has demonstrated sensitivity to lowharvest moisture, resulting in lower milling yields.Seedling vigor is excellent. The variety is similar inmaturity to Cypress (one to two days earlier). Wells

5

is 2 to 3 inches taller than Cypress but has goodstraw strength and stands quite well. The variety israted as susceptible to blast and sheath blight.

Other Long-grain VarietiesAhrent: (AR) – Ahrent is a very early long-grain

variety that is slightly earlier than Cocodrie. It hasshown good yield potential and milling quality.Ahrent is similar to Wells in plant height and appearsto be similar in lodging susceptibility. The variety israted resistant to blast and moderately susceptible tosheath blight. Seedling vigor appears to be good.

Maybelle: (TX) – Maybelle is the earliest varietyrecommended for Louisiana production. AlthoughMaybelle is not a true semidwarf, it is moderatelyresistant to lodging. It displays very good seedlingvigor, especially in a water-seeded system. It has good

first crop potential and excellent ratoonyield ability. Maybelle is susceptible to

blast and to sheath blight.

Priscilla: (MS) – Priscilla is asemidwarf early long-grain variety

that has shown good yieldpotential. It is approximatelythe same height as Cypressbut is somewhat more resis-

tant to lodging. The variety isslightly earlier than Cypress and

slightly later than Cocodrie inmaturity. Priscilla is somewhat

more resistant to sheath blight thanCypress. Milling yields are fair and seedling

vigor is good.

Saber: (TX) – Saber is an early long-grainvariety that has been between Cocodrie and Cy-press in days to 50 percent heading in Louisianatesting. However, the variety ripens quickly afterheading and will reach harvest maturity in about thesame period as Cocodrie. Saber has averaged slightlylower than Cypress in grain yield but has displayedexcellent milling quality and grain appearance. Saberis rated resistant to blast and moderately susceptibleto sheath blight in Louisiana screening. The variety isslightly taller than Cocodrie and Cypress.

XL-7 and XL-8: (RiceTec) – These are ricehybrids developed by Rice Tec, Inc. Hybrids are

produced by crossing selected male and femaleparents then harvesting the seed from the femaleparent, thus the seed plant is actually the first filial(F1) generation. In contrast, other commercialvarieties of rice are pure lines developed from seedharvested in a later generation such as the F6 genera-tion. Both of these hybrids have displayed very highyield numbers in two years of testing.

XL-8 has shown higher yield potential than XL-7on average. XL-7 is very early maturing, and XL-8maturity is similar to that of Cocodrie. Hybrids haveshown good results at very low seeding rates (35-40lb/A) in a drill-seeded system. Milling yields are fairto good; however, it is advisable that these hybrids beharvested as close as possible to optimum harvestmoisture (19 percent to 20 percent). As with somevarieties, milling yields can be dramatically reduced ifharvested at low grain moisture. These hybrids aretaller than Cocodrie and Cypress and are moresusceptible to lodging. Neither is as susceptible asXL-6, an earlier RiceTec hybrid. Both hybrids havedisplayed good ratoon potential.

Medium-grain Rice VarietiesBengal: (LA) – Bengal is a semidwarf variety

that has displayed very good yield potential andexcellent milling quality. The milled grains are plumperthan other commonly grown medium grains in theSouth, a characteristic favored for some processinguses. Seedling vigor is good, and Bengal has displayedgood, but variable, second crop yield potential. It issusceptible to blast and straighthead and moderatelysusceptible to sheath blight. Bengal has also displayedsusceptibility to panicle blight.

Earl: (LA) – Earl is a conventional medium-grainvariety that has displayed very high yield potentialand fair to good milling and grain appearance quality.The variety is moderately resistant to the predomi-nant races of blast disease. Earl has good seedlingvigor and has demonstrated good ratoon potential inlimited testing. The variety is taller than most cur-rently grown varieties, and care should be taken toavoid excessive rates of applied nitrogen fertilizerbecause this could increase the potential for lodging.

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Special Purpose Long-grainVarieties

Because of the unique characteristics ofthese special purpose long-grains, they should notbe commingled with standard U.S. long-grainvarieties.

Dellrose: (LA) – Dellrose is a Della-type aro-matic long-grain variety. It is a semidwarf, earlymaturing variety that has displayed excellent grain,milling and ratoon yield potentials. Dellrose has goodaroma and a slenderer grain shape than Dellmont.Disease reaction of Dellrose is similar to Lemont. It israted as very susceptible to sheath blight and suscep-tible to blast and straighthead.

Della: (LA) – Della is an aromatic long-grain thatmany consumers favor for its unique aroma and tastecharacteristics. It is grown on limited acreage inLouisiana. Della displays low yield potential whencompared to other currently grown varieties. Dis-ease susceptibility is often a problem because Della issusceptible to most major rice diseases. It is tall andis very susceptible to lodging, even under conditionsof low yield potential.

Dellmati: (LA) – Dellmati is a very early, tallBasmati-type long-grain. The variety has excellentaroma and grain elongation characteristics andemulates imported Basmati. Dellmati displays fairlylow grain and milling yield and fairly good secondcrop potential.

TORO-2: (LA) - TORO-2 is a special purpose,low amylose (sticky cooking) long-grain, semidwarf. Intaste tests, TORO-2 was judged to have acceptableTORO-type cooking and taste characteristics. TORO-2 is resistant to the predominant blast races andmoderately susceptible to sheath blight. It is also verysusceptible to straighthead.

Seeding DatesThe optimum seeding dates will vary by location

as well as from year to year because of environmen-tal conditions. Rice yields may be reduced by plantingtoo early as well as by planting too late. Average dailytemperature at seeding is crucial in stand establish-ment. Average daily temperature is calculated byadding the daily high and low temperatures anddividing by 2. Remember: At or below 50 degrees F,little or no rice seed germination will occur. From 50to 55 degrees F germination increases, but not to anygreat extent until temperature is above 60 degrees F.Plant survival is not satisfactory until the average dailytemperature is above 65 degrees F.

Based on this information and seeding dateresearch, the optimum planting dates are:

Southwest Louisiana – March 15 - April 20North Louisiana – April 5 - May 10

Extremely early seeding can lead to a number ofproblems including (1) slow emergence and poorgrowth under colder conditions because of theinherent lack of seedling vigor and cold tolerance inmany varieties, (2) increased damage from seedlingdiseases (predominantly water mold) under coolconditions, (3) increased damage from birds (black-birds, ducks and geese) which are more numerous inthe early spring and (4) decreased activity frompropanil (herbicidal activity greatly reduced undercooler conditions).

