Periphery Of Tree Research Articles

Apple, Concentrate and Dilute Acaricide Evaluation Test, 1992

Abstract Treatments were applied to single-tree plots in a randomized block design consisting of 3 replicates of ‘Yorking’ and 2 replicates of ‘Golden Delicious’. Trees were planted to a spacing of 20 x 20 ft and were 19 years old. All treatments were applied with a Myers Mity Mist sprayer calibrated to deliver 100 gal/acre, driven at 2 mph, except for HHE-3736 70 WG and Savey 50 WP which were applied dilute to run-off with a high pressure handgun at approximately 4 gal of spray per tree. Application dates varied between treatments and are as listed in the tables. All plots received a regular maintenance schedule of fungicides (captan 50 WP, Nova 40 WP, Penncozeb 80 WP and Topsin 85 DF) and nutrients (Solubor and CaCl). Post-bloom insecticides (Guthion 35 WP, Lannate 1.8 L) were applied at 1- to 2-wk intervals beginning at petal-fall in early May. Effectiveness of treatments on ERM was evaluated by counting mites at approximately weekly intervals during the season on samples of 25 leaves/tree (125 leaves/treatment). Effects of treatments on SP were measured by 3 minute counts of adults and larvae around the periphery of trees. Russet ratings are based on 30 ‘Golden Delicious’ apples/replicate, 60/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 are 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).

Influence of tree growth on spray chemical deposits on peach leaves

SUMMARYA 50–fold increase in peach tree growth over a 98-day spraying season resulted in a 64 and 96% reduction in nigrosine dye deposit in the periphery and centre of the tree, respectively. Drift from spraying of adjacent rows made a significant contribution (18–39%) to the total chemical deposit in the tree periphery in four of six applications. Drift between rows was not a factor in centre tree deposit, except for a 38% contribution in the initial application. A variable reduced application rate of methyl parathion, calculated using a regression equation, resulted in a more uniform deposit throughout the season than a full application rate, providing comparable control of Oriental fruit moth withc. 50% less insecticide.

Apple, Airblast Insect Experiment, 1991

Abstract Experimental sprays were applied to 3 tree plots in a randomized block design consisting of 3 replicates of'Yorking' and 2 replicates of'Golden Delicious' with a buffer row between blocks. These trees were planted to a spacing of 20 × 30 ft and were 16-yrs-old. Experimental sprays were applied with a Friend Airmaster '309' at 50 gpa per alternate side spray (100 GPA-both sides) driven at 2.3 mph. Rates for treatments are listed as amounts/acre/both sides spray. The Diazinon/Insegar treatment received complete sprays for all covers and the RH-5992 treatments received complete sprays on 22 May and 15 Jul. A routine schedule of fungicides (Benlate, Dikar, Nova, and Dithane M-45) was maintained throughout the experiment. For a complete schedule of all treatments, see the first table. Effectiveness on the aphid complex was evaluated by counting aphid-infested leaves/10 top terminals, and aphids/most infested leaf. Effect of sprays on WALH was evaluated by counting nymphs/25 injured leaves/tree. Effectiveness of test chemicals on ERM was evaluated by counting mites several times during the season on samples of 25 random leaves/tree, 100 leaves/treatment. Effect of sprays on the predator S. punctum was evaluated by 3-min counts of adults and larvae around the periphery of test trees. STLM were evaluated by a 5- min count of mines around the periphery of trees at the end of each of the three generations before peak emergence of the next generation adults. TABM were also evaluated with a similar 5-min count of shelters on 11 Jul during the first generation when most larvae were late fourth and fifth instars. Effectiveness of chemicals on fruit feeders was assessed by scoring for injury all drops between 3 Jul and 1 Sep and two picked samples on 21 Aug (35 apples/replicate) and 24 Sep (100 apples/replicate). All lepidopteran larvae from one replicate of each treatment that were found at the time of scoring were placed singly on an artificial lima diet normally used for rearing TABM. These larvae were then reared to adults in sealed 22 ml plastic cups at 25°C and 16:8 LD. Adults were identified to species and parasites noted to give an indication of the proportion of species attacking the apples at various times of the season. Pest pressure was extremely high throughout the season. 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 are 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).

