Master Gardener Entomology Module 2010
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Transcript of Master Gardener Entomology Module 2010
Entomology Crash Course for
Master Gardener Interns
Dr. Ayanava MajumdarExt. Entomologist, State SARE Coordinator
Gulf Coast Research & Ext. Center8300 State Hwy 104, Fairhope AL 36532
Tel: (251) [email protected]
Entomology Crash Course Objective: opportunity to closely examine insects and understand ecological functions
Course lay-out:
• Insect form & function
• Insect classification
• Types of insect injuries
• Integrated pest management
• Insect monitoring using traps
• IPM in tomatoes
• Citrus psyllid - a new invasive insect
LET’S TAKE THE PRE-TEST FIRST!
Insect Form & Function
This sign indicates study of real insect specimen using a digital microscope (Dino-Lite Pro)
Fun Facts about insects
• Insects have been around for at least 350 million years
• Over 900,000 described species (75% of all animal species)– U.S. has about 91,000 described species – Less than 1% of these are considered pests
• Four largest insect orders: beetles (Coleoptera), flies (Diptera), ants (Hymenoptera), moths (Lepidoptera)
• Small size, cryptic in nature• Small food requirement• Rapid and prolific reproduction
– Parthenogenesis• Grows by molting (control over
growth rate)• Life stages feed on different
substrate
Why are INSECTS so successful?
– Segmented bodies and jointed appendages– Exoskeleton shed periodically
• Characteristics Insects:– Three body regions (head, thorax and abdomen)– Six legs or less or zero (NEVER more!)
Characteristics of arthropods
Grasshopper specimen
• Insects have a cuticle, cuticle has chitin
Insect Exoskeleton
Chitin molecules interlink to provide strength!
Exocuticle
Endocuticle
Epicuticle (topmost)
Hard cuticle of a cockroach
• Insects need to shed (molt) old skin to grow in size.
• The period between molts is called an instar.
• Most insects have 4–8 instars before becoming adult.
Insect Growth
Cicada nymph molts into an adult
• Metamorphosis: drastic change in shape and form for growth and development.
• Two types: complete and incomplete.
• The stage of development of an insect will affect insecticide efficacy:
Insect Growth
Complete metamorphosis
EGG
LARVA (mobile stage)
PUPA
ADULT
WHAT COULD BE THE ADVANTAGES OF THE LIFE STAGES?
Incomplete metamorphosis
WHAT COULD BE THE ADVANTAGES OF THE LIFE STAGES?
Insect mouthpartsInsects can be classified according to mouthparts
TYPE 1. Chewing Mouthparts:
• Examples – grasshoppers, beetles, weevils, cockroaches
• 4 basic parts; Mandibles used for chewing!
• Cannot feed on liquid materials
Grasshopper mouthpartsBeetle mouthparts
Insect mouthpartsTYPE 2: Chewing-lapping Mouthparts
• Examples – honey bees (picture below), wasps
• Complex modifications of MP
• Mandibles used for chewing, proboscis for drinking (lapping) and exchanging fluid
• Mouthparts allow molding wax, feeding on pollen, nectar
Honey bee mouthparts
Insect mouthpartsTYPE 3: Siphoning (coiled) Mouthparts
• Examples – butterflies, moths
• Severe reduction of mouthparts – only a proboscis or coiled tube is present
• Short lived as adult, feed intermittently
Hawk moth mouthparts
Insect mouthpartsTYPE 4: Sponging Mouthparts
• Examples – flies
• Reduced mouthparts suitable for soaking up liquids
• No ability to eat solid food
• Some flies can “bite” but is actually scratching to feed on blood
Fly mouthparts
Insect mouthpartsTYPE 5: Piercing and Sucking MP
• Examples – mosquitoes (6 needles), plant bugs (4 needles)
• All mouthparts shaped like needles that form feeding tubes
