Journal of Nematology (1996) 28, 56-67

L.W. Duncan, C.W. McCoy and A.C. Terranova (1996)
Estimating sample size and persistence of entomogenous nematodes in sandy soils and their efficacy against the larvae of Diaprepes abbreviatus in Florida
Journal of Nematology 28 (1), 56-67
Abstract: In two studies to estimate sampling requirements for entomogenous nematodes in the field, highest persistence of Heterorhabditis bacteriophora after application occurred beneath the canopies of mature citrus trees. Nematode persistence declined with distance from the center-line of the tree row toward the row-middles. Immediately after nematode application to soil, 32 samples (15 cm deep, 2.5-cm diameter) beneath a single tree were required to derive 95% confidence intervals that were within 40% of mean nematode population density. The estimated probability, of measuring the mean density within 40%, using 32 samples, declined to 88% at 2 days post-application and to 76% at 7 days. The persistence in soil of Steinernema carpocapsae, S. riobravis, and two formulations containing H. bacteriophora and their efficacy against the larvae of Diaprepes abbreviatus were compared in a grove of 4-year-old citrus trees. Within 6 days, the recovered population densities of all nematodes declined to <5% of levels on day 0. The recovery of H. bacteriophora during the first 2 weeks was lower than that of the other two species. Steinernema riobravis and both formulations of H. bacteriophora reduced recovery of D. abbreviatus by more than 90% and 50%, respectively. Steinernema carpocapsae did not affect population levels of the insect.
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Database assignments for author(s): Larry W. Duncan

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
surveys/distribution/isolation
evaluation - screening - selection

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Diaprepes abbreviatus	Citrus (genus)	U.S.A. (SE)
Steinernema riobrave/Xenorhabdus cabanillasii (entomopathogen)	Diaprepes abbreviatus	Citrus (genus)	U.S.A. (SE)
Heterorhabditis bacteriophora/Photorhabdus (entomopathogen)	Diaprepes abbreviatus	Citrus (genus)	U.S.A. (SE)