Typhlocyba Pomaria Research Articles

Particle Films for Managing Arthropod Pests of Apple

A two-season study showed that a calendar-based spray program to manage arthropod pests with kaolin (60 g/liter) applied at the rate of 450 liters/ha was effective against European apple sawfly, Hoplocampa testudinea (Klug) (Hymenoptera: Tenthredinidae); white apple leafhopper, Typhlocyba pomaria McAtee (Homoptera: Cicadellidae); apple red bug, Lygidea mendax Reuter (Heteroptera: Miridae); pear plant bug, Lygocoris communis (Knight) (Heteroptera: Miridae); and the apple rust mite, Aculus schlechtendali (Nalepa) (Acari: Eriophyidae). Although it reduced Curculionidae damage, the level of damage was still too high. It had no effect on apple maggot, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae); codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae); and tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Heteroptera: Miridae). Laboratory studies showed fewer gravid twospotted spider mites, Tetranychus urticae Koch (Acari: Tetranychidae), and fewer eggs laid by these females. The study also showed no effect of kaolin on Neoseiulus fallacis (Garman) (Acari: Phytoseiidae).

Horticultural mineral oil applications for apple powdery mildew and codling moth, Cydia pomonella (L.)

Horticultural mineral oil (Orchex 796) was tested in two treatment regimes, either a three-spray early season program targeting apple powdery mildew, Podosphaera leucotricha (All. & Evherh.) Salm. (Oil/Disease treatment) or a six-spray program targeting both generations of codling moth, Cydia pomonella (L.) (Oil/CM treatment), on apple, Malus domestica Borkhausen. These treatments were compared with a check, which received no post-bloom applications of oil. Apple powdery mildew shoot infestation was suppressed only in 1 year of the study (1999) by the Oil/Disease treatment, but no differences in fruit damage were found. The six-spray program of horticultural mineral oil produced the highest percentage of clean fruit, and the lowest level of codling moth-damaged fruit, but only one out of the 3 years of the study. Even in the best treatment in this year, codling moth damage was unacceptably high. Campylomma verbasci (Meyer-Dür) fruit damage was reduced by the oil sprays timed for mildew, probably because of the petal fall spray included in this treatment. Rosy apple aphid, Dysaphis plantaginea (Passerini), densities were suppressed (1 year only) by both oil treatments, while apple aphid, Aphis pomi De Geer, populations were not influenced by oil treatments at any time during the study. White apple leafhopper nymphs, Typhlocyba pomaria McAtee, and tetranychid mite populations were consistently suppressed by both oil treatment regimes, with generally higher levels of suppression occurring with the higher number of applications, despite the lack of specific timing. The same was true of apple rust mite, Aculus schlechtendali (Nalepa), and the western predatory mite, Galandromus occidentalis (Nesbitt).

Effects of Seasonal Mineral Oil Applications on the Pest and Natural Enemy Complexes of Apple

This 3-yr study examined the use of two different apple, Malus domestica Borkhausen, pest management programs based on horticultural mineral oil. Whereas oil provided some additional control of codling moth, Cydia pomonella (L.), when targeting eggs of both generations (Oil/Direct Pest program, typically six applications per season), the additional benefit was difficult to detect when densities were high. With moderate densities, oil reduced the number of fruit infestations, but not stings (unsuccessful entries). There also were some measurable benefits to leafroller, Pandemis pyrusana Kearfott control. Oil was most useful, however, in suppression of secondary pests. White apple leafhopper, Typhlocyba pomaria McAtee, was the primary target of oil applications in the Oil/Indirect Pest program (typically three applications per season). However, leafhopper suppression in the Oil/Direct Pest program was generally greater because of the higher number of applications. Phytophagous tetranychid and eriophyid mites also were suppressed by more oil applications. Predatory mite populations were lower in both oil programs than in the check, but it is difficult to determine whether direct toxicity or reduction of prey was responsible for lower predator populations. There also was some evidence that oil suppressed woolly apple aphid, Eriosoma lanigerum Hausman. The six-spray oil program largely prevented a woolly apple aphid outbreak that occurred in July and August 1998 in the check, although the three-spray program seemed to provide some suppression despite the nonspecific spray timing.

