Pest Of Pears Research Articles

Pear, Insect Growth Regulator Tests, 1987

Abstract Mature pear trees were sprayed with handguns operating at 600 psi to evaluate pesticides for control of pear pests. Plots consisted of 5 single-tree replicates in randomized block design. Treatments were applied 3 times, 29 Apr (petal fall), 29 May, and 20 Jul. Treatments were evaluated for PP and mite control by counts made at 2-wk intervals. Adult PP were counted from a 5 beating-tray sample/ replication. PP nymphs and mites were counted from a 50-leaf sample/replication. Leaf samples consisted of the proximal, distal, and 3 leaves from between on each of 10 terminal shoots. Leaves were brushed and resulting slides were examined using a binocular dissecting microscope. PP and PRM russet were rated according to U.S. grade standards for fresh market Bartlett' pears on 2 samples of 25 mature fruits per replication. Fruit and foliage were examined after each spray for phytotoxicity. The test orchard was sprayed with Pydrin 2.4 EC 1 pt/acre at cluster bud stage of tree growth to reduce density of overwintered adult PP.

Pear, Pest Control, 1986

Abstract Mature pear trees were sprayed with handguns operating at 600 psi to evaluate pesticides for control of pear pests. Plots consisted of 5 2-tree replicates in randomized block design. Treatments were applied 4 times during the season, on 11 Apr, 1 May, 4 Jun and 22 Jul. Treatments were evaluated for PP and mite control by counts made at 2-week intervals, but PP populations declined in late Jul so counts made afterwards are not included in tables. Adult PP were counted from a 5 beating-tray sample/rep. Psylla nymphs and mites were counted from a 50-leaf sample/rep. Leaf samples through 27 May were collected from fruiting spurs. Later samples consisted of the proximal, distal and 3 leaves from between on each of 10 growing shoots. Leaves were brushed and resulting slides were examined using a dissecting microscope. PP and PRM russet were rated according to US grade standards for fresh market Bartlett pears on 2 samples of 25 mature fruits/rep. Fruit and foliage were examined after each spray for phytotoxicity.

Selective Control Program for the Pear Pest Complex in Southern Oregon

Selective chemical control programs were evaluated in four southern Oregon pear orchards with the goal of maximizing effect of biological control agents for suppression of pear pests. The programs used prebloom oil sprays for control of San Jose scale, Quadraspidiotus perniciosus (Comstock), and for ovipositional delay of pear psylla, Psylla pyricola Foerster; diflubenzuron for codling moth, Cydia pomonella (L.), suppression; Bacillus thuringiensis Berliner for leafrollers; and, where needed, half the usual rate of cyhexatin for spider mite control. Organophosphates, carbamates, pyrethroids, and amitraz were deleted from selective programs. Predator density increased in all selective plots and was sufficiently high in two of the four orchards to give commercially acceptable control of pear psylla and to lower acaricide use by 75%. Control costs were ca. $300 per ha and $700 per ha in selective and standard programs, respectively. Density and period of colonization by pests and predators varied from site to site and appeared to depend on previous treatment history within the study area, and on the nature and management of surrounding vegetation.

Pear, Pest Control, 1985

Abstract Twenty-two-year-old pear trees were sprayed with handguns operating at 600 psi to evaluate pesticides for control of pear pests. Plots consisted of 5, 2-tree replicates in randomized block design. Treatments were evaluated for PP control by counts of adults and nymphs at 2-wk intervals. Adults were counted from 5 beating-tray samples/rep. Nymphs were counted from 50 leaves/rep. First generation nymph samples, those prior to 1 Jun consisted of fruiting spur leaves. Later samples included the proximal, distal and 3 leaves from between, on each of 10 shoots. Leaves were brushed and the resulting slides were examined using a dissecting microscope. Phytophagous mites were counted from separate samples using the same procedure. Two 10-fruit samples/rep collected at normal harvest time were weighed and tested for firmness with a penetrometer. Soluble solids were measured with a refractometer on samples of the combined juice of each lot of 10 fruits. PP and PRM damage was rated according to US grade standards for fresh market Bartlett pears on 2 samples of 25 fruits/rep. Fruit and foliage were examined after each spray for phytotoxicity.

