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The abundance and diversity of eriophyid and phytoseiid mites in south and central Florida were assessed in six citrus orchards under three different pest management systems, conventional, organic, and untreated. Tree canopy, ground cover, and leaf litter were sampled every two months in two groves for each of the three pest management systems from April 2019 to February 2021. The citrus rust mite, Phyllocoptruta oleivora (Ashmead) represented 95 to 99% of the rust mites sampled in each grove except in one untreated orchard where it accounted for 45% of the samples (n = 938 total P. oleivora mounted specimens). The pink citrus rust mite, Aculops pelekassi (Keifer) was present in organic and untreated orchards at 5% and 28%, respectively, but absent from conventional orchards (n = 134 total A. pelekassi mounted specimens). Twenty-nine species of phytoseiid mites were identified from 1778 specimens. Thirteen species were present in the canopy, fifteen in the ground cover, and eighteen in the leaf litter with some common species among these habitats. In the tree canopy, Typhlodromalus peregrinus (39%), Euseius spp. (25%), and Iphiseiodes quadripilis (19%) were the dominant species. Typhlodromalus peregrinus (43%), Typhlodromips dentilis (25%), and Proprioseiopsis mexicanus (13%) were the major species in the ground cover. Species richness was lower in organic orchards (3.0) compared to conventional and untreated orchards (5.0 and 4.7, respectively). In the leaf litter, Amblyseius curiosus (26%), Proprioseiopsis carolinianus (15%), Chelaseius floridanus (14%), and Amblyseiustamatavensis (12%) were the most common species. Shannon index was significantly higher in conventional orchards (1.45) compared to organic and untreated orchards (1.02 and 1.05, respectively). Evenness was also higher in conventional orchards (0.86) compared to organic and untreated (0.72 and 0.68, respectively). Finding of several phytoseiids in abundance across pest management programs suggest the need for identifying their role in pest suppression particularly mites. [ABSTRACT FROM AUTHOR]

Predatory mites are effective natural enemies of small arthropods, including pest mites and insects, which provide biological control of several crop pests worldwide. The family Phytoseiidae (Acari: Mesostigmata) is a diverse group of predators found in cultivated crops and other habitats containing natural vegetation. Although some phytoseiid species are commercialized and widely used in biological control programs, the determination of natural populations and identification of the species is a vital first step in understanding their interactions with the crop, environment, and pests. The citrus crop is a diverse agroecosystem colonized by a variety of pests including mites and warrants an understanding of the complex of predators. We collected predatory mites from multiple citrus groves in Florida, to find and identify species for biological control in citrus crops. The examination of the specimens involved the use of Olympus CX-41 microscope, and drawings were prepared with the help of the attached camera Lucida. Any needed corrections were made using tracing paper, rapidograph pen, and Adobe Photoshop version CS6. Neoseiulus hexaporus sp. nov. is described and illustrated as a new species based on its distinct morphology compared with previously described species in paspalivorus group. We also provide a complementary redescription of Neoseiulus mumai (Denmark), including an important diagnostic character of leg chaetotaxy which had led to the description of a new species, Neoseiulus kikuyu Ma, Fan & Zhang. We also provide new illustrations of N. mumai to facilitate its diagnosis. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Population outbreaks and failures in controlling Tetranychus urticae Koch (Acari: Tetranychidae) were reported on ornamental plants in Miami-Dade County, Florida. We compared the susceptibility of two T. urticae field populations collected from commercial nurseries with a laboratory population to one new generation (cyflumetofen) and two conventional (abamectin and pyridaben) acaricides. The field populations were collected from hibiscus (Hibiscus rosa-sinensis, Malvaceae) and croton (Codiaeum variegatum, Euphorbiaceae). Resistance ratios based on LC50 values of the field and laboratory populations revealed high resistance levels to the two conventional acaricides (9.64 and 19.28-fold abamectin, 12.34 and 34.08-fold pyridaben), and low levels (1.88 and 2.39-fold) of cyflumetofen resistance in the hibiscus and the croton populations, respectively. Rotation of acaricides with different modes of action and biological control should be implemented to mitigate T. urticae resistance problems in ornamentals in south Florida. [ABSTRACT FROM AUTHOR]

