Mobile Mites Research Articles

Assessing the augmentation of Amblydromalus limonicus with the supplementation of pollen, thread, and substrates to combat greenhouse whitefly populations

Due to issues with establishment and persistence of natural enemies in biological control, the provision of alternative food sources and oviposition sites are important factors to enhance pest control. In this study, three different supplementation treatments were examined for their ability to increase the populations of the predatory mite Amblydromalus limonicus, and its implications for greenhouse whitefly control on peppers and eggplants. These were: (1) pollen (Typha orientalis), (2) pollen and thread, (3) pollen, thread, and a substrate mixture of buckwheat, gorse, and rice husks, which were compared to a control treatment that had no supplementation. Significant treatment effects were found on pepper for A. limonicus (mite eggs p = 0.008, mobile mites p = <0.0001). The predatory mite successfully established and persisted at high population levels in the pollen-thread, and pollen-thread-substrate treatments. All supplementation treatments were able to control whitefly populations on peppers, while the control treatment failed to. The results obtained were formulated into possible application techniques for greenhouse growers to utilise.

Impact of Relative Humidity and Net Treatments on Tyrophagus Putrescentiae (Schrank) Infestations and Mold Growth on Dry Cured Ham

ObjectivesDry cured hams are susceptible to mite infestations which are currently controlled in the U.S. dry cured ham industry via fumigation with methyl bromide. Since methyl bromide is an ozone depleting substance, food grade ingredient infused nets have been researched as an alternative to control mite infestations on dry cured hams. Mite infestations and mold growth vary on dry cured ham in untreated and treated nets due to environmental changes in relative humidity (RH) and temperature. Therefore, the objective of this research was to evaluate the effect of RH and infused nets on mite infestations and mold growth on dry cured hams.Materials and MethodsPatent pending food grade coating formulations consisting of 1) xanthan gum (XG) and propylene glycol (PG) and 2) carrageenan (CG), propylene glycol alginate (PGA), and PG were infused into ham nets. Dry cured ham cubes (2.5 cm3) and slices (2.5 cm × 9.0 cm × 15.5 cm) were wrapped with untreated (control) and 2 types of infused (treated) nets (XG + PG and CG + PGA + PG) and stored in ventilated glass jars. Three cubes and slices from each treatment were inoculated with 20 and 50 adult mites respectively, and stored in an environmental chamber for 14 d at 24°C and 65 ± 2, 75 ± 2, and 85 ± 2% RH. Mite infestation was determined by counting the mobile mites on ham cubes, slices, and nets using a microscope. Nine trained panelists rated the moldiness of ham slice surfaces on a 0 to 100% scale. A 3 × 3 factorial structure within a completely randomized design was used to determine the impact of RH and net treatment on mite infestations and mold growth. The least square means method was applied to separate treatment means.ResultsAt 65 and 75% RH, samples with treated nets had fewer (P < 0.05) mites than the control, but there were no differences (P > 0.05) between treated and control nets at 85% RH. On average, across net treatments, there were fewer mites (P < 0.05) at 75 and 85% RH in comparison to 65% RH. In addition, when averaged over RH, samples in XG and CG coated nets had fewer (P < 0.05) mites on ham slices compared to samples in untreated nets. Though there was no difference between XG and CG (P > 0.05) with respect to the number of mites on ham slices, the CG treatments were effective at controlling mites at all RHs. In contrast, the XG treatment did not control mites at 65% RH. There was a strong correlation (r = 0.98) between percentage of the ham slices covered with mold and number of mites present. Mold growth was greater (P < 0.05) at 65% RH in comparison to 75 and 85%, and XG and CG treatments had less mold growth than the control treatments, with the CG treatment completely inhibiting the presence of visual mold.ConclusionTreated nets inhibited mite infestations and mold growth on ham cubes at 65 and 75% RH and on ham slices at 65% RH. Results indicate that 75 and 85% RH would be more desirable in the ham industry if hams were aged at 24°C. Further testing will be performed to observe the impact of temperature on mite infestations and mold growth on ham cubes and slices at various RHs to optimize aging conditions that can used to help control mite infestations.

