NEMATOLOGY 

Bio-Matrix

  • Gram Negative and Gram Positive Bacteria.  Staining agents are used to classify bacteria as “gram negative” or “gram positive.” The staining agent attaches to the bacteria’s cell walls. Gram negative bacteria are generally the smallest bacteria and are sensitive to drought and water stress. Gram positive bacteria are much larger in size, have thicker cell walls, negative charges on the outside cell wall surface and tend to resist water stress.

  • Fungal, Bacterial Stained Computer Microscopy Evaluation.  Used to determine “Active and Total” diversity.  Fungal and Bacterial activities change naturally throughout the growing season and maintain the living matrix for the root zone.  Stained slides are analyzed with computer microscopy to evaluate active and inactive soil life.

Mycorrhizal, Protozoa, Nematode Microscopy Evaluation.  Used to determine anaerobic and aerobic soil indicators

 

Nematode ID

  • 200cc soil extract

  • Sieve separation

  • Centrifugation extraction

  • Microscopy Identification

 

Root Inspection - process to track nematode injury and detect parasitic nematode eggs.

  • Egg and enzyme staining agents

  • Microscopy evaluation.

 

Plant Parasitic Nematode Information

AWL - Dolichodorus heterocephalus is the most common species and is typically found in wet, sandy soils. They are at times found in and about golf greens that have been built near wet areas. Ornamental plants in such settings can suffer damage by awl nematodes. Awl nematodes feed from the outside of the root and often cause short, stubby roots and root lesions.

DAGGER - Xiphinema americanum is the most common species, although several other species could be present. The dagger nematodes are found in many habitats and seem to be particularly damaging to perennials. The roots of roses being fed on by these nematodes, for instance, become short, slightly swollen and darkened. Plants have an unthrifty appearance and do not respond well to good horticultural practices.  Dagger nematodes feed from the outside of the root. Nematodes in this group transmit plant viruses

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LANCE - Hoplolaimus galeatus and H. columbus are species common within the United States. Lance nematodes feed from both the outside and inside of roots. When they are inside the root, the body lies parallel with the root three to four cells deep, with the head curved toward the central part of the root. They generally feed on the conducting tissues of the root. Lance nematodes are fairly large plant-parasitic nematodes and their feeding does considerable damage to roots. Dark lesions and reduced root growth are common symptoms of lance nematode feeding.

PIN - Paratylenchus hamatus and Gracilacus spp are species common within the United States. Pin nematodes feed from the outside of the root by inserting their relatively long stylet several cells deep. They may feed on root tips and if so, the tips may become enlarged and cease to elongate. The nematodes sometimes appear attached to the roots. Pin nematodes are relatively small and maybe undetected if present in low numbers. Populations reach large numbers on some hosts. Paratylenchus spp. are not common in the Southeastern states, but they do occasionally occur in large enough numbers to cause noticeable symptoms.

RING - Mesocriconema spp and Criconemella xenoplax are the most common species of ring nematode associated with ornamentals, although other species are present. Ring nematodes are small nematodes with a heavy cuticle and deep annuals. They feed on roots from the outside by inserting their stylet. The cells from which the nematode feeds are transformed and damaged. There may be several hundred individuals in a few grams of soil. When feeding becomes heavy, symptoms appear in the form of unhealthy foliage, reduced growth, and "hairy,” darkened roots.

ROOT KNOT - Meloidogyne incognita, races 1 and 3, M. arenaria, races 1 and 2, and M. javanica are the root-knot nematodes most likely found in the United States. Other species may occur in fields or on plants shipped from other locations. As a group they are the most damaging nematodes of ornamental plants.  They enter the roots as young larvae and then enlarge as they become adults. Each female can produce 300 to 500 eggs. The most common symptoms are enlarged roots because the nematode has stimulated the root tissue cells to enlarge and divide. In a few cases there are no galls produced but the nematode is damaging the plant and reproducing well. Root-knot nematodes are hard to control because they are mostly inside the roots and reproduce rapidly, and the eggs are well-protected in a gelatin like material.  They can be carried either as live nematodes or as eggs in roots and soil. They do well in greenhouses and the field.

