White Bud Research Articles

Pear, Summer Control of Pear Rust Mite, 1991

Abstract Mature 'Bartlett' trees in Fennville, MI (VanVorhees West-Block) were sprayed with an FMC 1029 airblast sprayer at 100 gpa of finished spray. Trees were arranged in a completely randomized design of single trees replicated 4 times. Applications of all materials were made as indicated in the table on 10 May (PF), 21 May (IC). Guthion was applied to all treatments. Dates of PRM evaluation were 24 May, 30 May, 13 Jun, 28 Jun, 12 Jul, 26 Jul, 9 Aug. At each evaluation, 50 leaves/replication (200 per treatment) were picked and brushed in a mite brushing machine and examined under a stereo microscope for rust mite adults. On 21 Aug, 50 mature fruit per replicate (200 per treatment) were harvested and examined for russetting damage from PRM. Evaluations were based on visual inspection, with the scoring criteria listed in the table. White bud applications for this trial were not possible due to inclement weather.

Pear, Seasonal Pear Psylla Control Experiment, 1990

Abstract Experimental sprays were applied to replicated 9-15 tree plots consisting of the cultivar Bartlett (12-yr-old). Each treatment was replicated 4 times. Trees were planted to a spacing of 7.4 × 7.4 m. All treatments were applied with a handgun from a truck mounted hydraulic sprayer at 400 psi. Dates of application were: 28 Mar (bud burst, all plots); 12 Apr (white bud); 2 May (petal-fall); 23 May; 13 Jun (plots 23-27); 6 Jul; 23 Jul; and 30 Jul. Approximately 2.5 gal of spray were applied per tree (190 gal/acre). Treatments were evaluated for PP control by counts of eggs and nymphs at 1- to 2-wk intervals. Counts were made by sampling 10 spur leaves from the middle tree in each replicate. Beginning on 30 May counts were made by sampling 5 spur and 5 distal leaves (3rd most distal leaf) from each tree. On 13 Jun and thereafter 10 distal leaves (3rd most distal leaf) from each tree were sampled. PP pressure was heavy throughout the experiment. Russet ratings are based on 30 Bartlett pears/replicate, 120/treatment. Fruits were rated as 0 (no russet), 1 (raised lenticels), 2 (1-10% russeted surface), 3 (11-25% russeted surface), 4 (26-50% russeted surface) or 5 (> 51% russeted surface). Possible ranges were 0-30 (none to raised lenticels), 31-60 (raised lenticels to 1-10% russeted surface), 61-90 (1-10% to 11 - 25% russeted surface), 91-120 (11-25% to 26-50% russeted surface), and 121-150 (26-50% to >51% russeted surface).

Morphological and foliar terpene characters to distinguish between western and eastern white pine

To distinguish between western (Pinus monticola) and eastern (P. strobus) white pines, foliage, buds, and cones were examined and foliar terpenes were extracted and analyzed from representative samples. Needles of P. monticola were heavier, wider (>0.7 mm), and stiffer; buds were larger and usually nonresinous; cone scales, when viewed from the cone bottom, were arranged in five and eight spiralling rows. Needles of P. strobus were lighter, narrower (<0.7 mm), and droopy; buds were small and covered with white resin and bloom; cone scales were arranged in three and five rows. Needles and cones of P. monticola tended to be longer; cones were composed of more scales and contained more scales per centimetre and more scales per spiral row than those of P. strobus, but there was some overlap. Twig pubescence, bud apex shape, phyllotaxy, and seed wing length were not distinctive. Capillary gas-liquid chromatographic analysis of the leaf oils of white pine trees showed that bornyl acetate and β-elemene, present in P. monticola, were essentially absent in P. strobus, while α-humulene, present in P. strobus, was not found in P. monticola. In addition, the amount of β-caryophyllene could be used to differentiate between these species. However, the most obvious discriminating feature was the presence of a substantial and broad peak of unknown and decomposing compound(s) in the chromatograms for P. monticola and its complete absence in the chromatograms for P. strobus. A clone that was highly resistant to blister rust and previously classified as P. monticola is shown by terpene patterns and morphology to be P. strobus. Key words: Pinus monticola, Pinus strobus, terpene, Cronartium, morphology.

