Cotton Nematode Management Jimmy R. Rich and Mike Donahoe

Nematode Facts Nematode Facts

Nematodes are Highly Underrated Pests  Most numerous animal (s) in the world  Are the second most in number of animal species  Over 6000 known plant-parasitic species  Nematodes attack all crop plants  Present in greater than 90% of Florida cotton

Nematode Anatomy

Nematodes in Roots

Plant-Parasitic Nematode Stylet (Spear)

Plant Nematode Facts  Mainly plant root parasites  Very small - mostly microscopic  Five life stages (plus egg)  Mostly wormlike in shape  Some female nematodes swollen  Life cycle - every days  Female produces eggs  Over one season - 1 female = 8 billion and more nematodes (hence the problem!!)

Nematodes in Florida Cotton Nematodes in Florida Cotton

Major Florida Cotton Nematode Pests In order of importance: Southern Root-Knot Nematode, Meloidogyne incognita Southern Root-Knot Nematode, Meloidogyne incognita Reniform Nematode Reniform Nematode Rotylenchulus reniformis Rotylenchulus reniformis Sting Nematode Sting Nematode Belonolaimus longicaudatus Belonolaimus longicaudatus

North Florida Cotton Nematode Survey 2004  A survey was conducted in three counties: Santa Rosa, Escambia, and Okaloosa  Cotton fields randomly chosen by agents  Survey included 61 soil samples in about 35 fields  Sample represented soil cores taken in acres each  Sample represented soil cores taken in acres each

Cotton Nematode Survey 2004 Nematode Sample content (%) Root-Knot48 Reniform42 None10

Damaging Nematode Levels for Following Year Cotton County YesLikelyNo Sample, % Okaloosa Escambia Santa Rosa Average503020

Plant and Root Damage Symptoms Plant and Root Damage Symptoms

 Premature wilting in spots on plant or field ie spots  Leaf yellowing (some)  Plant stunting (stunted growth)  Irregular (oval) symptom patterns  Row patterns rarely evident  Nutrient deficiency symptoms Foliar Damage Symptoms Water and Nutrient Stress

Cotton Field Abandoned Due to Nematode Damage

Young Cotton Stunted by Nematodes

Nematode Damage Following Soil Type Change

Damage on Maturing Cotton

Purpling of Cotton Leaves by Reniform Nematodes

Plant Root Damage  Stunted roots  Fewer feeder roots  Root galling and swelling  Root cell death or cell malfunction  Openings for disease organisms

Root-Knot Nematode Galling on Roots, Not Very Apparent

Female Root-Knot with Eggs, Root is the Size of a Pinhead

Reniform Nematode Females Always Outside Root, No Root Galling

Nematode Damage Symptoms  When damage symptoms are observed in the field, losses have been occurring over several years  Most times nematodes cause economic losses without obvious symptoms

Comparison of Nematode Damage Symptoms on Cotton Root-KnotReniform Galled roots No galling Little leaf discoloring Leaf purpling Irregular patches General decline Patches obvious Less obvious Sands, loams Loams, clays Lower numbers Higher numbers

Nematode Problem Assessment Nematode Problem Assessment

Know Your Nematodes  Each nematode species is ‘different’  Management techniques should be ‘nematode specific’  Rotations must be planned for ‘key’ nematode pests  Nematicide rates can be adjusted for nematode species

Problem Identification  Foliar symptoms – stunted ovals/decline  Root symptoms – roots galled/stunted  Cropping history – declining yields and previous host crops  Laboratory analysis – which nematode type and numbers are present

Nematode Soil Samples Problem ID  Take anytime during crop maturity and prior to planting, best time is soon after harvest  Can take samples for nematodes when collecting soil fertility samples  Split soil samples, one for nematode analysis and one for fertility (1 pint each)  Remember extra care is required for nematode samples

Handling Nematode Soil Samples  Sample 8-10” deep if possible  Sample only in moist soils – Not dry or wet  Only use plastic bags which prevents soil drying  Do not allow samples to become hot or cold

Tools for taking nematode soil samples Choice of sampling tools Plastic bag Permanent ink marker Bucket

