scholarly journals Severity of Scab and its Effects on Fruit Weight in Mechanically Hedge-Pruned and Topped Pecan Trees

Plant Disease ◽  
2017 ◽  
Vol 101 (5) ◽  
pp. 785-793 ◽  
Author(s):  
Clive H. Bock ◽  
Michael W. Hotchkiss ◽  
Tim B. Brenneman ◽  
Katherine L. Stevenson ◽  
William D. Goff ◽  
...  
Keyword(s):  
United States ◽  
Shoot Growth ◽  
Southeastern United States ◽  
Fruit Weight ◽  
Tree Size ◽  
Mature Fruit ◽  
Air Blast ◽  
Sample Height ◽  
Tree Canopies

Scab is the most damaging disease of pecan in the southeastern United States. Pecan trees can attain 44 m in height, so managing disease in the upper canopy is a problem. Fungicide is ordinarily applied using ground-based air-blast sprayers. Although mechanical hedge-pruning and topping of pecan is done for several reasons, improved management of scab is an important reason in the humid, wet Southeast. Resulting shoot growth on cut limbs of susceptible cultivars could lead to more severe scab. In three experiments over three years, we explored the effect of hedge-pruning trees to ∼12 to 14 m compared with non-hedge-pruned trees. All trees received fungicide treatments (air-blast sprays and ≤3 aerial applications). Hedge-pruning either had no effect, or increased or decreased scab severity only slightly on leaflets, immature, or mature fruit (a –9.95 to +14.63% difference in scab severity compared with the control). However, height in the canopy invariably had a large and significant effect on scab severity, and amounted to a 0.05 to 73.77% difference in severity between the lowest and highest sample in the canopy. Fruit weight depended on sample height, with fruit most often weighing less when collected at greater sample heights. A robust relationship between fruit weight and scab severity was found at the highest sample heights where scab was also most often severe (R2 = 0.21 to 0.67, P < 0.0001). Hedge-pruning and topping pecan tree canopies to manage tree size will enable better fungicide coverage, reducing risk of a scab epidemic as more of the canopy is assured efficacious fungicide spray coverage.

scholarly journals The Effect of Tractor Speed and Canopy Position on Fungicide Spray Deposition and Peach Scab Incidence and Severity

Plant Disease ◽  
2020 ◽  
Vol 104 (7) ◽  
pp. 2014-2022
Author(s):  
Clive H. Bock ◽  
Glen C. Rains ◽  
Mike W. Hotchkiss ◽  
Chunxian Chen ◽  
Phil M. Brannen
Keyword(s):  
United States ◽  
Disease Control ◽  
Active Ingredient ◽  
Spray Deposition ◽  
Southeastern United States ◽  
Sample Height ◽  
Canopy Position ◽  
Lesion Number ◽  
All Speeds ◽  
Negative Linear Relationship

Peach scab, caused by Venturia carpophila, is a damaging disease of peach in the southeastern United States. Thus, fungicides are applied to reduce peach scab. Tractor speed was investigated as a variable affecting spray deposition and disease control in relation to volume applied. In experiments in 2015 and 2016, trees were sprayed with fungicide to control scab at petal fall to 1% shuck split and at shuck split to 10% shuck off. Speeds were 3.2, 4.8, and 6.4 kph resulting in 1,403, 935, and 701 liters/ha, respectively, with the dose of active ingredient (a.i.) per ha kept constant. Deposition declined for all speeds with later spray dates. There was a negative linear relationship between tractor speed and spray coverage on three of four dates the experiment was repeated. Tractor speed (different volumes, equal doses) affected peach scab. In 2015 and 2016, mean incidence at 3.2, 4.8, and 6.4 kph was 68.6, 59.2, and 38.3%, and 64.2, 53.0, and 40.4% of fruit scabbed, respectively. Effect of speed on lesion number per fruit depended on year: in 2015, lesions per fruit were reduced at 6.4 kph compared with 3.2 and 4.8 kph but were not different in 2016. Control trees had fewer lesions per fruit high in the canopy, but there was little effect of sample height in fungicide-treated trees. Concentration of a.i. in lower volumes applied at higher speed may provide some benefit in reducing incidence of peach scab, but there appeared to be less effect on severity.

scholarly journals Physiological Changes during Maturation, Ripening, and Storage of Asian Pears Grown in Southeastern United States

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 816G-817
Author(s):  
Nihal Rajapakse ◽  
William C. Newall
Keyword(s):  
United States ◽  
Ethylene Production ◽  
Southeastern United States ◽  
Fruit Size ◽  
Physiological Changes ◽  
Mature Fruit ◽  
Immature Fruit ◽  
Early Maturation ◽  
Nonclimacteric Fruit ◽  
Harvest Maturity

