Download - FACT SHEET: C. patherina - agriculture.gov.fj(Chrysomelidae), a leaf feeding beetle was introduced into Fiji from Papua New Guinea in 1997 to control Broom weed. • C. pantherina

Agriculture Fact Sheet

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INTRODUCTION• ThemalvaceousweedSida acuta(sida)Burmanf.(Asteraceae;hereafterBroomweed)issmall,erectshrub,usuallygrowingtoaheightofabout1metre.

• Thestemsarewoody,branchingseveraltimes,and there is a well-developed tap root. Theleavesarelance-shaped(taperedatbothends)withserratedmargins.

• The flowers are yellow, usually solitary orgrowinginpairsintheleafaxils.Seedcapsulesdivideintofivetoeightportions,eachofwhichhas two sharp points approximately 1.5 mmlongatoneend.

• Broom weed is native to Mexico and CentralAmericabuthasspreadthroughoutthetropicsandsubtropics.IthasbeenfoundtoaffectbothcropandlivestockproductioninFiji.

• Calligrapha pantherina (Calligrapha) Stål(Chrysomelidae), a leaf feeding beetle wasintroduced intoFiji fromPapuaNewGuinea in1997tocontrolBroomweed.

• C. pantherinawasrearedandreleasedinvariousislandswhichincludesthemainislandVitiLevu,Taveuni,Kadavu,Gau,Koro,Beqa,OvalauandpartofVanuaLevubetween1997and2008.

Figure 1 & 2:Broomweedinflorescence

OBJECTIVETheprincipleaimof thisstudywas tounderstandthecurrentstatusofC. pantherina inthefieldandlifetablestudiesforfuturemassproductionofC. pantherinatocontrolbroomweed.

MATERIALS & METHODS• Observations were made in field conditionsand further tested in laboratory conditions toascertainthelife-tableofC. pantherinaformassproduction.

• Biology of C. pantherina was studied underlaboratory conditions (room temperatureranging from 24°C to 28°C with a relativehumidity varying from 65 to 70%) during2017-2018.Thiswas todevelopmass rearingtechniquesforthebiologicalcontrolagent.

• Thefreshlylaideggsretrievedfromthepottedhost plant (Broom weed) was kept underobservationwithdailyrecordingofthelifecycledevelopments.

Prevalence and life-table studies of Calligrapha pantherina, biological control agent for Sida acuta

For more information contact: Ministry of Agriculture Raiwaqa or Koronivia on:Phone: (679) 338 4233 / 340/ Fax: (679) 340 0262 Website: www.agriculture.gov.fj Facebook: Ministry of Agriculture Fiji

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Agriculture Fact Sheet

RESULTS & DISCUSSION• Prevalenceofbiocontrolagent• Field observations revealed thatC. pantherina has been established and spreading fromwhereveritwascontinuouslyreleased.BothC. pantherinalarvaeandadultdefoliatetheleavesandfloweroftheplant.

LIFE TABLE STUDY• Thetotalincubationperiodoccupied2to7days(percentagesurvival81%) fromeggs to larvalstage,11to20days(percentagesurvival46%)forfromlarvaltopupastageand3to11days(percentagesurvival72%) fromPupa to adultstage.

• Thedatawascollectedoveraperiodofoneyearunderstandardlaboratoryconditions.

• ThepopulationofmaleC. pantherinaemergencefrompupastagewasslightlyhigherascomparedto femalewithmale to femalesex ratioof5:4recorded.

• Adult longevity data clearly showed thatmalehadshorterlifespanascomparedtofemale.

Figure 3 - 5: RearingofC. pantherinainlaboratoryanddamagesymptomsCONCLUSIONThe findings from the field observations revealedthat C. pantherina has been established andspreading from its released sites. The life-tablestudy over a period of one year under laboratoryconditions for C. pantherina revealed that massproductioncanbesuccessfullydone inamonth’stime.ThesexratiosofemergedC. pantherinaunderlaboratory conditions were estimated to be 5:4(maleandfemale)andmaleshadshorterlifespanthanfemales.

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Figure 6: Life cycle of the Calligrapha pantherina