Extremely late seedings can also be detrimentalto yield. Stand establishment can be equally difficult inhot weather. The yield potential of many varieties willdecrease significantly with later seedings. Panicleblight is thought to be associated with higher thannormal day and night temperatures during pollinationand grain fill. Late plantings are more likely to en-counter these conditions. Also, many diseases(especially blast) and insect problems are moresevere, and grain quality is often decreased with later-seeded rice. To assure adequate time for a ratoon orsecond crop to develop prior to the onset of coldweather, the first crop should be harvested beforemid-August. Rice planted by or before April 15 insouthwest Louisiana has the most potential formeeting this harvest deadline and producing goodgrain yields in the ratoon crop.

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Seeding RatesEstablishing a satisfactory stand is an essential

first step in a successful rice production program. Theamount of seed necessary to accomplish this dependsprimarily on the type of seeding system (dry or water-seeded) used.

Rice in Louisiana is planted in three basic ways.These are water-seeded (dry or presprouted seeddropped into a flooded field), drill-seeded (plantedwith a drill on 7- to 10-inch rows) and broadcast dry(broadcast on a dry seedbed by either ground equip-ment or airplane).

Regardless of the seeding system used, thedesired plant stand is constant. The optimum stand is10-15 plants per square foot; the minimum stand issix to eight plants per square foot. Rice (as mostgrasses) has the ability to tiller or stool. Several head-producing shoots can be formed from one plant. Thisis why a somewhat satisfactory stand can be pro-duced from as few as six to eight seedlings persquare foot if proper cultural practices are used.Stands can be too thick as well as too thin. Exces-sively thick stands can often lead to more severedisease pressure as well as spindly plants that may bemore susceptible to lodging.

Experimental results and commercial experi-ence have shown that different seeding rates areoften necessary to reach these desired stands,depending on the type of seeding system used.

Based on this, recommendations are:

Planting on the basis of seeds per acre to obtainthe desired plant population is more accurate thanplanting pounds per acre. For example, 125 poundsof Bengal or Jefferson will contain fewer seeds than125 pounds of Cypress or Cocodrie. An ideal plantpopulation is approximately 10-15 plants per squarefoot. Under typical conditions, about one-half of theseed survive to produce a plant. Use the informationin Table 3 to determine the pounds of seed per acrerequired to achieve the desired plant population,keeping in mind the considerations listed below.

When water-seeding or dry broadcasting, about100-150 pounds of seed per acre will be required.When drill-seeding, about 75-100 pounds of seed peracre will be required. Refer to plant growth regulator

section for recommendations on reduced drillseeding rates when using seed treated with gibberel-lic acid. Use the higher rates when planting underless than optimum conditions.

Considerations include:

a. Use higher recommended seeding rates whenplanting early in the season when there is potentialfor unfavorably cool growing conditions. Coolconditions will favor water mold (seedling disease)in water-seeded rice. This can reduce stands.Varieties also differ in tolerance to cool growingconditions in the seedling stage.

b. Varieties differ considerably in average seed weight.Thus, a variety with a lower average seed weightwill have more seed per pound. Table 3 showsseed weight per pound and the average number ofseed per square foot at several seeding rates formost of the varieties mentioned in this publication.Producers may want to adjust seeding rates forthis factor.

c. Where seed depredation by blackbirds is poten-tially high, use a higher seeding rate.

d. Where seedbed preparation is difficult and a lessthan optimum seedbed is prepared, use a higherseeding rate.

e. If it is necessary to use seed of low germinationpercentage, compensate with increased seedingrates. Always use high germination, certified seed ifpossible.

f. When water seeding into stale or no-till seedbedswith excessive vegetation, use higher seeding rates.

g. If any other factor exists which may cause standestablishment problems (such as slow flushingcapability or saltwater problems), consider it whenselecting a seeding rate.

h. Research has shown that the best stands areobtained when planting pre-sprouted fungicide-treated seeds. Pre-sprouted untreated and dryfungicide-treated seeds produce somewhatpoorer stands, and dry, untreated seed producethe weakest plant populations.

8

Plant Growth RegulatorsPlant growth regulators have several applications

in rice production systems. One type of plant growthregulator can increase seedling emergence andpromote shoot elongation. Another type is used tosuppress red rice seed production in set aside orfallow acreage. Because of the specific activity ofplant growth regulators, follow label instructions andconsult your county agent before application.

Seed treatment with gibberellic acid (1-2 gramsper 100 pounds of seed) promotes rapid, uniformemergence in dry-seeded systems. It is especiallyeffective on semidwarf varieties. With gibberellic acid,seeding depth can be increased up to 3 inches tominimize flushing. In drill-seeded rice, the seedingrate can be decreased to 60-70 pounds per acrewhen planting under warm conditions (daily averagetemperature higher than 70 degrees F). Under coolconditions (daily average temperature of 60 to 70degrees F), the higher application rate is recom-mended.

Gibberellic acid is labeled for foliar application inLouisiana and may be beneficial in certain situations.Consult your county agent for more information,and follow label directions.

ROYAL SLO-GRO (maleic hydrazide) is labeledfor red rice seed head suppression on set aside orfallow acreage. The product should be applied at1.5 lbs/A.I. per acre (1 gallon ROYAL SLO-GRO peracre) to booting and heading red rice. Read andfollow label directions.

9

Table 3. Seed per pound and average number of seed per square foot for important ricevarieties.

Average number of seed/ft2 at selected seeding rates

Variety Seed/lb* 75 lbs/A 100 lbs/A 125 lbs/A 150 lbs/A

Ahrent 20734 36 48 59 71

Bengal 15272 26 35 44 53

CL121 19290 33 44 55 66

CL141 18392 32 42 53 63

CL161 20244 35 47 58 70

Cocodrie 18045 31 41 52 62

Cypress 18151 31 42 52 63

Della 21429 37 49 61 74

Dellrose 18564 32 43 53 64

Dixiebelle 21919 38 50 63 75

Drew 21043 36 48 60 72

Earl 17048 29 39 49 59

Francis 20353 35 47 58 70

Jackson 18607 32 43 53 64

Jasmine-85 18088 31 42 52 62

Jefferson 16158 28 37 46 56

LaGrue 18088 31 42 52 62

Lemont 17322 30 40 50 60

Maybelle 18996 33 44 55 65

Priscilla 16122 28 37 46 56

Saber 20580 35 47 59 71

TORO-2 17869 31 41 51 62

Wells 17824 31 41 51 61

XL-7 21545 ** ** ** **

XL-8 21279 ** ** ** **

* These numbers may vary, depending upon year and seed source.

** The company does not recommend these seeding rates.

Rice FertilizationGenerally lime is not recommended for rice

production unless the pH of the soil is 4.9 or lower.Crops grown in rotation with rice such as cotton,soybeans and other pH sensitive crops may benefitfrom liming. The pH of the soil should not be in-creased to more than 5.8 for rice production.Overliming can induce zinc deficiency in rice.

Phosphorus and potassium should be appliedaccording to soil test recommendations. On soilswhere phosphorus and potassium are needed, applypreplant or before first flood. Potassium deficiencyhas been associated with increase in disease inci-dence and severity.