Apple, Dilute Insecticide Experiment, 1991

Abstract Experimental sprays were applied to run-off to single-tree plots in a randomized block design consisting of 2 replicates of'Golden Delicious' and 2 replicates of'Yorking'. Treated single trees were separated by others not sprayed with insecticides. The trees were planted to a spacing of 20 × 35 ft and were 35-yrs-old. Sprays were applied with a John Bean sprayer, 35 gpm pump, equipped with a spray mast carrying 7 spray guns arranged to wet to run-off the uniformly trimmed trees. Approximately 6.0 gallons of spray were applied per replicate tree (ca 400 GPA). Refer to the first table for application dates. Applications for Exp. Comp. 1 and 2 were timed for CM control based on pheromone trap catches and a degree day based computer predictive model. The first two treatments of Exp. Comp. 1 and 2 received Guthion applications at petal-fall (15 May) and 4th cover (9 Jul) to lessen OFM damage that might mask CM damage. The last two treatments of Exp. Comp. 1 and 2 were optimally timed single applications for peak egg deposition of each CM generation. Effectiveness on the aphid complex was evaluated by counting aphid-infested leaves/10 top terminals, and aphis/most infested leaf. Effect of sprays on WALH was evaluated by counting nymphs/25 injured leaves/tree. Effectiveness of test chemicals on ERM was evaluated by counting mites several times during the season on samples of 25 random leaves/tree, 100 leaves/treatment. Effect of sprays on the predator S. punctum was evaluated by 3-min counts of adults and larvae around the periphery of test trees. STLM was evaluated by a 5-min count of mines around the periphery of trees at the end of each of the three generations before peak emergence of the next generation adults. TABM were also evaluated with a similar 5-min count of rolled leaf shelters on 11 Jul during the first generation when most larvae were late fourth and fifth instars. Effectiveness of chemicals on fruit feeders was assessed by scoring for injury all dropped apples from 1 Jul to 28 Aug and picked samples of 25 fruit/tree on 9 Aug and 35 fruit/tree on 20 Aug. A final harvest pick evaluation of 120 fruit/tree was made on 18 Sep. All internal lepidopteran larvae from one replicate of each treatment at each drop and pick evaluation date were placed singly on an artificial lima diet normally used for rearing TABM. These larvae were then reared to adults in sealed 22 ml plastic cups at 25°C and 16:8 LD. Adult lepidoptera were identified to species and parasites were noted to give an indication of the proportion of species attacking apples at various times of the season. Lepidoptera pest pressure was extremely high throughout the season. 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 are 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).

Insecticide Evaluation, 1991

Abstract This experiment was conducted in a 5.4 acre block of 37-yr-old trees, which measured 16.5 ft in height and 23 ft in width and were planted at a spacing of 20 × 40 ft. The experimental design consisted of 6 single-tree plots (3 'Rome Beauty,' 3 'Golden Delicious') in a randomized block design. Insecticides were applied with a Swanson DA500A airblast sprayer, which traveled at 2.4 mph and delivered a spray volume of 100 gal/acre. Dates of application were 2 Apr (delayed dormant [DD]), 9 Apr (prepink [PP]), 8 May (petal fall [PF]), 21 May (first cover [1C]), 31 May (second cover [2C]), 13 Jun (third cover [3C]), 27 Jun (fourth cover [4C]), 16 Jul (fifth cover [5C]), 30 Jul (sixth cover [6C]), 12 Aug (seventh cover [7C]), and 29 Aug (eighth cover [8C]). Other materials applied separately to all treatments were Agristrep, Bordeaux mixture, Captan, Dodine, NAA, Nova, Rubigan, Solubor, and Topsin-M. Control of RAA was evaluated by counting colonies/tree. Effect of treatments against SA was determined by counting aphids on the most infested leaf on each of five terminals/tree around the periphery of'Rome Beauty.' Control of WALH and RLH was evaluated by counting nymphs on 25 leaves selected from the periphery of trees. Treatment effect against STLM was determined by counting mines observed in 5 minutes around the periphery of trees. Control of fruit-feeding insects was determined by scoring for injury 600 picked apples/treatment (100/replication) plus up to 600 drop apples/ treatment (up to 100/replication) sampled on 17 Sep. Fruit picked from 'Golden Delicious' trees were rated for finish as 0 (no russet), 1 (enlarged and raised lenticels), 2 (1-10% russeted surface), 3 (11-25% russeted surface), 4 (26-50% russeted surface), or 5 (>50% russeted surface).

