Nematode Suspension Research Articles

Scotch Pine, Control of Northern Pine Weevil, Carrol Co., Ohio, 1989

Abstract Scotch pine stumps, cut during the 1988 Christmas tree season at a plantation in Carroll Co., were used to evaluate an entomogenous nematode and an insecticide against northern pine weevil. Applications were made 28 Apr under cloudy skies, 10°C, and no wind. Slight rainfall occurred during application of treatments. A stock suspension of nematodes was prepared by placing 1 unit of Otinem (50,000,000 nemas) in 10 gal of water. Nemas were applied volumetrically in 4 pt of water to deliver predetermined numbers of nemas/stump. AgSorb flake was added (7.6 g) to half of the nematode treatments. Stock suspension was stirred thoroughly prior to removing measured amounts. Finished material was also stirred thoroughly in a sprinkling can and poured over and around each stump to achieve thorough coverage. Lindane was added to kerosene in a Hudson sprayer, and 100 ml of finished spray were applied to each stump. Each treatment was replicated 3 times with each replicate consisting of 5 stumps. Treatments were evaluated 24 Oct by counting the number of chip cocoons exposed by removing the bark from each stump to the first lateral root.

In vivo flow 31P FT‐NMR spectroscopy of a nematode parasite

31P NMR spectroscopy of a parasitic nematode. Steinernema carpocapsae, is described. In vivo spectra were generated from nematode suspensions continuously circulating through the spectrometer. By flowing the organism, saturation effects were avoided and short interpulse delays significantly reduced spectral generation time. To maximize sensitivity, 90 degrees pulses were employed. Changes in energetic status in response to oxygen availability were easily and rapidly monitored in circulating nematodes.

Investigations on the parasitism ofOtiorrhynchus salicicola andO. Sulcatus [Col.: Curculionidae] byHeterorhabditis sp. [Nematoda

Experiments were conducted to study the efficacy of the insect parasitic nematodeHeterorhabditis sp. (HW79) as a biological control agent ofOtiorrhynchus salicicola. This weevil species is reported as a pest of ornamental plants in Switzerland and Italy. Dipping plastic boxes containing heavily infested cuttings of laurel (Prunus laurocerasus) in a nematode suspension resulted in approximately 100% parasitisation of full-grown larvae, pupae and non-emerged young adults. The average dose resulting from dipping varied between 56,000 and 62,000 nematodes per liter soil. This experiment was run under natural outdoor conditions. In a further outdoor experiment, pottedLigustrum plants were inoculated with eggs ofO. salicicola and later 20,000 infective juvenile nematodes per liter soil were added to the soil surface. The resulting weevil mortality in the treated pots was 78%. In seven greenhouse tests using the same nematode dose in pots with horticultural soil to which weevil larvae had been added, weevil mortality varied between 76% and 100%, the arithmetic average being 90%. These results indicate that Heterorhabditid nematodes may provide an effective means of controllingO. salicicola. In an other experiment usingO. sulcatus larvae, the influence of application time on nematode efficacy was investigated. When nematodes were added a few days before weevil larvae had hatched from the eggs, no parasitic effect was obtained. Nematode applications done shortly after larval hatching however, resulted in complete weevil control. These results are of significance in timing nematode applications in practice.

昆虫寄生性線虫のセンチニクバエ Boettcherisca peregrina とイエバエ Musca domestica 幼虫に対する殺虫効力

Entomogenous nematodes, Steinernema feltiae (ALL and Mexican strains), S. bibionis, S. glaseri, and Heterorhabditis heriothidis were evaluated for their infectivity to larvae of a Japanese species of flesh fly, Boettcherisca peregrina by the contact method with nematode suspension. The 3rd instar larvae of B. peregrina were forced to contact with a suspension of infective larvae of nematodes for 48hr and the mortality of treated insects calculated from adult fly emergence was determined. Both strains (ALL and Mexican) of S. feltiae and S. bibionis were most infective to B. peregrina larvae, followed by H. heriothidis, whereas S. glaseri showed no significant infectivity to larvae of the fly. To investigate the effect of temperature on infectivity of nematodes, the 3rd instar larvae of B. peregrina were incubated with a suspension of nematodes at 5 different temperatures between 15 and 35℃ for 48hr. S. feltiae (ALL and Mexican strains) were most infective at 25 and 30℃, less infective at 30℃, and showed no remarkable activity at 15 and 35℃. Loss of S. feltiae infectivity at 35℃ was due to death or weakening of nematodes at higher temperature. Loss of infectivity at 15℃, on the contrary, was caused by immobility of nematodes at lower temperature. Housefly (SRS strain) larvae were reared in a medium containing S. feltiae (ALL strain) for evaluation of its infectivity. The 2nd instar housefly larvae were placed on standard barley bran media with infective larvae of the nematode and adult fly emergence was subsequently observed. S. feltiae almost completely inhibited house fly emergence at a concentration of (10)^5 per 100g larval medium.