Ten Acre Sampling Patterns (Take 15 To 20 Cores) Centered GridIntersected Grid Zig ZagRandom

Managing Cotton Nematodes

Management Methods  NEMATICIDES   Rotation  Sanitation  Resistance

Cotton Nematicides  Temik 15G - Bayer CropScience  Telone II - Dow AgroSciences  Nemacur - Bayer CropScience  (cancellation notice for 2007)

Temik 15G Product Information   Sold only as a 15% granular formulation   Formulation usually clay based   Used at-planting as a band or in-furrow   Pinhead square side dress applications can also be made   Temik 15G rarely kills nematodes (mainly paralyzes them)

Telone II Product Information  Sold as liquid formulation only  Movement by fumigant action in the soil  Applied preplant injected to 14 inches depth (do not apply in clay subsoil)  Usually applied with a single in-row chisel in cotton  Telone II kills nematodes on contact

Telone and Temik Are Restricted Use Pesticides  Reminder - both products have specific use restrictions!!  Temik has special reporting and use requirements in Florida  Temik 15G forms and other requirements can be found at FDACS Web Site -

Florida Cotton Nematicide Recommendations  Temik 15G (In Furrow)  Root-knot nematode – 7 lb./A  Reniform nematode – 5 lb./A  Telone II (In Row, Single Chisel)  Root-knot nematode – 4-5 gal./A  Reniform nematode – 3 gal./A

Comparative Cotton Yields Recommended Rates  Telone II (in-row application)  Root-knot – 1 gal = Minimum 50 lb. lint/A  Reniform – 1 gal = Minimum 35 lb. lint/A  Temik 15G (at-planting application)  Root-knot & reniform – 1 lb. formulation  = 8-10 lb. lint/A (variable)

Farmer Field Demonstration No Treatment Telone II

‘Other’ Nematicides  Mocap – Bayer CropScience  Vydate - DuPont  Counter - BASF  Furadan - FMC  Vapam – AmVac Corporation  Chlor-O-Pic - Hendrix and Dial

Management Methods  Nematicides  ROTATION   Sanitation  Resistance

Rotation  Know what nematode(s) are present  Use poor or nonhosts crops and rotate for at least two years  Consider using a nematicide if rotating only one year  Reniform nematode rotation: corn, sorghum, and peanuts are nonhosts; tobacco and soybeans are poor to moderate hosts. Cucurbits are good hosts.  Root-knot nematodes have a wide host range (see Cotton Management Guide for host list).

Management Methods  Nematicides  Rotation  SANITATION   Resistance

Sanitation Notes  Control weeds, many are nematode hosts including Morningglory, Florida Pusley, Tropical Spiderwort, Nut Sedge, etc.  Prevent crop regrowth in peanut and cotton to stop nematode population increase in the fall  Perennial grass rotation (bahiagrass) does not work with weed hosts present

Nematode Weed Hosts in Bahiagrass Pasture

Frequently Asked Questions

Is GPS/GIS Variable Rate Nematicide Application Feasible? This is ‘doable’ technology  Is it economical?  System Needs:  Accurate nematode population distribution map of a field, alternatively, a yield monitor map linked to nematode populations  Programmed GPS unit programmed for nematicide rate based on the nematode distribution map  Equipment suitable for nematicide rate adjustment

What Is The Link Between Nematodes And Fusarium Wilt In Cotton?  Fusarium is a soilborne fungus that causes cotton to wilt and die.  Most cotton varieties have Fusarium wilt resistance thanks to efforts by breeders.  However, when nematodes are present, they break this Fusarium wilt resistance.  Thus, two problems result, nematode damage and Fusarium wilt in cotton.

Cotton and Peanut Rotation  Cotton is attached by the southern root-knot and reniform nematodes.  Peanut is affected by the peanut root-knot and lesion nematodes.  This makes for a good rotation to reduce nematode problems in each crop.  However, do not use the same crop two years in a row.  Cotton, peanut, cotton, peanut are better rotations but must be supplemented with low nematicide rates.  The best rotation is adding another crop in the sequence – corn (sorghum), soybean (resistant), or perennial grass crops.

Additional Information  Visit the UF/IFAS EDIS Web Site  Search for ‘Cotton Nematodes’