N RATE AND TIMING AFFECT ON CRANBERRY YIELD AND YIELD COMPONENTS

Cranberries (Vaccinium macrocarpon Ait.) require low rates of N fertilizer compared to many horticultural and agronomic crops. Excess N promotes vegetative growth at the expense of yield. Growers desire information about N fertilization to achieve optimum yields without overgrowth, Little information has been published about N rate and timing influence on cranberries in south coastal Oregon. An N rate and timing field experiment with Crowley and Stevens cultivars was established to answer grower questions. N was applied at 0, 18, 36 and 54 kg/ha in various combinations at popcorn (white bud), hook, fruitset, early bud, and late bud. Yield, yield components, (fruit set, number of flowering and total uprights, berry size, flowers per upright and the proportion of uprights that flower), vegetative growth and anthocyanin content were measured. After 2 years of treatments, N rate or timing had little influence on yield or yield components in the previously heavily fertilized Crowley bed. In the previously lightly fertilized Stevens bed, N rate increased yield, vine growth, and the number of flowering uprights, N timing also influenced the number of flowering uprights. The total number of uprights was influenced by the interaction of N rate and timing.

Cherry, Broad Spectrum Control with Insecticides, All Season Test, 1989

Abstract Mature sweet cherry trees in Douglas, MI were treated with insecticides at the rate of 100 gal/acre of finished spray with an FMC 3000 CP airblast sprayer. Trees were arranged in a completely randomized design of single trees replicated 4 times. All materials were applied on 30 Apr (white bud), 23 May, 5 Jun, and 18 Jun. Cover sprays of Bravo, Rovral, and Mesurol were applied separately to all blocks. Evaluations on 7 Jun and 28 Jun were made by harvesting and examining 100 cherries/replicate for plum curculio and green fruitworm damage for a total of 400 cherries/treatment.

Cherry, Broad Spectrum Control with Insecticides, All Season Test, 1989

Abstract Mature tart cherry trees in Fennville, MI were treated with insecticides at the rate of 100 gal/acre of finished spray with an FMC 1029 airblast sprayer. Trees were arranged in a completely randomized design of single trees replicated 4 times. All materials were applied on 1 May (white bud), 22 May, 4 Jun, and 28 Jun. Cover sprays of Bravo, Ziram, and Tilt were applied separately to all blocks. Evaluation on 9 Jun was made by harvesting and examining 100 cherries/replicate for presence of plum curculio damage for a total of 400 cherries/treatment.

Prebloom Control of Pear Psylla with Pyrethroid Insecticides, 1989

Abstract Sprays were applied dilute by handgun operating at 200 psi to 28-yr-old pear trees. Trees were sprayed to the drip point. Treatments consisted of 4 single-tree replicates (2 of each variety) arranged in a randomized complete block design. All sprays were applied on 6 Apr at the white bud stage. Treatments were evaluated by beating tray counts of PP adults (2 trays/tree) and counts of PP eggs and nymphs on 5 spurs/tree. After trees leafed out, spur leaves were sampled (2 leaves/spur; 20 spur leaves/tree). Spurs and leaves were scanned under a stereo microscope. Samples were taken before and after treatment at about 1 to 2 wk intervals.

