fact sheet: c. patherina - agriculture.gov.fj(chrysomelidae), a leaf feeding beetle was introduced...
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Agriculture Fact Sheet
FACT SHEET:C. patherinaby Plant Protection UnitM
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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
Twitter: Fiji Agriculture Email: [email protected]
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