Fertilizer nutrients are most efficiently used byrice when applied immediately before permanentflood establishment. There are situations when fallapplication of some nutrients may be a suitablealternative. However, neither nitrogen nor zinc shouldbe applied in the fall. For more details, consult theLouisiana Rice Production Handbook (Pub. No. 2321).

Rice seedlings usually show nitrogen deficiencywithin 15-25 days after seeding, especially in soils lowin organic matter. A preplant application of 15-30pounds of nitrogen per acre is usually needed to meet

10

the seedling nitrogen requirement before permanentflood.

All or most of the nitrogen can be appliedpreplant in a water-seeded pinpoint flood system. In adrill-seeded, dry broadcast or water-seeded delayedflood system, all or part of the nitrogen may beapplied immediately before permanent flood. Thebalance of the nitrogen can be applied when deficiencysymptoms occur or anytime up to the panicle differen-tiation (2 mm panicle) growth stage. Avoid applyingnitrogen-containing fertilizers more than seven daysbefore planting.

Rice varieties may differ in their nitrogen re-quirements by location. Native soil fertility, soil typeand other factors determine the efficiency of nitro-gen. Rice growers should determine the N rate thatprovides optimum grain yield on their land. Thehigher nitrogen rates within the recommendedranges for each variety are generally required on claysoils in central and north Louisiana. Avoid N defi-ciency and excessive N fertilization.

Varieties vary in their nitrogen needs as follows.These recommendations are based on multi-year,multi-location research throughout Louisiana. Theserates assume proper timing.

Varieties N rate (lbs/A)CL 121, Dellrose, Jefferson ......................................................................................................120-180

Ahrent, Bengal, CL161, Cocodrie, Cypress, Francis, Priscilla, Saber, Wells .................120-165

CL141, Earl, Maybelle, TORO-2, XL7, XL8 ..........................................................................100-140

Della ................................................................................................................................................ 70-100

Saturn, Dellmati ............................................................................................................................. 60-90

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Ratoon or second crop rice should be fertilizedwith 45-75 pounds of nitrogen per acre when firstcrop harvest is before August 15. When first cropharvest is after August 15, fertilize with 30-45pounds of nitrogen per acre. When conditionsappear favorable for good second crop production(minimal field rutting, little or no red rice, healthystubble), apply the higher rate of nitrogen. Applynitrogen and establish a shallow flood within five daysafter harvest. When the main crop is harvested afterAugust 15, the potential for profitable second cropproduction is reduced because of the increasedlikelihood of unfavorable weather.

On soil with a history of zinc deficiency, orwhere soil tests indicate a need for zinc, a soil appli-cation of 7-8 pounds of zinc from an inorganicsource (zinc sulfate) or 1-2 pounds of zinc per acreas a chelate should be made. Zinc can be appliedfoliarly at the rate of 0.5-1.0 pound per acre as achelate.

Sulfur may be needed at a rate of 20-25 poundsper acre where large amounts of soil have beenmoved in land leveling. Sulfur deficiencies resemblenitrogen deficiencies, producing pale yellow plantswhich grow slowly. If these symptoms appear,applying 100 pounds of ammonium sulfate per acrewill provide 21 pounds of nitrogen and 24 pounds ofsulfur per acre.

Additional information on rice fertilization is inLCES Publication 2418, “Fertilization of LouisianaRice,” available in your county agent’s office.

DD-50 Rice ManagementProgram

The DD-50 Rice Management Program is acomputer-based management tool offered to theLouisiana rice industry by the Louisiana CooperativeExtension Service. It provides producers withgrowth stage predictions and management sugges-tions based on emergence dates of individual ricefields. It is only a tool and is not a substitute forregular monitoring of fields. Its accuracy may beinfluenced by unusual weather, plant stress and otherfactors. For more information on the program,contact your county agent.

Rice InsectsThe major insect pests of rice in Louisiana are

the rice water weevil and the rice stink bug. Inaddition, rice stem borers, rice leaf miners and riceseed midges have become increasingly important ricepests. Under high infestation levels, yield can beseverely decreased by all of these pests. Identificationand scouting information for these pests is pre-sented. If you suspect insect injury in your field(s),contact your county agent for verification and helpwith damage assessment.

Rice Water Weevil: Adults are grayish-brown (1/8" long x 1/16" wide) beetles which fly intorice fields to feed on the leaves of rice plants. Leaffeeding by adults causes narrow scars that run length-wise on the leaf, but this feeding rarely causes eco-nomic damage. Females lay eggs on the leaf sheath ator below the water line. The larvae are white, leglessgrubs with brown heads that feed on the roots,reducing rice yields. There are four instars that varyin size (1/32" to 3/16").

All commonly grown rice varieties are suscep-tible to the rice water weevil. Recent research,however, indicates there are some varietal differ-ences in susceptibility. The medium-grain varietiesappear to be more susceptible to infestation thanlong-grain varieties.

Infestations of rice water weevil also tend to bemore severe in late-planted rice than in early-plantedrice.

Management of the Rice Water Weevil withKarate or Fury. Karate and Fury are insecticides withsimilar characteristics; however, use rates for Furyare somewhat higher than Karate. Timing of Karateor Fury for management of rice water weevil iscrucial. Karate or Fury kills adult weevils only, noteggs or larvae. Scouting for adult weevils is importantand may begin at any time after emergence of rice,but efficacy of Karate or Fury is maximized whenadults are controlled just before oviposition (egglaying). Oviposition is possible when the field hasbeen saturated by rainfall or flushing or when perma-nent flood has been established. In most fields, themajority of oviposition is likely to occur after theestablishment of permanent flood. Check at leastfive to 10 locations per field for the presence of

adults or their feeding scars. Treat when adultweevils or their scars are observed and conditionsfor egg laying are favorable as described above.Applications made 24 hours before initiation ofpermanent flood can be effective when adults arepresent. More than one application may be required.Once fields have been treated, begin sampling againafter seven days.

Karate or Fury kills adult weevils, but not eggsand larvae. Egg laying (oviposition) must be pre-vented. Once eggs are laid in rice stems or larvae arein the roots, Karate or Fury will not be effective.Applications of Karate or Fury for eggs or larvae are awaste of money in addition to the loss caused byweevils. Work on managing rice water weevil usingfoliar insecticides is ongoing. Recommendations forthe management of the rice water weevil with foliarinsecticides may change.

Karate or Fury also is effective against severalminor pests of rice including fall armyworm andchinch bugs.

Management of the Rice Water Weevil withDimilin. Dimilin kills the eggs of rice water weevils,not adults or larvae. Dimilin should be applied tofields only after permanent flood is established and ifadults are present. Begin scouting as soon as, or justprior to, permanent flood establishment. Scout fieldsevery three to four days until treatment is requiredor rice reaches internode elongation (green ring).Seven days after the first treatment with Dimilin,resume scouting as described above. More than oneapplication may be required.