Pear Psylla Control, 1988

Abstract Experimental sprays were applied to replicated 3-tree plots (10 yr old). Each treatment was replicated 5 times. Trees were planted to a spacing of 7.4 by 7.4 m. Treatments were applied with a handgun from a truck-mounted hydraulic sprayer at 375 psi. Dates of application were 4 Apr (BB, bud burst), 20 Apr (WB, white bud), 10 May (PF, petal fall), 27 May, 3 Jun, 10 Jun, 13 Jun, 24 Jun, 8 Jul, 14 Jul, and 27 Jul. Approximately 2.4 gal of spray was applied to each tree (185 gal/acre). Treatments were evaluated for PP control by counts of eggs and nymphs at 1- to 2-wk intervals. Counts were made by sampling 10 mid-terminal or spur leaves from the middle tree in each replicate. Beginning on 7 Jun counts were made by sampling 5 spur and 5 distal leaves from each tree. On 29 Jun and thereafter 10 distal leaves from each tree were sampled.

Evaluation for PP, 1988

Abstract The trial was conducted in a 3-acre block of primarily ‘Bartlett’ pear trees near Arendtsville, Pa. Plot size was approximately 1 acre except for control trees. Five ‘Bartlett’ trees were randomly selected within each plot for monitoring. Control trees were five 3-tree plots of ‘Bartletts’ located in an adjacent pear block. Chemicals were applied as complete sprays to both sides of trees with a Myers Mity Mist airblast sprayer calibrated to deliver 50 gal/acre. Application dates and rates were as follows 5 Apr (BB, bud burst); 22 Apr (WB, white bud); 10 May (PF, petal fall); and 2 Jun (IC, first cover). Treatments were evaluated for control by counts of eggs and nymphs at 1- to 2-wk intervals. Counts were made by sampling 10 spur leaves/tree.

Insect and Mite Control, Highland, N.Y., 1988

Abstract Treatments were applied to 8-tree plots replicated 3 times in a randomized complete block design. Each plot contained 4 ‘Bartlett’ and 4 ‘Bosc’ cultivars, spaced 12 by 18 ft., 12 ft. high, and 14 yr old. Treatments were applied by high-pressure handgun sprayer dilute to run-off at 350 psi using 1.9-3.1 gal/tree (380–623 gal/acre, depending on time of season and leaf canopy present). Treatments were applied at bud burst, 12 Apr; white bud, 1 May; petal fall, 16 May; and in cover sprays on 3 Jun, 19 and 20 Jun, 5 Jul, and 1 Aug. Applications for disease control over the entire block included Captan 50 W 2 lb/100 gal, on 27 May, 9 Jun, and 30 Jun. PP were evaluated by collecting 5 Bartlett spurs (25 leaves) from each plot on 19 May and 1 Jun, and thereafter 5 Bartlett shoots (25 leaves) from each plot on 14 Jun, 27 Jun, 11 Jul, 25 Jul, and 8 Aug. All live nymphs and eggs on each leaf were counted in the laboratory with a binocular scope. PRM populations were assessed by examining the same leaves used in most of the preceding PP samples. These leaves were viewed with the aid of a binocular scope and all live mites were counted. Insect injury and fruit finish were evaluated by examining 100 Bartlett fruits per plot (25 fruits/tree) which were harvested on 6 Sep. Fruit finish was rated using the following indexes: 0, 0-10% russet; 1, 10-40%; 2, 40-75%; 3, >75%. Rainfall was below normal during April, June, and August but above normal during July. Temperatures were above normal during June, July, and August. Pest pressure, especially from PP and PRM, was greater than usual early, but for PP was below normal after the intense heat of late June, which may have contributed to the population’s decline.

ULTRASTRUCTURAL AND HISTOCHEMICAL CHARACTERISTICS OF THE STIGMA OF CICER ARIETINUM

The stigma of Cicer arietinum L. cv. UC‐5, a self‐compatible legume, is comprised of a small central region of papillate cells which exhibit a localized surface secretion at the white bud stage of development, and of surrounding peripheral cells which lack surface secretion at the white bud stage and at anthesis. The cuticle of cells of the central region is thin and smooth and is displaced from subtending cells and fragmented as a result of secretory production. The cuticle of peripheral cells is thick and rugose. Although it is also displaced by secreted material, it is not disrupted during the white bud stage of development or at anthesis. The contents of central and peripheral papillate cells are similar. Cells are densely cytoplasmic, often with starch‐containing plastids. Mitochondria, Golgi bodies, and associated vesicles are abundant, along with strands of smooth and rough endoplasmic reticulum. The limited stigma surface area covered by the secretion may restrict pollen capture and retention. This limited area may partly account for the notably unsuccessful hybridization attempts to broaden the genetic base and to develop improved cultivars of Cicer.

