celeste welty extension entomologist april 2015 · 2017. 12. 23. · 4/1/15 1 phenology as a tool...
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4/1/15
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Phenology as a Tool in Commercial
Fruit & Vegetable Pest Management
Celeste WeltyExtension Entomologist
April 2015
Phenology & insects?
• Predictions– Events hard to see
• Methods– Calendar– Temperature– Indicator plants
Phenology & insects?
• Predictions– Events hard to see
• Methods– Calendar: rough estimate– Temperature: better– Indicator plants: best; easy to see
Topics today• Strict phenology
– Apple – Cabbage
• Related: predictions based on phenology + biofix + temperature– Codling moth– San Jose scale
• Related: temperature-only models– Corn flea beetle– European corn borer
Apple & peach bud stages: uses in IPM
• When to set up traps• When to scout• Optimal timing of tactics
– Insecticides– Pheromone mating disruption
Stages of
Apple Growth
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Apple buds
dormant silver tip
green tip Columbus: 3/24 - 4/11
Apple budshalf-inch
green tight cluster
pink
3/21 - 4/17
3/19 - 4/13
3/23 – 4/26
Apple buds
petal-fall
fruit set
bloom
3/28 – 5/2
4/28 – 5/16
king bud = king fruit
• Bud in center of cluster• Develops faster• Makes the best fruit
Trap set-up time in applesTiming Target species
Green tip Spotted tentiform leafminerRedbanded leafrollerOriental fruit moth
Pink bud San Jose scaleBloom Codling moth
Lesser applewormPetal-fall Obliquebanded leafroller
Tufted apple budmothVariegated leafrollerDogwood borer
Mid-June Apple maggot
Trap set-up time in applesTiming Target species
Green tip Spotted tentiform leafminerRedbanded leafrollerOriental fruit moth
Pink bud San Jose scaleBloom Codling moth
Lesser applewormPetal-fall Obliquebanded leafroller
Tufted apple budmothVariegated leafrollerDogwood borer
Mid-June Apple maggotIn red: pest with trap-based control rules
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Apple pest scoutingTime Target pest
Early pink rosy apple aphid
Early petal-fall spotted tentiform leafminer
Early petal-fall white apple leafhopper
June green apple aphid
June San Jose scale, crawlers
June - August European red miteJune - August woolly apple aphid
Rosy apple aphid• Scout once, at early pink• Choose:
– 10 trees per block – 10 fruit clusters per tree– Best from inner canopy
• Look for curled, distorted leaves
• If ANY rosies found, then use aphicide at pink
Spotted tentiform leafminer• Scout at early petal-fall• Randomly choose:
– 5 trees per block– 3 fruit clusters per tree– Examine 2nd, 3rd, & 4th leaves
leaf from base• Look for early mines
– Underside of leaf– Pale-green blisters
• Treat if > 4 mines per cluster• Sequential sampling graphs
available for more precise sampling
White Apple Leafhopper• Scout at petal-fall• Randomly choose:
– 10 trees per block– 5 fruit clusters per tree– 3 mid-cluster leaves per cluster
• Look for young nymphs– Underside of leaf
• Threshold at petal-fall:> 0.5 nymph per leaf
Spray programs Optimal timing of insecticide, if pest present
Time Target pestpink rosy apple aphid
pink San Jose scale, adultspetal-fall spotted tentiform leafminerpetal-fall white apple leafhopperJune San Jose scale, crawlers
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Optimal timing of pheromone mating
disruption
Isomate dispensers being deployed in northern Ohio at apple bloom:
• Crew of 10 workers • Covered 70 acres • 1 day, 8 AM to 5 PM • 200 dispensers/A • 1 dispenser in every
tree, in every other row
Cabbage Maggot
Cabbage Maggot
• 4 generations / year• Stages:
adult egg larva pupa(fly) (maggot)
• Crop most susceptible if in seedling stage when new adults are laying eggs
• Transplanted crops are most susceptible during the first 2-3 weeks after planting
Cabbage Maggot
• Adults emerge at same time that certain well known plants are flowering
GEN. PLANT AVG. BLOOM (Ohio)1 yellow rocket early May2 day lilies late June3 Canada thistle early August4 New England aster early Sept.
