Date post: | 21-Jun-2015 |
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Preventing Sticky Cotton Caused by Whitefly & Aphid
Peter B GoodellCooperative Extension Advisor
Overview
• On January 23rd, 2014, the cotton industry met to discuss the increasing threat of sticky cotton on SJV cotton.
• One outcome of that meeting of PCAs, growers, ginners & processors was – that early populations of whitefly are being missed– Surrounding areas are putting more whitefly
population pressure on neighboring cotton fields
• OUR GOAL TODAY IS TO ADDRESS THESE ISSUES
Program
• Sticky Cotton – What is and Why we Should Care – Pete Goodell, UCCE IPM
• Whitefly & aphid biology – Pete Goodell UCCE – IPM
• Monitoring and Managing Whitefly– Dr. Larry Godfrey, Dept Entomology, UCD
Sugar, The Sticky Source
• What’s the problem?• What’s the source• Are all sugars the same?
What’s the Problem?
• Producing Quality Cotton in the SJV is everything,
• Quality in the lint characteristics but just as important, free from all contamination.
• This is NOT an individual problem. One bad apple……
• Mills will blacklist: gins, states, regions, if they have had bad stickiness experience
How Can We Think About Sticky Cotton?
Like Cotton Candy in the Hands of a Small Child!
Remember trying to clean all the sticky spots off your childAnd everything with which they came in contact ?
That is how this boll with sticky honeydew will interact with the precise machinery in the spinning mills
Sticky Cotton Affects Spinning Mills!
Sugars Found on Cotton Lint
Hequet et al
Plant Sugar• Always present and evenly distributed on fiber• Mainly glucose based, an be detected with
titration• Tends to cause “Chronic” spinning problems,
resulting in lower efficiency• Normal cleaning would be at end of shift, plant
sugar issues require cleaning several times throughout shift
• Will breakdown with storage over time but can result in yellowing
• If detected – “aging” and mixing is best solution
Insect Sugar
• Not always present • Not evenly distributed on fiber• Not glucose based• Cannot be detected with “Sugar Tests”• Sugars can be detected HPLC• Causes “Immediate” spinning problems• Will shut a mill down as 1 or 2 bales is enough
to create massive problem
Insect Sugar
Whitefly Aphid
Trehalulose & Melezitose Mainly Melezitose
Melting Point of Sugars
0
50
100
150
200
250
Tem
pera
ture
°C
Temperature of Machines
0
10
20
30
40
50
60
Card DrawingFront Roll
Roving RingSpinning
RotorSpinning
Tem
pera
ture
°C
Highest TLowest T
Whiteflies and Aphids Can CreateSticky Cotton
• To ensure our reputation for high quality cottons, whiteflies and aphids must be managed
• Dr. Godfrey’s will focus on whitefly management while this presentation will focus on the biology of whitefly and aphid
• Details of the sampling, treatment decisions and control approaches are incorporated in UC Pest Management Guidelines
• www.ipm.ucanr.edu
Management Begins with IPM IDEAS
• Identification• Determining population through scouting• Evaluating risk using established thresholds• Acting to manage using multiple approaches• Studying the results
Sweet Potato WhiteflyBemisia tabaci Biotype B
• Once known as Silverleaf (B. argentifolii)
Greenhouse Whitefly
• Trialeurodes vaporariorum
Banded Winged Whitefly
• Trialeurodes abutilonia
Whitefly Life Cycle
Whitefly Population Dynamics
Whitefly Population Development
• Developmental thresholds established 1985– Lower Development: 50° F– Upper Development: 90° F– Number DD required for generation: 569
• Average number of generations in:– El Centro: 13.7– Five Points: 8.8
0
2
4
6
8
10
12
14
16
1-Jan 1-Feb1-Mar 1-Apr 1-May
1-Jun 1-Jul 1-Aug 1-Sep 1-Oct 1-Nov 1-Dec
No. WF Generations
Five Pts
El Centro
0
200
400
600
800
1000
1200
1400
1600
1800
2000
1-Jan 1-Feb 1-Mar 1-Apr 1-May 1-Jun
Accumulated WF DD (50,90)
2009
2010
2011
2012
2013
2014
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
2009 2010 2011 2012 2013 2014
Number of WF Generations 1/1 - 6/8
Number of accumulated degree days between January and June 8th.
Note 2012,2013, & 2014 have been the warmestin the past 6 years
Number of possible generations between January and June 8th.
Estimated Number of GenerationsBemisia, 1/1 to 9/1, WSREC
5
5.5
6
6.5
7
7.5
8
No. Gen by Sept 1
Whitefly Damage• Direct damage to plants
– Phloem feeder–Extract proteins from plant sap
• Honeydew formation– Excess sugars passed–Accumulate on plant tissue–Sooty mold
• Virus transmission
SJV Management Scenarios• Initial buildup – selective insecticides
– July in most years– Low population but building– Control nymphs and adults with selective materials
• Gradual Invasion by adults – Partially selective insecticides aimed at adults– August– No or few bolls open– Adults fly from melons, tomatoes, other sources?– Employ partially selective insecticides
• Lint exposed – Managing with broad spectrum insecticides – September/October– Heavy migration pressure from other cotton fields, tomatoes, melons– Use synergized pyrethroid combinations
• Consult UC Pest Management Guidelines for details – ipm.ucanr.edu
Management Approaches
• Cultural Control– Limited to managing crops nearby to prevent
movement and – Strive to defoliate ASAP– Manage water and nitrogen to avoid excess late
season growth– No specific WF host plant resistance available
Management Approaches
• Biological Control– Conserve natural enemies– Use selective insecticides in early phase of
invasion– No single enemy is the answer, use them all– Main threat late adult migration which can
overwhelm existing natural enemies
Encarsia formosa
Eretmocerus sp
Hippodamia convergensChrysopa spp., Chrysoperla sppGeocoris spp.
Cotton AphidAphis gossypii
• Can be present throughout the season
• Wide host range• Two forms (morphs)
– Light (yellow, green) –population builds more slowly
– Dark (dark green, larger) –population can expand quickly
• Asexual reproduction• Telescopic generations
Biological Control
• Parasitic wasp , Lysiphlebustestaceipes, is a key population control agent
• Lacewing, lady beetles and syrphid flies are more specific predators
• Damsel, big eyed and minute pirate bugs will attack but are generalist predators attacking a wide variety of prey.
Cultural Control• Strive to produce as early a crop as possible• Manage water and nitrogen to avoid excessive late
season growth• No specific host plant resistance available, aphids
tend to prefer hairy leaf varieties• Time and manage defoliation to maximize leaf drop
using Nodes Above Crack Boll as your guide.• Avoid “regreening” or regrowth in top of plant
Chemical Control
• Scout regularly• Use UC IPM Guidelines• Watch for boll
maturation and split• Action threshold shifts
quickly after boll opens and lint becomes exposed
• Use selective materials early
• Examine the 5th leaf from top of plant, same as WF
• Count and record number and color (yellow or black).
• Before open bolls, 50/leaf• After boll opening, 5/leaf
Chemical Control
• Use selective insecticides during early in the season to conserve natural enemies
• Rotate insecticide mode of actions to prevent development of insecticide resistance
• Consult UC Pest Management Guidelines for details – ipm.ucanr.edu
Concluding Remarks
• Protect the lint from ALL contamination including honeydew
• Once a region develops a poor reputation for quality, it “sticks” with you
• Look early and look frequently for insect sources of contamination
Thanks for Your Interest