Entomopathogenic Nematode Ecology and Biological Control in Florida Citrus Orchards

Author(s):  
Raquel Campos-Herrera ◽  
Robin J. Stuart ◽  
Fahiem El-Borai ◽  
Carmen Gutierrez ◽  
Larry Duncan
Nematology ◽  
2009 ◽  
Vol 11 (2) ◽  
pp. 231-241 ◽  
Author(s):  
Diane Bright ◽  
Fahiem El-Borai ◽  
Robin Stuart ◽  
James Graham ◽  
Jaime Cubero ◽  
...  

AbstractLaboratory experiments were conducted to study the effects of various trapping and endoparasitic nematophagous fungi (NF) isolated from Florida citrus orchards on five entomopathogenic nematode (EPN) species that show various distributions across Florida's citrus industry. Four trapping NF (Arthrobotrys oligospora, A. dactyloides, A. musiformis and Gamsylella gephyropaga) and two endoparasitic NF (Catenaria sp. and Myzocytium sp.) were tested against Steinernema diaprepesi (Sd), S. glaseri (Sg), S. riobrave (Sr), Heterorhabditis zealandica (Hz) and H. indica (Hi). Fungi were added to soil microcosms either as a pure culture on agar plugs (trapping NF) or as fungal-colonised nematodes (endoparasitic NF) on agar plugs, concurrently with 2000 EPN of a given species. After 7 or 14 days exposure, nematodes were recovered from the soil using Baermann funnels. The recovery of all EPN species was reduced between 56-92% by G. gephyropaga. Neither Sd or Sg were affected by any species of Arthrobotrys, whereas A. musiformis reduced recovery of all other EPN and A. oligospora reduced numbers of all other species except Hi. Both endoparasitic NF reduced the recovery of all EPN except Hi by at least 82%. The data are consistent with the hypothesis that NF may play a role in regulating regional patterns of abundance and diversity of EPN species in Florida, which in turn regulate the abundance of a major citrus pest, the Diaprepes root weevil, Diaprepes abbreviatus.


PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255455
Author(s):  
Emilie P. Demard ◽  
Ismail Döker ◽  
Jawwad A. Qureshi

Predatory mites in the family Phytoseiidae (Acari: Mesostigmata) are of great importance as biological control agents of pest mites and other arthropods. Correct identification of species is crucial to implement effective biological control of target pests. Here, we provide re-descriptions of seven phytoseiid mite species collected from citrus orchards in Florida. The several important morphological features including dorsal setae lengths, dorsal solenostomes, shape of calyx of spermatheca, chelicera dentition, measurements, and shape of macrosetae on legs currently used to discriminate phytoseiid species were missing in the original descriptions and re-descriptions of these species. Additionally, we observed the presence of a previously unnoted taxonomically important character on Proprioseius meridionalis Chant. Therefore, the re-description was essential for further diagnosis of this species. Accordingly, the validity of the presence/absence of this structure as a diagnostic character to separate species groups in the genus Proprioseius should be re-considered. Furthermore, Typhlodromalus peregrinus, a species for which a series of morphological variations are reported in previous descriptions, is re-described and illustrated from Clermont, Florida, a location very close (10 km) to its type location (Minneola), and the leaves of type host citrus. The macrosetae StIV was knobbed apically in all our specimens of T. peregrinus indicating invalidity of sharp-pointed or knobbed StIV to separate this species from a closely related species, T. aripo De Leon. These re-descriptions and species are important to utilizing authentic and promising candidates for biological control.


2010 ◽  
Vol 54 (3) ◽  
pp. 166-171 ◽  
Author(s):  
Z. Ipek Ekmen ◽  
Selcuk Hazir ◽  
Ibrahim Cakmak ◽  
Nurdan Ozer ◽  
Mehmet Karagoz ◽  
...  