Field control of Heliothis zea (Boddie) (Lepidoptera: Noctuidae) using a parasitic nematode

Field trials were conducted to assess the effectiveness of a parasitic nematode, the DD136 strain of Neoaplectana carpocapsae Weiser in controlling Heliothis zea (Boddie) on naturally infested sweetcorn. Nematode suspensions at concentrations of 0, 4 × 103, 4 × 104, 4 × 103 (applied twice) and 4 × 104 (applied twice), nematodes/ml respectively, were sprayed on the ears at early silking stage. Treatments with 4 × 104 nematodes/ml sprayed twice at 3 days interval gave significantly better control (55%) than the rest. The mean number of surviving H. zea larvae was also significantly reduced with increasing concentrations of nematodes. Economic damage was not prevented but damage to treated ears was significantly lower than that of the untreated plots.

Evaluation of Steinernema feltiae and S. bibionis (Rhabditida: Steinernematidae) for suppression of Lymantria dispar (Lepidoptera: Lymantriidae) in Pennsylvania, U.S.A.

Lymantria dispar L. larvae exposed to the entomogenous nematodes Steinernema feltiae Filipjev and S. bibionis (Bovien) for ⩾ 16 h in laboratory petri dish tests averaged 93 and 91% mortality, respectively. Nylon pack cloth bands, lined with Pellon fleece or terry cloth, placed around oak tree boles were treated with nematode suspensions in central Pennsylvania. Fifth and 6th stage host larvae collected from beneath these bands after nematode treatment averaged 28% mortality.

ゴマダラカミキリ幼虫に対する昆虫寄生性線虫のバーク堆肥混入施用について

Application of bark compost containing infective juveniles (J 3) of Steinernema feltiae DD-136 at the dose rates of 63, 125, 250, 500, 1000/ml resulted in 72 to 100% mortality for the 1st to 3rd instar larvae of Anoplophora malasiaca burrowing into citrus-limb under laboratory conditions at 25°C. In August, the application of bark compost containing nematodes (500, 000J 3/plant) on the soil surface around the trunk of a 6 year old navel orange tree resulted in 85% mortality for the 2nd and 3rd instar larvae in the laboratory, 77% for those in the trees shaded by cheesecloth, and 59% for those in trees exposed to direct. sunlight without shading. Spraying of the nematode suspension at the rate of 300, 000 per plant on the surface of the trunk resulted in 66%, 77%, and 25% mortality under the above conditions, respectively.

The susceptibility of the spruce budworm, Choristoneura fumiferana (Lepidoptera: Tortricidae), to Heterorhabditis heliothidis (Nematoda: Heterorhabditidae) in the laboratory

Exposure of 4th, 5th, and 6th instar Choristoneura fumiferana to Heterorhabditis heliothidis (120 nemas per larva) resulted in 100% mortality within 48 h at 24 ± 1 °C. At 17 °C, 100% mortality was achieved within 120 h. Reduction of the dose to 15 nemas per 5th–6th instar larva caused 70% mortality at 24 ± 1 °C and 15% mortality at 17 °C within 120 h. At the higher temperature, mortalities of 80 and 73% were recorded for pupae exposed to 150 and 60 nemas per pupa, respectively. When 6th instar larvae on foliage of balsam fir or blue spruce were treated with the nematode suspension (120 nemas per larva) 100% mortality was obtained within 72 h at 24 ± 1 °C. The potential of using this nematode in biological control of spruce budworm is discussed.

Suitability of Scolytus multistriatus and Dendroctonus ponderosae as Hosts for the Entomogenous Nematode Neoaplectana carpocapsae12

The suitability of the lesser European elm bark beetle, Scolytus multistriatus (Marsham), and the mountain pine beetle, Dendroctonus ponderosae Hopkins, as hosts for the entomogenous nematode Neoaplectana carpocapsae Weiser was evaluated in laboratory and greenhouse experiments. These two species also were compared with larvae of the wax moth, Galleria mellonella (L.), with respect to suitability for nematode reproduction. All stages of both bark beetle species were susceptible to parasitism by N. carpocapsae, with rates of infection ranging from 10 to 66%. Adults of D. ponderosae were the least susceptible of all stages tested of both species. The rate of infection in D. ponderosae was dosage dependent up to 85 dauerlarvae (infective juvenile nematodes) per insect. A comparison of total yield of nematodes among the three insect species tested suggests that S. multistriatus and G. mellonella larvae are about equally suitable hosts for the nematodes; D. ponderosae appears considerably less suitable. Greenhouse trials showed that dauerlarvae of N. carpocapsae could be recovered alive from frass in beetle-infested pine bolts sprayed several weeks previously with a water-plus-antidesiccant suspension of infective nematodes.

Action of a nematode-trapping fungus shows lectin-mediated host–microorganism interaction

Many nematode-trapping fungi capture nematodes using an adhesive present on specific capture organs (for review see ref. 1). Until recently, the mechanism of adhesion was completely unknown. In the case of Arthrobotrys oligospora, one of the most common nematophagous fungi, nematodes are trapped in three-dimensional structures of the adhesive network type (Fig. 1a). When a suspension of nematodes is added to an agar culture of the fungus, nematodes are immediately captured and firmly held by the traps. The nematode cuticle is lysed at the point of contact and penetrated by a hypha within one hour2. An increased secretion by the fungus of a mucilaginous substance in the presence of prey has been shown by scanning and transmission electron microscopy2,3. Our hypothesis is that the firmness of attachment to the traps despite the struggle of the nematode is due to a series of events, beginning with an interaction between complementary molecular configurations on the nematode and fungal surfaces. We show evidence here for the presence of a lectin on the traps of A. oligospora which binds to a carbohydrate on the nematode surface.