Management of the Rice Water Weevil with Icon.The decision to treat for rice water weevils with Iconmust be made before planting because Icon isregistered only as a seed treatment in Louisiana.Icon-treated seed is available only from seed dealersapproved by the manufacturer. Icon can be usedwith both pre-sprouted and dry seed in water-seeded systems or with dry seed on dry-seededsystems. Consult Table 7 to determine rates of Iconon a per acre basis under several seeding rates andseveral seed treatment rates. Refer to the productlabel for additional information.

Icon kills larvae of the rice water weevil but willhave no effect on adult weevils. The presence of

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adults in Icon-treated fields does not indicate thefailure of Icon.

Rice Stink Bug: These tan and gold bugs(about 1/2" long) feed on rice when it begins to head.Females lay light-green, cylinder-shaped eggs in two-row clusters on leaves and stems. Eggs turn red-blackjust before larval emergence. Nymphs (immatures)are black with red marks on the abdomen. Oldernymphs resemble adults. Nymphs and adults suckthe sap from developing rice grains. During theflowering and milk stages, this causes empty grainsand reduces yield. During the soft-dough stage,diseases enter the grain at the feeding spot and causepecky rice.

Using a 15" diameter sweepnet, take 10 sweepsat 10 different areas around each field. Count thenumber of bugs collected after every 10 sweeps. Inthe first two weeks of heading, treat fields whenthere are 30 or more bugs per 100 sweeps. Fromthe dough stage until two weeks before harvest, treatfields when there are 100 bugs per100 sweeps.

Rice Leaf Miner:Adult flies are less than 1/4" long,with a metallic blue-green to graythorax and clear wings, and they layeggs on rice leaves as they lie on thewater. The larvae are transparent to cream-colored after hatching but become yellow to lightgreen within a few days. Larvae tunnel between thelayers of the leaf, attacking and killing leaves closest tothe water. Larvae move up the plant, killing additionalleaves, and, under heavy infestations, the entire plantmay die.

Rice is attacked in the early spring, and infesta-tions usually occur on the upper side of leveeswhere water is deepest. Rice leaf miner is not usuallya problem in water 4 to 6 inches deep. Leaf minerproblems are more severe in continuously floodedrice than in periodically flooded rice. Leaf minersappear to attack rice fields in the same vicinity fromone year to the next.

Check for rice leaf miner larvae by pulling a riceleaf gently between the thumb and forefinger. Iflarvae or pupae are there, a bump can be felt in theleaf blade. The larvae or pupae can be found by

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separating the layers of the leaf. If plant populationsare being reduced to less than optimum stands (10-15 plants per square foot), chemical control may benecessary.

Rice Seed Midge: Adult midges resemblesmall mosquitos and swarm over rice fields, ricelevees, roadside ditches and other bodies of water.Elongate eggs are laid on the surface of open water instrings. Larvae live on the bottom of flooded ricefields in spaghetti-like tubes. Larvae injure rice byfeeding on the embryo of germinating seeds or onthe developing roots and seeds of very youngseedlings. Midge injury occurs in water-seeded riceand is usually not important once seedlings areseveral inches long. The potential for midge injuryincreases when fields are flooded far in advance ofwater seeding rice.

Water-seeded fields should be scouted formidge injury, checking for hollowed out seed withinfive to seven days after seeding. Injury from themidge can be insignificant (not economically impor-tant) to very severe. Injury can also be very localized,making damage assessment difficult. In some in-stances, whole fields may need to be replanted. Inother instances, only parts of fields may requirereseeding. Monitor fields until rice seedlings areseveral inches tall.

Rice Stem Borers: The sugarcane borerand the rice stalk borer are increasingly importantpests of rice in Louisiana. Both species overwinter aslast instar larvae in the stalks of rice and other hostplants. These larvae pupate in the spring, and adultmoths emerge during early May. Adult sugarcaneborers are straw-colored moths about 1 inch longwith a series of black dots, arranged in a V-shapedpattern, on the front wings. Adult rice stalk borersare also 1 inch long with pale white fore and hindwings tinged on the edges with metallic gold scales.Front wings are peppered with small black dots.

Egg-laying of both species on rice can begin asearly as May, but economically damaging infestationsgenerally do not occur until July through September.Eggs are flat, oval, cream-colored, and positioned likefish scales in clusters of two to 100 eggs. Larvaeemerge in four to five days. Young larvae crawl to thebase of the leaf while feeding on the leaf surface for afew days, leaving small streaks or feeding scars on the

leaf. A few days after, larvae feed on the inside of theleaf sheath before boring into the stem. They feedinside the stem for three or four weeks. Maturelarvae of both species may reach 1 inch in length.

Larvae of the sugarcane borer are cream-colored, with a series of brown spots on the back.Larvae of the rice stalk borer are cream-colored butlack the brown spots on the back. Instead, they havetwo pairs of dark stripes running the entire length ofthe body. Pupation occurs inside the stem. Thepupae are brown, about ½ inch long and cylindrical.The pupal stage lasts seven to 10 days. Early infesta-tions by both species are noticed when the youngestpartially unfurled leaf of the rice plant begins towither and die, resulting in a condition calleddeadheart. Stem feeding that occurs during panicledevelopment causes partial or complete sterility andresults in the whitehead condition. Severe infesta-tions cause stalk breakage and plant lodging above thewater surface.

Scouting for stem borers should start at greenring to detect adults, egg masses or fresh feedingscars on the leaves. Chemical applications mustcoincide with larval emergence so small larvae arekilled before they enter the rice stalks. Once larvaeenter the stalks, pesticides are not effective.

No insecticides are labeled specifically for stemborer control in rice, and no economic thresholdshave been developed for these insects in rice inLouisiana. LSU AgCenter personnel have not con-ducted studies with Karate and Fury against stemborers. However, recent studies in Texas and Arkan-sas indicated that Icon seed treatment reduceswhitehead incidence by 40 percent to 60 percent indrill-seeded rice. In addition, early planting allows therice crop to avoid high population levels of stemborers, especially where populations of the sugarcaneborer increase in host plants such as corn and grainsorghum and move to rice plants later in the season.

Rice DiseasesSince the list of labeled fungicides may change,

check with your county agent for current recom-mendations. For more information, consult publica-tion number 2321, “Louisiana Rice ProductionHandbook,” available in your county agent’s office.

Blast: Blast can be found from the seedlingstage to near maturity. The leaf blast phase occursbetween the seedling and late tillering stages. Spotson leaves start as small white, gray or blue-tingedspots. Spots enlarge quickly under moist conditionsto either oval diamond-shaped spots or linear lesionswith pointed ends with gray or white centers andnarrow brown borders. Leaves and whole plants areoften killed under severe conditions. Lesions onresistant plants are small brown specks that do notenlarge.

Rotten neck symptoms appear at the base ofthe panicle, starting at the node. The tissue turnsbrown to chocolate brown and shrivels, causing thestem to snap and lodge. If the panicle does not fall off,it may turn white to gray, or the florets that do notfill will turn gray. Panicle branches and stems offlorets also have gray-brown lesions.