2011 ◽  
Vol 35 (6) ◽  
pp. 1149-1156 ◽  
Author(s):  
Viviane Santos ◽  
Alcides Moino Junior ◽  
Vanessa Andaló ◽  
Camila Costa Moreira ◽  
Ricardo Alves de Olinda

Entomopathogenic nematodes (EPNs) are used in biological control of soil insects and show promise in the control of D. speciosa. The objective of this work was to evaluate the potential of native and exotic entomopathogenic nematode isolates in the control of D. speciosa under laboratory and greenhouse conditions. Results showed that all of EPNs caused larval mortality. The most virulent were Heterorhabditis sp. RSC01 (94%), Steinernema glaseri (84%), Heterorhabditis sp. JPM04 (82%) and Heterorhabditis amazonensis RSC05 (78%). There was no effect of the Heterorhabditis sp. RSC01 and S. glaseri isolates on eggs. The maximum mortality of D. speciosa larvae by Heterorhabditis sp. RSC01 was observed at a concentration of 300 IJ/ insect, while by S. glaseri observed the highest mortality at the concentration of 200 IJ/ insect. The Heterorhabditis sp. RSC01 isolate caused over 80% pupal mortality at a concentration of 250 IJ/insect. The virulence of Heterorhabditis sp. RSC01 and S. glaseri was affected by temperature. The Heterorhabditis sp. RSC01 isolate caused reduction in larva survival under greenhouse conditions at all of the tested concentrations and there was no difference in mortality among different concentrations of infectid juveniles.


Nematology ◽  
2019 ◽  
Vol 21 (1) ◽  
pp. 35-44 ◽  
Author(s):  
Chau N. Nguyen ◽  
Anh T. Do ◽  
Phap Q. Trinh ◽  
Phuc K. Hoang

Summary The virulence and efficacy of two species of entomopathogenic nematodes, Steinernema sp. (strain PQ16) and Heterorhabditis indica (strain KT3987), against nymphs of the coffee cicada, Dundubia nagarasingna, was evaluated under laboratory and glasshouse conditions. The highest mortality rates of coffee cicada nymphs caused by these two nematode strains were 93.5 and 100%, respectively, at an inoculation dose of 600 infective juveniles (IJ) nymph−1. The virulence (LC50) was established as 137.5 IJ and 149.1 IJ for strains S-PQ16 and H-KT3987, respectively. The highest IJ yields of these nematode strains were 66 × 103 IJ (for S-PQ16) and 134.4 × 103 IJ (for H-KT3987) at a dose of 500 IJ nymph−1. The efficacies of the two nematode strains to coffee cicadas at treated dose of 60 × 103 IJ pot−1 were 84.4 and 88.9% after 30 days, higher than the efficacies at treated dose of 40 × 103 IJ pot−1. The number of IJ in 250 ml of soil at 10, 20 and 30 days after treatment, increased from 0.38 × 103 to 4.80 × 103 IJ in soil treated with a dose of 40 × 103 IJ and from 0.66 × 103 to 5.02 × 103 IJ in soil treated with a dose of 60 × 103 IJ (for S-PQ16). Similarly, for H-KT3987 the number of IJ increased from 0.43 × 103 to 8.99 × 103 IJ and from 0.62 × 103 to 9.64 × 103 IJ, at the respective doses. Based on results of a pot trial from glasshouse modelling, an IJ application dosage for biological control of coffee cicada nymphs in coffee plantations was proposed.


Nematology ◽  
2011 ◽  
Vol 13 (5) ◽  
pp. 569-587 ◽  
Author(s):  
Nomakholwa F. Stokwe ◽  
Antoinette P. Malan ◽  
Khuong B. Nguyen ◽  
Rinus Knoetze ◽  
Louwrens Tiedt

Abstract During a survey for entomopathogenic nematodes in citrus orchards throughout South Africa, a new species of Steinernema was isolated from a citrus orchard on Rietkloof farm, near the town of Piketberg in the Western Cape Province, South Africa. The nematode was isolated from soil using the Galleria-baiting technique. Steinernema citrae n. sp. is characterised by the following morphological characters: third-stage infective juvenile with a body length of 754 (623-849) μm, distance from head to excretory pore of 56 (49-64) μm, tail length of 71 (63-81) μm, and ratio E value of 110 (85-132). The lateral pattern for the new species is 2, 7, 8, 6, 4, 2 and is not typical for the genus. Steinernema citrae n. sp. is closely related the feltiae-group. The body length of the IJ is close to that of S. texanum and S. weiseri, though it differs in body diam., the length of the pharynx and E%. The male of S. citrae n. sp. differs from S. feltiae in the length and shape of the spicule and body diam. Steinernema citrae n. sp. differs from all species in the feltiae-group in the morphology of the vulva, as it has a single flapped, low, epiptygma. It also differs from the most closely related species, S. feltiae, as there is no interbreeding between the two species. In addition, the new nematode differs from other species of the feltiae-group by characteristics of the ITS and D2D3 regions of its rDNA.


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