• Only female mosquitoes bite
• All sexes of plant bugs can feed on plant juices
Leaf-footed bug mouthparts
Mosquito
Plant bugs
Assassin bug mouthparts
Insect Orders
Key insect orders• Coleoptera• Diptera• Hemiptera• Lepidoptera• Orthoptera• Thysanoptera
Coleoptera (beetles,weevils)
Mexican bean beetle
Some insect have defense markings
(click beetle)
Wireworms
Vegetable weevil
Facts about beetles (Coleoptera)
• Characteristics: forewings are hard, hindwings are membranous, poor fliers
• Have four life stages – egg, larva (grub), pupa, adult
• Grubs have strong mouthparts & are root feeders
• Beetles (adult) are foliage/flower feeders and may transmit diseases
• Often overwinter as adult or larva
Beetle wings
Diptera (flies)
Vegetable leafminerSeedcorn maggots
Mouth hooks of maggots
Facts about flies (Diptera)• Characteristics: good flier (one
pair of wings), larva (maggots) with reduced head
• Have four life stages – egg, larva, pupa, adult
• Larva have mouth hooks to scrape root surface
• Adult flies feed on nectar or solids (sponging mouth type)
• Often overwinter in larval stages
Fly wings
Hemiptera (true bugs)
Piercing-sucking mouthparts (beak)
Stink bug
Leaf-footed bug
Aphids
Facts about true bugs (Hemiptera)• Characteristics: wings are partially
hardened, antennae short
• Some are beneficial species
• Have three life stages – egg, larva (nymph), adult
• Overwinter in adult stage – immatures are vulnerable to predation.
• Piercing-sucking mouthparts
Stink bug wingsPredatory stink bug
Lepidoptera (moths, butterflies)Fa
ll ar
myw
orm
Granulate cutworm
Tomato hornworm
Imported cabbageworm
Identifying larvae by appendages
Thoracic legs
Abdominal prolegs
Normal number of prolegs = 4 (cutworms, armyworms)
< Number of prolegs = 3 (green cloverworm)
Number of prolegs = 2 (cabbage looper) >>
Anal prolegs
• Complete lifecycle – egg, larva, pupa, adult
• Larvae are damaging stages…
• Some members have become insecticide tolerant (diamondback moth, corn earworm)
• Try controlling these pests in early stages (small larva)
Facts about moths & butterflies
Head of butterfly showing siphoning mouthparts (coiled
beak)
Orthoptera (grasshoppers)
• Short-horned grasshopper (Acrididae)• Crickets (Gryllidae)• Mole crickets (Gryllotalpidae)
• Life stages: egg, nymph, adult
• Damage is caused by overlapping generations
• Damage intense in dry years
• Eggs laid in clusters in soil, food for many natural enemies
• Extremely migratory and have unique behavior patterns (e.g., infections)
Facts about grasshoppers
Grasshopper ovipositor
Thysanoptera (thrips)
Flower thrips
Actual size = 5 mm
Tobacco thrips
• Actual size = 5 mm, commonly seen on flowers
• Life stages: egg, larva, prepupa, pupa, adult
• Damage is caused by the rasping MP
• Damage intense in dry years
• Transmit diseases between plants
Facts about thrips
Types of Insect InjuryPresentation + Simulated training
First know the definitions…INJURY
DAMAGE
Damage = injury + economic loss
Plant injury by INSECTS• Direct injury caused by feeding:
chewing mouthparts VS. sucking mouth parts
• Direct injury caused during oviposition: dimpling on tomato by thrips egg-laying
Image: UFL IFAS Ext.
Image: UFL IFAS Ext.
Plant injury by INSECTS
• Indirect injury from insect products: honeydew causes sooty mold (aphids, whiteflies)
Image: TopTurf.netImage: Iowa State
Plant injury by INSECTS
• Injury from disease transmission: aphids, thrips
Transmit cucumber mosaic virus (CMV), potato virus Y (PVY)
Transmit tomato spotted wilt virus (TSWV)
Images: U Wisconsin & Queensland Govt., Australia
Plant injury by INSECTS
Is it really an INSECT injury?