Effects of Seasonal Mineral Oil Applications on the Pest and Natural Enemy Complexes of Apple

This 3-yr study examined the use of two different apple, Malus domestica Borkhausen, pest management programs based on horticultural mineral oil. Whereas oil provided some additional control of codling moth, Cydia pomonella (L.), when targeting eggs of both generations (Oil/Direct Pest program, typically six applications per season), the additional benefit was difficult to detect when densities were high. With moderate densities, oil reduced the number of fruit infestations, but not stings (unsuccessful entries). There also were some measurable benefits to leafroller, Pandemis pyrusana Kearfott control. Oil was most useful, however, in suppression of secondary pests. White apple leafhopper, Typhlocyba pomaria McAtee, was the primary target of oil applications in the Oil/Indirect Pest program (typically three applications per season). However, leafhopper suppression in the Oil/Direct Pest program was generally greater because of the higher number of applications. Phytophagous tetranychid and eriophyid mites also were suppressed by more oil applications. Predatory mite populations were lower in both oil programs than in the check, but it is difficult to determine whether direct toxicity or reduction of prey was responsible for lower predator populations. There also was some evidence that oil suppressed woolly apple aphid, Eriosoma lanigerum Hausman. The six-spray oil program largely prevented a woolly apple aphid outbreak that occurred in July and August 1998 in the check, although the three-spray program seemed to provide some suppression despite the nonspecific spray timing.

Fixed Precision Sampling Plans for White Apple Leafhopper (Homoptera: Cicadellidae) on Apple

Constant precision sampling plans for the white apple leafhopper, Typhlocyba pomaria McAtee, were developed so that it could be used as an indicator species for system stability as new integrated pest management programs without broad-spectrum pesticides are developed. Taylor's power law was used to model the relationship between the mean and the variance, and Green's constant precision sequential sample equation was used to develop sampling plans. Bootstrap simulations of the sampling plans showed greater precision (D = 0.25) than the desired precision (Do = 0.3), particularly at low mean population densities. We found that by adjusting the Do value in Green's equation to 0.4, we were able to reduce the average sample number by 25% and provided an average D = 0.31. The sampling plan described allows T. pomaria to be used as reasonable indicator species of agroecosystem stability in Washington apple orchards.

Mineral Oil Inhibition of White Apple Leafhopper (Homoptera: Cicadellidae) Oviposition

Various rates, types and residue ages of horticultural mineral oils were tested for inhibition of oviposition by white apple leafhopper, Typhlocyba pomaria McAtee, in laboratory bioassays. The numbers of nymphs produced from females exposed to treated apple leaf surfaces were used to determine the behavioral effect. No differences in effect were found among the three oils tested (Orchex 796, Orchex 692, and Orchex 892). Inhibition of oviposition was found in concentrations of Orchex 796 as low as 1% vol:vol (2-fold reduction in nymphs), with complete inhibition at 4%. The inhibitory effect of this material at 1% vol:vol persisted for at least 3 d, with no difference between the 7-d-old residues and the check.