Insecticide Evaluation, 1990

Abstract This experiment was conducted in a 5.4 acre block of 36-yr-old trees, which measured 16.5 ft in height and 23 ft in width and were planted at a spacing of 20 × 40 ft. The experimental design consisted of 6 single-tree plots (3 Rome Beauty,' 3 Golden Delicious) in a randomized block design. Insecticides were applied with a Swanson DA500A airblast sprayer, which traveled at 2.4 mph and delivered a spray volume of 300 gal/acre at the delayed dormant stage and 100 gal/acre for the remainder of the season. Dates of application were 22 Mar (delayed dormant [DD]), 5 Apr (prepink [PP]), 14 May (petal fall [PF]), 31 May (first cover [1C]), 14 Jun (second cover [2C]), 28 Jun (third cover [3C]), 16 Jul (fourth cover [4C]), 27 Jul (fifth cover [5C]), 13 Aug (sixth cover [6C]), 28 Aug (seventh cover [7C]) and 6 Sep (eighth cover [8C]). Other materials applied separately to all treatments were Agristrep, Benlate, Captan, Dithane Z-78, Folpet, Manzate 200, NAA, Nova, Polyram, Rubigan, Solubor, Topsin-M, and Zineb. Control of SA was evaluated by counting infested leaves on each of 10 terminals and aphids on the most infested leaf/terminal around the periphery of each tree. The effect of treatments on WALH was determined by counting nymphs on 25 leaves selected from the periphery of each tree. Control of STLM was evaluated by counting mines observed in a 5 min search around the periphery of each tree. Treatment effect on ERM was determined by sampling 33 leaves from the periphery of each 'Rome Beauty' tree, removing mites with a mite-brushing machine, and counting active stages with a binocular microscope. Impact of treatments on SP was determined by counting adults and larvae observed in 3 min counts around the periphery of test trees. Control of fruit-feeding insects was determined by scoring for injury 600 apples/treatment (100/replication) plus all fallen apples sampled on 26 Sep. Fruit picked from Golden Delicious' trees were rated for finish on a scale of 0 - 5 ; 5 being worst.

Acaricide Evaluation Experiment I, 1990

Abstract This test was conducted in a 1/3 acre block of 5-yr-old 'Redchief trees on M26, which measured 10.5 ft in height and 6.5 ft in width and were planted at a spacing of 10 × 15 ft. The experimental design consisted of 4 single-tree plots in a randomized block design, with each replicate surrounded by at least one unsprayed tree on each side. Acaricides were applied to runoff on 3 Jul with a handgun attached to a Durand-Wayland 100 LTS sprayer operated at 100 psi. Each tree received approximately 0.5 gal of spray (ca. 145 gal/acre). Other materials applied separately to all treatments were Agristrep, Asana, Benlate, Captan, Dimethoate, Guthion, Lannate, Manzate 200, Nova, Oil, Penncap-M, Polyram, Rubigan, Sevin, Solubor, Topsin-M, and Zineb. ERM control was evaluated by sampling 25 leaves from the periphery of each tree, removing mites with a mitebrushing machine, and counting active stages with a binocular microscope. The effect of treatments on S. punctum was determined by counting adults and larvae observed in 3 min counts around the periphery of test trees.

Acaricide Evaluation Experiment II, 1990

Abstract This test was conducted in a 0.6 acre block of 11-yr-old 'Topred' trees on MM106, which measured 14 ft in height and 10 ft in width and were planted at a spacing of 14 × 14 ft. The experimental design consisted of 4 single-tree plots in a randomized block design, with each replicate surrounded by at least one unsprayed tree on each side. Acaricides were applied to runoff on 19 Jun and 17 Jul with a handgun attached to a Durand-Wayland 100 LTS sprayer operated at 100 psi. Each tree received approximately 1.5 gal of spray (ca. 333 gal/acre). Other materials applied separately to all treatments were Agristrep, Benlate, Captan, Dimethoate, Dithane Z-78, Guthion, Lannate, Lorsban, Nova, Oil, Penncap-M, Polyram, Rubigan, Sevin, Solubor, Topsin-M, and Zineb. European red mite control was evaluated by sampling 25 leaves from the periphery of each tree, removing mites with a mite-brushing machine, and counting active stages with a binocular microscope. The effect of treatments on S. punctum was determined by counting adults and larvae observed in 3 min counts around the periphery of test trees.

