MSU Extension Pesticide Education Ornamental Pest Management (Category 3B) Non-Pest Disorders and Landscape Weeds Chapter 5

Environmental & Cultural Disorders Most landscape plant injury is caused by poor growing conditions. Weakened plants are more susceptible to pest attack than non-stressed plants.

MSU Extension Pesticide Education Environmental and Cultural Disorders F Construction F Salt F Dessication F Mechanical damage F Pesticides F Compaction F Drought F Flooding F Improper planting F Improper cultural practices F Poor plant selection

MSU Extension Pesticide Education Tough environmental conditions.

MSU Extension Pesticide Education Site too wet for this species.

MSU Extension Pesticide Education Tough environmental conditions.

MSU Extension Pesticide Education Poor planting technique. Note the twine that has not decayed.

MSU Extension Pesticide Education Herbicide injury through root absorption.

MSU Extension Pesticide Education Black walnut trees and stunted white pine.

MSU Extension Pesticide Education Excavation and construction activity caused this tree to die early.

MSU Extension Pesticide Education Poor site conditions post-construction.

MSU Extension Pesticide Education Flooded conditions suffocate roots.

MSU Extension Pesticide Education Desiccation

MSU Extension Pesticide Education Cold temperature injury.

MSU Extension Pesticide Education Lightening injury on oak.

MSU Extension Pesticide Education Environmental and Cultural Disorders F Construction F Salt F Dessication F Mechanical damage F Pesticides F Compaction F Drought F Flooding F Improper planting F Improper cultural practices F Poor plant selection

MSU Extension Pesticide Education Landscape Weed WEED = any plant growing where it is not wanted.

Change the location and any plant can become a weed. For example, bluegrass invading a flower bed is a weed.

MSU Extension Pesticide Education Weeds Compete For: F Growing space F Water F Nutrients F Sunlight

MSU Extension Pesticide Education Knotweed is tolerant of compacted soil.

MSU Extension Pesticide Education Weeds are Indicators of Site Conditions F Hot soil –Purslane, spurge F Compacted, wet –Annual bluegrass F Wet, shady –Rough bluegrass, horsetail F Deep shade –Ground ivy, chickweed

Weeds can... - Girdle plants - Harbor pests - Injure people

MSU Extension Pesticide Education Vines can girdle established plants.

MSU Extension Pesticide Education F Monocots: parallel leaf veins, growth points at/below soil level –Grass family Crabgrass, quackgrassCrabgrass, quackgrass –Sedge family NutsedgeNutsedge –Lily family Wild garlicWild garlic

MSU Extension Pesticide Education F Dicots: net-like leaf veins, diverse growing points –Composite family Dandelions, thistles –Mustard family Shepherd's purse –Carrot family Wild carrot Many others

MSU Extension Pesticide Education Stages of Weed Development F 1. Seedling –Tender, vulnerable F 2. Vegetative –Great uptake of water and nutrients F 3. Seed production –Reduced uptake, energy directed to flowers, fruit F 4. Maturity –Little uptake or energy production

MSU Extension Pesticide Education F Annual weeds: live one year –Summer annuals: seed and die by winter. Pigweed, crabgrassPigweed, crabgrass –Winter annuals: germinate in late summer, overwinter, produce seed, die the next season. Chickweed, pennycressChickweed, pennycress

MSU Extension Pesticide Education Lambsquarter

MSU Extension Pesticide Education F Biennial weeds: broadleaf plants with a two year life cycle –vegetative growth first year –mature, seed and die in second year Queen Anne’s lace, bull thistleQueen Anne’s lace, bull thistle

MSU Extension Pesticide Education Queen Anne’s lace.

MSU Extension Pesticide Education F Perennial weeds: live 3 or more years –most persistent –difficult to control –propagules rhizomes, stolons, bulbs, tubersrhizomes, stolons, bulbs, tubers –wide range of dicots and monocots quackgrass, dandelion, poison ivyquackgrass, dandelion, poison ivy

MSU Extension Pesticide Education Quackgrass Dandelion

MSU Extension Pesticide Education Scout, identify and inventory populations.

MSU Extension Pesticide Education Managing Landscape Weeds F Maintain vigorous ornamentals F Prevent seed production F Prevent seed germination F Limit emerged weeds early F Limit susceptible stages of mature weeds.

Alternative Weed Controls F Sanitation F Tillage F Cultivation F Cutting F Mulching

MSU Extension Pesticide Education Chemical designed to control weeds. Plant, soil and weather conditions influence herbicidal activity. Chemical designed to control weeds. Plant, soil and weather conditions influence herbicidal activity.

MSU Extension Pesticide Education Herbicide Characteristics Contact Systemic

MSU Extension Pesticide Education Herbicide Characteristics Persistent Non Persistent

MSU Extension Pesticide Education Herbicide Characteristics Selective Non Selective

MSU Extension Pesticide Education Herbicide Characteristics F Application in relation to plant development –Pre-plant Before crop is plantedBefore crop is planted –Pre-emergent Before weeds emergeBefore weeds emerge –Post emergent After weeds emergeAfter weeds emerge

MSU Extension Pesticide Education Herbicides and Plant Characteristics F Growing points F Leaf shape and orientation F Wax and cuticle

MSU Extension Pesticide Education Herbicides and Plant Characteristics F Leaf hairs F Deactivation F Life cycle stage

Herbicide Effectiveness

Climatic Factors F Relative humidity F Light F Precipitation F Temperature