Declan J. Fallon

Honolulu University, Honolulu, Hawaii, United States

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Publications (6)6.75 Total impact

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    ABSTRACT: The quality of entomopathogenic nematodes (EPN) is critical to their success as biological control agents, but it is difficult to evaluate quality because standard procedures are not available. Generally, the quality of biological control agents is determined by field performance because end users may have minimal knowledge pertaining to the condition of biological control agents before application. This study assessed the variability in quality of commercially available EPN products. The authors evaluated preapplication survival of five EPN formulations, Steinernema feltiae (NemaShield, Nemasys, Gnat Not, Horticultural Scanmask), and Heterorhabditis indica (GrubStake-Hi), based on eight shipments/samples of each EPN product received during a 5-month period (July to November). The estimated total number of EPN delivered per shipment (i.e., sample) was compared with the expected quantity listed on the label, and percent live EPN was determined for each shipment. One-half of the shipments of Gnat Not (four of eight) contained 40% to 70% of the number of EPN expected based on the label (25 million). The remaining shipments contained consistently higher numbers, with 99% of the expected quantity of EPN received. Entomopathogenic nematode mean percent survival was highest for Nemasys (98%) and lowest for Horticultural Scanmask (56%). The overall mean percent survival for Gnat Not and GrubStake-Hi, both from the same supplier, was more than 85%. Survival of EPN in the NemaShield product was as low as 50%, but was typically between 65% and 75%. NemaShield and Nemasys were the only two EPN products that provided return policy information if the product was damaged in any way. It is important for distributors and suppliers to ensure that EPN products are in quality condition before shipping to avoid performance failures and loss of customers. In addition, end users need to evaluate shipments upon receipt to determine the viability of EPN products.
    No preview · Article · Jan 2008 · HortTechnology
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    ABSTRACT: Entomopathogenic nematodes were screened for efficacy against the cottonwood borer, Plectrodera scalator (Fabricius). Steinernema feltiae SN and S. carpocapsae All killed 58 and 50% of larvae, respectively, in filter paper bioassays but less than 10% in diet cup bioassays. S. glaseri NJ, S. riobrave TX, and H. indica MG-13 killed less than 10% of larvae in both assays. H. marelata IN was ineffective in the diet cup bioassay and killed 12.9% of larvae in a filter paper bioassay. The nematode isolates we tested are not suitable for use as biological control agents against P. scalator.
    Full-text · Article · Jun 2006 · Journal of Invertebrate Pathology
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    Declan J. Fallon · Harry K. Kaya · Randy Gaugler · Brent S. Sipes
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    ABSTRACT: Isolates of Steinernema feltiae MG-14 from Hawaii and SN from France, and the symbiont Xenorhabdus bovienii from each nematode isolate, were tested for their glasshouse efficacy against the root-knot nematode, Meloidogyne javanica, on several vegetable plants. Steinernema feltiae application for 3-5 consecutive days at rates of 1000 or 10 000 infective juveniles (IJ) did not affect M. javanica root penetration and development in glasshouse pot experiments. IJ were recovered from the cortical tissue of tomatoes, soybeans, snow peas and cow peas. Xenorhabdus bovienii applied at 1010 colony-forming units (CFU) ml–1 reduced root-knot nematode penetration in cow peas but was ineffective in tomato or snow pea. Xenorhabdus bovienii metabolites had no effect on M. javanica root penetration and egg production in soybean. Soybean plant growth was unaffected by nematode and bacterial treatment; biomass was lower in M. javanica-infected soybean, irrespective of treatment, than in non-infected soybean, but the differences between the treatments were non-significant. Accordingly, the Steinernema feltiae-Xenorhabdus bovienii complex did not meet the objective for the suppression of M. javanica root penetration and development.
    Full-text · Article · Jun 2004 · Nematology