Effect of two bio-based liquid formulations from Brassica carinata in containing red spider mite (Tetranychus urticae) on eggplant

Two liquid formulations based on Brassica carinata oil and defatted seed meal were tested as treatments to control the red spider mite (Tetranychus urticae Koch) on eggplants in open field conditions. These products were compared to a commercial chemical acaricide (fenazaquin), which is very effective, but whose use was recently limited to ornamentals in greenhouse due to its environmental risks. The application in these trials was therapeutic, the first treatment was distributed at the time of appearance of at least five mobile mites (adults and/or larvae) per plant. The 2-year results indicated that the application of both formulations have a clear effect in containing mites, statistically different from the untreated control. Moreover, the ability of pest control of the formulation with the higher concentrations of oil and defatted seed meal was not different from the chemical treatment. Treatment efficacy clearly decreased after 21 days, but within a preventive treatment plan these formulations could represent an interesting additional bio-based option both in conventional and organic farming.

Miniature Inverted-Repeat Transposable Elements ofStowawayAre Active in Potato

Miniature inverted-repeat transposable elements (MITEs) are dispersed in large numbers within the genomes of eukaryotes although almost all are thought to be inactive. Plants have two major groups of such MITEs: Tourist and Stowaway. Mobile MITEs have been reported previously in rice but no active MITEs have been found in dicotyledons. Here, we provide evidence that Stowaway MITEs can be mobilized in the potato and that one of them causes a change of tuber skin color as an obvious phenotypic variation. In an original red-skinned potato clone, the gene encoding for a flavonoid 3',5'-hydroxylase, which is involved in purple anthocyanin synthesis, has been inactivated by the insertion of a Stowaway MITE named dTstu1 within the first exon. However, dTstu1 is absent from this gene in a purple somaclonal variant that was obtained as a regenerated plant from a protoplast culture of the red-skinned potato. The color change was attributed to reversion of flavonoid 3',5'-hydroxylase function by removal of dTstu1 from the gene. In this purple variant another specific transposition event has occurred involving a MITE closely related to dTstu1. Instead of being fossil elements, Stowaway MITEs, therefore, still have the ability to become active under particular conditions as represented by tissue culturing.

Commercial colonies of Bombus terrestris (Hymenoptera: Apidae) are reservoirs of the tracheal mite Locustacarus buchneri (Acari: Podapolipidae)

We investigated the prevalence of infestation by the bumblebee tracheal mite, Locustacarus buchneri (Acari: Podapolipidae), in four commercial colonies of Bombus terrestris (Hymenoptera: Apidae). All the foundresses, 91.8±5.67% (mean±SE) of worker bees, 73.9±6.85% of males, and 77.4±21.5% of new queens had the mite in their abdominal air sacs. The mean number of eggs, adult females, and mobile mites infesting a single bumblebee worker were 76.9±76.8 (range: 4–301, n=40), 3.78±3.45 (1–11, 40), and 3.45±2.98 (1–11, 20), respectively. From these values, we calculated the number of eggs per adult mite female to be 23.9±21.7 (range: 4–126, n=40). As a single worker bee had about 76 mites in her abdominal air sacs and approximately 90% of the bees in a colony of about 160 bees were infested by the mite, an infested B. terrestris colony has the potential to produce more than 10,000 L. buchneri individuals during colony development.

Effect of Spinosad Formulations and Other Miticides on Twospotted Spider Mite, 1995

Abstract A trial was conducted in a commercial nursery with overhead irrigation in East Granby, CT. This experiment was conducted as a 10 (treatments) X 2 (one or two application) factorial RCB experiment (6 single-plant replicates) with spinosad (NAF-coded formulations), plus four positive controls and an untreated check. All surfaces of leaves were sprayed to run-off with a CO2-pressurized sprayer using 35 psi and a TeeJet 8002 flat fan nozzle. All plants were sprayed 1 Aug, with 95°F and 10 mph winds; the second treatment was 8 Aug, with 0-5-mph wind and 78°F. Leaf samples for mite counts were taken on 1 Aug (immediately prior to the first spray), and on 4, 7, 11, 14, and 21 Aug. One leaf was pulled from each plant, enclosed in aplastic bag, then immediately refrigerated (3-8 d). Mites on leaves were first evaluated under a dissecting microscope; when there were 30 or less mobile mites, then counts of mites were made directly. More heavily infested leaves were brushed onto an oiled glass plate and the number of mites estimated by subsampling the plate. Sections of a plate were counted until a minimum of 30 eggs or mobile stage mites were found. The number of mites on the entire plate was then determined by proportions. The leaf length and area were also recorded so that mites per unit area could be calculated. Data (mites per 10 cm2) required logarithmic transformation for analysis.