Nematode-Induced Morphogenesis in the Predacious Fungus Arthrobotrys Oligospora

Living nematodes induced trap formation in Arthrobotrys oligospora more rapidly than did additions of morphogenetic peptides. In nematode-induced morphogenesis, excreted substances as peptides and amino acids were only partly responsible for the effect. Additional effects were due to volatile substances from nematodes or to direct contact between living nematodes and the hyphae. Ammonia was shown by gas chromatography to be excreted in nematode suspensions in amounts that could affect trap formation. It is proposed that living nematodes act primarily through another mechanism than peptide-induced morphogenesis.

Evaluation of Alfalfa for Stem‐Nematode Resistance1

An improved laborsaving technique for evaluating stem‐nematode [Ditylenchus dipsaci (Kühn) Filipjev] resistance in alfalfa (Medicago sativa L.) was developed. To demonstrate the technique, seedlings of three resistant and three susceptible varieties were inoculated by watering with nematode suspensions at seeding and again at 2, 4, and 6 weeks and were rated 16 weeks after seeding. Resistant varieties ‘Apalachee,’ ‘Lahontan,’ and ‘Washoe’ averaged 90.1, 67.8, and 63.7% resistant plants, respectively. Susceptible varieties ‘Saranac,’ ‘Vernal,’ and ‘Ranger’ averaged 34.9, 15.1, and 12.2% resistant plants. Because of its ease of application and its ability to differentiate clearly between resistant and susceptible varieties, this method should appeal to many workers.

Field Control of the Nantucket Pine Tip Moth by the Nematode DD-13612

Field investigations showed that the nematode DD-136 would kill Rhyacionia frustrana (Comstock) larvae under natural conditions. More first-generation tip moth larvae were killed than second or third. Nematode suspensions were aided in effectiveness by addition of 10% glycerin and to a lesser degree by addition of wetting agents or spreader-stickers, namely, 2% solution of Emgard 2050, Sole-onic CDS, and IGEPON AP-78. However, it was concluded that under the conditions of this study, DD-136 did not provide sufficient control of the Nantucket pine tip moth to recommend its use.

Use of Gelgard M and an Evaporation Retardant to Facilitate Control of Larch Sawfly by a Nematode-Bacterium Complex1

A manipulation of the microenvironment to increase the period of viability of the insect-parasitic nematode, DD-136 strain of Neoaplectana carpocapsae Weiser, 1955 and its associated bacterium Achromobacter nematophilus Poinar and Thomas, sprayed onto larch foliage infested with larch sawfly, Pristiphora erichsonii (Hartig), was successful in laboratory tests. By adding to the aqueous suspension of nematodes, the water thickener Gelgard M® (0.13%), an evaporation retardant, Folicote 351® (0.2%), and a surfactant, Arlatone T® (0.1%), the average mortality of the larch sawfly larvae was increased from 24 to 90%.

Modifications of the Elutriation Method for Extracting Nematodes From Soil

Clay soil can be rapidly dispersed in water without damaging the nematodes present with a vibromixer. The most efficient width of the tubes of the elutriator was determined. Methods for the extraction of nematodes > 2 mm from soil and special banks of sieves for sieving nematode suspensions are described.

PRELIMINARY STUDIES OF THE TRANSFER OF FOUR STRAINS OF DITYLENCHUS DIPSACI (KÜHN 1858) FILIPJEV 1936

The bulb and stem nematode, Ditylenchus dipsaci, attacks narcissus, iris, red clover and strawberry in the Pacific Northwest. The isolations from each of these important crops are herein described as strains.Preliminary studies of the transfer of these strains establish the existence of three strains of D. dipsaci in the Pacific Northwest, viz.:(i) Red clover strain; characterized by causing swollen crowns and stunt in red clover seedlings.(ii) Strawberry strain; characterized by a limited host range, swollen crowns in strawberry seedlings, and entrance into red clover seedlings without visible tissue reactions.(iii) Narcissus and iris strain; characterized by a wide host range and entrance into clover and strawberry seedlings without visible tissue reactions.No satisfactory technique of establishing the host range of the biological strains of D. dipsaci has been developed. The clamping of glass rings filled with a nematode suspension in moist pulverized peat to the foliage of test plants did not affect the test plants in a constant manner. The examination of seedlings after clarification in a lacto-phenol solution containing acid fuchsin gave more constant results. The seedlings were removed from infested soil shortly after they appeared above ground.The reports of host specificity of the red clover strain were not confirmed, for the red clover strain entered white clover and alfalfa, hitherto considered resistant. Likewise, the reports of host specificity of the narcissus strain were not supported by our experimental results. The narcissus strain entered red clover and oats, also considered resistant hitherto.