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    ABSTRACT: Isolates of Steinernema feltiae SN from France, Steinernema glaseri NJ from New Jersey, Steinernema riobrave TX from Texas, Steinernema carpocapsae Sal from Indiana, S. carpocapsae All from Georgia, and Heterorhabditis marelata IN from Indiana were screened for efficacy against laboratory colonies of Asian longhorned beetle, Anoplophora, glabripennis collected from Queens, New York and Chicago, Illinois. Two bioassays were used to screen nematode effects on beetle larvae; a filter paper assay using a 24-h exposure of nematode-to-target-insect, and a diet cup bioassay using a 72-h exposure of host larvae to infective juveniles applied to the larval bore hole made in the artificial diet in the cups. First- and third-stage larvae were susceptible to all isolates using a filter paper bioassay. S. feltiae and S. carpocapsae Sal were the most effective, causing 100% mortality. S. feltiae was more infectious than S. carpocapsae Sal against third, sixth, and seventh instars. S. riobrave, S. glaseri, and H. marelata were ineffective against the older instars. In the diet cup bioassay, S. feltiae and S. carpocapsae Sal killed 71-100% of mid-to late instar larvae, but the remaining isolates screened were ineffective. Nematode preconditioning to aqueous A. glabripennis frass extracts inhibited S. carpocapsae Sal infectivity but had no effect on nematode pathogenicity. S. feltiae juveniles were positively attracted to A. glabripennis frass extracts. Our results demonstrate the potential use of S. feltiae and S. carpocapsae isolates as control agents for A. glabripennis.
    Full-text · Article · Jun 2004 · Biological Control
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    Declan J Fallon · Harry K Kaya · Randy Gaugler · Brent S Sipes
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    ABSTRACT: Two Hawaiian isolates of Steinernema feltiae MG-14 and Heterohabditis indica MG-13, a French isolate of S. feltiae SN, and a Texan isolate of S. riobrave TX were tested for their efficacy against the root-knot nematode, Meloidogyne javanica, in the laboratory and greenhouse. Experiments were conducted to investigate the effects of treatment application time and dose on M. javanica penetration in soybean, and egg production and plant development in tomato. Two experiments conducted to assess the effects of entomopathogenic nematode application time on M. javanica penetration demonstrated that a single application of 10 S. feltiae MG-14 or SN infective juveniles per 100 cm(3) of sterile soil, together with 500 (MG-14) or 1,500 (SN) second-stage juveniles of M. javanica, reduced root penetration 3 days after M. javanica inoculation compared to that of a water treatment. Entomopathogenic nematode infective juveniles applied to assess the effects on M. javanica egg production did not demonstrate a significant reduction compared to that of the water control treatment. There was no dose response effect by Steinernema spp. On M. javanica root penetration or egg production. Steinernema spp. did not affect the growth or development of M. javanica-infected plants, but H. indica MG-13-treated plants had lower biomass than untreated plants infected with M. javanica. Infective juveniles of S. riobrave TX, S. feltiae SN, and MG-14 but not those of H. indica MG-13 were found inside root cortical tissues of M. javanica-infected plants. Entomopathogenic nematode antagonism to M. javanica on soybean or tomato was insufficient in the present study to provide a consistent level of nematode suppression at the concentrations of infective juveniles applied.
    Full-text · Article · Oct 2002 · Journal of nematology
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    ABSTRACT: Entomopathogenic nematodes were screened for eYcacy against the cottonwood borer, Plectrodera scalator (Fabricius). Steinernema feltiae SN and S. carpocapsae All killed 58 and 50% of larvae, respectively, in Wlter paper bioassays but less than 10% in diet cup bioas- says. S. glaseri NJ, S. riobrave TX, and H. indica MG-13 killed less than 10% of larvae in both assays. H. marelata IN was ineVective in the diet cup bioassay and killed 12.9% of larvae in a Wlter paper bioassay. The nematode isolates we tested are not suitable for use as biologi- cal control agents against P. scalator.
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