Impacts of seasonal kaolin particle films on apple pest management

AbstractThe impact of multiple applications of the kaolin-based particle film M96-018 on the population density of selected pests of apple, Malus domestica (Borkh) (Rosaceae), and their natural enemy populations were measured in several Washington State orchards from 1997 to 1999. Densities of western tentiform leafminer, Phyllonorycter elmaella (Doganlar and Mutuura) (Lepidoptera: Gracillariidae), were significantly higher and percent parasitism was generally lower in treated plots than in untreated plots. The effect of M96-018 on green aphids (Aphis spp.) (Hemiptera: Aphididae) was variable between orchards; however, populations of rosy apple aphid, Dysaphis plantaginea Passerini (Hemiptera: Aphididae), were higher in treated plots than in untreated plots. M96-018 reduced the mean density of the white apple leafhopper, Typhlocyba pomaria (McAtee) (Hemiptera: Cicadellidae), and the density of spiders (Araneae) compared with untreated plots. Fruit injury by codling moth, Cydia pomonella (L.), and fruittree leafroller, Archips argyrospilus (Walker) (Lepidoptera: Tortricidae), was significantly reduced in the treated plots compared with the untreated plots. The effect of M96-018 on the mullein bug, Campylomma verbasci (Meyer) (Hemiptera: Miridae), was variable between orchards and years. Stink bug (Hemiptera: Pentatomidae) density and related fruit injury were unaffected by M96-018. Fruit infestation by San Jose scale, Quadraspidiotus perniciosus (Comstock) (Hemiptera: Diaspididae), was significantly higher in treated plots than in untreated plots. Discontinuing applications of M96-018 at mid-season reduced the number of aphid-infested leaves and increased fruit injury by leafroller compared with a full-season program. No differences in pest densities occurred in plots treated for one versus two consecutive years; however, the density of phytophagous mites (Acari: Tetranychidae) was significantly higher the subsequent year after plots were treated with M96-018. Further studies are needed to elucidate how these disruptive impacts of particle films can be minimized.

Ground Cover Plants and Selective Insecticides as Pest Management Tools in Apple Orchards

The quantity and quality of fruit in 2 adjacent apple orchards in eastern West Virginia were compared between 1 conventionally managed orchard and 1 with ground cover plantings underneath apple trees and reduced insecticide applications. Four species of plants [dill, Anethum graveolens L.; buckwheat, Fagopyrum esculentum Moench; dwarf sorghum, Sorghum bicolor (L.) Moench; and rape, Brassica napus L.] were planted in alternating, single-species strips under the tree canopy, and only 1 broad-spectrum insecticide (phosmet) plus Bacillus thuringiensis was applied in the ground cover orchard over the 2-yr period (1995–1996) of the study. The conventional orchard received 5 applications of an organo-phosphate each year. Disease management was the same for both orchards. The ground cover orchard had significantly greater populations of spirea aphid (Aphis spiraecola Patch) and leafhoppers [Typhlocyba pomaria McAtee, Edwarsiana rosae (L.), and Emposaca fabae (Harris) ] than the conventional orchard. The conventional orchard had more damage from fire blight than the ground cover orchard. Total yield of apples from the ground cover orchard was significantly less than in the conventional orchard, probably because of competition by the ground cover plants for water and nutrients. Fruit quality was lower in the ground cover orchard in 1995 (76% undamaged fruit compared with 80% undamaged in the conventional orchard), but in 1996 there was no difference in fruit quality between orchards (75% undamaged fruit). Plum curculio, Conotrachelus nenuphar (Herbst), damage was significantly different between orchards, but different orchards had greater damage in each year. In 1996, fruit in the conventional orchard had more apple scab, but in the ground cover orchard fruit had higher levels of summer rots and other diseases. In this study, ground covers and reduced insecticide use were not an acceptable alternative to conventional pest management because of reduced yield. However, with better management of ground cover plantings to avoid excessive competition with the apple trees, this strategy of pest management shows promise for reducing insecticide use in apple orchards.

Clarifying the Roles of White Apple Leafhopper and Potato Leafhopper (Homoptera: Cicadellidae) in Fire Blight Transmission in Apple

White apple leafhopper, Typhlocyba pomaria McAtee, and potato leafhopper, Empoasca fabae (Harris), were evaluated for their potential to incite fire blight infection in apple in the presence of the causal organism, Erwinia amylovora (Burrill) Winslow et al. Each leafhopper species was used as one factor in a series of 2 × 2 factorial experiments; the other factor was the presence or absence of E. amylovora. There was no evidence for a role for white apple leafhopper which feeds in the mesophyll of middle-aged and older leaves. There was sometimes a significant role for potato leafhopper which feeds in the vascular tissue of growing shoot tips.

