Understanding Insects as Friends or Foes

Transcription

1 Grade Level: 2 Understanding Insects as Friends or Foes Approximate Length of Activity: One class period Objective Teacher 1. Discuss good and bad insects. 2. Share with the students the methods that farmers use to control insects. 3. Discuss insect life cycles Students 1. Will learn about good and bad insects and the role that insects play in agriculture. 2. Discuss insect life cycles and methods for controlling them. Michigan Content Standards: () S.IA.02.12, L.OL Introduction Today we are going to talk about crops and orchards and insects. Insects can be found nearly everywhere. Some insects are helpful to man. Other insects are harmful and cause damage to trees and crops. Farmers and growers need to know which insects are friends and which are not. Today you will learn about good and bad insects. Materials Needed Insect pictures (included) Citronella candles Access to a board to write on 3 Scents (vinegar, vanilla, potpourri) 3 jars for scents Stickers Copies of Insect Trap for each student Find and Seek worksheets Insect Key One good apple, one bad apple Example of a growers trap with record sheet on back Envelopes labeled containing 20 of each of the insects included in this lesson One copy of Plant Life Cycle diagram One copy of Insect Life Cycle diagram 39

2 Activity Outline 1. Divide students into groups. 2. Introduce insects. 3. Discuss insect control. 4. Discover scouting. 5. Discuss life-cycles. 6. Pass out Find and Seek worksheets. 7. Trap retrieval. 8. Review. 1. Divide students into groups Explain: As we look at pictures, put your thumbs up if it s good and down if it s bad for each of the following insects. Use accompanying pictures of insects. Ladybug-Ladybugs are good, they eat aphids, mealy bugs and scale mites. They can eat up to 24 insects every day. Praying Mantis-Praying Mantises are good; they eat cut worms, beetles, flies, aphids, and insect eggs. They eat much more than they weigh. Honey Bees- They re also a thumbs up. They help pollinate crops and produce honey. Grasshopper-A grasshopper is a thumbs down. That s because grasshoppers eat crops and can do a lot of damage. Tomato Horn Worm- Tomato Horn Worm is thumbs down. You may see him on a tomato plant. Gypsy Moth-This is a gypsy moth, it can be very dangerous to trees and other crops. Show a good and bad apple. Ask: Which apple would you like to eat? (Good apples are best) Discuss why are we concerned about insects in our food? Answer: Insects carry diseases; damage crops, make fruits and vegetables look bad and limit available food. 2. Introduce insects Ask: What are some of the bugs you deal with? (Some responses might be: black flies, houseflies, spiders, mosquitoes, wasps, bees, aphids, yellow jackets, hornets, fleas, lice and ants, or little brother/sister.) 3. Discuss insect control Ask: How do you control or get rid of these bugs? (Some responses might be: swat or hit, stomp, fly strips, traps, natural predators, net, molasses, rubbing posts, flea collar, candles, ear tags and sprays.) 40 Where do you use sprays? Do you use something to control mosquitoes?

3 What else can you use instead of sprays? Show example of Citronella candles. In addition to spays, citronella candles, like this one can be used. Also a bug zapper, fly swatter, fly paper strips, fly or ant traps can all be used. What do you think farmers/growers use to control insects? Write these words on the board: Crop Spray or Powder Crop Rotation Good Insects Sometimes farmers use sprays and powder on their crops for each specific bug. The farmers use as little as needed to protect the environment. Do farmers grow the same crop every year? No, and it s called crop rotation. Certain bugs like certain crops. By growing different crops year after year, bugs will leave to find crops they like. Farmers also use good or beneficial insects to protect their crops and get rid of harmful insects. Who can tell the class the good bugs? (Answers: Ladybugs, Praying Mantis, Honey Bee) Some insects are harmful and can do a lot of damage to crops and orchards. Do you remember what insects these are? (Answers: Grasshoppers, Tomato Horn Worms and Gypsy Moths) 4. Discover Scouting and Make Traps Explain: Farmers and growers must watch their fields or orchards closely. Farmers look on the leaves of the trees or plants for insects. This is called scouting. To help find the insects, farmers use traps. When pests are found that could damage the crop the farmer/grower must choose the best way to rid of the pest. You are going to make your own traps a little later. Traps are hung in fruit trees, in greenhouses and on posts in fields for other crops. Contact a MSU Extension Educator for information on locating a trap to show your class. This is a scent (show scent), called a pheromone inside the trap; this attracts the bugs to the trap. The trap is sticky inside, so when the bugs fly into the trap to smell the pheromone they get stuck. Now the entire class will make their own trap. See included instructions and pass out trap page. After assembled, place traps in a location to fill with bugs. 5. Discuss Life-Cycles Ask: Does anyone remember life cycles? Hold up illustrations of insect life stages. Back in first grade you might have studied the life cycle of a butterfly. Today we re going to learn about the life cycle of insects and plants. Insects and plants have different life cycles or stages. Insects start as an egg, develop into a larvae, and then a pupa and adult. 41