• Do not transplant during time that plant is blooming• Do not seed ~2 weeks before plant is blooming• Ideal time to seed is toward tail end of bloom period
Temperature-based predictions
• Common sense:– Calendar NOT good predictor of
when biological events occur– Development is slower when cool– Development is faster when hot
• More precise:– Calculate degree-days
Degree-Days (DD or oD)
• Way to summarize development time• Can be used to predict insect activity• For one day, degree-days =
(average temp) minus (threshold temp)• Accumulate DD over consecutive days
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Degree-Days: methods
• Calculate yourself using simple min & max temperature
• Look-up chart• Interactive websites
– MSU, Cornell, or UCal
Degree days: starting point?
• Calendar date– In places with cold winter, start
on January 1st or March 1st
• Biofix:– Use a biological event, such as
catch of first moth in a trap
Degree-Days (DD): For one day, DD = (avg temp) minus (threshold temp)
Accumulate DD over consecutive days.
Example, base temp = 50o F:Day Tmax Tmin Tavg DD50
1 62 52 57 7
2 66 50 58 8
3 58 54 56 6
4 70 56 63 13
Degree-Days (DD): For one day, DD = (avg temp) minus (threshold temp)
Accumulate DD over consecutive days.
Example, base temp = 50o F:Day Tmax Tmin Tavg DD50 DDcumul
1 62 52 57 7 7
2 66 50 58 8 15
3 58 54 56 6 21
4 70 56 63 13 34
Insect Development Rates• Each species has limits
– Minimum temperature (often 50oF)– Maximum temperature (often 90oF)
• Between min & max is linear
Apple IPM Tools: Degree-day models
• Codling moth
– Egg hatch
• San Jose scale
– Crawler emergence
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Predicting Codling Moth Egg Hatch
• Apply insecticide when eggs begin to hatch• Rule developed 30+ years ago in Michigan (1976)• Eggs begin to hatch
– 2 to 3 weeks after moths begin to fly– 250 degree-days (base 50F) after moths begin
sustained flight• Use pheromone trap for moth flight• ‘Biofix’ is the date that flight begins
Traps for monitoring codling moth
• Trap choices:– Sticky trap– Multi-Pher (bucket) trap
• Use pheromone lure• 3 traps / orchard block
DD look-up chart for codmothmin max
Timing for codling moth
• 1st spray: – 250 degree-days after biofix
(for most products)
• 2nd spray: – 14 days after first spray
Timing for 1st spray for codling moth DD after biofix
Approximate timing
Products*
250 1st cover Imidan, Altacor, Delegate, pyreth-roids, Avaunt
150-250 late petal-fall Assail, Calypso, Belay
100-200 mid petal-fall Intrepid, Confirm 50-75 early petal-fall Rimon
* & related home garden products
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0
1
2
3
Apr/22 May/3 May/15 May/27 Jun/7 Jun/19
Codling Moth Pheromone Trapping at O.S.U. Orchard, Columbus
Mea
n nu
mbe
r of m
oths
per t
rap
per d
ay
biofix5/18
optimalspray6/4
pink4/24
petalfall5/9
bloom5/2
1st cover5/17
normal2nd cover
5/31
normal3rd cover
6/14delayed2nd cover
6/4
250 DD
Range of biofix for codmoth in Columbus
• Average 5/7-5/11
• Earliest 4/20
• Latest 5/24
San Jose scale
• Sucking pest • Overwinters on bark
• Disperses to fruit in crawler stage (starts mid-June)
San Jose scale
When are crawlers crawling? • Start about 4-6 weeks after bloom • Emergence lasts several weeks • Monitoring methods:
– Predict using trap & temperature – Detect with black sticky tape
San Jose scale When are crawlers crawling? • Use pheromone trap
– Set up trap at pink bud stage – First adults usually caught at
bloom • Track temperature
– Crawlers expected 300-350 DD degree-days (base 50°F) after catch of adults in trap
adult
trap
San Jose scale
When are crawlers crawling? • Use black sticky tape
(electrical tape) – Wrap sticky-side out around
branch – Look for tiny bright yellow
crawlers
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Temperature models
• Winter temperature• Degree-day development
Pest Forecasting by Winter Temperature Model
• Corn flea beetle on sweet corn– Vector of Stewarts bacterial wilt– Disease depends on survival of beetle– Beetle does not overwinter well if too
cold• Management:
– Host plant resistance– Systemic insecticide– Most critical in years with mild
winter
Corn Flea Beetle• Vector of Stewart’s bacterial wilt
– Varies among varieties– Worst on early yellow varieties– Greatest effect if infection < 7-leaf stage
• Worse after mild winter
Corn Flea Beetle Index
• Winter temperature model• Sum of mean temperatures
Dec. + Jan. + Feb.
