Pests and Diseases

1. Pests and Diseases 28.00: Examine distinguishing characteristics of pests so as to determine best management practices. 29.00: Compare methods of control of horticulture plant pests.

2. What is an insect? • Small animals that have three body regions and three pairs of legs equaling six legs • Body regions • head • thorax • abdomen

3. Types of Insects • The five types of mouthparts are important in identifying and controlling insects. • Chewing • Piercing • Rasping • Siphoning • Sponging

4. Chewing Insects • Insects tear, chew or grind food • Examples • grasshopper • beetle

5. Piercing Insects • Punctures plant and sucks the sap

6. Rasping insect • Rasps or breaks surface and sucks sap • Example • thrips

7. Siphoning insects • Have a coiled tube they dip into liquid food such as nectar and draw it in • Example • butterfly

8. Sponging Insects • Have two sponge-like structures that collect liquid food and move it into the food canal • Example • housefly

9. Life Cycles • Complete metamorphosis has four stages • egg • larva-worms or caterpillars • pupa • adult-flies, beetles, etc.

10. Life Cycles • Incomplete metamorphosis has three stages • egg • nymph • adult

11. Life Cycles

12. Chewing Insects • Parts of leaves are eaten away • beetles • cutworms • caterpillars • grasshoppers

13. Chewing Insects • Beetles • eat leaves, stems, flowers, fruit and nuts • Cutworms • usually attack stems, but may eat other plant parts

14. Chewing Insects • Caterpillars • larva of moths and butterflies • fuzzy or hairy • eat young leaves and stems • roll up in leaves making leaves curl • Grasshoppers • eat all parts of plants

15. Sucking Insects • Aphids • Leaf bugs • Mealy bugs • Scale • Thrips • Whiteflies

16. Aphids • Pierce and suck juices • known as plant lice • cause stunted growth and yellow spotted leaves • causes sticky substances and black mold • will attract ants

17. Aphids

18. Leaf Bugs • Cause plants to look unhealthy • plants will lose their normal color and wilt

19. Leaf Bugs

20. Mealy Bugs • Pierce and suck from underside of leaves and in leaf axils causing yellow appearance and sticky secretions

21. Mealy bugs

22. Scale • Appear as black or brown raised lumps attached to stems and underside of leaves causing yellow leaves and stunted growth

23. Scale

24. Thrips • Chew and then suck causing plant tissue to become speckled or whitened, leaf tip to wither, curl up, or die

25. Thrips

26. Whiteflies • Feed on underside of young leaves causing yellowing • will look like flying little white specks when plants are shaken

27. Whiteflies

28. Mites • Attack underside of leaves causing gray to grayish-green spots • severe infestations cause webbing

29. Mites

30. Plant Diseases

31. Diseases • A disease is a plant disorder caused by an infectious pathogen or agent

32. Diseases • There are 3 conditions necessary for diseases in plants • host plant • disease causing organism or pathogen must be present • favorable environment for disease organism to develop

33. Pathogens • There are four groups of pathogens • bacteria • fungi • viruses • parasitic plants (attach to plants) • mistletoe • dodder • lichens

34. Blight • Causes plants to quickly turn brown or black as if they had been burned

35. Blight

36. Canker • Causes open wounds on woody plants

37. Canker

38. Damping off • A fungal disease that causes young plants and seedlings to rot off at soil level

39. Damping Off

40. Gall • Swellings or growths on plants

41. Leaf Spots • Rings of different shades of brown, green or yellow that make spots on leaves

42. Mildew • Grows on leaf surfaces--both upper and lower--as white, gray or purple spots

43. Mosaic • Caused by viruses that make the leaves have irregular mottled areas with patterns ranging from dark green to light green to yellow to white

44. Mosaic

45. Rots • Cause plant to decay and die

46. Rust • Causes small spots on leaves that resemble yellow, orange, brown or red rust mainly on the underneath side of leaves

47. Rust

48. Smut • A black, powdery disease that causes blisters that burst open releasing black spores

49. Smut

50. Wilt • A disease that blocks the uptake of water in plant stems causing plants to wilt