Ultrastructural and Histochemical Characteristics of the Stigma of Cicer arietinum

The stigma of Cicer arietinum L. cv. UC-5, a self-compatible legume, is comprised of a small central region of papillate cells which exhibit a localized surface secretion at the white bud stage of development, and of surrounding peripheral cells which lack surface secretion at the white bud stage and at anthesis. The cuticle of cells of the central region is thin and smooth and is displaced from subtending cells and fragmented as a result of secretory production. The cuticle of peripheral cells is thick and rugose. Although it is also displaced by secreted material, it is not disrupted during the white bud stage of development or at anthesis. The contents of central and peripheral papillate cells are similar. Cells are densely cytoplasmic, often with starch-containing plastids. Mitochondria, Golgi bodies, and associated vesicles are abundant, along with strands of smooth and rough endoplasmic reticulum. The limited stigma surface area covered by the secretion may restrict pollen capture and retention. This limited area may partly account for the notably unsuccessful hybridization attempts to broaden the genetic base and to develop improved cultivars of Cicer.

Pear, Insecticide Evaluation, 1987

Abstract Insecticides were applied to 27-yr-old 'Bartlett" trees in unreplicated blocks of approximately one-third acre with 36 trees. Applications were made with a Bean C-336 CP sprayer, which traveled at 4.03 km/h and delivered 200 gal/acre. Dates of application were 21 Apr (white bud), 20 May (petal fall), 3 Jun (2nd cover), 15 Jun (3rd cover), 29 Jun (4th cover), 12 Jul (5th cover), 23 Jul (6th cover), 5 Aug (7th cover), and 18 Aug (8th cover) for all materials. Rust mites were evaluated on 5 Jun, 26 Jun, and 24 Jul for all materials, and all other pests were evaluated for damage at harvest on 25 Aug. For broad-spectrum evaluations, 50 fruit were picked from each of 4 centrally located trees in the block for a total of 200 fruit/ replication. Fruit were examined for injury categorized according to pest. The 3 pear rust mite evaluations taken during the season consisted of 50 leaf samples from 4 centrally located trees in each block. The leaves were then brushed in a mite-brushing machine. The resulting plates were examined under a microscope, and the number of eggs and mites were recorded.

Pear, Prebloom Control of Pear Psylla with Pyrethroids, 1987

Abstract Sprays were applied dilute by handgun operating at 200 psi to 14-yr-old pear trees. Test plots consisted of 4 single-tree replicates in a randomized block. Treatments consisted of single sprays applied on 18 Mar (delayed dormant) or two sprays applied on 18 Mar and 8 Apr (white bud). Treatments were evaluated by beating-tray counts of PP adults (2 trays/tree) and counts of PP eggs and nymphs on 5 spurs/tree.