Mechanical Release of Predacious Mites for Biological Pest Control in Strawberries

A mechanical system for field distribution of predacious mites was developed for use with ground vehicles. The system released commercial formulations of vermiculite carrier and Phytoseiulus persimilis. Mites were found to be highly mobile within the mixture and easily damaged by agitation of the vermiculite-mite mixture. The handling system consisted of an insulated storage reservoir that kept the mixture stationary and chilled, a rotating metering plate, and an air-cleared ejection port. The components were mounted on a standard tractor tool bar and electrically powered. As the metering plate rotated, the formulation filled cylindrical cells in the plate. As the filled cells passed an opening on a stationary bottom plate, the cell contents fell downward while a brief pulse of compressed air insured that each cell was cleared. Release rate of the mites was controlled through rotational speed of the metering plate and the size of cells on the plate. In laboratory and field tests, the system uniformly released mobile mites with an average application rate error of 1.9% and an error range of 12.0% to +9.5% for desired release rates from 32,000 to 100,000 predators/ha. A single distributor mounted on a vehicle tool bar achieved productivity of 1.9 worker-h/ha while manual release required 3.6 worker-h/ha. Machine productivity would be increased in direct proportion to the number of units installed on the vehicle.

Evaluation of screening methods and search for resistance in muskmelon, Cucumis melo L., to the twospotted spider mite, Tetranychus urticae Koch

Three techniques of screening for resistance in muskmelon, Cucumis melo L., to the twospotted spider mite, Tetranychus urticae Koch, were compared in a laboratory test. Coefficient of variation values were approximately equal for a whole-leaf and floating-disc technique in terms of mean number of mobile mites and eggs, whereas both were substantially lower than that associated with a clip cage. Therefore, both the floating-disc and whole-leaf technique are indicated as superior techniques for isolating mites on melon leaves in screening trials. In greenhouse mass screening trials (using a whole-leaf technique), many lines exhibited lower densities of adult twospotted spider mites compared with a standard commercial variety ‘Perlita’. Melon lines ‘BUS’, ‘CHI’, Plant Introduction (PI) 164343 and PI 17895 exhibited resistance in greenhouse mass screenings and had significantly lower numbers of female mites per leaf in more intensive greenhouse screenings. PI lines 124101, 124431, 125896 and 125956, which expressed resistance in greenhouse mass screenings, also had low densities of mites in field screening.

Peach, Evaluation of Insecticides, 1985

Abstract This experiment was conducted at the Rutgers Fruit Tree Research &amp; Developmen Center, Cream Ridge, NJ, in a 10-year-old peach orchard, variety ‘Red Haven’. Single-tree plots, replicated 5 times in a randomized complete blocl design, were sprayed to runoff (ca 3 gal/tree, 300 gal/A) with a hydraulic sprayer equipped with a handgun and operated at 200 psi. Treatment were applied on Apr 23 (PF), May 14 (IC), May 28 (2C), Jun 10 (3C), and Jun 24 (4C). For disease control the entire orchard was sprayed with sulfur as needed. ERM estimates were made by randomly picking 25 leaves per replicate, brushing the mites onto glass plates and counting the number of mobile mites. Sampling methods for various insects in the table are as follows: OFMa = no. of OFM damaged terminals/tree (Is generation); OFMb = no. of OFM damaged terminals/tree (2nd generation); OFMc = no. of OFM damaged fruit/tree (3rd generation, 100 frui evaluated); PC = no. of PC damaged fruit/tree (100 fruit evaluated); TPB = no. of TPB damaged fruit/tree (100 fruit evaluated). Mite-days wen calculated as follows: MD = MD1 + [(M1 + M2)/2 × Y], where MD1 = mite days already accumulated, M1 = avg ERM/leaf on a given counting date, M2 = avg ERM/leaf on the next counting date after M1 and Y = number of days between M1 and M2. Data were transformed to × + 1 o arcsin (x) prior to analysis of variance and comparison of means. In tables numbers followed by the same letter are not significantly different a alpha = 0.05, DMRT.