Image: Missouri Bot. Garden
General steps to diagnosis:• Define the problem
• Look for patterns: abiotic problems have patterns!
• Used a scouting technique
• How fast are symptoms spreading?
• Process of elimination to arrive at a diagnosis
VS.
Simulated Insect Injury10-minute Group Exercise:
• Divide into 5 groups – each group designate a leader
• Take a sheet of paper and write names of team members
• Take any one sample from the table
• Describe of the problem, leader take notes (normal vs. abnormal)
• What insect could have caused the injury? Direct/Indirect?
• Team leader will present – 1 minutes
• Diagnosis will be discussed (5 minutes)
Intelligent Plant Management
• Ecological approach to plant production• Common sense approach to solving plant health problems
Integrated Pest ManagementBasic concept, status of IPM in AL,
implementation
What is IPM?• “Integrated pest management (IPM) is a threshold
based decision management system which leads to judicious use of multiple pest control tactics.”
• IPM is currently insecticide-intensive…• 70% area under IPM yest major losses occur due to:
• Lack of early detection of insects• Insecticide resistance by misuse• Loss of natural control with insecticides
Need for IPM• Loss of tomatoes in the absence of insecticides: 95% (AL)*• Nationally, average gain from IPM is $19 for every dollar
spent (field crops)*
• There is increasing demand for organic crops…
• Insecticide use in AL is reducing, 1992-2002:
• Asparagus (-30%)
• Green peas (-73%)
• Green beans (-36%)
• Tomatoes (-20%)
*L. Gianessi, 2009. Crop Protection Research Institute.
IPM in home & garden• Remove abiotic stresses• Conserve natural enemies (habitat)• Correctly identify insect pest• Biological control agents (microbials)• Cultural tactics – variety, rotation, trap crop• Chemical insecticides• Correct insecticide delivery system: correct
application rate, timing, coverage
NE Conservation System
• Grass shelters natural enemies
• Many night-feeding insects hide in grass during day…treat the edges!
• Sample in grass and keep it under control
Grassy buffers
Grassy buffer zone in
temporary agroecosystem
Grassy buffer zone in
permanent ecosystems
Trap cropping arrangements
• Trap crop = early planted squash, apply insecticide on borders
• Squash lured away 66% cucumber beetles and 90% squash bugs (USDA res.)
Perimeter Trap Cropping
Main crop (watermelon, cantaloupe, cucumber)
Trap crop (squash)
Trap cropping arrangements
Plant trap crop (alfalfa) in rows within the main crop (strawberry) & a using vacuum!
Row Trap Cropping (contd.)
Alfalfa
Strawberry(34 rows)
Strawberry(34 rows)
Strawberry production in California
Western tarnished plant bug damage
Recommendations for trap cropping• Try it on a small scale to gain confidence• Integrate with biological/chemical i-cides,
pheromone trapping, etc.• Trap cropping can manage 1-2 insect species• Works great against sucking pests (plant bugs)
and slow fliers (beetles)• Spray only the trap crop…reduce cost
Alternative Insecticides for Gardeners
• Use them in rotation:
– Thuricide, Dipel (Bt)
– M-pede (soap)
– Safer pyrethrin
– Oils (with caution!)
• Contact a nursery for supplies & purchase early
• Do not use unlabeled insecticides (e.g., RTU home pesticides)
• Always read the label!
Toxicity of Some Insecticides (General Use Pesticides)
Ref.: “General use insecticides for home gardening” by Dr. Ric Bessin (UK)
Rule 1: Higher the LD50 safer will be the product!
Rule 2: Products containing highly toxic AI have very low % chemical.