Morphological and physiological changes during maturation and ripening of eight Asian pear cultivars grown in the southeastern United States were evaluated. Fruit size increased throughout maturation. Flesh firmness decreased as fruit matured and averaged ≈30 to 35 N at harvest maturity. The average TSS in mature fruit ranged from 10% to 13%, with `Shinko' having the lowest and `Shinsui' having the highest. TSS increased during 4 weeks of storage at 1C, but the increase was greater in immature fruit than in mature fruit. Respiration rate declined as fruit matured. Ethylene production was low in `Hosui', `Kosui', `Nijisseiki', `Shinseiki', `Chojuro', and `Shinko' fruit. Mature `Ichiban' and `Shinsui' fruit produced high amounts of ethylene. `Kosui', `Shinsui', `Chojuro', and `Ichiban' fruit showed a climacteric rise in respiration and ethylene production at 20C, while `Hosui', `Nijisseiki', `Shinseiki', and `Shinko' behaved as nonclimacteric fruit. Ethylene production by 1C-stored `Kosui', `Shinsui', `Chojuro', and `Ichiban' fruit was increased on removal to 20C. Glucose and fructose were low during early maturation but sharply increased ≈80 to 85 days after full bloom (DAFB). Sucrose was low in immature fruit but accumulated rapidly late in maturation ≈100 to 107 DAFB. In mature `Hosui', `Kosui', `Nijisseiki', `Shinsui', `Shinko', and `Ichiban' fruit, fructose was the predominant sugar, while in `Shinseiki' and `Chojuro' fruit, sucrose was the predominant sugar.

scholarly journals Mechanical Hedge Pruning of Pecan in a Relatively Low-light Environment

HortScience ◽  
2009 ◽  
Vol 44 (1) ◽  
pp. 68-72 ◽  
Author(s):  
Bruce W. Wood
Keyword(s):  
United States ◽  
Southeastern United States ◽  
Carya Illinoinensis ◽  
Alternate Bearing ◽  
Low Light ◽  
Tree Canopies ◽  
Interior Zone ◽  
Dormant Season ◽  
Annual Summer

Long-term productivity of commercial pecan [Carya illinoinensis (Wangenh.) K. Koch] enterprises in relatively low-light environments such as the southeastern United States are limited by excessive tree crowding as orchards age. An effective horticultural strategy for countering this problem in relatively high-light environments is mechanical hedge-type pruning; however, uncertainty persists regarding the best strategies in low-light environments. This report describes the results of a 4-year study regarding the response of ≈25-year-old ‘Desirable’ pecan trees to different mechanical hedgerow-type, moderate canopy width (i.e., 2.43-m cuts from tree axis) pruning strategies. Canopy treatments were nonpruned control (NPC), annual dormant season side-hedge pruning on two faces, annual summer season side-hedge pruning on two faces, and alternating annual dormant season side-hedge pruning on a single alternating face. Relative to the NPC treatment, all three pruning strategies: 1) reduced in-shell nut yields by roughly 19% to 38%; 2) reduced marketable nut-meat yield by ≈19% to 36%; 3) failed to stimulate shoot development or fruiting within the central interior zone of tree canopies; 4) increased kernel percentage of nuts; 5) increased nut-meat grade; 6) substantially reduced alternate bearing intensity (I = 0.51 to ≈0.20); and 7) reduced orchard crowding. Pruning-associated reductions in nut yield appear sufficient to limit the commercial usefulness of annual or biennial mechanical hedgerow-type pruning of ‘Desirable’ pecan orchards at moderate canopy widths in relatively low-light environments such as the southeastern United States.

Does Enhancing Mind Perception Affect Conspiracy Belief?

2019 ◽  
Author(s):  
Jorge Noguera
Keyword(s):  
United States ◽  
Southeastern United States ◽  
Social Discourse ◽  
Psychological Processes ◽  
Social Psychological ◽  
Conspiracy Theories ◽  
Mind Perception ◽  
Mixed Anova ◽  
Interaction Term ◽  
The Mind

This study was conducted to determine the effectiveness of a novel mind perception manipulation. Mind perception is currently theorized to be an essential aspect of a number of human social psychological processes. Thus, a successful manipulation would allow for the causal study of those processes. This manipulation was created in an attempt to explore the downstream impact of mind perception on the endorsement of conspiracy theories. Conspiracy theories are steadily becoming more and more prominent in social discourse. Endorsement of conspiracy theories are beginning to show real world ramifications such as a danger to human health (e.g., in the anti-vaccination movement). A sample of college students (valid N = 53) from a large rural institution in the southeastern United States participated for course credit. These participants completed a mind perception pretest, were randomly assigned to either the manipulation in question (in which participants are asked to consider the ‘mind’ of several targets and write their thoughts about them) or the control condition, and then they completed a posttest. The mixed ANOVA revealed that the interaction term between Time and Condition was not significant. Because the manipulation did not work, other analyses were aborted, in accord with the pre-registration. My Discussion focuses on the procedures and potential shortcomings of this manipulation, in an effort to lay the groundwork for a successful one.

Selected fluvial monazite deposits in the southeastern United States

1971 ◽  
Author(s):  
William C. Overstreet ◽  
A.M. White ◽  
P.K. Theobald ◽  
D.W. Caldwell
Keyword(s):  
United States ◽  
Southeastern United States
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