Pear, Insect and Mite Control, Hudson Valley Lab, Highland, N.Y., 1987

Abstract Treatments were applied to 8 tree plots replicated 3 times in a randomized complete block design. Each plot contained 4 'Bartlett' and 4 'Bosc', spaced 12 × 18 ft., 12 ft. high, and 13 yr old. Treatments were applied dilute to runoff using a high-pressure handgun sprayer at 350 psi delivering from 1.9 to 2.9 gal/tree (380 to 583 gal/acre), depending on time of season and leaf canopy present. Danitol was applied at white bud, 20 Apr; petal fall, 8 May, and in cover sprays on 23 May, 7 and 24 Jun, and 13 Jul for the first treatment. The same rate was applied in a reduced schedule (20 Apr, 8 May, 7 Jun, and 13 Jul) as a comparison for the second treatment. Danitol was also applied along with Superior oil on 8 May. This application was followed by Guthion applications on 23 May, 7 and 24 Jun, and 7 Aug. There was a Mitac application on 13 Jul. Abamectin was applied at 3 different rates without oil on 8 May and with oil on 7 and 24 Jun, 13 Jul, and 7 Aug. Asana was applied 20 Apr, followed by Zolone + Sevin on 8 May, and Zolone + Mitac on 7 and 24 Jun, 13 Jul, and 7 Aug. An additional appliction over the entire block for fire blight control consisted of Agri-Strep, 8 oz/100 gal on 13 May. Applications were made for Fabraea leafspot control on 11 Jun and 1 Jul. Each replicate was treated with a separate fungicide at these applications. One replicate received Manzate 200 80W 1.5 lb/100 gal, another received Captan 50W 2 lb/100 gal, and the third received Benlate 50W 2.0 oz/100 gal + Manzate 200 80W 1.5 lb/100 gal. Pear psylla were evaluated by collecting 5 'Bartlett' spurs (25 leaves) from each plot on 7 and 18 May and 4 Jun and thereafter 5 'Bartlett' shoots (25 leaves) from each plot on 15 Jun, 3 and 20 Jul, and 4 and 13 Aug. All live nymphs and eggs on each leaf were counted in the laboratory using a binocular microscope. Mite populations were assessed by examining 5 'Bartlett' leaves per plot from the 20 Jul pear psylla sample. These leaves were viewed with the aid of a binocular microscope, and all live mites were counted. Insect injury was evaluated by examining 50 'Bartlett' fruit per plot harvested on 4 Sep. Rainfall during May and June was less than normal; during April and July rainfall was above normal. April and July temperatures were above normal and temperatures in May and June were below normal. Pest pressure, especially pear psylla and pear rust mite, was greater than usual due to the early onset of warm weather in the spring.

Pear, Seasonal Pear Psylla Control Experiment, 1987

Abstract Experimental sprays were applied to replicated 4- to 5-tree plots consisting of Bartlett (9 yr old). Each treatment was replicated 5 times. Trees were planted to a spacing of 7.4 × 7.4 m. Treatments were applied with a handgun from a truck-mounted hydraulic sprayer at 375 psi. Dates of application were bud burst (BB), 3 Apr; white-bud (WB), 21 Apr; petal fall (PF), 6 May; first cover (IC), 26 May; third cover (3C), 19 Jun; fourth cover (4C), 8 Jul; sixth cover (6C), 30 Jul. Approximately 1.75 gal of spray was applied/tree. Treatments were evaluated for pear psylla control by counts of eggs and nymphs at 1- to 2-wk intervals. Counts were made by sampling 10 mid-terminal or spur leaves from the middle tree in each replicate. Beginning on 1 Jun counts were made by sampling 5 mid-terminal and 5 distal leaves from each tree. Pear psylla pressure was moderate through the experiment.

FLOWER AND POD ABSCISSION IN SNAP BEAN AS INFLUENCED BY INFLORESCENCE POSITION, RACEME NODE, IRRIGATION AND PLANT DENSITY