4 Hold up illustrations of plant life stages. Plants start with a seed. The seed is planted and it germinates. It then grows into a seedling, a mature plant and finally produces a flower or fruit. A fruit can be a flower, apple, tomato, or as in field crops, corn or soybeans. Put life cycles on board or bulletin board. 6. Pass out Scent Test worksheet Show the scents. These are going to be our pheromones today, remember they attract certain insects. Scientists have figured out what smells insects like the best and growers use those scents to attract the insects into the trap. Now have students choose which pheromone they like best. Display scents with a piece of paper. Smell each of the three different smells. Put your sticker on the paper you like the best and return to your seats. Have the students report to the class which scent they like the best and record it on the board. (Scent #1 vanilla; Scent #2 vinegar; Scent #3- potpourri) Instruct: Now have students complete the bar graph worksheet using a crayon or marker to color the graph completely up through the number of scents 1,2 and Trap Retrieval Before trap retrieval place the included insect pictures in the traps. Dismiss the class to retrieve their traps, waiting until everyone is seated before they look inside. Does everyone know what kind of insects you found in your trap? Sometimes farmers need help identifying the insects they find. They use a key, or guide like this one. A key uses color, the number of legs or other things to determine what bug they have found. Choose two insects from your trap, one that looks like an adult and one that looks like a worm. To use the key, follow the arrows and answer the questions. Pass out Key. Farmers check their traps at least one or two times a week or more if necessary. They use a key to identify insects. Record the insects you found in your traps as a group on the lab sheet. Farmers record on the trap. Refer back to the trap each student has. The record is printed on the reverse side of the trap. If you were a farmer and had more good insects, that s good! If you were a farmer and had more bad insects you would need to use crop rotation, sprays or good bugs to help your crops. 8. Review Using traps, scouting, identifying insects and controlling insects are all important for farmers to understand. American farmers are the most productive farmers in the world. They produce safe and abundant food. 42

5 Discussion Questions 1. What are some examples of good insects? 2. What are some examples of bad insects? 3. Why are insects considered friends? Why are they considered foes? 4. How do farmers get rid of the bad insects? Related Activities 1. Contact your local Michigan State University Extension specialist to visit the classroom and talk more about insects. 2. Schedule a field trip to an orchard or have a farmer visit the classroom and talk about how they use good insects and how they control insects. Resources 1. Bugs, Bugs, Bugs! by Mary Reid 2. Bees by Ann Heinrichs 3. Nature s Friends, Ladybugs by Anne Heinrichs 4. Praying Mantises (A True Book) by Larry Dane Acknowledgement: This lesson was provided by the Michigan Farm Bureau Promotion & Education Department. 43

6 Instructions on How to Make a Trap 1. Pass out Trap Page to students. 2. Have students write their name on the back of the trap. 3. Have students put their trap on their desk name-side down. 4. Fold on the dotted lines 1 and 2, then unfold them and carefully cut on the solid cut lines, just to the dotted lines, not past the dotted lines. 5. Now fold lines 3, 4 and 5 and hold your trap at the top X and tape it. 6. Have students hang their trap on the wall. See if you catch anything. 44

7 45

8 46

9 47

10 48

11 49

12 50

13 51

14 52

15 53

16 54

17 55

18 56

19 57

20 X 58

21 59

22 60

23 Scent Test Worksheet 61

24 62