turf insect pest

Turf Insect Pest

Introduction

Turfgrass value: functional, aesthetic, and economic

• All values adversely affected by pest• Over 300 million acres of turf in the US• 81 percent in more than 50 million lawns• 19 percent in parks, golf courses, athletic fields,

cemeteries, sod farms, roadsides, other sites• Turfgrass culture a 25 plus billion dollar per year

industry in the US

Introduction

• 500,000 plus people make their living directly from the establishment and maintenance of turf

• 25 to 30 million households use pesticides at least once yearly on lawns to control insect pests @ cost > 1 billion dollars

Driving Factors in Turfgrass Pest Management

• Increasing demand for high quality turf

• Increasing public concern about potential risks to human health and environment

Diagnosis and Sampling of Insect Pests

• Damage caused by insects can often be confused with diseases, drought, or pesticide injury

• Therefore, proper diagnosis is the first step in any successful control program

Diagnosis and Sampling of Insect Pests

• Specific pest identification (start with ‘suspects’)

• Sampling (based on suspected causes of damage)

Diagnosis Guided by the Use of the Knowledge Regarding

• Type of damage

• Location of habitat

• Season of occurrence

• Other clues

General Indications of Potential or Actual Insect Pest Problems

Surface Feeding• Large numbers of birds feeding on turf

area• Small moths flying zigzag patterns over

the turf surface, especially in late evening• Rapid loss of green color similar to

fertilizer burn or drought injury, even though the area is adequately irrigated

• Frass at or near the soil surface

General Indications of Potential or Actual Insect Pest Problems

Subsurface feeding

• Loose turf surface indicated by poor footing or excessive traffic injury

• Damage to turf by insect feeding mammals (moles, skunks, and raccoons)

• Overall thinning of turf

• Chlorotic areas/ patches of browning turf

Three Major Habitat areas for Insects in Turf

• Leaves and stems

• Thatch

• Soil

Insect Pest in/on Leaves and Stems

• Most easily controlled because treatments may be applied directly; timing of application is the most important criterion

• Detected by careful examination of stems, leaf sheath and leaves (May require magnification)

• Bermudagrass mite• Winter grain mite• Rhodesgrass mealybug• Greenbug• Fruit fly

Insect Pest in Thatch

• Thick thatch (grater than ½ inch) attracts chinch bugs and others. May impede penetration of pesticides into the soil

• Chinch bugs

• Sod webworms

• Cutworms

• Armyworms

• Fiery skipper

Insect Pest in ThatchDetection

• Flotation primarily to determine the presence or absence of chinch bugs

• Detergent flushes for caterpillars, weevils, mole crickets and other insects

• With either of these techniques, it is important to sample at the edges of heavily damaged areas since the highest insect populations are often located here rather than in areas already exhibiting severe damage

Insect Pest in the Soil

• Much more restricted in movement• Mole crickets• Ground pearls• White grubs• Billbugs• European cranefly• Primary sampling by examination of the root

zone and the soil and sod• Soap flushes work well for mole crickets

Types of Damage

• Chewing insects most common type among turfgrass insects

• They have strong mandibles which bite or sever tissues

• Damage symptoms exhibit physical removal of plant tissues

• Stripping away of the epidermis of leaves• Notching of leaves and stems• Complete severing of plant parts

Types of DamageChewing Insects Cont.

• Hollowing out of stems and crowns

• Pruning of roots

• Most chewing insects of turf are immature forms (larvae and nymphs) but a few adults are also included

• Common chewing pest: White grubs, armyworms, mole crickets, sod webworms

Types of DamageSucking Insects

• Sucking insects pierce and suck plant tissue with modified mouthparts that form a beak which surrounds needle-like mandibles and maxillae

• Salivary secretions (sometimes toxic to the plant) are pumped into the plant to aid in sucking up plant sap and cell contents

• Plants injured by this method of feeding generally remain completely intact

Types of DamageSucking Insects Cont.

• The entire plant starts to deteriorate because of the loss of plant sap or in the response to the injection of toxic salivary secretions

• Early symptoms: Yellowing, wilting, blasting of leaves, necrosis, followed by browning and death of plant

• Both adults and nymphs of piercing sucking insects damage turf

• Common insects in this group include chinch bugs, greenbugs, and ground pearls

Seasonal Occurrence

• Differences in seasonal occurrence of insects and damage provides diagnostic clue

• Winter: only the winter grain mite causes damage during winter

• Spring: European crane fly, mole crickets in warm humid regions, and the single generation scarabaeids may cause damage in the spring

• Summer: everything else (for example multiple generations of scarabaeids)

• Fall: Mole crickets and white grubs

Value of early Detection

• Early symptoms frequently evident before the actual pest is observed

• Damage can progress rapidly when large numbers of insects are present

• Some insects easier to control in early stage of development

Early Symptoms

• First symptom of damage caused by leaf and stem-feeding insects is yellowing of leaves in small isolated patches

• Root feeders cause a gradual thinning of the turf• Positive attribution of symptoms to a pest

requires determination that the pest is present in a damaging stage

• Dead or brown turf may no longer be harboring the pest responsible

• Proper identification is important for proper treatment and prevention

Insect Control Strategies for TurfCultural Control

Host plant resistance• The underling susceptibility or suitability or the

lack thereof… principle method of control…exhibits constant pressure of each pest generation…immunity is the ultimate level but rarely obtainable…exhibition of various degrees of resistance or susceptibility to best

• Endophytes sometimes contribute to resistance


Turf Vigor

• Vigorous, steadily growing stands can deter permanent turf damage

• Rapidly growing rhizomes and stolons quickly fill in small localized dead patches

• High nitrogen fertilizer can help recover a generally thinned stand


Soil Moisture• In high temperature and moisture stress, two

groups of insects, chinch bugs and sod webworms, do most of their damage, with the grass going into dormancy, making damage difficult to detect

• When adequate moisture is present, symptoms of damage are easier to detect in the form of yellow leaves and small brown patches


Thatch Management• Affects some insects directly (chinch bugs), also

affects the efficacy of insecticide applications• Many organic insecticides adsorb to organic

matter• Dursban is very readily bound to thatch• Many registered pesticides are broken down

readily in UV light, and so they must penetrate quickly to do their job

Insect Control Strategies for TurfBiological Control

Predators, parasites, and pathogens that attack pest species. Predators include other insects and sometimes vertebrates

Advantages of natural controls include their safety, relative permanence, and relative economy, although all of these don’t apply in all cases


Predators

• Free-living organisms that consume a prey; relatively non-specific such as:

• Ground beetles, spiders, some ants, big-eyed bugs, phytoseiid mites and staphalinids common


Parasitoids

• Insects that have a parasite-like relationship to their host, resulting in host death, develop inside host; quite host-specific, include a number of Hymenoptera and Diptera


Pathogens• Fungi, viruses, and bacterial organisms, with some

nematodes and protozoans; host specific, potentially self-sustaining, depend heavily on environmental conditions to work

• milky disease (bacterial disease of Japanese beetle grubs)

• B. thuringiensis, a commercially used pathogen of lepidoptera and others

• Nematodes , commercially inoculated with a bacterial pathogen, used against a number of soil-dwelling turf pests

Insect Control Strategies for TurfChemical Controls

• Pesticides (see current state recommendations)

• Important to follow label directions accurately

• Adherence to legal requirements may be necessary

• Most must be watered in after application

turf insect pest

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