Active ingredient (AI)
% AI in product
Use MOA Oral LD50 (mg/kg)
Dermal LD50 (mg/kg)
Toxicity to bees
Pyrethrin 0.02 Insecticide Contact 2600 370 Toxic
Cyfluthrin 0.75 Insecticide Contact 869-1271 >5000
Bifenthrin 0.01 Insecticide Contact 54 Toxic
Imidacloprid 1.47 Insecticide Systemic 450 >5000 Highly toxic
Acephate 9.4 Insecticide Systemic + Contact
866 Moderately toxic
Bacillus thuringiensis
0.80 Insecticide Stomach - Mild eye irritant
Practically non-toxic
Decision making in IPM…• Insect detection & monitoring• Insect identification• Population pressure• Economic threshold• Make treatment decision• Choosing right insecticide
Monitoring insects with TRAPPING DEVICES
What are insect pheromones?• Pheromones are chemicals
released into environment in small amounts by insects.
• Pheromones are species specific, stimulates opposite gender.
• Male moths detect pheromones with antennae.
• Synthetic sex pheromones are manufactured & used as lures.
Types of Insect Traps• Passive traps: do not use a lure of any kind,
e.g., pit-fall traps, ground sticky traps, water traps, flight interception trap (beat sheet)
Pit-fall trap with a metal sheet as hood
Interception trap (can be used with or without light)
Types of Insect Traps• Active traps:
– use a lure of some kind, e.g., food, color, shape, light…PHEROMONES
Dome Fly Trap with liquid bait for mass trapping fruit fliesLight trap
Types of Insect Traps• Active traps (contd.): use a lure of some kind
Active/passive trap: yellow water pan trap
Yellow/white Sticky Trap with grid
Use many traps for accuracy
Ball trap for dipteran flies
• Know what to scout for & when to scout INTENSIVELY
• Automatic identification of closely related species• Prediction models will be avail.
Why use pheromone traps?
Wing trap Pherocon trap Bucket trap
Stink bug trap
Parts of a Pheromone Trap
Top section (fixed)
Bottom section (replaceable sticky card with grid)
Metal support
Lure with lure holder
Wing Pheromone Trap
Types of Pheromone TrapsWing Traps
Simple wing trap with grid on sticky bottom
Wing trap with baffles (large trap surface)
Popular due to easy assemblage, large trap area, & low cost
Suitable for larger moths: armyworm, cutworm, fruitworms
Problem: weather & animals could ruin trap
Types of Pheromone TrapsDelta Traps
Delta traps with sticky insert having a printed grid. Sides fold to hold the sticky insert in place.
>>
Advantages: easy assemblage, low maintenance, less interferenceSuitable for small moths – diamondback moth, warehouse pestsProblem: small trapping surface
Types of Pheromone TrapsMass trapping kits
Advantages:Relatively inexpensiveConvenient cleaningLure lasts longer
Disadvantages:Needs a killing agent(“No Pest Strip”)
Trap & Lure SuppliersTRAPS:• Great Lakes IPM (MI)• Arbico Organics (AZ)• Gemplers
LURES:• Great Lakes IPM – Scentry Biologicals
(MT) & Trece, Inc.• APTIV, Inc. (OR)
AL Insect Monitoring Project(new in 2009)
• Use traps for early detection of pests
• What does trap catch tell you?
Catch = pop. density x activity
• Trap network (operated by REAs):
N-S: vegetable fields
E-W: peanut fields
• Commercial traps/lures used
• Trapping period: June-October
• Trapping interval (2009): 14 days
What is it?HINT: Several outbreaks of these insects occurred in AL, 2009
Beet armyworm, Spodoptera exigua Fall armyworm, Spodoptera frugiperda
Fall armyworm
20
19
15
32
48
27
36
29
17
1216
13
Monthly average activity (statewide)
Insect density (overall) per site
Year 2009
What are these?Tomato fruitworm, Helicoverpa zea
Tobacco budworm, Heliothis virescens
Corn earworm6
10
25
12
16
5
3
11
8
3
8
17
7
Monthly average activity (statewide)
Insect density (overall) per site
Year 2009
Impact of Weather on Trap CatchesSign. Correlation of TEMPERATURE :County BAW FAW CEW TBW LCB CRW
Cullman NS NS NS 0.9655 (-) NA NS
Chilton 0.9989 (-) 0.9028 (-) 0.6599 (-) 0.9913 (-) NA NS
Baldwin NS NS 0.5863 (-) NS NS NS
Escambia NS 0.8603 (-) NS 0.6295 (+) NS NS
Henry NS NS NS NS NS NS
Numbers indicate significant correlations at P = 0.10. +/- indicates direction of relationship (preliminary findings). Rain days indicate number of days rainfall exceeded 0.1 inch.
