sapsucking insects
Post on 02-Jan-2016
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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
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
Gall Forming Insects
• Tend to be host specific• Interesting life cycles• Leaves, twigs, stems, petioles• Unsightly• Urban vs Forest settings
Hemiptera: Adelgids - many species
Once called aphids
Differ in insect:Morphology - no cornicles Life Cycle - always lay eggs Hosts - only conifers
Hemlock Woolly Adelgid
Feeding causes needledrop. Complete defoliation & death of tree.
Can kill a tree in a single year
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
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
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
Hemiptera - Scale Insects
Soft Scales – cottony, waxyArmored Scales – hard coversEriococcid ScalesMargaroid Scales
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
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
Hemiptera
Spittle bugs
Pine spittle bug – serious pine pest in forest, urban and Christmas tree plantations
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