Scouting for blast should begin early in theseason during the vegetative phase and continuethrough the season to heading. Leaf blast will usuallyappear in the high areas of the field where the floodhas been lost or is shallow. Areas of heavy nitrogenfertilization and edges of the fields are also potentialsites. If leaf blast is in the field or has been reportedin the same general area, and if the variety is suscep-tible, fungicidal applications are advisable to reducerotten neck blast.

Sheath Blight: Sheath blight is character-ized by large oval spots on the leaf sheaths andirregular spots on leaf blades. Infections usually beginduring the late tillering-joint elongation stages ofgrowth. The fungus survives between crops asstructures called sclerotia or as hyphae in plantdebris. Sclerotia or plant debris floating on thesurface or irrigation water serve as sources ofinoculum that attack and infect lower sheaths of riceplants at the waterline. Fungus mycelium grows upthe leaf sheath, forms infection structures, infectsand causes new lesions. The infection can spread to

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leaf blade. After the panicle emerges from the boot,the disease progresses rapidly to the flag leaf onsusceptible varieties. With very susceptible varieties,the fungus will spread into the culm from earlysheath infections. Infected culms are weakened, andthe tillers may lodge or collapse.

The lesions have grayish-white or light greencenters with a brown or reddish-brown margin. Aslesions coalesce on the sheath, the blades turn yellow-orange and eventually die. As areas in the field withdead tillers and plants enlarge, they may coalesce withother affected areas to cause large areas of lodged,dead and dying plants. Damage is usually most com-mon where wind-blown, floating debris accumulates inthe corners of cuts when seedbeds are prepared inthe water.

Disease severity can be reduced by integratingseveral management practices. Dense stands andexcessive use of fertilizer both tend to increase thedamage caused by this disease. Broadcast seedingtends to increase stand and canopy density. Rotationwith soybeans or continuous rice increases theamount of inoculum in field soils. Fungicides areavailable for reducing sheath blight.

Stem Rot: The fungus Sclerotium oryzaecauses stem rot. Losses are not usually detecteduntil late in the season when control practices aretoo late. Damage appears as severe lodging, whichmakes harvesting difficult. Seed sterility also hasbeen reported. No high level of resistance to stemrot is available. High nitrogen and low potassiumlevels favor the disease. Stem rot is more serious infields that have been in rice for several years.

The pathogen over winters as sclerotia in thetop 2 to 4 inches of soil and in plant debris. After apermanent flood is established, the sclerotia float tothe surface, come in contact with the plant, germi-nate and infect the tissues near the water surface.The first symptom is irregular black angular lesionson leaf sheaths near the water line at tillering or latergrowth stages. As lesions develop, the outer sheathmay die, and the fungus penetrates into the innersheaths and culm. These become discolored andhave black or dark brown lesions.

The fungus then penetrates the inner sheathsand culm, often killing the tissues. The fungus can

15

continue to develop in the stubble after harvest, andnumerous sclerotia are produced. At maturity thesoftened culm breaks over, infected plants lodge, andnumerous small, round black sclerotia develop in thedead tissues.

Suggested control measures include using earlymaturing varieties, avoiding very susceptible varieties,burning or cultivating stubble after harvest to de-stroy sclerotia, using crop rotation when possible,applying potassium fertilizer, avoiding excessivenitrogen rates and using foliar fungicides recom-mended by the LSU AgCenter.

Grain and Head DisordersMany fungi and bacteria infect developing grain

and cause spots and discoloration on the hulls orkernels. Damage by the rice stink bug, Oebalus pugnaxF., also causes discoloration of the kernel. Kernelsdiscolored by fungal infections or insect damage arecommonly called pecky rice. This is a complexdisorder in rice that involves many fungi, the white-tip nematode and insect damage. High winds at theearly heading stage may cause similar symptoms.Proper insect control and disease management willreduce this problem.

Panicle Blight: Panicle blight or grain blightwas recently identified as being caused by the bacte-rium Burkholderia glumae. The bacterium is seedborneand can cause a seedling blight that can thin standssignificantly. The bacterial population appears tofollow the growing plant as an epiphytic populationon the foliage. This population infects the grain atflowering and causes grain abortion and grain rottingsoon after pollination. Loss estimates vary from atrace to 50 percent reduction in yield and quality.

Initial symptoms of grain infection appear as agray discoloration of the glumes. Infected grains canbe unevenly distributed on the panicle. In severeinfections, all of the seed can be damaged. Diagnosisis difficult because of other causes of seed infectionand sterility producing similar symptoms and maskingpanicle blight symptoms after lesion maturity. A keydiagnostic characteristic is that the stem stays greenup to the seed.

High temperatures favor the disease. Thedisease usually develops in a circular pattern in the

field with severely affected plants in the center andless affected plants around the edge. Infected headscan be confused with straighthead because of theirupright stature. No parrot beaks are present. Somevarieties are less susceptible than others are. Chemi-cal control measures are being developed. Seedtreatments have shown some activity in reducingseedborne pathogen populations and subsequenthead severity.

False smut: A fungus that infects rice atflowering causes false smut. The disease is character-ized by large orange to olive green spore balls thatreplace one or more grains on a head. In the middleof the spore masses are sclerotia that act as thesurvival structure. These sclerotia can be spreadwith the seed and infect the next crop. Removal ofthe sclerotia in seed cleaning reduces spread. Seedtreatment with a fungicide also reduces inoculumpotential. False smut spores cause discoloration ofmilled rice, but no significant yield loss is associatedwith the disease. Presence of the smut sclerotia ingrain for export has caused problems.

Kernel smut: Symptoms from this fungaldisease appear just before maturity. A black mass ofsmut spores replaces all or some of the endospermof the seed. Often the spores ooze out of the grain,leaving a black mass along the seam of the hulls. Thefungus infects immature, developing grain. The fungusoverwinters as spores in soil of affected fields and inseed. Significant quality and yield reductions arepossible. It has been reported, from other states, thatboot applications of propiconazole containing fungi-cides reduce damage significantly.

Straighthead: This physiological disorder isassociated with sandy soils, fields with arsenic resi-dues or fields having anaerobic decomposition oflarge amounts of organic matter incorporated intothe soil before flooding. Panicles are upright atmaturity because the grain does not fill or paniclesdo not emerge from the flag leaf sheath. Hulls may bedistorted and discolored, with portions missing orreduced in size.

Distorted florets with a hook on the end arecalled “parrot beak” and are typical of straighthead.Plants are darker green or blue-green and oftenproduce new shoots and adventitious roots from thelower nodes. These symptoms can be mimicked by

herbicide damage. Management is by using resistantvarieties and draining the field approximately 10 daysbefore internode elongation (green ring) and allowingthe soil to dry until it cracks. This growth stage canbe determined by slicing the crown of the plantlengthwise and counting the nodes. When threenodes are distinctly visible, internode elongation isapproximately 10 days away. The DD-50 Rice Man-agement Program may also be consulted to deter-mine the correct drain tine. It is important that theflood be established again by internode elongation.

