1. Nematode Management in Florida Peanut Production
Jimmy R. Rich Nematologist
Jimmy Rich, Extension Nematologist-Agronomic Crops, University of Florida, IFAS/NFREC, 155 Research Road, Quincy, FL All comments for improvement would be greatly appreciated.

2. Plant Nematode Characteristics
Root parasites, mostly microscopic
Five life stages (plus egg)
Mostly wormlike, some females swollen
Life cycle every days
Female produces eggs
Over one season 1 female = 8 Billion and more nematodes (hence the problem!!)
Peanut root-knot nematodes, the major nematode parasites on peanut, reproduce every days in the summer and the females of these nematodes are swollen and immobile. The other major nematode parasite of peanut, lesion nematodes, remain wormlike and mobile throughout their life cycle.

3. Nematodes, Highly Underrated Pests
Most numerous animal in the world
Are the second most numerous animal species
Over 6000 known plant-parasitic species
Nematodes attack all crop plants
Present in greater than 90% of Florida fields
The Phylum Nematoda is composed of plant, animal and insect parasites. In addition, numerous free-living species exist, e.g. those that feed on soil flora and fauna and are considered beneficial.

4. Nematode Anatomy
The nematode is a ‘ring’ nematode and generally not a problem in peanut production. However, it is illustrated here to show general nematode anatomy. Nematodes are considered ‘simple’ animals and lack a circulatory and skeletal systems.

5. Plant-Parasitic Nematode Stylet (Spear)
This is an actual stylet (spear) from a plant-parasitic nematode. Stylet parts include from left to right – stylet knobs, stylet shaft, and stylet extension.

6. Nematodes Damaging Peanut
Peanut Root-Knot Nematode:
Causes 90% of nematode damage
Causes galls on roots and pods
Lesion Nematode:
Causes 10% of nematode damage
Emerging problem after cotton and grass crops
Nematode Names – Plant nematodes are generally given common names according to either damage symptoms they produce on plants or some striking morphological feature they possess. For example, root-knot nematodes produce root ‘knots’ while lesion nematodes cause ‘lesions’ on plant roots. The scientific names of the peanut root-knot and lesion nematodes are Meloidogyne arenaria and Pratylenchulus brachyurus, respectively.

7. Root-Knot Nematode Life Stages
Peanut root-knot nematodes are a key pest in the Florida peanut crop. The above photograph represents the gradual swelling of the second stage juvenile to become an immobile adult (juvenile stages 2 and 3 shown here).

8. Female Root-Knot with Eggs, Root is the Size of a Pinhead
The root-knot nematode adult female is encased inside the root gall. Unlike many nematodes, she gradually enlarges from penetration as a second-stage juvenile to the fifth stage adult. In this slide, the female and egg mass (left) have been stained red for easier viewing. In nature, the female and egg mass appear white to almost transparent. (Photo credit to the Society of Nematologists Slide Set Committee).

9. Ways Root-Knot and Lesion Nematodes Affect Peanut
Reduced nutrient and water uptake due to stunt plant roots
Redirected plant manufactured food resources for nematode growth
Peanut peg abortion and poor development of surviving pegs/pods
Providing an entrance for disease and pod-rotting organisms
Reducing nut quality hence final peanut grades
Nematodes usually reduce root growth and function in most plants. Additional damage to peanut, however, occurs due to abortion of the developing pegs and poor quality nuts.

10. Foliar Damage Symptoms Caused By Nematodes
Premature wilting in spots
Leaf yellowing
Plant stunting
Irregular (oval) symptom patterns
Plant death at mid to late season
Foliar Symptoms - Root feeding nematodes produce foliar symptoms that mirror root damage. In fact, most foliar-induced symptoms are the same as plants show when not receiving sufficient water and nutrients – wilting, yellowing, and stunting. As a result, nematode problems are often misdiagnosed and blamed on a lack of fertilizer and water.

11. Root-Knot Nematode Damage Browning And Wilted Spots
Root-knot nematodes may cause plant death, particularly from mid-season until harvest. At or near harvest is an excellent time to determine nematode damage and presence in a peanut field. Close inspection will provide greater accuracy for predicting future nematode problems than soil sampling.

12. Root-Knot Damage Late Season Plant Death
Root-knot nematode damage appears as more or less oval spots in a field. However, actual yield losses occur in areas much larger than the obvious ‘spots’.

