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

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Temperature of Machines

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Card DrawingFront Roll

Roving RingSpinning

RotorSpinning

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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

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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

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Accumulated WF DD (50,90)

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2014

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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