Master Gardener Entomology Module 2010

Entomology Crash Course for Master Gardener Interns
Dr. Ayanava Majumdar
Ext. Entomologist, State SARE Coordinator
Gulf Coast Research & Ext. Center
8300 State Hwy 104, Fairhope AL 36532
Tel: (251) 331-8416
bugdoctor@auburn.edu

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)

Why are INSECTS so successful?
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

Characteristics of arthropods
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!)
Grasshopper specimen

Insect Exoskeleton
Insects have a cuticle, cuticle has chitin
Exocuticle
Epicuticle (topmost)
Chitin molecules interlink to provide strength!
Endocuticle
Hard cuticle of a cockroach

Insect Growth
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.
Cicada nymph molts into an adult

Insect Growth
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:

Complete metamorphosis
EGG
ADULT
LARVA (mobile stage)
PUPA
WHAT COULD BE THE ADVANTAGES OF THE LIFE STAGES?

Incomplete metamorphosis
WHAT COULD BE THE ADVANTAGES OF THE LIFE STAGES?

Insect mouthparts
Insects 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 mouthparts
Beetle mouthparts

Insect mouthparts
TYPE 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 mouthparts
TYPE 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 mouthparts
TYPE 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 mouthparts
TYPE 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
Plant bugs
Mosquito
Leaf-footed bug mouthparts
Assassin bug mouthparts

Insect Orders

Key insect orders
Coleoptera
Diptera
Hemiptera
Lepidoptera
Orthoptera
Thysanoptera

Coleoptera (beetles,weevils)
Some insect have defense markings
(click beetle)
Mexican bean beetle
Vegetable weevil
Wireworms

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)
Mouth hooks of maggots
Vegetable leafminer
Seedcorn 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)
Leaf-footed bug
Stink 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 wings
Predatory stink bug

Lepidoptera (moths, butterflies)
Fall armyworm
Imported cabbageworm
Granulate cutworm
Tomato hornworm

Identifying larvae by appendages
Anal prolegs
Thoracic legs
Abdominal prolegs
Normal number of prolegs = 4 (cutworms, armyworms)
< Number of prolegs = 3 (green cloverworm)
Number of prolegs = 2 (cabbage looper) >>

Facts about moths & butterflies
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)
Head of butterfly showing siphoning mouthparts (coiled beak)

Orthoptera (grasshoppers)
Short-horned grasshopper (Acrididae)
Crickets (Gryllidae)
Mole crickets (Gryllotalpidae)

Facts about grasshoppers
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)
Grasshopper ovipositor

Thysanoptera (thrips)
Tobacco thrips
Actual size = 5 mm
Flower thrips

Facts about 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

Types of Insect Injury
Presentation + 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.

Indirect injury from insect products: honeydew causes sooty mold (aphids, whiteflies)
Image: TopTurf.net
Image: Iowa State

Injury from disease transmission: aphids, thrips
Transmit tomato spotted wilt virus (TSWV)
Transmit cucumber mosaic virus (CMV), potato virus Y (PVY)
Images: U Wisconsin & Queensland Govt., Australia

Is it really an INSECT injury?
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.
Image: Missouri Bot. Garden

Simulated Insect Injury
10-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

Steps to
Intelligent Plant Management
Choose the right plant for right season
Choose the right plant for location
Plant vigorous stress-free plants
Maintain good cultural practices (sanitation, chemical applications, weed control)
Pin-point stress & take action early
Stressed plants will be overcome by insects
Manage insects by Integrated Pest Mgmt

Integrated Pest Management
Basic 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
Grassy buffers
Grassy buffer zone in permanent ecosystems
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 buffer zone in temporary agroecosystem

Trap cropping arrangements
Perimeter Trap Cropping
Trap crop (squash)
Trap crop = early planted squash, apply insecticide on borders
Squash lured away 66% cucumber beetles and 90% squash bugs (USDA res.)
Main crop
(watermelon, cantaloupe, cucumber)

Trap cropping arrangements
Row Trap Cropping (contd.)
Plant trap crop (alfalfa) in rows within the main crop (strawberry) & a using vacuum!
Strawberry production in California
Strawberry
(34 rows)
Strawberry
(34 rows)
Western tarnished plant bug damage
Alfalfa

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. RicBessin (UK)
Rule 1: Higher the LD50 safer will be the product!
Rule 2: Products containing highly toxic AI have very low % chemical.

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)
Interception trap
(can be used with or without light)
Pit-fall trap with a metal sheet as hood

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 flies
Light trap

Active traps (contd.): use a lure of some kind
Use many traps for accuracy
Active/passive trap:
yellow water pan trap
Yellow/white Sticky Trap with grid
Ball trap for dipteran flies

Why use pheromone traps?
Know what to scout for & when to scout INTENSIVELY
Automatic identification of closely related species
Prediction models will be avail.
Stink bug trap
Wing trap
Pherocon trap
Bucket trap

Parts of a Pheromone Trap
Metal support
Top section (fixed)
Lure with lure holder
Bottom section (replaceable sticky card with grid)
Wing Pheromone Trap

Types of Pheromone Traps
Wing 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

Delta 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 interference
Suitable for small moths – diamondback moth, warehouse pests
Problem: small trapping surface