Sheath Rot: Sheath rot is caused by thefungal pathogen Sarocladium oryzae. Symptoms aremost severe on the uppermost leaf sheaths thatenclose the young panicle during the boot stage.Lesions may be oblong or irregularly oval spots withgray or light-brown centers and a dark reddish-brown diffuse margin. Early or severe infections mayaffect the panicle so that it only partially emerges.The unemerged portion of the panicle rots, withflorets turning red-brown to dark brown. A pow-dery white growth consisting of spores and hyphaeof the pathogen may be observed on the inside ofaffected leaves. Insect or mite damage to the boot orleaf sheaths increases the damage from this disease.Emerged panicles may be damaged with floretsdiscolored reddish-brown to dark brown and grainnot filling.

Some varietial resistance is available. The diseaseis usually minor, affecting scattered tillers in a field andplants along the levee. Occasionally large areas of afield may have significant damage. No control mea-sures are recommended. Fungicidal sprays used in ageneral disease control program may reduce damage.

Rice Disease ManagementYield potential of any rice variety can be se-

verely reduced under high levels of disease. Anintegrated disease management program includingthe following practices should be implemented:

• Plant resistant varieties• Avoid late planting• Maintain proper fertility levels• Maintain adequate flood (avoid loss of flood)• Use fungicides if necessary

The use of foliar fungicides is justified in many

16

cases. Some factors to consider in making thisdecision are whether or not: a) the field has a historyof disease, b) the variety is susceptible, c) the yieldpotential is good, d) the rice is being grown for seed,e) the rice was planted late (Late-planted rice is morelikely to encounter foliar disease problems thanearly-planted rice.) or f) a second crop is planned.(Disease not suppressed in the first crop may causesignificant damage in the second crop.)

Scouting for diseases should begin early in theseason. For sheath blight, very susceptible to suscep-tible cultivars will experience an economic loss if 5percent to 10 percent of the tillers are infectedduring vegetative stages. For moderately susceptiblecultivars, the level is 15 percent. At these levels,consider using a fungicide.

Apply a foliar fungicide at early boot when leafblast symptoms are present. Leaf blast does notalways precede rotten neck blast, but preventiveapplications of a fungicide are warranted if a blast-susceptible variety is grown. The incidence andseverity of blast increase when rice plants arestressed (loss of flood, fertility imbalance, etc.).Draining for straighthead and/or water weevil controlmay increase incidence and severity of blast. Also,blast is normally worse on later planted rice.

For reaction of rice varieties to major diseases,disorders and insects, see Table 4 on page 19.

Weed Management in RiceManagement of weeds is critical for optimum

rice production in both dry- and water-seededsystems. Although herbicide options and manage-ment strategies differ under these systems, managingboth herbicides and water in a timely manner iscritical.

In dry-seeded production, four to six weeksmay elapse between planting and permanent floodestablishment, and controlling weeds during thisperiod is critical for maximizing yields. During thistime weeds such as barnyardgrass, broadleafsignalgrass, morningglories and hemp sesbania canbecome established. Although these weeds cansurvive a permanent flood, establishment and mainte-

17

nance of a sufficient flood over these weeds canenhance control.

Herbicide Options for Weed Control

PreemergenceCommand – Command provides economical

residual control of annual barnyardgrass, broadleafsignalgrass, sprangletop and fall panicum when appliedbefore weed emergence. Command may be appliedas a surface broadcast application before rice emer-gence or as an early postemergence treatment torice at the one- to two-leaf growth stage to dry-seeded rice only. Early postemergence applicationswith Command usually include a postemergenceherbicide such as propanil or Arrosolo to controlemerged grasses and broadleaves. Command ratesare soil texture dependent, and applications to lighttextured soils are prohibited. Because of off-sitemovement of spray drift, the herbicide must beapplied by ground equipment. Aerial applicationsare restricted.

Facet – Facet provides both preemergence andpostemergence control of annual barnyardgrass,hemp sesbania, signalgrass and morningglory. Theherbicide does not control sprangletop or nutsedge.Preemergence applications are restricted to drill-seeded rice only. Rainfall or flushing is necessary forherbicide activation. Tomatoes and cotton areextremely sensitive to Facet drift.

Newpath – Apply only to Clearfield(imidazolinone-tolerant rice) varieties that have beendry seeded or drill planted. Newpath selectivelycontrols red rice and annual grasses. The herbicide isweak on broadleaf weeds such as hemp sesbaniaand jointvetch. For complete red rice controlwith Newpath, two applications are re-quired. The herbicide must be appliedpreplant incorporated or preemergenceand postemergence prior to permanentflood. Adequate soil moisture is requiredfor optimum herbicide activation for allmethods of soil application. Newpathmust be applied preflood when rice is inthe three- to five-leaf growth stage. Per-manent flood should be initiated withintwo days after postemergence applications.

Delayed PreemergenceProwl + Facet – Tank-mix controls most annual

grasses including sprangletop and several broadleafweeds in drill-seeded rice. Rice seed must haveimbibed germination water prior to herbicide appli-cation or five to nine days after planting. Do notapply to water-seeded rice as a delayed preemer-gence application.

Bolero – Bolero controls barnyardgrass,sprangletop, annual sedges and suppresses someaquatic broadleaf weeds. The herbicide should beapplied post plant to dry seeded rice after soil hasbeen sealed by flushing or rainfall. Residual controlusually will not exceed three weeks.

PeggingCommand Impregnated on Fertilizer – Com-

mand impregnated on fertilizer may be applied by airto water-seeded rice. Applications are restricted toselected parishes (consult label for specific parishesin Louisiana). Use a minimum of 150 pounds of dryfertilizer per acre. Apply Command impregnatedfertilizer at pegging when rice is in the one- to two-leaf stage. Field must be drained prior to application.Delay reflooding for at least 48 hours.

PostemergenceAim – Contact broadleaf herbicide that controls

morningglory, hemp sesbania and jointvetch. Herbi-cide has no soil activity. Aim is more effective whentank-mixed with Grandstand or propanil.

Arrosolo – Herbicide is a mixture of propaniland molinate. Expect similar control to propanil.

Arrosolo, however, may be more active onlarger grasses than propanil when com-

pared at an equivalent rate andprovides up to one week of

residual control.

Basagran – Herbicidecontrols annual and yellownutsedge plus redstem,ducksalad and dayflower.Basagran is a contact herbicidethat must be applied to small,

actively growing weeds. Lowering the flood may berequired to expose weeds. Basagran may be appliedto ratoon rice.