Pear: Pest Control, 1984

Abstract Twenty-one year-old pear trees were sprayed with handguns operating at 600 psi to evaluate pesticides for control of pear pests. Plots consisted of five 2-tree replicates in randomized block design. Plots 1 and 2 were sprayed 4 May, 22 Jun and 11 Jul, plot 3 was sprayed 26 Apr, 13 Jun and 11 Jul and plots 4-9 were sprayed 4 May, 13 Jun and 11 Jul. Treatments were evaluated for pear psylla control by counts of adults and nymphs at 2-week intervals. Adults were counted from a 5 beating-tray sample/rep. Nymphs were counted from 50-leaf samples/rep. First generation nymph samples, those prior to 26 Jun, consisted of fruiting spur leaves. Later samples included the proximal, distal and 3 leaves from between, on each of 10 shoots/rep. Leaves were brushed and the resulting slides were examined using a dissecting microscope. Two 10-fruit samples/rep collected at normal harvest time were weighed and tested for firmness with a penetrometer. Soluble solids were measured with a refractometer on samples of the combined juice of each lot of 10 fruit. Pear psylla and pear rust mite russets were rated according to US grade standards for fresh market Bartlett pears on 2 samples of 25 fruit/rep. Fruit and foliage were examined after each spray date for phytotoxicity.

Pear: Pest Control, 1983

Abstract Twenty-year-old pear trees were sprayed with handguns operating at 600 lb/in2 to evaluate pesticides for control of pear pests. Plots consisted of five two-tree replicates in randomized block design. Treatments were evaluated for pear psylla control by counts of adults and nymphs at 2-week intervals. Adults were counted by taking five beating-tray samples per rep. Nymphs were counted from 50-leaf samples per rep. The proximal, distal, and three leaves from between were collected from each of 10 randomly selected shoots. Phytophagous mites were counted from the same leaf samples but mite data are presented for only those dates when populations were dense enough to show differences between treatments. Leaf samples were brushed and resulting slides were examined using a dissecting microscope. Two 10-fruit samples per rep were weighed and tested for firmness with a penetrometer. Soluble solids were measured with a refractometer on samples of the combined juice of each lot of 10 fruit. Pear psylla russet and pear rust mite russet were rated according to US grade standards for fresh market Bartlett pears on samples of 25 fruit per rep. Fruit and foliage were examined for phytotoxicity after each spray date.

Pear, Pest Control, 1982

Abstract Eighteen-year-old pear trees were sprayed with handguns operating at 600 psi to evaluate pesticides for control of pear pests. Plots consisted of five 2-tree replications in randomized block design. Treatments were evaluated for pear psylla control by counts of adults and nymphs at 2-wk intervals. Adults were counted by taking 5 beating-tray samples/rep. Nymphs were counted from 50-leaf samples/rep. The proximal, distal and 3 leaves from between were collected from each of 10 randomly-selected shoots. Phytophagous mites were counted from 50-leaf samples selected at random from each rep. All leaf samples were brushed and 20% of the resulting discs were examined with a dissecting microscope. Two harvest samples of 10 fruits/rep were weighed, tested for firmness with a penetrometer and rated for pear psylla honeydew russet and pear rust mite russet according to U.S. grade standards. Soluble solids were measured with a refractometer on samples of the combined juice of each lot of 10 fruit. Fruit and foliage were examined for phytotoxicity after each spray date. Pear psylla density was low in the block throughout the season so that test materials were not subjected to a severe test.

Grape Mealybug (Homoptera: Pseudococcidae) on Pear in North-Central Washington1

The grape mealybug, Pseudococcus maritimus (Ehrhorn), is an occasional serious pest of pears in north-central Washington state (NCW). A tree-banding study indicates the occurrence of a single generation of P. maritimus on pear in NCW. An encyrtid parasite, Acerophagus notativentris (Girault), is common in infested orchards and completes two to three generations per year. A. notativentris is solitary in 1st-instar P. maritimus and gregarious in later host instars. The parasite was observed ovipositing in P. maritimus eggs. Crawlers hatching from these eggs were parasitized.