Mass trapping kits
Advantages:
Relatively inexpensive
Convenient cleaning
Lure lasts longer
Disadvantages:
Needs a killing agent
(“No Pest Strip”)

Trap & Lure Suppliers
TRAPS:
Great Lakes IPM (MI)
Arbico Organics (AZ)
Gemplers
LURES:
Great Lakes IPM – ScentryBiologicals (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
Insect density (overall) per site
20
17
Monthly average activity (statewide)
19
29
15
27
32
16
12
13
48
36
Year 2009

What are these?
Tomato fruitworm, Helicoverpazea
Tobacco budworm, Heliothisvirescens

Corn earworm
Insect density (overall) per site
6
3
17
Monthly average activity (statewide)
10
8
25
3
12
7
5
8
16
11
Year 2009

Impact of Weather on Trap Catches
Sign. Correlation of TEMPERATURE :
Year 2009
Sign. Correlation of RAIN DAYS :
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.

Biological Control Agents
Asian citrus psyllid: has many natural enemies

General predators
Lacewings:
Chrysoperla rufilabris

General predators
Ash-gray lady beetle, Olla v-nigrum
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
SB feeding on armyworm
Podisus maculiventris
Euthyrhynchus floridanus
Alcaeorrhynchus grandis

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?
Monitoring/scouting techniques:
Sample ten plants in several locations
Yellow sticky traps at edge of field
Like cool, dry weather
Watch for ants and lady beetles
ET = 50% leaves with aphids
Potato aphid, Macrosiphumeuphorbiae
Green peach aphid, Myzus persicae

What is it?
Use sticky cards (yellow, blue)
Bag and shake technique
No action threshold
Use resistant varieties (BHN 444, 589, 640, Bella Rosa)
Western flower thrips, Frankliniella occidentalis
Tobacco thrips, Frankliniella fusca
Tomato spotted wilt destroys plants

What is it?
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?
Colorado potato beetle, Leptinotarsa decemlineata
Start looking on border rows
Scout intensely short crop (<6 inch)
ET = 5 beetles per 10 seedling or 10% defoliation in short crop
Larva of lady beetle (beneficial insect!)

What is it?
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?
Southern green stink bug, Nezara viridula
Use a sweep net
Use pheromone trap (expensive? cumbersome?)
Intensify scouting at fruit setting
ET = 0.25 bugs per 10 plants (green fruit stage)
Lygus bug, Lygus lineolaris
Brown stink bug, Euschistus servus

What is it?
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(Diaphorinacitri, Hemiptera: Psyllidae)

First Reports of ACP
ACP was first detected in 1998 in backyard plantings of Murrayapaniculata
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

ACP Life cycle
Host plants: all citrus plants, 2 species of Murraya (all Rutaceae)
ACP EGGS
Eggs are almond shaped
Eggs pale when fresh, turn yellow or opaque
Eggs laid on tips of growing shoot or tender leaves in clusters

Life Cycle & Identification
NYMPHS
53F*
51F
50F
51F
*Liu & Tsai 2000
52F
Nymphs: 5 instars, red eyes, large wing pads
Development fails below 50oF
Live in feeding pits created by adults

ACP specimen
ADULT PSYLLID
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

Behavior of ACP
Auburn Team at a Baldwin County location
Active insect that rests with body at an angle
Adult psyllids readily jump on approach
Dispersion: good fliers, moved by wind

Defense mechanism:
Masses of waxy filaments produced by nymphs to keep honey dew away!

Citrus Injury due to ACP
ACP has piercing-sucking mouthparts
Loss of plant sap from foliage
High reproductive capacity & survival of eggs/nymphs can cause rapid infestation (check new terminals)

Citrus Injury due to ACP (contd.)
CITRUS GREENING DISEASE (CGD) or Huanglongbing:
Worst disease of citrus transmitted by ACP
Bacterium Liberibacter
Short feeding inoculates ACP

SYMPTOMS OF CGD:
Slowly kills the tree (vascular)
Deformed yellow leaves
Blotchy mottling, asymmetrical
Twig dieback

SYMPTOMS OF CGD:
Lopsided fruit
Partially green
Distasteful fruit
Aborted 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!
Trash bug (trash-carrying lacewing)
Brown citrus aphid
(Toxoptera citricida)
Have tail-pipes!

SOURCES OF INFORMATION on ACP

www.SaveOurCitrus.org
Has insect ID section
Has a Citrus Greening Tracker
Has a list of high risk activities
“What to do if you sight ACP?”

Select a state
Directs you to local contact
USDA Animal & Plant Health Inspection Service (USDA-APHIS)

Internet Resources
YouTube videos
eXtension.org
Image repositories:
Flickr.com
BugGuide.net
Bugwood.org

NEW ONLINE RESOURCES
Subscribe to Blogs/email alerts
Follow on SlideShare

IPM COmmunicationREsources
(IPM-CORE) Project
Goal: Synchronized rapid IPM information delivery to growers
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

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
Acknowledgements to AL IPM Team
Thank you very much.
Please take the POST-TEST

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Master Gardener Entomology Module 2010

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Master Gardener Entomology Module 2010 — Presentation Transcript