Bolero – For dry-seeded rice, apply to wet soilafter rice has emerged or to dry soil when rice is inthe two- to three-leaf stage. For water-seeded rice,apply after rice is in the two-leaf stage. Treatment isusually tank-mixed with a postemergence herbicideand flushed or flooded within three days. Do notsubmerge rice when applying permanent flood.Residual control usually will not exceed three weeks.

Clincher – A contact grass herbicide thatcontrols barnyardgrass, broadleaf signalgrass, fallpanicum, knotgrass, and sprangletop. Clincher has noactivity on broadleaf weeds. Apply to small activelygrowing grasses in the two- to four-leaf stage.Clincher has activity as a post-flood treatment onfour-leaf to two-tiller grasses. Clincher works bestunder saturated soil conditions. Refer to label forapproved tank-mixes.

Facet – Herbicide will control barnyardgrass,signalgrass, jointvetch and hemp sesbania. Follow thelabel concerning the addition of crop oil or surfac-tants. Apply herbicide after rice is in the two-leafstage. Do not apply to rice in spiking stage.

Grandstand – Grandstand controlsalligatorweed, hemp sesbania, texasweed, jointvetchand other broadleaf weeds. It does not controlducksalad. Do not overlap swaths or dress endsduring application. Grandstand may be applied toratoon rice.

Hi-Dep 2,4-D – Herbicide controls mostbroadleaf weeds in rice. Apply herbicide after tilleringbut before panicle initiation. A shallow flood shouldbe present at the time of application. Hi-Dep is theonly formulation of 2,4-D that is labeled for ratoonrice.

Londax – Londax controls ducksalad,pickeralweed and other aquatic broadleaf weeds andsedges. The herbicide is most effective when appliedone to seven days after the permanent flood isestablished to submerged weeds. When appliedbefore permanent flood, tank-mix with propanil tobroaden weed control spectrum. Londax may beused for aquatic broadleaf weed control in areaswhere 2,4-D cannot be used.

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Ordram 15 G – Ordram controls barnyardgrass,seedling yellow nutsedge, fimbrystilis and spike rush.Apply to flooded field only. Successful grass controlwith Ordram can be accomplished if grass is at leasttwo-thirds submerged at the time of application.

Permit – Permit is very effective on annual andperennial sedges and hemp sesbania and jointvetch.Permit may be tank-mixed with other post-emergence herbicides to broaden weed controlspectrum. Label prohibits post-flood applications.

Propanil (common name of a herbicide soldunder several trade names) – Propanil is a contactherbicide that controls annual grasses, some sedgesand broadleaf weeds in the seedling stage. Bestcontrol is achieved when applied 10-14 days afterseeding. Propanil is often tank-mixed with a residualherbicide such as Command, Prowl or Bolero.

Regiment – A contact herbicide with activity onbarnyardgrass and broadleaf weeds. The herbicidehas little to no soil activity. Do not apply to riceprior to the three-leaf stage. Temporary crop injury,in the form of stunting, may occur. Refer to label forapproved surfactants and tank-mixes.

Ricestar – A contact grass herbicide thatcontrols barnyardgrass, broadleaf signalgrass, andsprangletop. Ricestar has no activity on broadleafweeds. Apply to small actively growing grasses in thetwo- to three-leaf stage. Ricestar works best undersaturated soil conditions. Refer to label for approvedtank-mixes.

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Table 4. Reaction of Rice Varieties to Major Diseases, Disorders and Insects

Narrow RiceBrown Brown Water Rice

Sheath Leaf Leaf Leaf Straight- Weevil StinkVariety Blast Blight Spot Spot Smut head Larvae Bug

Long Grain

Ahrent R S S MS S MR S S

CL161 S S MS MS MS MR S S

CL121 S S MR MS MS MS S S

CL141 VS S S MS S S S S

Cocodrie MS VS MR MR MS S S S

Cypress S S MR MR MS MR S S

Della S MS MR S MS S S S

Dellrose S S MR S MS MR S S

Dixiebelle MS S MR MS MR VS S S

Drew MR MS MR MR MR MS S S

Francis S MS MR MS MS MR S S

Jackson S S MR MS MR MR S S

Jasmine 85 R R MS-S R R VS S S

Jefferson MS S MR MR MR MS S S

LaGrue VS MS R-MR R R S S S

Lemont S VS MS-S S S MR S S

Maybelle VS VS S S S MR S S

Priscilla MS MS MR MR MR MS S S

Saber R S R MR MR R S S

TORO-2 R MS-S MR-MS MS MR-MS VS S S

Wells S MS R MR MS MR S S

XL6 R MR R MS R VS S S

XL7 R MS R S R MR S S

XL8 R MS R S R MR S S

Medium Grains

Bengal S MS MS MR MS VS VS VS

Earl MR MS R MS MR VS VS S

Mars S MS MS MR MS VS VS S

Rico 1 S MS S MS MS MR S S

Saturn MR MS-S MS S S S S S

R=Resistant, MR= Moderately resistant, MS=Moderately susceptible, S=Susceptible and VS=Very susceptible.Varieties labeled S or VS for a given disease may be severely damaged under conditions favoring diseasedevelopment.

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Table 5. Effectiveness of selected rice herbicides

Herbicide

PREPLANT BURNDOWN2,4-D 9 9 0 0 0 0 0 5 8 8 9 9 9 8 5 7 9Gramoxone Extra 8 9 9 8 9 9 9 53 6 7 9 9 7 8 4 7 9Grandstand 9 8 0 0 0 0 0 5 9 7 9 9 8 8 - 7 9Roundup 7 8 9 7 9 9 9 7 7 7 9 7 7 7 6 6 9

PREPLANT INCORPORATED OR PREEMERGENCENewpath 8 7 8 8 8 9 5 9 6 8 8 4 6 4 6 7 8

PREEMERGENCEBolero PPS 4 0 8 8 8 7 - 5 4 7 3 0 6 4 - 7 5Bolero (Delayed) 5 8 8 0 8 5 - 5 4 8 8 6 8 5 5 8 6Command 0 0 9 0 8 8 - 0 0 7 0 0 - 0 - 7 0Facet (Drill seeded) 8 8 9 0 0 9 5 2 4 3 4 7 6 7 0 5 4Ordram (PPI) 4 2 8 81 5 7 6 4 0 0 0 2 2 0 5 3 0Prowl (delayed drill seeded) 0 0 8 0 8 8 7 0 0 0 0 0 0 0 0 0 0