Ultrastructural and Surface Features of Apple Leaves following White Apple Leafhopper Feeding

White apple leafhopper (WALH; Typhlocyba pomaria McAtee) feeding damage on apple (Malus domestica Borkh.) leaves was examined with scanning and transmission electron microscopy. WALH created feeding holes in the (lower) abaxial epidermis, with no visible exterior evidence of cell injury to the adaxial (upper) epidermis. Feeding holes were located in areas of the leaf with high stomatal density and were near stomata. Groups of cells in the palisade layers were empty or contained coagulated cell contents. Adjacent, apparently noninjured, palisade cells contained an abundance of starch granules, possibly indicating that photoassimilate export was impaired. Spongy mesophyll cells abaxial to the feeding area were left intact as were the epidermal cells adaxial to the feeding area. External views of either epidermis and internal leaf views of injured cells indicated no cell wall collapse.

White Apple Leafhopper (Homoptera: Cicadellidae) Effect on Fruit Size, Quality, and Return Bloom of Apple

Studies were conducted during 1987 and 1988 on the effect of single season injury by white apple leafhopper, Typhlocyba pomaria McAtee, to the ‘Oregon Spur Delicious’ apple. In 1987, the internal fruit flesh color (yellow) was increased, indicating that fruit from leafhopper-injured trees was slightly more mature than fruit from uninjured trees. In 1988, external fruit skin color was slightly redder (Hunter a) in fruit from injured trees, but titratable acidity was slightly lower. No effect on fruit weight, fruit firmness, soluble solids, percentage red skin color, retum bloom, or retum crop as a result of leafhopper injury occurred in either year, despite high leafhopper populations (≈6.5 nymphs per leaf) and relatively high foliar injury. Current action thresholds for white apple leafhopper are likely too conservative, and the potential for biological control can be explored without economic loss to the producer.

Modeling Postdiapause Egg and Nymphal Development of the White Apple Leafhopper (Homoptera: Cicadellidae)

Constant-temperature development studies were conducted with overwintering postdiapause eggs and first-generation nymphal stages of white apple leafhopper, Typhlocyba pomaria McAtee. Plots of development rates versus temperature were nonlinear over the range of temperatures tested, 13–30°C. Optimum nymphal development for each stage occurred over a narrow range of temperatures, 26–28°C. Developmental rates (times) for each life stage were normalized and fit to cumulative curves of development (Weibull and logistic functions) to produce a predictive phenology model. Comparison of these curves with the development of two nymphal cohorts under field temperatures showed that the model was significant. However, the fit of the model to data on cumulative egg hatch from three orchards was poor. Comparison of the model with cumulative counts of first generation nymphal stages sampled weekly or biweekly in several orchards between 1986 and 1989 showed the model was on average 0–4 d late in predicting 1, 50, and 99% completion of each nymphal stage. Yet, the model predicted the occurrence of these three events within 7 d of the observed event in > 90% of the comparisons. Prediction of the timing of peak population density of instars 1–3 (the most susceptible life stages to organophosphate insecticides) was < 3 d when stage-specific survivorship rates of <70% were included in the model.

Effects of two sterol-inhibiting fungicides on populations of pest and beneficial arthropods on apple

