Whole Manual - Michigan State University: Integrated Pest ...

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C 6 H A P TE R WEED MANAGEMENT LEARNING OBJECTIVES After completely studying this chapter, you should: ■ Be able to define a weed and its four stages of development. ■ Understand the differences between annual, biennial, and perennial weeds. ■ Be able to give examples of cultural weed controls. ■ Know the advantages and disadvantages of the various methods of herbicide applications. ■ Understand herbicide carryover and how to prevent it. ■ Know what herbicide adjuvants are. Weeds are plants growing where they are not wanted. They can reduce yields by competing with crops for water, nutrients, and light. Some weeds release toxins that inhibit crop growth; others may harbor insects, diseases, or nematodes that attack crops. Weeds often interfere with harvesting operations, and at times contamination with weed seeds or other plant parts may render a crop unfit for market. Profitable crop production depends on effective weed control. DEVELOPMENT STAGES Most crop plants and weeds have four stages of development: ■ SEEDLING—small, delicate, newly emerged plants. ■ VEGETATIVE—plant grows quickly, producing stems, roots, and leaves. ■ SEED PRODUCTION—plant’s energy is directed into producing flowers and seeds. ■ MATURITY—plant produces little or no energy. Some plants begin to dry out or desiccate. LIFE CYCLES OF WEEDS Weeds can be classified according to their life cycle. The three types of plant life cycles for weeds are annual, biennial, and perennial. ANNUAL Plants that complete their life cycle in one year are annuals. They germinate from seed, grow, mature, produce seed, and die in one year or less. Annuals reproduce by seed only and do not have any vegetative reproductive parts. Summer annuals may germinate from seed in the spring, flower and produce seed during the summer, and die in the summer or fall. Winter annuals germinate from seed in the fall and reproduce and die the following year. Annual weeds are easiest to control at the seedling stage. Cocklebur. Vegetable Crop <strong>Pest</strong> Management 51 Chapter 6
BIENNIAL Biennials complete their growth cycle in two years. The first year, the plant produces leaves and stores food. The second year, it produces fruits and seeds. Biennial weeds are most commonly found in no-till fields, pastures, and unmowed fencerows. They are easiest to control in the seedling stage. PERENNIAL Perennials are plants that live for two or more years. Perennials can reproduce by seed or vegetatively. The plant parts that allow perennials to spread without producing seeds are stolons (creeping aboveground stems—e.g., white clover and strawberries), rhizomes (creeping belowground stems— e.g., milkweed, quackgrass), tubers (enlarged underground stems— e.g., potato, yellow nutsedge), and bulbs (underground stem covered by fleshy leaves—e.g., tulip). Because perennial weeds can propagate (spread) underground, they can be the most difficult weeds to control. Removing the aboveground vegetation will not stop the weed from spreading. Annuals, biennials, and perennials can reproduce from seed. Many weeds produce large quantities of seeds. Seeds are easily dispersed across a field by wind, rain, machinery, animals, and people. Weed seeds can germinate after being dormant for long periods of time. They can also tolerate extremes in weather such as temperature and moisture. To prevent seed dispersal, you should control weeds before they produce seeds. COMMON WEEDS IN MICHIGAN GRASS AND GRASSLIKE WEEDS Annuals ■ ■ ■ ■ ■ ■ ■ ■ ■ Barnyard grass Large crabgrass Smooth crabgrass Giant foxtail Yellow foxtail Green foxtail Fall panicum Wild-proso millet Witchgrass Bull thistle is a biennial. Johnsongrass is a creeping perennial. Monocot or Grass plant. Perennials ■ ■ ■ Johnsongrass Yellow nutsedge Quackgrass BROADLEAF WEEDS Annuals ■ Ladysthumb ■ Pennsylvania smartweed ■ Wild buckwheat ■ Common lambsquarters ■ Redroot pigweed ■ Eastern black nightshade ■ Common cocklebur ■ Jimsonweed ■ Common purslane ■ Common ragweed ■ Giant ragweed ■ Velvetleaf ■ Common chickweed ■ Shepherd’s purse ■ Horseweed (Marestail) ■ Prickly lettuce ■ Wild mustard ■ Yellow rocket Biennials ■ White campion ■ Wild carrot ■ Bull thistle Perennials ■ Milkweed ■ ■ ■ ■ ■ ■ ■ ■ Hemp dogbane Canadian thistle Dandelion Field bindweed Perennial sow thistle Swamp smartweed Goldenrod Plantain Yellow Nutsedge. Redroot Pigweed. Velvetleaf. Chapter 6 52 Vegetable Crop <strong>Pest</strong> Management
Page 1 and 2:
Vegetable Crop Pest Management A Gu
Page 3 and 4:
Acknowledgements We would like to e
Page 5 and 6:
General Vegetable Insect Pests . .