POSTEMERGENCE2,4-D Amine 9 9 0 0 0 0 0 23 8 9 9 9 9 5 6 8 9Aim4 8 6 0 0 0 0 0 5 5 4 6 9 - 9 - 5 -Aim + Grandstand 9 8 0 0 0 0 0 5 8 6 9 9 8 9 - 6 9Arrosolo 6 9 9 0 82 9 82 53 5 82 72 9 9 92 62 82 8Basagran 8 8 0 0 0 0 0 8 4 8 9 4 8 3 72 9 2Blazer 5 4 0 0 0 0 0 0 4 3 9 9 0 0 0 0 5Bolero + Propanil 5 9 9 0 9 9 - 7 5 72 72 9 9 82 62 82 8Clincher 0 0 9 0 9 9 8 0 0 0 0 0 0 0 0 0 0Facet 8 9 9 0 0 9 52 4 6 3 3 8 3 8 0 3 6Facet + Propanil 8 9 9 0 72 9 82 53 6 72 72 9 8 92 62 72 8Grandstand 9 8 0 0 0 0 0 5 8 6 9 9 8 8 - 6 9HiDep 2,4-D 9 9 0 0 0 0 0 23 8 9 9 9 9 5 6 8 9Londax 5 8 0 0 0 0 0 8 7 9 9 6 9 6 6 8 8Newpath 8 6 8 8 6 9 4 8 3 2 8 3 6 3 4 6 74

Ordram 0 5 9 0 5 7 - 5 0 0 0 2 2 0 4 6 2Permit - - 0 0 0 0 0 9 4 5 - 9 - 9 - 8 -Permit + Londax 5 8 0 0 0 0 0 9 7 9 9 9 9 9 - 8 8Propanil 5 8 9 0 72 9 82 43 5 62 72 7 8 82 62 62 6Propanil + Aim 9 8 9 0 7 9 82 6 5 6 7 9 8 9 82 6 6Propanil + Londax 9 9 9 0 72 9 82 9 7 7 9 9 8 92 8 82 9Prowl & Facet 8 8 9 0 8 9 52 4 6 3 2 8 4 7 0 3 6Prowl + Propanil 5 9 9 0 9 9 82 5 5 7 9 9 82 82 62 7 6Regiment 8 6 9 0 3 3 0 73 7 82 8 8 7 8 7 7 84

Ricestar 0 0 9 0 8 9 72 0 0 0 0 0 0 0 0 0 01With proper water management 5Soil-applied preplant incorporated or preemer-2Controlled only when small (less than two-leaf) gence only, with no activity applied3Annual sedge suppression postemergence.4Weeds must be less than 4 inches tall

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Table 6. Crawfish Production and Rice Herbicide Guidelines

Aim Commercial crawfish not specifically mentioned; however, herbicide is moderately toxic to fish.

Arrosolo Commercial crawfish production not specifically mentioned; however, herbicide is consideredextremely toxic to fish, and drift and runoff may be hazardous to aquatic organisms inneighboring areas.

Basagran Do not use Basagran on rice fields in which the commercial cultivation of crawfish is practiced.

Blazer Do not harvest crawfish from treated rice areas for food.

Bolero Crawfish production not specifically mentioned. Toxic to shrimp.

Command Do not apply on rice fields in which concurrent crawfish farming is included in the culturalpractices.

Duet Do not apply to fields where commercial crawfish farming is practiced.

Facet Do not use treated fields for aquaculture of edible fish or crawfish.

Grandstand Do not grow shellfish or crustaceans commercially on treated acres during the year oftreatment.

Hi-Dep Commercial crawfish production is not specifically mentioned; however, the label statesproduct is toxic to aquatic invertebrates.

Londax Do not harvest crawfish prior to harvesting rice.

Ordram 15G Crawfish not specifically mentioned. Product is extremely toxic to fish, however.

Permit Crawfish production not specifically mentioned in restrictions.

Prowl Crawfish not specifically mentioned. Product may be hazardous to aquatic animals.

Ricestar Ricestar must not be applied to fields where crawfish are commercially cultured.

RoundupUltra Max Crawfish production not mentioned in restrictions. Herbicide cannot be applied to areas

where surface water is present.

Stam Crawfish not specifically mentioned in restrictions. Commercial catfish production prohibited.

Storm Do not use Storm on rice fields where commercial crawfish production is practiced.

2,4-D (UAP) Commercial crawfish production not specifically mentioned. May be toxic to aquaticinvertebrates.

Whip Do not apply in areas where crawfish are commercially cultivated.

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Table 7. Icon† Insecticide Rates as Influenced by Seed Treatmentand Planting Rate

Pounds of Active Ingredient per Acre

Rate of Icon† Rough Rice Seeding Rates (lbs. per acre)per 100 lbs.of Seed(fl. oz.) 80 90 100 110 120 125 130 140 150

0.35 0.014 0.016 0.017 0.019 0.021 0.022 0.022 0.024 0.026

0.40 0.016 0.018 0.020 0.022 0.024 0.025 0.026 0.028 0.030

0.50 0.020 0.022 0.025 0.027 0.030 0.031 0.032 0.034 0.037

0.60 0.024 0.027 0.030 0.032 0.035 0.037 0.038 0.041 0.044

0.70 0.028 0.031 0.034 0.038 0.041 0.043 0.045 0.048 0.052

0.80 0.032 0.035 0.039 0.043 0.047 0.049 0.051 0.055 0.059

0.90 0.035 0.040 0.044 0.049 0.053 0.055 0.058 0.062 0.066

1.00 0.039 0.044 0.049 0.054 0.059 0.062 0.064 0.069 0.074

1.10 0.043 0.049 0.054 0.060 0.065 0.068 0.070 0.076 0.081

1.20 0.047 0.053 0.059 0.065 0.071 0.074 0.077 0.083 0.089

1.25 0.049 0.055 0.062 0.068 0.074 0.077 0.080 0.086 0.092

- Active ingredient is not within label limits on a per acre basis

- Active ingredient is within label limits on a per acre basis

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Visit our Web site: www.lsuagcenter.com

This publication is available through the LSU AgCenter’s rice Web page at: www.lsuagcenter.com/subjects/rice/ricehome.htm

SummaryThis publication was prepared by the following personnel of the Louisiana State University

Agricultural Center:

Dr. John Saichuk, AgronomyDr. Pat Bollich, Agronomy

Dr. Boris Castro, EntomologyDr. Tim Croughan, BiotechnologyDr. Richard Dunand, Physiology

Mr. Eddie Eskew, County Agent (Jeff Davis)Dr. Donald Groth, Pathology

Dr. Clayton Hollier, PathologyDr. Steve Linscombe, Rice Breeding

Dr. Michael Stout, EntomologyMr. Ron Strahan, Weed Science

Mr. Shane Theunissen, AgronomyDr. Eric Webster, Weed Science

Mr. Larry White, Foundation Seed

Louisiana State University Agricultural CenterWilliam B. Richardson, ChancellorL. J. Guedry, Executive Vice ChancellorLouisiana Agricultural Experiment StationWilliam H. Brown, Vice Chancellor and DirectorLouisiana Cooperative Extension ServicePaul D. Coreil, Vice Chancellor and DirectorPub. 2270 (4M) 10/02 Rev.Issued in furtherance of Cooperative Extension work, Acts of Congress of May 8 and June 30, 1914, incooperation with the United States Department of Agriculture. The Louisiana Cooperative ExtensionService provides equal opportunities in programs and employment.