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 & Hemiptera Sapsucking 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 enemies 2. Dust accumulation 3. Very cold weather 4. 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 aphidPoplar Petiole gall aphid

Oak Sower Gall (a Wasp Gall)

Spruce Gall Adelgid

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 ’s Found in Virginia in 1953

Adelgid Bole infestation

Hemlock Woolly Adelgid Feeding causes needle drop. 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 Woolly adelgids – Feeding on tree trunk

Feeding Damage Bole infestations cause formation of reddish colored compression wood Poor H2O conduction qualities Toxic saliva causes increase in cell number cell size thickened cell walls and tracheids

Butterscotch wood of a balsam woolly adelgid infested tree

Feeding Damage Heavy crown infestations cause formation of twig gouting 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 and Ponderosa 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, waxy Armored Scales – hard covers Eriococcid Scales Margaroid 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 Bark Disease Expansion Hemiptera Beech Scale

Black area Current Distribution Of beech Disease Grey area Distribution Of Beech Trees

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 ScalesEuropean Elm Scale

HemipteraRed 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

HemipteraMargaroid 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

HemipteraPlant Bugs - Miridae

Hemiptera Boxelder Bug

HemipteraLace bugs

Spider Mite Damage

Spider Mite Damage

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 mortality dieback, growth loss

Saratoga Spittlebug Damage 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 Spittlebug also feeds on willow shoots

Saratoga Spittlebug Decision Model