• Used to predict severity of Stewart’s bacterial wilt
Corn Flea Beetle IndexFlea beetle index
Predicted Stewarts Wilt Severity
>100 Severe
95-100 Moderate
90-94 Light
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Temperature-based predictions• Length (in days) of life stages
– Egg– Larva– Pupa– Pre-mating adult– Pre-egglaying adult– Complete generation
• % of population in a life stage– 1% (start)– 25%– 50%– 100%
Degree day example: European Corn Borer
• Pest of sweet corn & peppers• Start DD count:
– January 1st– OR when 1st spring moth caught
• Threshold temp. = 50oF
egg 1st instar larva
pupa adult5th instar larva
European Corn Borer Base 50oF, start Jan. 1st
% Pupa Adult Flight Egg 1L 2L 3L 4L 5L
1 250 420 550 610 750 970 1140 1290 1420
25 340 540 690 790 920 1070 1220 1360 1490
50 390 600 740 850 960 1110 1250 1390 1520
75 450 650 790 900 1000 1140 1280 1420 1550
peak 560 760 900 990 1090 1210 1350 1490 1620
European Corn Borer Base 50oF, start 1st moth
DD Event Avg # days
Activity
212 egg hatch to 1st instar
16 Pin hole leaf feeding
318 2nd instar 7 Shot hole leaf feeding435 3rd instar 6 Midrib & stalk boring567 4th instar 7 Stalk boring792 5th instar 10 Stalk boring
1002 pupa 9 Changing to adult1192 Adult moth 8 Mating & egg laying
Vegetable pests with known DDLOCAL• Cabbage maggot• Carrot weevil• Corn leaf aphid• Crucifer flea beetle• Green peach aphid• Imported cabbageworm• Onion maggot• Onion thrips• Seedcorn maggot• Squash bug• Two-spotted spider mite
MIGRATORY• Beet armyworm• Black cutworm• Cabbage looper• Diamondback moth• Tomato fruitworm
Tomato Fruitworm
• Lower threshold = 55oF• Upper threshold = 92oF• In California: if eggs found on leaves by
scouting in July, then use DD to predict egg-laying of generation in August that attacks the fruit
• Takes 968 DD to complete a generation
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Challenge to us!
• Gather phenology data for some key vegetable pests?
• Some adult emergence data for past 27 years
Resources• Cornell
– Apple insect phenology models and IPM forecasts: newa.cornell.edu/index.php?page=apple-insects
• U. California– www.ipm.ucdavis.edu/WEATHER/
• MSU’s Enviro-weather– www.enviroweather.msu.edu/
Apple bud stage pictures
• https://www.pinterest.com/pin/396035360954363789/
• http://www.hrt.msu.edu/faculty/langg/Apple_Critical_Temp.html
• https://fruitgardener.wordpress.com/2012/05/01/apple-bud-stages/
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Peach bud stage pictures• http://www.ent.uga.edu/peach/
peachhbk/pdf/stages.pdf• https://www.pinterest.com/pin/
396035360954363863/• http://county.wsu.edu/chelan-
douglas/agriculture/treefruit/Pages/Peach.aspx
• http://www.hrt.msu.edu/faculty/langg/Peach_Critical_Temp.html
Info on veg. & fruit pest management old site: bugs.osu.edu/welty/
new site: u.osu.edu/pestmanagement/
Questions? e-mail: welty.1@osu.edu
office phone: 614-292-2803 cell phone: 614-746-2429
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