13. Root-Knot Nematode Damage Pod Galling and Rotting
These are the pods that survived root-knot nematodes, most pods and pegs were aborted or rotted before harvest.

14. Lesion Nematode - Plant Death is Seldom Evident
Lesion nematode damage symptoms occurs in ‘spots’ in a field, however, these are generally more widespread than those caused by of root-knot nematodes.

15. Lesion Nematode Damage A Dull Yellowing
Lesion nematodes seldom cause widespread plant death but rather plant foliage shows a dull yellowing appearance. Foliar symptoms are often confused with nutrient deficiencies so roots and pods should be examined careful for signs of lesion nematode damage. CBR disease in peanut looks similar, however, the yellow color is much deeper and plants die quickly in those areas.

16. Lesion Nematode Damage Brown Spots on Pods
Presence of bright brown specks and spots on the peanut pod is indicative of lesion nematode presence. These pods show a moderate infection level of lesion nematodes, however, some losses occurred earlier due to peg abortion and decay of developing pods.

17. Lesion Nematode Damage Brown Spots and Pod Rotting
Lesions on the peanut eventually cover the whole pod and pod decay progresses.

18. Know Your Nematodes For Accurate Management Decisions
Each nematode species is ‘different’
Management techniques should be ‘nematode species specific’
Rotations must be planned for ‘key’ nematode pests
Nematicide rates can be adjusted for individual nematode species

19. Nematode Soil Samples Problem ID
Take anytime during crop maturity and prior to planting, the best time is soon after harvest
Can take these samples 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

20. Tools for Taking Nematode Soil Samples
Choice of sampling tools
Plastic bag
Permanent ink marker
Bucket
The sampling tool is not as important as obtaining good vertical slices of soil from the surface to 10-12” deep.

21. Ten Acre Sampling Patterns (Take 15 To 20 Cores)
Centered Grid
Intersected Grid
Zig Zag
Random
Soil samples to predict nematode problems in a following crop should be taken at or near crop harvest for best results, however, samples taken anytime are better than none at all. Take samples in moist soil to inches deep, mix sample, place a 1 pint subsample ina plastic bag and submit to the Extension Nematology laboratory via you local County Extension Office. Include roots as possible with the soil sample.

22. Handling Nematode Soil Samples
Sample 10-12” deep if possible
Sample only in moist soils – Not dry or wet
Only use plastic bags to prevent soil drying
Do not allow samples to become hot or cold
Remember, nematodes are living animals, treat samples gently
Nematodes are quite fragile and can be killed through rough handling of soil, high or very low temperatures and from desiccation. Dead nematodes decay rapidly and are not recovered during soil extraction in the laboratory.

23. Management Methods
Nematicides
Plant Resistance
Sanitation
Rotation

24. Peanut Nematicides Only a Few Choices!!
Telone II - Dow AgroSciences
Temik 15G - Bayer CropScience
Nemacur - Bayer CropScience
(cancellation notice for 2007)
By mutual agreement of EPA and Bayer CropScience, all uses of Nemacur will be cancelled in 2007.

25. 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)
May be applied as a single in-row chisel, dual chisels or broadcast
Telone II kills nematodes on contact
The ability of Telone II to move in soil by vaporization and nematode death on contact make it the most effective nematicide for nematode control in peanut. Non-fumigant nematicides provide somewhat variable nematode control due to the need to move in soil water and
Mainly just paralyzing rather than outright killing nematodes.

26. Temik 15G Product Information
Sold only as a 15% granular formulation
Formulation may be corncob (lighter) or clay based
Used at-planting as a band or in-furrow treatment
May be applied as an at-pegging time treatment

27. 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 -

28. Nematicide Recommendations
High nematode levels or continuous peanut: Telone II at 6 gal./A + Temik 15G at 10 lb./A (at pegging)
Moderate nematode levels: Telone II at 6 gal./A or Temik 15G at 10 lb./A (at planting) and Temik at 10 lb./A (at pegging)
Low nematode levels: Temik 15G at 7-10 lb./A (at planting)
These nematicide recommendations are based on the peanut root-knot nematode. Lesion nematodes require nematicides but at lower rates than root-knot nematodes. Low, moderate and high nematode levels are relative terms. The actual number of nematodes extracted from a soil sample and prediction of damage must be used in conjunction with the time of year the sample was taken, future crop susceptibility, and past cropping history.