Population outbreaks and failures in controlling Tetranychus urticae Koch (Acari: Tetranychidae) were reported on ornamental plants in Miami-Dade County, Florida. We compared the susceptibility of two T. urticae field populations collected from commercial nurseries with a laboratory population to one new generation (cyflumetofen) and two conventional (abamectin and pyridaben) acaricides. The field populations were collected from hibiscus (Hibiscus rosa-sinensis, Malvaceae) and croton (Codiaeum variegatum, Euphorbiaceae). Resistance ratios based on LC50 values of the field and laboratory populations revealed high resistance levels to the two conventional acaricides (9.64 and 19.28-fold abamectin, 12.34 and 34.08-fold pyridaben), and low levels (1.88 and 2.39-fold) of cyflumetofen resistance in the hibiscus and the croton populations, respectively. Rotation of acaricides with different modes of action and biological control should be implemented to mitigate T. urticae resistance problems in ornamentals in south Florida. [ABSTRACT FROM AUTHOR]

• Intra- and interspecific interactions among four species of phytoseiids were studied. • Single and combined releases of A. swirskii and N. longispinosus were evaluated against spider mites on papaya. • N. longispinosus was the most canibalistic species in the absence of prey. • N. longispinosus had the greatest potential to control Tetranychus urticae on papaya. • Releases of A. swirskii negatively affected N. longispinosus due to intraguild predation. Intraguild interactions can be crucial for the success of biological control programs involving multiple natural enemies. The two-spotted spider mite (TSSM), Tetranychus urticae (Acari: Tetranychidae) is a major pest of papaya, Carica papaya , in south Florida, where a newly naturalized predator, Neoseiulus longispinosus (Acari: Phytoseiidae), has become the most abundant predator associated with this pest. Amblyseius largoensis and Neoseiulus californicus are other, less common, phytoseiid predators on papaya and the exotic predator, Amblyseius swirskii , is often released to control other mite and insect pests of this crop. We investigated intra- and interspecific interactions among these four predatory mite species and their effects on biological control of TSSM. Cannibalism and intraguild predation were evaluated in the laboratory for all four predator species in the absence and presence of TSSM. Neoseiulus longispinosus was the most cannibalistic species in the absence of spider mites, and A. largoensis when spider mites were available. Whereas A. swirskii was the most aggressive intraguild predator, N. longispinosus was the least aggressive and most often the intraguild prey of other predators. Single and combined releases of A. swirskii and N. longispinosus were evaluated to assess the effects of cannibalism and intraguild predation on biocontrol of TSSM on potted papaya plants. Single releases of N. longispinosus significantly suppressed TSSM populations but releases of A. swirskii alone or in combination with N. longispinosus resulted in gradual increases in TSSM populations. Our results showed that N. longispinosus has potential to control TSSM on papaya, but the level of control can be negatively affected by 1) high levels of cannibalism at low prey densities, 2) intraguild predation by other mite predators and 3) releases of aggressive intraguild predators like A. swirskii. [ABSTRACT FROM AUTHOR]

• Natural enemies can regulate populations of Brevipalpus yothersi. • Phytoseiid and cheyletid predators were evaluated for control of Brevipalpus yothersi. • Amblyseius largoensis suppressed Brevipalpus yothersi on citrus plants. • Predatory mites can be important in IPM programs tailored to manage citrus leprosis. Citrus leprosis is a serious viral disease of citrus transmitted by Brevipalpus mites. The disease is present in South America, Central America, and Mexico, but not in the United States. One of its primary vectors, however, is present in Florida and other southern states. Non-viruliferous Brevipalpus yothersi (Acari: Tenuipalpidae) are present in Florida and could facilitate the spread of the disease if citrus leprosis viruses (CiLVs) are introduced into the state. In preparation for the possible incursion of CiLVs, we evaluated the biological control potential of four predatory mite species (Neoseiulus longispinosus , N. californicus , Amblyseius largoensis ; Acari: Phytoseiidae) and Hemicheyletia bakeri (Acari: Cheyletidae) that are naturally associated with Brevipalpus spp. in citrus. In laboratory no-choice assays, the phytoseiid mites preyed mostly upon immature stages of B. yothersi , while H. bakeri preyed mainly on adults. In dual choice assays, all predators preferred Tetranychus urticae (Acari: Tetranychidae) over B. yothersi , but A. largoensis consumed more B. yothersi than the other three predators. A greenhouse experiment was performed to evaluate the potential of A. largoensis and H. bakeri to suppress B. yothersi populations on citrus trees. Four predator release treatments consisting of single or combined releases of A. largoensis and H. bakeri at a 1:10 (predator: B. yothersi) ratio were tested. Releases of A. largoensis alone or in combination with H. bakeri effectively suppressed B. yothersi and reduced damage to citrus plants. Release of H. bakeri alone, however, had no suppressive effect on B. yothersi populations. Overall, our results show that A. largoensis could be an efficient biological control agent of B. yothersi and could play an important role in citrus IPM programs tailored to manage citrus leprosis. [ABSTRACT FROM AUTHOR]