Apple, Apollo Summer Threshold Test, 1985

Abstract A 15-year-old orchard located at the Rutgers Fruit Research &amp; Development Center, Cream Ridge, NJ was used in this test. Sprays were applied to 3 single-tree replicates of ‘Yellow Delicious’ arranged in a randomized complete block design. Trees were sprayed to runoff (ca 5 gal/tree; 300 GPA) using a hydraulic sprayer equipped with a handgun and operated at 200 psi. Sprays were applied on 9 Jul. For disease control the entire orchard was sprayed with Captan and Polyram as needed. European red mite estimates were made by randomly picking 25 leaves per replicate, brushing the mites onto glass plates and counting mobile mites. S. punctum densities were estimated by 3-minute counts of larvae, pupae and adults. Mite-days were calculated as follows: MD = MD1 + [(Ml + M2)/2 × Y], where MD1 = mite days already accumulated, Ml = avg ERM/leaf on a given counting date, M2 = avg ERM/leaf on the next counting date after Ml and Y = number of days between Ml and M2. Data were transformed to × + 1, or arcsin (x) prior to analysis of variance and comparison of means. In the table numbers followed by the same letter are not significantly different (alpha = 0.05, DMRT).

Apple, All Season Insecticide Test, 1985

Abstract A 15-year-old orchard located at the Rutgers Fruit Research &amp; Development Center, Cream Ridge, NJ was used in this test. Sprays were applied to single-tree plots consisting of 2 replicates of ‘Yellow Delicious’ and 1 of ‘Red Delicious’ arranged in a randomized complete block design. Trees were sprayed to runoff (ca 5 gal/tree; 300 GPA) using a hydraulic sprayer equipped with a hand-gun and operated at 200 psi. Spray dates were 12 Apr (P), 1-4 May (PF), 13 May (1C), 28 May (2C), 10 Jun (3C), 25 Jun (4C), 15 Jul (5C), 5 Aug (6C), and 2 Sep (7C). For disease control the entire orchard was sprayed with Captan and Polyram as needed. European red mite (ERM) estimates were made by randomly picking 25 leaves per replicate, brushing the mites onto glass plates and counting mobile mites. Sampling methods for the various insects in the tables are as follows: RAA = no. of RAA colonies/tree; AA = avg. no. of AA/terminal/tree (20 terminals counted); WALHa = no. of WALH nymphs and adults/3 minute count; WALHb = no. of WALH damaged leaves/3 minute count; EASFa = no. of EASF damaged fruit/3 minute count; STLM = no. of STLM mines/3 minute count; Stethorus = no. of S. punctum larvae, pupae and adults/ 3 minute count; PC = no. of PC damaged fruit/100; TPB = no. of TPB damaged fruit/100; AM = no. of AM damaged fruit/100; FS = no. of flyspeck damaged fruit/100; BR = no. of brown rotted fruit/100; RAA = no. of RAA damaged fruit/100; JB = no. of JB damaged fruit/100; TABM+LR = no. of TABM and/or LR damaged fruit/100; OFM+CM = no. of OFM and/or CM damaged fruit/100; EASFb = no. of EASF damaged fruit/100. Russet = avg. % russet/fruit (100 fruit evaluated); Sugar = avg. sugar content (% soluble solids)/fruit (100 fruit measured); Press = avg. pressure (Kg)/fruit (100 fruit measured); Diam = avg. diameter (mm)/fruit (100 fruit measured). Mite-days were calculated as follows: MD = MD1 + [(Ml + M2)/2 × Y], where MD1 = mite days already accumulated, Ml = avg ERM/leaf on a given counting date, M2 = avg ERM/leaf on the next counting date after Ml and Y = number of days between Ml and M2. Data were transformed to × + 1, or arcsin (x) prior to analysis of variance and comparison of means. In tables numbers followed by the same letter are not significantly different (alpha = 0.05; DMRT).