Mid-Summer Mite Control on Apple, 1989

Abstract Four miticides were compared for efficacy against ERM and for impact on mite predators inhabiting semidwarf 'Empire' trees at Guilford, Conn. Single-tree plots were arranged in a randomized complete block design, with 4 replicates/treatment. Omite, Kelthane, Carzol, Vendex, and water (control) were applied dilute to runoff on 11 Jul with a Solo Master 412 mistblower capable of delivering a maximum of 590 m3/h. The orchard was sprayed throughout the growing season, with Captan and Penncap M applied on 20 Jul and Captan and Benlate on 29 Jul. Densities of ERM and A. fallacis were measured prior to treatments on 10 Jul and after treatments on 14 Jul, 20 Jul, and 1 Aug by collecting single leaves randomly from 20 vigorously growing shoots/tree. Active stages were counted with a Zeiss stereoscope. Abundance of S. punctum was assessed by making 3-min counts of adults and pupae located around the periphery of trees.

Apple, Insecticide Evaluation, 1986

Abstract Insecticides were applied to 5 single-tree plots (3 ‘Rome Beauty', 2 ‘Golden Delicious') of 32-year-old trees in a randomized block design. Applications were made with a Swanson DA500A airblast sprayer which traveled at 3.86 k/hr and delivered 935 1/ ha. Dates of application were 3 Apr [delayed dormant (DD)], 12 Apr [pre-pink (PP)], 5 and 6 May [petal fall (PF)], 19 May [first cover (1C)], 3 Jun [second cover (2C)], 13 Jun [third cover (3C)], 27 and 28 Jun [fourth cover (4C)], 11 Jul [fifth cover (5C)j, 28 Jul [sixth cover (6C)], 10 and 11 Aug [seventh cover (7C)] and 24 and 25 Aug [eight cover (8C)]. Other materials applied separately to all treatments were Benlate, Bordeaux mixture, Captan, Dithane M-45, Manzate 200, Polyram, Solubor and Streptomycin. Effect of treatments on RAA was determined by counting colonies on the periphery of each tree. AA control was determined by counting infested leaves on each of 10 top terminals and AA/most infested leaf/terminal for each tree. Effect of treatments on ERM was determined by sampling 20 leaves from the periphery of each tree, removing mites with a mite-brushing machine and counting active stages with a binocular microscope. Treatment effect on SP was determined by counting adults and larvae on the periphery of test trees observed during a 3-minute period. Control of WALH was evaluated by counting nymphs found on 25 leaves selected from the periphery of each tree. Treatment effectiveness on fruit feeding insects was determined by scoring for injury 500 apples per treatment (100/replication) plus all fallen apples sampled on 18 Sep. Fruit picked from ‘Golden Delicious’ trees were rated for finish (1-9 worst).

Apple, Acaricide Evaluation, 1986

Abstract Acaricides were applied to 4 single-tree replicates of 32-year-old trees in a randomized block design. Applications were made with a Swanson DA500A airblast sprayer which traveled at 3.86 k/hr and delivered 935 1/ha. Dates of application were 14 Apr [pink (P)] and/or 6 May [petal fall (PF)] and 11 Jul, or 27 Jun, depending upon treatment. Other materials applied separately to all treatments were Benlate, Bordeaux mixture, Captan, Dithane M-45, Manzate 200, Polyram, Solubor and Streptomycin. ERM control was evaluated by sampling 25 leaves from the periphery of each tree, removing mites with a mite-brushing machine and counting active stages with a binocular microscope. Treatment effect on SP was determined by counting adults and larvae on the periphery of test trees observed during a 3-minute period.

Apple, Eup Evaluation of a New Formulation of Plictran, 1986

Abstract The trial was conducted in a 12 acre commercial apple orchard in the Buchanan Valley near Arendtsville, PA. The block was further divided into two 6 acre blocks. One block was treated with XRM-4868 5F (Plictran 5F), the other with Plictran 50WP. Seven ‘York Imperial’ apple trees were randomly selected in each block for monitoring. Treatments were applied using the alternate-row middle technique with a Myers airblast sprayer calibrated to deliver 50 gal/acre at 2 mph. Spray dates for Plictran treatments were 11 and 18 Jul, 1 Aug. Amounts are listed as complete sprays. If only one half was applied, reduce amounts by one half. All blocks received the same insecticide and fungicide schedule. The effect of sprays on ERM was evaluated by counting mites on samples of 25 leaves/tree (7 trees/treatment). The mite predator S. punctum was monitored by making 3 min counts of adults and larvae around the periphery of trees.