Pear, Pest Control, 1981

Abstract Seventeen-yr-old pear trees were sprayed with handguns operating at 600 psi to evaluate pesticides for control of pear pests. Plots consisted of five 2-tree replications in randomized block design. Treatments were evaluated for pear psylla control by counts of adults and nymphs at 2-wk intervals. Adults were counted by taking 5 beating-tray samples/rep. Nymphs were counted on 5 fruiting spurs through Jun 1 and on 5 growing terminal shoots/rep thereafter. All tissues on fruiting spurs were examined with a dissecting microscope. Five leaves were examined from each shoot including the proximal and distal leaves and 3 evenly-spaced leaves from the area between. Phytophagous mites were counted from 25-leaf samples/rep by the brushing technique. Harvest samples of 10 fruits/rep were weighed, tested for firmness with a penetrometer and for soluble solids with a refTactometer. Fruit and fol iage were examined for phototoxicity after each spray.

Potential of Tree Washes as a Management Tactic Against the Pear Psylla12

The effects of tree washes on populations of Psylla pyricola Foerster and fruit quality were examined. Handgun applications of tree washes removed pear psylla honeydew and reduced fruit russet. In addition, tree washes which contamed a wetting agent increased mortality of pear psylla nymphs. Tree washes applied by a speed sprayer were as effecttve as handgun washes in removing pear psylla honeydew. Tree washing holds promise as a tactic to be integrated with biological and chemical control to manage arthropod pests of pear in north central Washington.

Pear, Insect and Mite Control, 1980

Abstract Field tests were conducted in a 15-year old block at the U. C. Deciduous Fruit Field Station in San Jose, CA, to determine seasonal Impact of spray programs with Pydrin and SD 57706 on major pear pests. Four treatments (and a check) each consisting of three 6-tree (2x3) replicates were arranged in a completely randomized design. Sprays were applied until run-off with a hand gun sprayer at 300 psi. Leaves (120/trearmenr) were collected twice during the season and brushed to determine numbers of psylla immatures and phytophagous mites. Fruit (300/ treatment) was examined in July and at harvest for codling moth damage.

Codling Moth Control by Release of Radiation-Sterilized Moths in a Pome Fruit Orchard and Observations of Other Pests12

Release of radiation-sterilized male and female Laspeyresia Pomonella (L.) in a 40-ha pome fruit orchard from 1969–72 in the Similkameen Valley of British Columbia reduced the wild population of this pest to a very low level without causing serious problems in contral of other apple and pear pests. Percent apples injured by codling moth larvae at harvest were 0.1 in 1968 (after 3 sprays of azinphosmethyl), and 0.05, 0.02, 0.007, and 0.001 from 1969–72.

Control of the Pear Psylla with Insect Growth Regulators and Preliminary Effects on Some Non-target Species1

Two insect growth regulators (IGR) ZR-512 (Ethyl 3,7,1l-trimethyldodeca-2,4-dienoate) and ZR-515 (Isopropyl 11-methoxy-3,7,11-trimethyldodeca-2,4-dienoate) were evaluated for their control of the pear psylla, Psylla pyricola Forster, and for their effect on nontarget pear pests and predators. Under laboratory conditions, adult psylla exposed to residues of IGR's failed to lay viable eggs, though the number laid and the general appearance of eggs seemed normal. Adult psylla from late-instar nymphs which were exposed to ZR-515 failed to lay viable eggs. In field tests no direct reduction in adult psylla levels was observed following application with IGR's, but 3 weeks post treatment the ratio of psylla eggs per nymphs was much greater in these plots. The effect of IGR's was minimal on other pest species, and no significant decrease in predator species was noted.