LESION - Pratylenchus spp. are common in most soils within the United States. They spend most of their life inside roots. They remain vermiform and as roots deteriorate for any reason they move into the soil.  Feeding on susceptible ornamental plant roots results in darkened spots and heavy infestations result in reduced and discolored root systems. Because they are inside the roots, they are easily transported with live plants.  It is difficult to control lesion nematodes because both the nematode and the eggs are inside roots.

SHEATH - Hemicycliophora spp are common within the United States. However, they are not common in all sites with ornamental plants. They are most often found in soil with a high pH and which tends to be wet. They feed from outside the roots on root tips resulting in swollen, knoblike structures. Any damage probably will be limited to a small geographical area.

SHEATHOID - Hemicriconemoides spp are common in most soils in California.  They feed from outside the roots on root tips resulting in swollen, knoblike structures. Any damage probably will be limited to a small geographical area.

SPIRAL - Spiral nematodes include Helicotylenchus spp. and Scutellonema spp. Species of both generaare common to the United States. These nematodes generally feed from outside the root. Often their heads will penetrate the root tissues for several cells. Occasionally they will be found inside the root, especially fleshy roots. They will increase to relatively large populations when feeding on suitable hosts. Foliage will be unthrifty and the roots reduced in size and often discolored. It generally takes a relatively large population to cause serious damage.

STING - Belonolaimus longicaudatus, along with other Belonolaimus related sting nematode species, are A-Rated in California.   A-Rated Organisms:  An organism of known economic importance subject to action enforced by the state (or County Agricultural Commissioner acting as a state agent) involving:  eradication, quarantine regulation, containment, rejection, or other holding action.  STING nematode spp are common in the sandy areas of some United States soils. They are very damaging to root systems. Sting nematodes are ectoparasites and feed on root tips, causing the roots to stop elongating. The result is a short, stubby root system with a reduced number of fibrous roots. It takes only a few of these nematodes to cause economic damage.  For some crops, only one nematode per 100 cubic centimeters of soil will cause economic damage.

STUBBY ROOT - Paratrichodorus minor is the most common of several genera and species that belong to the stubby root group of plant-parasitic nematodes. This group of nematodes transmit plant viruses as they feed. Their life is spent in the soil about plant roots with the eggs being deposited near the roots. They destroy the cells on which they feed and, in most situations, cause the roots to cease to grow. The result is stunted plants with much reduced and, as the name implies, stubby root systems. The population can become quite large if a favorable host is present.  These are common in warmer California vineyards even in the absence of weeds or other vegetation.

STUNT - Tylenchorhynchus spp. are very common throughout the United States.  Tylenchorhynchus cylindricusis perhaps the best-known.  It has a wide host range and inhabits several soil types. Under favorable conditions, the populations become large. Plants are stunted with a reduced root system which is discolored and somewhat shriveled. Stunt nematodes spend their life cycle in the soil and feed from the outside of the root.

Tylenchus - This is a very common nematode found within most soils.  Though most commonly observed feeding on soil fungi, they have been observed feeding on roots when fungi is unavailable.   Their small stylet only allows surface feeding and normally are not observed as an economic pest.  However, when populations are high and soil fungi is low they may cause some root damage.

The Bio-Matrix example below is from a “Good Harvest” vs. “Weak Harvest”.  In this example we see the “Weak” site with what appears to be a very healthy bacterial and fungal environment.  However, many of the organisms detected in the soil were anaerobic and/or pathogen related.  Several of the pathogen related issues were directly related to the plant parasitic nematode population.  Heavy plant parasitic nematode populations can increase root decay and pathogenic fungi.  We also find that some combinations of nematode do more damage than others.  Example would be a Root-Knott nematode spp. combined with even a few Needle or Dagger spp. of nematode.

                      Nematode Sample Form.

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