Students learn to identify and manage insect pests on a cranberry bog. How do growers identify, monitor populations of, and control insect pests?

Transcription

1 Challenges Await Yu Bugs n the Bg Students learn t identify and manage insect pests n a cranberry bg. Hw d grwers identify, mnitr ppulatins f, and cntrl insect pests? Lessn Overview In this lessn students cntinue t manage their adpted bgs by respnding t insect pest threats with an apprach called Integrated Pest Management (as described in Backgrund). T be successful students must carefully bserve samples f insects fund in their bgs and identify which stages f the life cycle are represented in these samples. They als use infrmatin abut pest treatment t decide n a respnse strategy. Because the success f many pest treatments depends upn carefully matching the treatment t the pest s stage f develpment, this lessn prvides an pprtunity fr students t reinfrce their knwledge f insect life cycles. Backgrund Insect pests and IPM There are many different kinds f insects that can be fund n a cranberry bg. Over twenty insects can cause cnsiderable damage t a cranberry crp. These include the cranberry girdler, the cranberry fruitwrm, weevils, and cutwrms. Fr the purpse f this lessn, the insect pest fcus is n the gypsy mth caterpillar, the black-headed firewrm, the brwn spanwrm and the false armywrm. It is essential t understand that nt all insects fund n a cranberry bg are destructive t the cranberry plant. Harmless visitrs t the bg include butterflies, sme mths, and wasps. Of curse, bees are majr cntributrs t the survival f the cranberry crp, serving as critical pllinatrs. There are als beneficial insects that parasitize the eggs f ptential pests. Fr example, the trichgramma wasp lays its eggs inside the eggs f the cranberry fruitwrm. When the wasp eggs hatch, the larvae cnsume the fruitwrm eggs. It is very imprtant, therefre, that insects are nt destryed indiscriminately. Integrated Pest Management (IPM) is a brad based apprach t insect cntrl which takes int cnsideratin eclgical, scietal, and ecnmic cncerns. IPM Bugs n the Bg Page 1 f 6

2 seeks t carefully weigh and intelligently cmbine multiple strategies t effectively manage harmful pest ppulatins. A critical cmpnent f IPM is the cranberry grwer s awareness f the different types (and numbers) f insects - bth harmful and beneficial - that are part f the cranberry ecsystem. Sweep netting is ne tl that allws farmers t mnitr their bgs as they cllect, identify, and cunt their insect ppulatin. Typically, cranberry grwers sweep net their bgs weekly frm the time buds first appear in the early spring until late August when berries are abundant. Once grwers understand the nature and makeup f the insect ppulatin, they can take carefully cnsidered actins t prevent and limit crp damage. Cranberry farmers utilize a prtcl t identify when it is time t take steps t limit harmful insect ppulatin. This is called an actin threshld. An actin threshld is the numerical ceiling advised fr a particular pest ppulatin. Once that ceiling is reached, grwers knw t take actin. Sme pest management strategies include: trapping insects, which utilizes hrmnes that attract adults t sticky traps; this enables grwers t mnitr ppulatin grwth and time treatment strategies. use f bilgical agents (such as bacteria) which target specific pests and yet are benign t ther insects. chemical cntrls. specific farming practices which include shrt term flding and/r extra sanding f the bg t inhibit the grwth f an insect ppulatin. Nte: Additinal infrmatin n these methds is prvided in the student resurce, Brief, What is IPM? This infrmatin is intended fr yu as well the students t better understand IPM. Materials Explring Cranberries Web Resurces: Challenges Await Yu Intrductry Presentatin (ptinal) Demnstratin Sweep Net Sample Bugs n the Bg Page 2 f 6

3 Student Web Resurces: Blue Sky Bg Sweep Net Sample Sunrise Bg Sweep Net Sample Student Wrksheets: Bugs n My Bg: Sweep Net Results (2 per student pair) Bugs n My Bg: Taking Actin (1 per student pair) Student Handuts: Brief: Insects n Yur Bg? (1 per student pair) Brief: What is IPM? (1 per student pair) Preparatin 1. Print all student wrksheets and handuts listed in Materials. 2. Optinal: Make additinal cpies f Bugs n My Bg: Sweep Net Sample Results (1 cpy per student pair) t supprt Optinal Step Set up the cmputer statins s that students can access the web resurces fr this lessn. Plan t have students wh adpted the same bg wrk tgether in pairs at the cmputer statins. 4. Arrange t prject Demnstratin Sweep Net Sample t the whle class. Lessn 1. Set the stage fr this lessn by inviting students t reflect n prblems the bg may encunter during the springtime. (T launch this cnversatin, yu might find it helpful t review all r part f the Challenges Await Yu Intrductry Presentatin.) Recrd all respnses. If students have nt already dne s, help guide them t the understanding that spring is when insects (typically in the larval stage) are very busy, grwing and feeding. Bugs n the Bg Page 3 f 6