29. ‘Other’ Nematicides Mocap - Bayer CropScience Counter - BASF
Furadan - FMC
Vapam - AmVac Corporation
Chlor-O-Pic - Hendrix and Dial
Nematicide registrations may change so please consult labels before using these materials. These ‘other nematicides’ can be used but are recommended only for special circumstances in Florida peanut.

30. Center Untreated Strip Telone II Applied on Either Side
This 100 acre field had been continuously cropped to peanut for about 8 years and heavily infested with peanut root-knot nematodes. By harvest, few plants in the untreated strip were alive. Yields were 700 lbs. per acre in the untreated strip and 2500 lbs per acre in the Telone II treatment.

31. Telone Treatment (Background) and Untreated Control (Foreground)
Pictured is Bill Smith, Columbia County Extension Agent who initiated this Telone demonstration in the grower field.

32. Peanut Resistance/Tolerance
No commercially adapted varieties to Florida production conditions
Active pursuit of root-knot nematode resistance is being made in Florida peanut breeding programs
Early data indicate some tolerance to nematode damage in some varieties: Southern Runner, AP3, Hull, and DP1
The Texas A&M peanut breeding program has release a root-knot nematode resistance runner variety, NEMATAM, later replaced by COAN. These varieties exhibit good resistance to the peanut root-knot nematode, however, they lacks adequate resistance to common fungal and viral diseases prevalent in Florida peanut. Crosses of these varieties with varieties adapted to Florida are progressing well.

33. Sanitation Notes
Prevent crop regrowth (peanut, cotton) to stop nematode population increase in the fall
Control of nematode host weeds including morningglories, florida pusley, tropical spiderwort, and nutsedge
Implement perennial grass rotation (bahiagrass) with good weed control
Fall and spring growth of weeds and volunteer peanuts maintains and sometimes increases nematode populations, hence problems in future crops. Planting bahiagrass without follow-up weed control limits the effectiveness of this rotation for nematode management.

34. Sanitation - Prevent Volunteer Peanut Growth
Volunteer peanuts may allow one or more additional generations of nematodes in the fall after harvest. Also, volunteer peanuts the following year will maintain or increase nematode populations.

35. Weed Hosts of Nematodes in Bahiagrass Pasture
If weed hosts to nematodes are allowed to grow, rotations lose much of their value in reducing nematode damage to following crops.

36. Crop Rotations to Manage Nematodes in Peanut
Plan rotations to manage the peanut root-knot nematode, the ‘key’ nematode pest on peanut
Lesion nematodes are less damaging to peanut but rotation is difficult due to wide host range
Hence, nematicidal control may be needed for lesion nematodes, but at lower rates than for root-knot

37. Crop Rotation to Reduce Peanut Root-Knot Nematodes
Grass crops are the best for reducing root-knot nematode problems
Among the grass crops, bahiagrass is a non-host and provides other good advantages as well
Cotton is an excellent rotation crop for managing the peanut root-knot nematode

38. Crop Rotation to Reduce Lesion Nematodes
It is difficult to reduce lesion nematodes using crop rotations
Lesion nematodes reproduce well on most grass crops
Bahiagrass is a non-host
Cotton, tobacco and soybean are moderate hosts

39. Frequently Asked Questions (FAQ)

40. FAQ – My Bahiagrass Rotation did not Prevent Nematode Damage?
Bahiagrass is non-host for root-knot and lesion nematodes, but the rotation is not perfect:
Length of bahiagrass rotation must generally be a minimum of three years
Weed Management is sometimes more important than rotation length with bahiagrass
Weed hosts of nematodes in bahiagrass must be controlled or nematodes remain to damage a future peanut crop

41. FAQ - What About GPS/GIS Variable Rate Nematicide Application?
This technology is available, however, the economics are still uncertain?
System Needs:
Accurate nematode population distribution map of a field, alternatively, a yield monitor map linked to nematode populations
GPS unit programmed for nematicide rate based on the nematode distribution map
Equipment suitable for nematicide rate adjustment

42. Root-Knot Nematode Numbers in a 100 Acre Field
2.5 Acre Grid Pattern,
Nematodes/ ¼ Pint Soil
This field was contained high levels of root-knot nematodes. Colors indicate the use of variable rates of nematicide (Telone II) as follows: Green – no nematicide, Yellow – low nematicide rate, Orange – moderate nematicide rate, Red – high rates.

43. For More Information
Visit the UF/IFAS EDIS Web Site at
Search ‘Peanut Nematodes’