THE BIOLOGY OF AND EFFECT OF PESTICIDES ON DERAEOCORIS BREVIS PICEATUS (HETEROPTERA: MIRIDAE)

AbstractDeraeocoris brevis piceatus Knight overwinters in the adult stage on pear and several other plants. Within pear orchards there are apparently two generations of D. brevis per year. Under laboratory conditions the developmental time from first instar to adult is about 25 days. During this period D. b. piceatus consumed nearly 400 eggs and nymphs of the pear psylla, Psylla pyricola Foerster. Most organophosphate pesticides tested were highly toxic to D. b. piceatus when applied directly to nymphs or adults but 7-day-old residues of these chemicals were only moderately toxic. Nonphosphate pesticides allowed fair to good survival of D. b. piceatus but do not fit into the total summer control program for pear pest control.

Pest Status of Insects and Mites on Pear in Southern Oregon2

The economic status of 7 pear pests in southern Oregon was evaluated over an 8-year period, 1964-71. Comparisons of pest levels and economic losses were made in treated and untreated situations. Of the 7 pests which are targets for spray applications, the twospotted spider mite, Tetranychus urticae Koch; the European red mite, Panonychus ulmi (Koch); the yellow spider mite, Eote tranychus carpini borealis (Ewing); and the pear psylla, Psylla pyricola Foerster, apparently have been promoted to pest status through use of spray chemicals. Despite the undesirable side effects resulting from use of pesticides, the added material and labor costs are compensated for by a minimum ratio of 5:1 by the increased value of fruit received by control of the codling moth, Laspeyresia pomonella (L.): the pear rust mite, Epitrimerus pyri (Nalepa): and the San Jose scale, Quadraspidiotus perniciosus (Comstock). The grower benefits also by obtaining control of nontarget phytophagous species.

Behavior and Control of the Grape Mealybug on Pear

The grape mealybug, Pseudococcus maritimus (Ehrhorn), is a chronic pest of pears which became a serious problem in several pear-growing areas in 1960 and 1961. Biology studies showed that the over wintering crawlers invaded and fed upon tissue in the fruit buds from the period of bud crack until petal fall. After this time, the mealy bugs migrated to the base of sucker shoots where rough bark provided protection. Because the insects are exposed within the open fruit buds, a spray timed at the cluster bud stage of tree development is preferred. Spray trials were conducted at the dormant, cluster bud, and petal fall periods on Bartlett pears. The results indicated that parathion or Diazinon® ( O,O -diethyl O -(2-isopropyl-4-methyl-6-pyrimidinyl) phosphorothioate) at a dosage of 2 pounds 25% per 100 gallons or a 1 pound dosage combined with either oil or a welting agent provided the best control. Dormant oil combined with lime sulfur, polysulfide, dinitrophenol, and dimethoate did not provide acceptable control. Zectran® (4-dimethylamino- 3,5 -xylyl methylcarbamate) and Dilan (a mixture of I part of 1,1-bis( p -chlorophenyl)-2-nitropropane (Prolan) and 2 parts of 1,1-bis( p -chlorophenyl)-2-nitrobutane (Bulan)) reduced meal. bugs. but were less effective than either parathion or Diazinon.

ON THE OCCURRENCE IN ENGLAND OF THE PEAR FRUIT SAW‐FLY, HOPLOCAMPA BEE VIS KLUG

SUMMARYLarvae of Hoplocampa brevis Klug., the Pear Fruit Saw‐fly, have been found attacking pears in two gardens in Cambridge. In some continental countries this is a serious pest of pears; this is the first record of damage by this pest in England.A preliminary study of the biology of this species has been made, and the egg, larval stages and cocoon have been briefly described.The writer is indebted to Dr H. W. Miles for the identification of the saw‐fly and for helpful criticism.

Plant Bugs as Pests of Pear and Other Fruits in the Hudson Valley

Late in August Acrosternum hilaris, Euschistus euschistoides, and E. variolarius were observed in pear orchards thruout the Hudson valley. They were found to attack several varieties of pears as the fruit was maturing, resulting in serious commercial damage.

The Woolly Aphis as a Pear Pest

Journal Article The Woolly Aphis as a Pear Pest Get access G. P. Weldon G. P. Weldon Sacramento, Cal. Search for other works by this author on: Oxford Academic PubMed Google Scholar Journal of Economic Entomology, Volume 8, Issue 5, 1 October 1915, Page 450, https://doi.org/10.1093/jee/8.5.450 Published: 01 October 1915