County BAW FAW CEW TBW LCB CRW
Cullman NS 0.9905 (+) NS NS NA 0.5988 (+)
Chilton NS NS NS NS NA NS
Baldwin 0.9154 (+) 0.9838 (+) NS NS 0.8347 (+) 0.5882 (-)
Escambia 0.6661 (+) NS 0.7080 (+) NS NS NS
Henry NS 0.9851 (+) NS NS 0.7368 (+) 0.8819 (-)
Sign. Correlation of RAIN DAYS :
Year 2009
Biological Control Agents
Asian citrus psyllid: has many natural enemies
General predators
Lacewings:Chrysoperla rufilabris
Ash-gray lady beetle, Olla v-nigrum
General predators
Multi-colored Asian lady beetle, Harmonia axyridis
Spotless lady beetle, Cycloneda sp.
Predacious stink bugs • Typically have short beak
• Abundant in orchards, weedy borders
• Voracious feeders of caterpillars
• Watch numbers: a sudden increase may indicated pest presence
Euthyrhynchus floridanus Podisus maculiventris Alcaeorrhynchus grandis
SB feeding on armyworm
Introduced parasitoid (Eulophidae)
Tamarixia radiata, in FL from Taiwan• Female wasp lays eggs under ACP nymph
• Parasite develops inside the body (arrow in picture)
• Adult wasp emerges from an exit hole
IPM in Vegetables:Tomato
(Applied Entomology: insect biology meets insect control)
What is it?Potato aphid, Macrosiphum euphorbiae
Green peach aphid, Myzus persicae
Monitoring/scouting techniques:Sample ten plants in several locationsYellow sticky traps at edge of fieldLike cool, dry weatherWatch for ants and lady beetlesET = 50% leaves with aphids
What is it?Western flower thrips, Frankliniella occidentalis
Tobacco thrips, Frankliniella fusca
Monitoring/scouting techniques:Use sticky cards (yellow, blue)Bag and shake techniqueNo action thresholdUse resistant varieties (BHN 444, 589, 640, Bella Rosa)
Tomato spotted wilt destroys plants
What is it?Monitoring/scouting techniques:
Monitor level of defoliation
Sample small plants with sweep net during morning hours
Observe activity of parasitoids, predators (sweep net)
ET = 5-10% defoliation early season, 25-30% defoliation mid-season
Flea beetles (many species)
What is it?Monitoring/scouting techniques:
Start looking on border rows
Scout intensely short crop (<6 inch)
ET = 5 beetles per 10 seedling or 10% defoliation in short crop
Colorado potato beetle, Leptinotarsa decemlineata
Larva of lady beetle (beneficial insect!)
What is it?Monitoring/scouting techniques:
Examine green fruit, stem terminals
Scout for egg masses or larvae
Use pheromone traps to detect first flight; ET = 5-10 moths per night when temp. is <85F
ET is ½ if temp. is >85F
Tomato fruitworm, Helicoverpa zea
Tobacco budworm, Heliothis virescens
What is it?Monitoring/scouting techniques:
Use a sweep net
Use pheromone trap (expensive? cumbersome?)