Apple, Insecticide Evaluation, 1985

Abstract Insecticides were applied to 4 single-tree plots of 33-year-old trees in a randomized block desgn. Applications were made with a Swanson DA400PT024 airblast sprayer which traveled at 3.86 k/hr and delivered 2805 1/ha at the delayed dormant and pre-pink stages, and 935 I/ha for the remainder of the season. Dates of application were 8 Apr [delayed dormant (DD)], 13 Apr [pre-pink (PP)1, 6 May [petal fall (PF)], 20 May [first cover (1C)], 3 Jun [second cover (2C)], 17 Jun [third cover (3C)], 3 Jul [fourth cover (4C)], 17 Jul [fifth cover (5C)], 1 and 2 Aug [sixth cover (6C)], 21 Aug [seventh cover (7C)], 3 Sep [eighth cover (8C)]. Other materials applied separately to all treatments were Benlate, Captan, Dikar, Dithane M-45, Dithane Z-78, Solubor, Streptomycin and Topsin-M. Treatment effectiveness was determined for AA by counting infested leaves on 10 top terminals and aphids/most infested leaf/terminal for each tree. Effect of treatments on ERM was determined by sampling 25 leaves from the periphery of each tree, removing mites with a mite-brushing machine and counting active stages with a binocular microscope. Treatment effect on Stethorus punctum was determined by counting adults and larvae on the periphery of test trees observed during a 3-minute period. Control of STLM was evaluated by counting mines observed in 5 min while walking around the periphery of each tree. The effect of treatments on WALH was determined by counting nymphs found on 25 leaves selected from the periphery of each tree. Treatment effectiveness on fruit feeding insects was determined by scoring for injury 400 apples per treatment (100/replication) plus all fallen apples sampled on 24 Sep.

Apple, Summer Acaricide Evaluation, 1985

Abstract Acaricides were applied to single-row plots of 32-year-old trees on 26 Jun. Appli-cation was with a Swanson DA400PT024 airblast sprayer delivering 935 1/ha at a travel speed of 3.86 k/hr. Treatment effect on European red mite was determined by sampling 20 leaves from the periphery of each of 5 trees, removing mites with a mite-brushing machine and counting active stages with a binocular microscope. The effect of acaricides on Stethorus punctum was evaluated by counting the number of adult and larval stages observed during a 3-minute period while walking around the tree periphery.

Apple, Insecticide Evaluation, 1984

Abstract Insecticides were applied to 4 single-tree plots in a randomized block design, using a Swanson DA400PTO24 airblast sprayer. The sprayer traveled at 3.86 kph and delivered 2805 liters/ha for delayed dormant and pre-pink applications, and 935 liters/ ha for the remainder of the season. Dates of application were 20 Apr (delayed dormant (DD)), 1 May (pre-pink (PP)), 24 May (petal fall (PF)), 6 Jun (first cover (1C)), 18 Jun (second cover (2C)), 3 Jul (third cover (3C)), 24 Jul (fourth cover (4C)), 9 Aug (fifth cover (5C)), 23 and 24 Aug (sixth cover (6C)), and 6 Sep (seventh cover (7C)). In the Imidan + Lannate alternate middle applications (beginning at first cover), the west side of trees was treated on the dates above, and the east side was treated on 14 Jun (first cover), 28 Jun (second cover), 12 Jul (third cover), 2 Aug (fourth cover), 16 Aug (fifth cover), 30 Aug (sixth cover) and 12 Sep (seventh cover). Other materials applied separately to all treatments were Baycor, Benlate, Captan, Dithane M-45, Polyram, Streptomycin and Topsin-M. Treatments were evaluated for RAA control on 31 May by counting colonies observed on the periphery of trees. Treatment effectiveness was determined for AA on 9 Jul by counting infested leaves on 10 top terminals and aphids/most-infested leaf/terminal. Control of WALH was determined on 6 Jun by counting nymphs found on 25 leaves selected from the periphery of each tree. Effect of treatments on ERM was determined on 2 Aug by sampling 25 leaves from the periphery of each tree, removing mites with a mite-brushing machine and counting active mites with a binocular microscope. Treatment effect on SP was determined on 7 Aug by counting adults and larvae observed during a 3-min period on the periphery of test trees. Treatment effectiveness on fruit feeding insects was determined by scoring for injury 400 apples per treatment (100/replication) plus all fallen apples sampled on 25 Sep.

