Sapsucking Insects

OBJECTIVES OF SAPSUCKING INSECTS

At the end of this section students should be able to:

1) Describe the symptoms and damage of sapsucking pests.

2) List the major types of sucking pests and give example of one of each type that is important in commercial or urban forests.

3) Explain why control of these pests is so difficult.

4) Describe the relationship between some sapsucking pests and forest pathogens.

5) Describe control approaches used in management programs for these pests.

Sapsucking pests are difficult problems

1) Inconspicuous

2) Hard to control

Because they are:

Sapsucking pests have piercing-sucking mouthparts

Sapsucking pests are Homoperta & HemipteraSapsucking pests are also Arachnida (mites)

Sapsucking pests rarely kill trees Scale insects, some adelgids are the exceptions

Sapsucking Pests

Population Dynamics – P/S Insects

Insect populations are affected by:

1. Destruction of natural enemies2. Dust accumulation3. Very cold weather4. Dispersal (wind, people, quarantines)5. Plant Resistance

1.Numbers increase dramatically when insecticides are used as often they kill beneficial insects more effectively than the pest.

2. Numbers increase when dust accumulates on plants as dust interferes with natural enemies searching ability

4. Numbers decrease in very cold weather as this kills individuals and reduces quantity quality of food supply

5. Natural dispersal by wind, crawling, flight. Most major pests introduced on infested nursery stock so quarantines significantly reduce spread

3. Plant Resistance reduces population numbers. Sometimes only reasonable approach to controlling sapsucking pests

Discolored and/or curled foliage

1) Damage from removal of nutrients and toxic saliva

Symptoms and Damage

1) Damage from removal of nutrients and toxic saliva

Abnormal shoot growth

1. Damage from removal of nutrients and toxic saliva

Premature leaf drop

1) Damage from removal of nutrients and toxic saliva

Branch and/or tree mortality

Adelgid Caused Mortality on Fir

1) Damage from removal of nutrients and toxic saliva

2. Damage from excretions

Honeydew and/or black mold on foliage

3. Damage from oviposition activities

Cicadas, tree hoppers, sawflies Tree crickets

Cicada oviposition damage

4. Disease Transmission

Aphids and Leafhoppers

Elm Phloem Necrosis my kill more elms than Dutch Elm Disease

Cause: A Phytoplasma

Vector: Leafhoppers

Characteristic “butterscotch” Discoloration of inner bark

4. Disease Transmission

Common & Important / Unimportant Sapsucking pests

• Asian Hackberry Woolly Aphid• Gall Forming Insects• Hemlock Woolly Adelgid• Spruce Adelgid• Beech Bark Scale• Saratoga spittlebug

Alate (winged) aphid

Apterous (non-winged)aphids

Cornicles

Hemiptera Aphids - Many species and types

Asian Woolly Hackberry Aphid

White pine aphids

Pine Aphids (Cinera spp)

Spruce Aphids

Spruce aphid damage

Gall Forming Insects

• Tend to be host specific• Interesting life cycles• Leaves, twigs, stems, petioles• Unsightly• Urban vs Forest settings

Hackberry gall psyllid

Aphid Galls on Hickory

Vagabond gall aphid Poplar Petiole gall aphid

Oak Sower Gall (a Wasp Gall)

Spruce GallAdelgid

Hemiptera: Adelgids - many species

Once called aphids

Differ in insect:Morphology - no cornicles Life Cycle - always lay eggs Hosts - only conifers

Adelgids

Hemlock Wooly Adelgid

Accidentally introduced to PNW - 1920’s

Found in Virginia in 1953

Adelgid Bole infestation

Hemlock Woolly Adelgid

Feeding causes needledrop. Complete defoliation & death of tree.

Can kill a tree in a single year

Introduced Predator of Hemlock Woolly Adelgid

Video – Hemlock at Risk

Management - Hemlock Woolly Adelgid

Private vs Public Lands

Balsam Woolly Adelgid

•Another conifer pest killing trees•Imported pest from Europe•Weakens and/or kills true firs•1 of most important sucking pests •2- 4 generations / year•No Males Known to exist•Few economical controls

Balsam Woollyadelgids – Feedingon tree trunk

Feeding Damage

Bole infestations cause formationof reddish colored compression wood

Poor H2O conduction qualities

Toxic saliva causes increase incell numbercell size thickened cell walls and tracheids

Butterscotchwood of abalsam woollyadelgid infestedtree

Feeding Damage

Heavy crown infestations cause formation of twiggouting and reduces new shoot growth and eventual death of the tree

Impact on true firs in North America is severe

•Complete stand mortality•Significant timber losses•Reduced tree growth•Reduced seed production•Killed millions of board feet

Management & Control in US

Few controls available

Pine bark adelgids – native insect

Found throughout North America

Attack Scots, jack, pitch, white andPonderosa pines

Stunt growth, produce honey dew, & occasionally kill trees

Spread is slow due to reduced mobility

Pine bark adelgid

Hemiptera - Scale Insects

Soft Scales – cottony, waxyArmored Scales – hard coversEriococcid ScalesMargaroid Scales

Cottony Maple Leaf Scale

Cottony Cushion Scale

Tortoise Scale and Sooty Mold

Pine Tortoise Scale and Sooty Mold

Striped pine scale and sooty mold

Hemiptera

The Armored Scales: covered with a hard wax or protective coating

HemipteraOystershell scale

White Pine Needle ScaleHemiptera

Beech BarkDiseaseExpansion

Hemiptera

Beech Scale

Black areaCurrent Distribution Of beech Disease

Grey areaDistribution Of BeechTrees

Beech Bark Disease Cycle – Insect & Fungus

Beech Bark Scale

Beech Bark Scale – Close up

Fruiting bodies of fungus – infecting scale wounds

Cankers coalescing – fungus/insect

Yellowing & Declining American Beech

Management & Outlook

Beech Bark Scale

Eriococcid Scales European Elm Scale

Hemiptera Red Pine Scale

Red Pine Needle Scale Adult Male

Red pine scale – Matsucoccus resinosae

•Introduced pest•Large numbers of Red pine killed•Infested trees die within 5 years•No effective controls (except cold (-23 C)•Currently large tracts in Connecticut being harvested due to mortality

Hemiptera Margaroid Scales

Pit Scales - they cause small pits

Asterolecanium spp - Pests of Oaks

Heavy infestations kill trees, especially when associated with drought or Anthracnose fungi

Pit Scales

Hemiptera Plant Bugs - Miridae

Hemiptera Boxelder Bug

Hemiptera Lace bugs

Spider MiteDamage

Spider MiteDamage

Management Approaches

Do Nothing

Insecticides

Natural Enemies

White Pine Needle Scale & Lady Bird Beetle Predator

Management Approaches

Cultural Management Strategies

Keep trees healthy

Regulations – Quarantines

Integrated Pest Management

Example: Rating system for Saratoga Spittle bug on Red Pine

Saratoga spittle bug

Immature insects feed on alternate host which includes sweet fern

Adults feed on pine (no spittle)Serious pine pest – lots of mortalitydieback, growth loss

Saratoga SpittlebugDamage on Red Pine

Hemiptera

Spittle bugs

Pine spittle bug – serious pine pest in forest, urban and Christmas tree plantations

Spittlebug adult

Saratoga spittlebug on Alternate Host

Sweet Fern - Alternate Host of Saratoga Spittlebugalso feeds on willow shoots

Saratoga Spittlebug Decision Model