Page 7 and 8: vi Vegetable Crop Pest Management
Page 9 and 10: accurately written records of field
Page 11 and 12: Ladybird beetle adults and larvae c
Page 13 and 14: Phytotoxicity—when a pesticide da
Page 15 and 16: 19. How are tolerance and pesticide
Page 17 and 18: Always: ■ Select pesticides label
Page 19 and 20: ■ Select the least hazardous pest
Page 21 and 22: C 2 H A P TER Review Questions Chap
Page 23 and 24: 16 Vegetable Crop Pest Management
Page 25 and 26: Hydraulic Sprayers Water is most of
Page 27 and 28: Nozzles Nozzles are important to co
Page 31 and 32: 24. Granular applicators are design
Page 33 and 34: will not double the flow rate - you
Page 35 and 36: 6. The average output of the nozzle
Page 39 and 40: 32 Vegetable Crop Pest Management
Page 41 and 42: stages. Larvae and adults are often
Page 43 and 44: down into the crown and eventually
Page 45 and 46: INSECT PESTS OF CUCURBITS (CUCUMBER
Page 47 and 48: CABBAGE LOOPER (Trichoplusia ni) Ca
Page 49 and 50: Damage: First-generation European c
Page 51 and 52: ■ Natural enemies such as ground
Page 53 and 54: educed yields. They feed on a wide
Page 55 and 56: C 5 H A P TER Write the answers to
Page 57: Chapter 5 50 Vegetable Crop Pest Ma
Page 61 and 62: Advantages of preemergence applicat
Page 63 and 64: 9. Which of the following is true o
Page 65 and 66: BACTERIA Bacteria are very small, m
Page 67 and 68: DISEASE MANAGEMENT Options for dise
Page 69 and 70: Outbreaks occur first as isolated p
Page 71 and 72: FUSARIUM YELLOWS Environmental cond
Page 73 and 74: Pathogen type: fungus (Peronospora
Page 75 and 76: MOSAIC VIRUSES POWDERY MILDEW Cucum
Page 77 and 78: DOWNY MILDEW SMUT Severe downy mild
Page 79 and 80: humidity. The disease is more likel
Page 81 and 82: BLACK SCURF/STEM CANKER DISEASES OF
Page 83 and 84: ■ Remove or destroy crop residue
Page 87 and 88: 26-29. Match the following cucurbit
Page 89 and 90: PLANT-PARASITIC NEMATODES Plant-par
Page 91 and 92: depending on age. Males are worm-li
Page 93 and 94: Needle nematode feeding can result
Page 95 and 96: 7. Which female nematodes, of those
Page 97 and 98: Chapter 4 Calibration (1) Calibrati
Page 99 and 100: APPENDIX C GLOSSARY ABDOMINAL PROLE
Page 101 and 102: DERMAL TOXICITY—The ability of a
Page 103 and 104: MESOTHORAX—The second segment of
Page 105 and 106: STOMACH POISON—A pesticide that m
Page 107 and 108: Notes 100
Page 109:
MICHIGAN STATE U N I V E R S I T Y
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