Intensify scouting at fruit setting
ET = 0.25 bugs per 10 plants (green fruit stage)
Southern green stink bug, Nezara viridula
Brown stink bug, Euschistus servus
Lygus bug, Lygus lineolaris
What is it?Monitoring/scouting techniques:
Minor foliar pests (ET = 5 larvae per 10 plants)
Easy to collect & identify – shake and collect
Watch for sun scald on fruits, esp. 20% defoliation
Look for fecal pellets on leaves
Cabbage looper, Trichoplusia ni
Soybean looper, Pseudoplusia includens
Asian Citrus Psyllid(Diaphorina citri, Hemiptera: Psyllidae)
First Reports of ACPACP was first detected in 1998 in backyard plantings of Murraya paniculata
At present, 33 counties in FL have ACP
ACP has been found in many states, but Citrus Greening Disease (CGD) is present in LO & FL
ACP in Baldwin County (2008)
No detection of ACP or CGD in 2009
www.SaveOurCitrus.org
• Eggs are almond shaped
• Eggs pale when fresh, turn yellow or opaque
• Eggs laid on tips of growing shoot or tender leaves in clusters
ACP Life cycleHost plants: all citrus plants, 2 species of Murraya (all Rutaceae)
ACP EGGS
• Nymphs: 5 instars, red eyes, large wing pads
• Development fails below 50oF
• Live in feeding pits created by adults
Life Cycle & Identification
53F*51F
50F51F
52F
NYMPHS
*Liu & Tsai 2000
• Adult is 3 mm long, forewings broad apically• Tip of antennae black• Brown band on wings around the border• Wings with reduced venation, prominent veins
ADULT PSYLLID
Life Cycle & IdentificationACP specimen
• Active insect that rests with body at an angle• Adult psyllids readily jump on approach• Dispersion: good fliers, moved by wind
Auburn Team at a Baldwin County location
Behavior of ACP
Defense mechanism:Masses of waxy filaments produced by nymphs to keep honey dew away!
Life Cycle & Identification
• ACP has piercing-sucking mouthparts
• Loss of plant sap from foliage
Citrus Injury due to ACP
High reproductive capacity & survival of eggs/nymphs can cause rapid infestation (check new terminals)
CITRUS GREENING DISEASE (CGD) or Huanglongbing:
• Worst disease of citrus transmitted by ACP
• Bacterium Liberibacter
• Short feeding inoculates ACP
Citrus Injury due to ACP (contd.)
Citrus Injury due to ACP (contd.)SYMPTOMS OF CGD:Slowly kills the tree (vascular)Deformed yellow leavesBlotchy mottling, asymmetricalTwig dieback
Citrus Injury due to ACP (contd.)SYMPTOMS OF CGD:Lopsided fruitPartially greenDistasteful fruitAborted black seeds
Remember: other disorders may cause diagnostic problems
What can confuse you?Citrus thrips
(Scirtothrips citri)Long bristles on
wings
Citrus mealybug (Planococcus citri)
No wing-pads!
Brown citrus aphid (Toxoptera citricida)
Have tail-pipes!
Trash bug (trash-carrying
lacewing)
SOURCES OF INFORMATION on ACP
• Has insect ID section
• Has a Citrus Greening Tracker
• Has a list of high risk activities
• “What to do if you sight ACP?”
www.SaveOurCitrus.org
• Select a state• Directs you to
local contact
USDA Animal & Plant Health Inspection Service (USDA-APHIS)
YouTube videos
Internet Resources
eXtension.org
Image repositories:Flickr.comBugGuide.netBugwood.org
NEW ONLINE RESOURCES
Subscribe to Blogs/email alertsFollow on SlideShare
IPM COmmunication REsources (IPM-CORE) Project
Project archive: www.aces.edu/go/85 or www.aces.edu/go/88 “AU Pest Alert” (direct email): May-October Web outreach: Blogs, YouTube, AlabamaCrops.com,
AGFAX.COM IPM Hotline (messages): 1-800-446-0375 Make sure you see the AL IPM EXHIBIT Timely revisions to Extension bulletins
Goal: Synchronized rapid IPM information delivery to growers
Acknowledgements to AL IPM Team
• IPM Trapping Coordinators: – A. Majumdar– H. Fadamiro– K. Flanders
• IPM Team Members:– Lloyd Chapman– Neil Kelly– Michael Reeves– Gary Gray– James Miles– William East, Jr.– Brandon Dillard– Leonard Kuykendall– Chris Becker– Timothy Reed
Thank you very much.
Please take the POST-TEST