4 2. Advise students that during tday s lessn they will manage their adpted bgs t prtect them frm insect pest damage. 3. If this is yur students first encunter with a lessn frm Challenges Await Yu, intrduce the meeting as a way t learn mre abut managing a cranberry bg t discuss decisins, get advice, etc. 4. Cnvene a meeting abut insect pests and the challenge f managing them. Distribute Insects n Yur Bg? Read and discuss as a grup. 5. Tell students that during this meeting, the class will examine ne sweep net sample tgether and make a decisin as t an apprpriate pest management plan. This demnstratin sample will help prepare students t face their wn challenges with their adpted bgs. 6. Prject Demnstratin Sweep Net Sample fr the class t view. Explre the page tgether, using the fllwing questins t guide student thinking: What d yu see? Describe the insects. At what stage f the life cycle are these insects? Why is there mre than ne type f insect? Other than insects, what else d yu see n this page? Hw d peple rganize infrmatin in rder t understand it better? What are sme ways we culd rganize the insect infrmatin n this page? If students have nt already suggested a bar graph, ask: What is a bar graph? Hw des a bar graph display infrmatin? 7. Explain t students that the class will cllectively create a bar graph f the insects in this sample. 8. As yu, the teacher, click n a particular insect, invite students t determine its apprpriate lcatin n the hrizntal axis. Drag that insect t its lcatin. Cntinue t cmplete the graph tgether. 9. Distribute t each student pair the student wrksheet, Bugs n My Bg! Sweep Net Sample Results. Tell students t use infrmatin frm the graph and the Grwers Brief t cmplete the student wrksheet. Bugs n the Bg Page 4 f 6

5 10. Have students determine if any the insects in this sample pse a threat t their cranberry crp. Nte: All students shuld cnclude that at this time n insect pses a threat t the bgs. 11. Explain t students that they will nw examine a sweep net sample frm their adpted bgs. Direct students t the apprpriate student web page (either Blue Sky Bg Sweep Net Sample r Sunrise Bg Sweep Net Sample). 12. Distribute a secnd cpy f the student wrksheet, Bugs n My Bg! t each student pair. 13. Allw minutes fr students t cmplete their sweep net bar graph and recrd the relevant infrmatin n their student wrksheet, Bugs n My Bg! 14. Recnvene the and invite students t reprt their findings. Nte: The numbers f gypsy mth larvae n Sunrise Bg exceed the actin threshld while the numbers f false army wrm exceeds the actin threshld n Blue Sky Bg. Therefre, the results f the sweep will require students t take actin, n matter which bg they have adpted. 15. The rest f this lessn challenges students t slve their insect pest prblems. Raise the questin, What actins are pssible? Discuss. 16. Distribute What is IPM? Read and discuss, addressing the fllwing questins: What are sme typical treatments cranberry grwers use t manage insect pests? What is the benefit t the bg when using these ptins? What is the risk t the bg using these ptins? Are there any treatments that pse n risk? 17. Intrduce student wrksheet, Taking Actin. Instruct students t use this table t rganize their infrmatin and decide n a curse f treatment fr their prblem insect pests. 18. After student pairs have cmpleted Taking Actin, rganize same bg student pairs int discussin grups (2 t 3 student pairs per grup). NOTE: As in the real wrld, there is n ne right answer t this challenge. This Bugs n the Bg Page 5 f 6

6 lessn prvides a rich pprtunity fr students t defend their psitins with data. Explain t students that each student pair shuld review their data gathering and decisin making with the rest f the small grup. Direct the small grups t address the fllwing discussin questins: What insects psed a threat t yur cranberry crp? What were sme treatment ptins that yu cnsidered? What treatment ptins did yu reject? Why? Which treatment did yu select? Why? Wuld yu nw change yur decisin based n the cmments f the ther members f yur grup? 19. OPTIONAL: If yu wish, yu might have pairs f students wh have adpted Sunrise Bg exchange data with student pairs wh have adpted Blue Sky Bg, s that these teams might serve as cnsultants t each ther. This prvides and additinal pprtunity fr students t practice the IPM analysis and cmmunicatin abut decisins in depth. 20. Assign each student a writing piece fr Bg Blg, where they prvide a ratinale fr their pest management strategy r critically respnd t ther student grwers decisins. Bugs n the Bg Page 6 f 6