Apple, Petal-Fall vs Pink Test, 1985

Abstract A 15-year-old orchard located at the Rutgers Fruit Research &amp; Development Center, Cream Ridge, NJ was used in this test. Sprays were applied to 3 single-tree replicates of ‘Red Delicious’ arranged in a randomized complete block design. Trees were sprayed to runoff (ca 5 gal/tree; 300 GPA) using a hydraulic sprayer equipped with a hand-gun and operated at 200 psi. Spray dates were 11 Apr (P) and 30 Apr (PF). For disease control the entire orchard was sprayed with Captan and Polyram as needed. European red mite estimates were made by randomly picking 25 leaves per replicate, brushing the mites onto glass plates and counting mobile mites. Sampling methods for insects listed in the table are as follows: EASF = no. of EASF damaged fruit/3 minute count; AA = avg no. of AA/terminal/tree (20 terminals counted); RAA = no. of RAA colonies/tree; STLM = no. of STLM mines/3 minute count; WALHa = no. of WALH nymphs and adults/3 minute count; WALHb = no. of WALH damaged leaves/3 minute count; Stethorus = no. of S. punctum larvae, pupae and adults/3 minute count; Russet = % russet/fruit (100 fruit evaluated). Mite-days were calculated as follows: MD = MD1 + [(Ml + M2)/2 × Y], where MD1 = mite days already accumulated, Ml = avg ERM/leaf on a given counting date, M2 = avg ERM/leaf on the next counting date after Ml and Y = number of days between Ml and M2. Data were transformed to × + 1, or arcsin (x) prior to analysis of variance and comparison of means. In tables, numbers followed by the same letter are not significantly different (alpha = 0.05, DMRT).

Apple, European Red Mite, Screening for Resistance to Acaricides, 1983

Abstract Susceptibility of 14 populations of ERM to Plictran, Kelthane, and Omite was assayed in the laboratory using a foliage dip test. A field test was conducted in two orchards to determine whether laboratory tests would predict field performance. In laboratory test bouquets of terminals were collected in each orchard within 3 days of the test, placed in 5 gal pails of water and brought back to the laboratory. Foliage from all orchards except Cream Ridge carried residues of previous acaricide applications. Terminals were pruned to shoots of five to eight leaves; each shoot was considered a replicate. Six to 10 replicates were used for each dosage per orchard. Shoots were dipped for 3 sec in a suspension of the test acaricide, then placed in an Erlenmeyer flask of water. Counts of live motile mites were made after 72 h, except for one test with CG 121633 (96 h), and Vendex (120 h). Control shoots were dipped in water containing a drop of (B-1956). The effect of treatment is expressed as % reduction in number of live mites on treated foliage compared to controls. Higher dosages were equivalent to field rates for acaricides, and lower rates were 0.25 field rates. Field tests were conducted at 2 locations, the Rutgers Tree Fruit Research Center at Cream Ridge, N.J. Treatments were applied (Hurff) at Monroeville, N.J. Treatments were applied to single-tree plots of a spur-type Red Delicious with four replicates per treatment. Trees were sprayed to runoff, using a hydraulic sprayer equipped with a handgun. Treatments were applied on 28 Jul. at Cream Ridge and 5 Aug. at Hurff’s and counts were made after 72 h. Mite population estimates were made by randomly picking 10 leaves per replicate and counting mobile mites.

Apple, Midsummer Test of Acaricides, 1983

Abstract A 12-yr-old orchard located at Cream Ridge, N.J., was used in this test. Acaricides were applied on 7 Jul., 28 Jul., or both. Treatments were applied to single-tree plots replicated three times in a randomized complete block design. The trees were sprayed to runoff (ca. 7 gal/tree) using a hydraulic sprayer equipped with a handgun operated at 250 lb/in2. Mite population estimates were made by randomly picking 15 leaves from each tree, brushing the mites onto glass plates, and counting mobile mites. Data were transformed to log x+1 before analysis of variance and comparison of means.