Apple, Alsystin Test, 1984

Abstract Plots consisted of unreplicated 0.5 acre blocks containing the cultivars York Imperial and Golden Delicious. Pest and predator samples were taken from 6 tagged trees per block. Experimental sprays were applied with a Myers Mity Mist airblast sprayer calibrated to deliver 50 gpa. Applications were made on alternate row middles every 7 to 11 days. Spray dates were: 5, 13, 22, 29 Jun; 10, 20, 31 Jul; 10, 20, 29 Aug. Captan was added to experimental sprays to control diseases. Average temperatures were: Jun 70.3° F, Jul 71.3° F, Aug 72.6° F, and Sep 60.9° F. Rainfall in inches totaled: Jun 4.42, Jul 5.86, Aug 7.33, and Sep 1.11. Effectiveness on AA was evaluated by counting aphid-infested leaves on 20 terminals around the periphery of the tree. Effectiveness of test chemicals on ERM, TSSM and AF was evaluated by counting mites several times during the season on samples of 25 leaves/tree, 150 leaves/treatment. Effect of sprays on S. punctum was evaluated by 3-min counts of adults and larvae around the periphery of test trees. Effectiveness of chemicals on tufted apple budmoth was assessed by scoring for injury one pick sample at harvest (both cultivars). Apple samples averaged 1200 apples per treatment. Pest pressure was moderate throughout the season. Alsystin provided better control of TABM than standard materials, but poorer control of AA. There was no apparent effect oh phytophagous or predatory mite species, however, populations of the coccinellid predator S. punctum were suppressed by Alsystin used in a seasonal schedule.

Apple, Summer Pest Control, 1984

Abstract Sprays were applied to 4- or 5-tree plots in a randomized block design consisting of 5 replicates of each treatment. Each plot consisted of alternating Golden Delicious and York Imperial trees. Treatments were applied with a Friend Airmaster 393 sprayer driven at 2 mph using the alternate side technique of spraying (75 gpa/full spray). Rates for treatments are listed as amounts/acre/both sides spray. Application dates were: 7, 14, 21, 29 Jun; 9, 16, 23, 30 Aug; 6 Sep. Treatments which included Pydrin or Payoff were not applied on 6 Sep. Plictran 50WP (142 g/acre) plus Carzol 92SP (142 g/acre) was applied to all treatments on 19 Jul. Guthion 50WP (340 g/acre) was applied to all treatments on 31 Jul. Average temperatures were: Jun 70.3° F, Jul 71.3° F, Aug 72.6° F and Sep 60.9° F. Rainfall in inches totaled: Jun 4.42, Jul 5.86, Aug 7.33, and Sep 1.11. Effect of treatments on ERM was evaluated by counting mites several times during the season on samples of 20 leaves/tree (cv. York only), 100 leaves/treatment. Effect of sprays on the mite predator SP was evaluated by 3-min counts of adults and larvae around the periphery of test trees. Effectiveness on AA was evaluated by counting aphid-infested leaves on 20 terminals around the upper periphery of the tree. Effectiveness of chemicals on fruit feeders was assessed by scoring for injury all drops (Yorks only) after 1 Jul and 1 pick sample at harvest (Golds and Yorks). Apple samples averaged 222 fruits/replicate and 1110/treatment. Pest pressure was moderate throughout the season.