This research demonstrated that sterol-inhibiting fungicides alter the population structure of some pest and beneficial arthropods in apple orchards. Orchard populations of European red mite, Panonychus ulmi (Koch) (Acarina: Tetranychidae); the predacious mite, Typhlodromus caudiglans Schuster (Acarina: Phytoseiidae); the spotted tentiform leafminer, Phyllonorycter blancardella Fabr. (Lepidoptera: Gracillariidae); the leafminer parasite Pholetesor ornigis Weed (Hymenoptera: Braconidae); the green apple aphid, Aphis pomi DeGeer (Homoptera: Aphididae); white apple leafhopper, Typhlocyba pomaria McAtee (Homoptera: Cicadellidae); Campylomma verbasci Meyer (Hemiptera: Miridae); chalcids, primarily Sympiesis sericeicornis Nees (Hymenoptera: Chalcididae), were monitored for two growing seasons in a McIntosh apple orchard that had received applications, at 2-week intervals, of two sterol-inhibiting fungicides, bitertanol and flusilazole. High rates of flusilazole were associated with increased numbers of European red mite and decreased numbers of predacious mite species, particularly T. caudiglans. Trees receiving a high rate of bitertanol had fewer European red mites and predacious mite species. Fungicides did not influence spotted tentiform leafminer oviposition or the number of leafminer larvae in May and June 1985. However, in September 1985 there were fewer leafminer pupae in plots treated with the two lower rates of flusilazole and more larvae in plots treated with the high rate of bitertanol, relative to trees sprayed with captan. In 1986, there were more leafminer eggs in plots treated with the low rate of bitertanol compared with captan and non-sprayed trees. However, by 24 June, all treatments showed similar levels of leafminer larvae and pupae. Populations of P. ornigis were generally higher in trees treated with flusilazole in both years. Numbers of aphids and mullein bug were higher in trees treated with flusilazole relative to non-sprayed and captan-treated trees. Chalcid populations were higher in bitertanol-treated trees. Fungicides had no apparent effect on populations of white apple leafhopper.

Impact of Four Synthetic Pyrethroids on Major Natural Enemies and Pests of Apple in Pennsylvania1

The impact of four synthetic pyrethroids upon major apple pests and natural enemies was studied in Pennsylvania orchards from 1975 to 1980, The pyrethroids were tested alone in dilute and airblast applications and at reduced rates in combination with standard insecticides recommended for use in Pennsylvania’s integrated pest management (IPM) system, These materials were generally very active against the codling moth, Laspeyresia pomonella (L.), the oriental fruit moth, Grapholitha molesta (Busck), an apple budmoth, Platynota idaeusalis (Walker), and the white apple leafhopper, Typhlocyba Pomaria McAtee, The pyrethroids showed some potential for reducing populations of the apple aphid, Aphis pomi De Geer. Fenvalerate and permethrin were somewhat active against mites, but European red mite, Panonychus ulmi (Koch), and twospotted spider mite, Tetranychus urticae Koch, populations generally reached highest densities on pyrethroid plots, The pyrethroids were very toxic to the predatory mites, Amblyseius fallacis (Garman) and Zetzellia mali (Ewing), but less toxic than standard insecticides to a mirid predator, Hyaliodes vitripennis (Say), Stethorus punctum (LeConte), the key natural enemy in Pennsylvania’s apple IPM program, also was susceptible to these pyrethroids, but results after applying low rates of pyrethroids for 3 years indicated possible selectivity in favor of S. punctum with these new chemicals. These studies indicated several potential avenues for the careful introduction of the synthetic pyrethroids into existing IPM programs for deciduous-tree fruits.

Spatial Distribution of Overwintering Eggs of the White Apple Leafhopper, Typhlocyba pomaria , and Parasitism by Anagras epos1

Overwintering eggs of the white apple leafhopper (WALH), Typhlocyba pomaria McAtee, parasitized and unparasitized by the mymarid, Anagrus epos Girault, were randomly collected from apple twigs taken from within quadrants and levels of apple trees in 3 Michigan orchards. Subsamples included host eggs from twig bark of different age classes and at varying distances from the apex of the branch terminal. WALH eggs were most common on twig wood 3–4 yr old or 45–75 cm from the apex. In 2 of 3 orchards more dense populations were found in the upper tree canopy as compared to the lower. From ANOVA, variations in WALH densities more often were significantly different between trees (P ≦ 0.01 level) as compared to within trees in different quadrants and levels. The distribution of eggs parasitized by A. epos within trees and between trees was very similar to the distribution of the WALH, indicating that parasite search was well adapted to the ovipositional site preference of the host. Analysis of percent parasitization of WALH eggs per tree indicated a density dependent association between these 2 species in an orchard having the highest WALH density.