Apple, Summer Mite Test, 1982

Abstract Mature 'Starkrimson Delicious' trees at Griggsville, Illinois, were sprayed with air blower equipment at 350 GPA on July 6. Two rows were randomly selected for each treatment. Four pairs of trees were selected within each treatment and 50 leaves from each tree were picked from the inside of the rows on each sample date. The leaves were immediately brushed and the mites counted in the field. Most mobile mites were adults beginning to lay eggs when treatments were applied.

Apple, Test of Acaricides, 1982

Abstract A 12-year-old orchard of apples located at Cream Ridge, N.J. was used in these tests. In the first experiment acaricides were applied on Jul 14 to single-tree plots of Golden Delicious replicated 3 times and arranged in a randomized complete block design. In the second experiment, single-tree plots of Red Delicious, replicated 3 times in a randomized complete block design, were sprayed on Jul 16. The trees were sprayed to run-off (ca 5 gal/tree) using a hydraulic sprayer equipped with a handgun. Mite population estimates were made by randomly picking 15 leaves from each tree, brushing the mites onto glass plates, and counting mobile mites.

Apple, Insecticide Test, 1977

Abstract An experimental insecticide pydrin was compared with two rates of Guthion and Penncap M for the control of codling moths as well as for the harmful effects on a common predatory mite species, Typhlodromus arboreus. Sprays were applied to single tree plots in a randomized block design. Each treatment was replicated four times. Trees were thoroughly sprayed to the point of run-off using a powered, pull-tank type sprayer with a hand gun. Chemicals were applied at about 350 psi pressure and at a rate of 350-400 gallons/acre. The codling moth emergence was monitored using Zoecon’s pherocon traps and spray timing determined accordingly. The first spray was applied June 11, 1977 and repeated on July 14 and August 16. The effectiveness of various treatments against codling moth was determined by examining approximately 100 apples/plot at harvest. The harmful effect of these insecticides on the predatory mite population was determined by collecting 25 leaves/plot at weekly intervals and examining for the number of eggs and mobile mites.

Effect of Phosphine on Mites, Insects, and Microorganisms1

Phosphine (PH3) produced from Phostoxin® (aluminum phosphide) tablets was used to fumigate 2 bins, each containing about 450 bushels of Selkirk wheat with wellestablished natural infestations of 10 species of mites and insects. The history of the grain bulk ecosystems was studied for 5¾ years prior to fumigation. The distribution and persistence patterns of phosphine in the interstitial air, as measured by gas chromatography at periodic intervals for 7 days following fumigation, indicated stratification with greater amounts of the gas at the 4-foot levels than at the 1- and 2-foot levels when measured from the top; no phosphine was detected after 7 days. No live insects or mobile mites, except Aeroglyphus robustus (Banks), were detected 6 days after fumigation. However, Acarus siro L., Glycyphagus destructor (Schrank), and Spinibdella bifurcata Atyeo reappeared in both bins within 1-3 months and continued to thrive for 6 months afterward, as in previous years. It is suggested that elimination of the natural predator Cheyletus eruditus (Schrank) by phophine would permit unusual increase in numbers of G. destructor and thus disrupt the natural balance in the ecosystems. Such a trend was observed for G. destructor . While phosphine was ineffective against A. robustus , it was effective against all stages of C. eruditus, Haemolaelaps casalis (Berlese). Tarsonemus sp., Tydeus interruptus Thor, and insects Lepinotus reticulatus Enderlein and Oryzaephilus surinamensis (L.)., Adults of Cryptolestes ferrugineus (Stephens), Rhyzopertha dominica (Fauvel), Sitophilus granarius (L.), Tribolium castaneum (Herbst), and larvae of Plodia interpunctella (Hubner) and Trogoderma parabile Beal were killed upon 6 days’ exposure in test cages to phosphine concentrations as encountered 2½ feet below the bin surface. Phosphine had no detectable effect on the germination and the microflora of the stored grain.