Abscission and/or retention of flowers and pods formed on inflorescences arising from mainstem nodes 6 (terminal) and 2 (first trifoliolate leaf) of Oregon 1604 snap bean (Phaseolus vulgaris L.) were studied during the 1978 and 1979 seasons to determine the effects of irrigation and plant population. Inflorescences at these two nodes account for the majority of the yield produced in this determinate cultivar. The influence of high (−0.06 MPa) and low (−0.25 MPa) soil water potential and plant density were also assessed. High and low plant densities were 45 vs. 18 in 1978, and 54 vs. 33 plants m−2 in 1979. Percent flower and pod abscission was signficantly less under high (62%) than low (74%) irrigation at node 6 in 1978, and at node 2 in 1978 (48 vs. 71) and 1979 (37 vs. 60). Although plant density had no effect at node 6, percent abscission at node 2 was significantly less under low than high plant density in both years. An acropetal increase in percent abscission occurred within the inflorescence at node 6, with a value of 45% at the proximal, first raceme node, and from 65 to 86% at the most distal, third raceme node. The acropetal pattern of abscission was less marked in inflorescences at node 2. A sharp rise in reproductive abscission was observed in 1978 after a 3-d period when maximum daily temperatures exceeded 34 °C. This early rise in abscission (which did not occur in the cooler 1979 season) was reduced by high irrigation (nodes 6 and 2) and low plant density (node 2). Abscission of flowers at the white bud stage or at anthesis was relatively low. The major portion of reproductive organs were shed after anthesis. High irrigation delayed abscission at both main-stem nodes, thus increasing the proportion of organs which abscised as pods. Low plant density also postponed abscission of reproductive organs at node 2, but had less effect at node 6.Key words: Phaseolus vulgaris L., anthesis, first bloom

Pear, Pest Control with IGR CME 13406, 1986

Abstract Trees in a 25-year-old pear orchard were sprayed by handgun operating at 200 psi. Test plots consisted of 4 single-tree replicates (2 of each variety) arranged in a randomized block. All treatments except the untreated check received a ‘delayed dormant’ spray of Pydrin 2.4EC at 4 oz/100 gal plus 1.5% superior oil and a ‘white bud’ spray of Morestan 2.5WP at 1 lb/100 gal. Three cover sprays of Guthion were timed according to codling moth development (see Washington State University Extension Bull. 1072). Each spray of CME 13406 was applied about 150 to 250 degree-days (base 50°F) earlier than Guthion to coincide with the beginning and peak of egg laying. PP populations were sampled at 2- to 4-week intervals. During May, nymphs were counted on 20 spur leaves/tree (2 leaves/spur). In the 2nd generation and later, terminal leaves were sampled. A top, middle and bottom leaf were collected from each of 6 terminals/tree. Leaves were examined under a stereo microscope. Fruit was evaluated for PP russet and CM damage at harvest. Mite counts were taken by brushing 100 leaves/treatment (25/tree). Leaves were sampled on 3 scaffold limbs from the center to the periphery of the canopy.

Pear, Prebloom Control of Pear Psylla with Pyrethroid Insecticides, Commercial Test, 1986

Abstract One half of a 1.25 acre 35-eyar old commercial pear orchard was treated with Pydrin, the other half with Pounce. Sprays were applied dilute at ‘delayed dormant’ by an Aerofan sprayer delivering 200 gal/acre. Otherwise, the entire orchard received a standard commercial insect and mite control program before and after bloom: Superior oil and flowable sulfur at ‘dormant’ (26 Feb), Morestan at ‘white bud’ (31 Mar), and Guthion at ‘1st cover’ (27 May). Cyprex and Bayleton were applied as needed for disease control. PP populations in the test plots were sampled by beating tray counts of adults (1 tray/tree from 25 trees) and by nymph counts on spur (6 May) and shoot (23 Jun) leaves (108/treatment). Leaves were examined under a stereo microscope. In addition, the proportion of leaves with PP eggs as well as TSSM was also recorded.

Pear, Early Season Pear Psylla Control, 1986

Abstract Experimental sprays were applied to replicated 3-tree plots of 8-year-old Bartlett trees. Each treatment was replicated 5 times. Trees were planted to a spacing of 7.4 x 7.4 m. Treatments were applied with a handgun from a truck-mounted hydraulic sprayer at 375 psi. Dates of application were: bud burst (3 Apr), white bud (19 Apr), and petal fall (6 May). Approximately 2 gal of spray was applied per tree. Treatments were evaluated for PP control by counts of eggs and nymphs at 1 to 2 week intervals. Counts were made by sampling 10 mid-terminal or spur leaves from the middle tree in each replicate. The count on 30 May was made by sampling 5 mid-terminal and 5 distal leaves from each tree. PP pressure was moderate through the experiment.