Stethorus punctum and Pest-Population Responses to Pesticide Treatments on Apple Trees12

In 1970, 1971, and 1972, 32 pesticide treatments were tested for their effect on the predatory coccinellid Stethorus punctum (LeConte) and apple pests. Outstanding treatments with commercially satisfactory effectiveness on lepidopterous pests and only slight effect on S. punctum were: 0.0625 lb AI dinocap + 0.125 lb AI azinphosmethyl + 1.341 lb AI lead arsenate/100 gal; the same amounts of dinocap and azinphosmethyl + 0.125 AI Imidan® ( O, O -dimethyl S-phthalimidomethyl phosphorodithioate)/100 gal; and the same amounts of dinocap and azinphosmethyl + 0.125 lb AI phosalone/100 gal. The last-mentioned treatment was more effective than the former 2 treatments on the white apple leafhopper, Typhlocyba pomaria McAtee. These 3 treatments demonstrate the dinocap + S. punctum interaction with the European red mite, Panonychus ulmi (Koch). Phosvel® ( O -(4-bromo-2,5-dichloropheynl) O -methyl phenylphosphonothioate) at 1 lb AI/100 gal was effective on the lepidopterous pests, and at 0.5 lb AI/acre it is effective on the white apple leafhopper. At these rates, Phosvel is only slightly toxic to S. punctum. Phosvel was not effective on the apple aphid, Aphis pomi De Geer. Hercules 16801 (Phenyl N-dimethoxyphosphinodithioacethyl N-methylcarbamate) was more effective on the lepidopterous pests at 1 lb AI/100 gal than at 0.5 lb AI. It was not effective on the apple aphid or the white apple leafhopper, and it had low toxicity to S. punctum .

Integrated Control of the Fruit-Tree Leaf Roller and the White Apple Leafhopper in British Columbia123

Azinphosmethyl, diazinon, or parathion applied at the pinkbud stage ‘McIntosh’ apple, and DDT applied at the petal-fall stage gave good control of the fruit-tree leaf roller, Archips argyrospilus (Walker), on McIntosh, ‘Delirious,’ and ‘Spartan’ apple trees. Dormant oil-ethion at the 1/2-inch green stage and endosulfan at the petal-fall stage were less effective and aldicarb as a soil treatment was ineffective. DDT and endosulfan as pedal-fall sprays gave excellent control of the white apple leafhopper, Typhlocyba pomaria McAtee. A pink-bud spray of azinphosmethyl, diazinon, or parathion and a petal-fall spray of endosuIfan could be used in conjunction with a sterile-codling moth pro!(ram to control fruit-tree leaf roller and white apple leafhopper. In addition, the above materials and timing of sprays did not affect either phytophagous or predator mites.

The Leafhopper Typhlocyba froggatti Baker as an Apple Pest in Ontario

A large apple orchard at Queenston, Ont., was sprayed regularly with DDT in 1946, 1947, and 1948, but in 1949 part of it was left unsprayed. The unsprayed trees became so heavily infestcd with leafhoppers that by the end of August the foliage was severely injured. The injury was similar to that caused by the white apple leafhopper, Typhlocyba pomaria McAtee.A collection of more than 200 nymphs was made on August 11 and reared to maturity, and additional adults were collected on August 29. All of the males, except a few specimens of Erythroneura lawsoniana Baker, proved to be Typhlocyba froggatti Baker.

THE WHITE APPLE LEAFHOPPER (TYPHLOCYBA POMARIA McA.)

Typhlocyba pomaria McA., the white apple leafhopper, a pest of apple in Canada and the United States, has two generations a year in the Vineland district of Ontario. The insect spends the winter in the egg stage, the newly hatched nymphs make their appearance in May, and adults are present on the trees in June and July. Summer eggs are deposited chiefly in the midribs of the foliage, and take from 20 to 64 days to hatch. The second generation of adults matures in August and September. Detailed information on all phases of the life history is presented, including the type of feeding and nature of the injury produced on apple foliage. The associated species of leafhoppers which cause injury to apple are listed.

Experiments in Spray Residue Removal

Preliminary tests are given on commercial methods of removing apple spray residues in New York. Acid-insoluble spray residues (especially sulfur), road dust and spotting from the leafhopper ( Typhlocyba pomaria ) are also considered.