Apple Insecticide Evaluations, 1983

Abstract Insecticides were applied to trees in four single-tree replications in a randomized block design, using a Swanson DA400PT024 airblast sprayer. The sprayer traveled at 1.07 m/sec and delivered 2805 1/ha for delayed dormant and pre-pink applications, and 935 1/ha for the remainder of the season. Dates of application were 13 Apr. (delayed dormant (DD)), 28 Apr. (pre-pink (PP)), 11 and 12 May (petal fall (PF)), 27 May (first cover (lc)), 13 June (second cover (2C)), 25 and 28 June (third cover ((3C)), 12 July (fourth cover (4C)), 28 July (fifth cover (5C)), 15 Aug. (sixth cover (6C)), and 30 and 31 Aug (seventh cover (7C)). Baycor 50WP and Streptomycin were also applied separately to all treatments. Trees were evaluated for rosy apple aphid control on 1 and 2 June by walking around the periphery of the trees and counting colonies. Treatment effectiveness was determined for apple aphid on 1 and 2 June by counting infested leaves on each of 20 terminals (10 from each sprayed side) around the periphery of trees at a height of 1.8 m. Control of white apple leafhoppers was determined by counting nymphs found on 25 leaves selected from outside of each tree. Effects of treatments on European red mites were determined by sampling 25 leaves from the periphery of each tree, removing mites with a mite-brushing machine and counting active mites with a binocular microscope. Effects on Stethoruspunctum were determined by counting adults and larvae observed during a 3-min period while walking around the tree periphery. Treatment effectiveness on fruit feeders was determined by scoring for injury 400 apples per treatment (100 per replication), plus all fallen apples found from 19-21 Sept.

Seasonal Changes in Specific Leaf Weight, Net Photosynthesis, and Chlorophyll Content of Peach Leaves as Affected by Light Penetration and Canopy Position

Abstract Diffuse photon flux density of photosynthetically active radiation (PAR) was measured throughout the season in peach trees [Prunus persica (L.) Batsch. cv. Harken] trained to an open center. Penetration of PAR generally decreased as shoot extension continued through the season. PAR was greater at the tree periphery and center than midway between the 2 points. PAR also decreased from the upper levels to the lower levels of the tree canopy. Specific leaf weight (SLW) at all positions increased from early June until August. SLW generally followed the same pattern as PAR, with lowest SLW developing midway between the tree periphery and center. Net photosynthesis (Pn) was greatest for peripheral leaves, lowest for leaves midway into the tree, and intermediate for leaves from the tree center. Pn and SLW were linearly correlated. Leaves developing at different distances from the tree center had similar stomatal resistances. There was no consistent influence of canopy position on chlorophyll content, but interior leaves tended to have greater chlorophyll content than peripheral leaves.

Apple, Ovicidal Effects of Lannate-L, 1979

Abstract Egg masses of females of P. flavedana from the overwintering and first generation were treated with Lannate L to assess ovicidal activity. Lannate L (dilute rate of 0.95 liter/378.5 liter = 2 pt/100 gal) was applied as a 6X concentrate (467.69 liter/ha) with a Swanson truck-mounted airblast sprayer operating at 7.04 kg/cm . On Jun 14 egg masses of the overwintering generation (Experiment 1) were collected from Red Delicious trees with their associated leaf clusters and taped to other Red Delicious trees in an optimum position for spray coverage (outer periphery of tree facing spray). Following spraying and 15 minutes' drying, clusters were returned to an open-air insectary. They were maintained in ventilated, 50-dram, clear plastic cages until egg hatch. Similar water-treated controls were established. On Jul 27 egg masses of the first generation females (Experiment 2) were located on Red Delicious trees in the same orchard as Experiment 1, tagged for identification, and sprayed in their natural positions on the tree. Only one side of the tree was sprayed. The egg masses were left on the tree to hatch. Water controls were treated in a similar manner. There were 15 replicates of the Lannate L treatment in Experiments 1 and 2 and there were 17 and 12 replicates of the water control for Experiment 1 and 2, respectively. Data were collected as percent hatch. The effects of Lannate L on the eggs of two important orchard insect and mite predators, O^ insidlosus and L. mali were assessed (Experiment3). L. mali females were allowed to oviposit on mite-infested apple leaves in the laboratory. Leaves (with the eggs in situ along the leaf midvein) were dipped in the appropriate concentration of Lannate L or a water control. The leaves were maintained with their petioles in water for 5 da, after which the eggs were transferred to moist filter paper in a petri dish held at 23.9 ± 1°C. Eclosion was recorded for 10 da.O. insidiosus oviposits eggs in the leaf midvein with only the operculum exposed. preliminary studies showed high mortality of controls due to shrinkage of the leaf midvein.To circumvent this O. insidiosus was allowed to oviposit in green bean pods which did not shrink. The pods were then dipped and hatch was recorded over a 14-do period. Data for J., moli and (X jnsidiosus were recorded as percent hatch.