scholarly journals California Red Scale Pesticide Efficacy Trials, 1994

1996 ◽  
Vol 21 (1) ◽  
pp. 75-76
Author(s):  
E. E. Grafton-Cardwell ◽  
C. A. Reagan

Abstract Efficacy of two insect growth regulators (IGR) for the control of California red scale (CRS) were compared to an organophosphate insecticide. Additionally, the effects of the treatments on parasitism by Aphytis melinus and Comperiella bifasciata were evaluated. Insecticides were applied to CRS infested 11 yr old ‘Washington navel’ orange trees at the Lindcove Research and Extension Center, Exeter, California. Seven treatments included a water control, Supracide 2E applied once, CGA 59205 (an IGR) applied once at 20.0 gm(ai), and applied twice at 30.0 gm(ai), S-71639 (an IGR) applied twice both alone and in combination with 0.5% Volck Supreme Spray oil, and 0.5% Volck Supreme Spray oil applied twice. Treatments were assigned based on laboratory evaluation of population densities of live 1st and second instar males and females as well as third instar and gravid females on five randomly selected twig samples (2nd year growth) per tree. Treatments were applied to single trees and replicated 10 times. All treatment applications were timed for emergence of 1st generation CRS crawlers; four of the treatments were reapplied when the 2nd generation of crawlers emerged. Insecticides were applied on 12-13 May and 19 Jul with a Bean hand-sprayer at 450 psi and approximately 1000 gpa (11-12 gal/tree). After treatment, twig samples were evaluated in the same manner as the pretreatment samples. Additionally, we evaluated scale densities on five randomly selected fruit per tree. Sample collections were completed at approximately 30 d intervals after the first treatment. Pretreatment sampling was conducted on 13 Apr. Post treatment counts were conducted on twigs on 13 Jun and 12 Jul and both twigs and fruit on 17 Aug, and 27 Sep. We evaluated the percentage of fruit infested with >10 CRS per fruit in each of the treatments at harvest on 6-7 Dec. Concurrently we determined the percentage of parasitism by A. melinus and C. bifasciata of scale on fruit by evaluating live CRS for the presence of the parasitoids or evidence of host feeding by A. melinus.

1998 ◽  
Vol 23 (1) ◽  
pp. 64-65
Author(s):  
E. E. Grafton-Cardwell ◽  
C. A. Reagan

Abstract Two insecticide efficacy trials for the control of citrus cutworm were conducted in 1997. In the first experiment, three formulations of Bacillus thuringiensis were tested and compared with a water (check) spray in a commercial block of 32-year-old ‘Washington’ navel orange trees of Exeter Farms, Exeter, California. Applications of MYX 300, MYX 324, and CRYMAX WDG were made on 8 Apr using a Bean hand-sprayer at approximately 300 gpa, 300 psi. In the second experiment, two rates of RH-5992 70 WP and one rate of RH-2485 80WP, each combined with the surfactant Latron CS-7, and a treatment of Spinosad 2SC were compared to a water control spray in a block of 14-yr-old ‘Washington’ navel oranges at the Lindcove Research and Extension Center, Exeter, California. The applications were made on 11 Apr using the same equipment, rate, and pressure as the Exeter Farms test. In both experiments, eight replicated single-tree treatments were used and treatments were assigned on the basis on pre-treatment sampling of larvae. Larvae were collected by placing a canvas beating sheet (112 cm X 75 cm) beneath the outside foliage of the tree and vigorously shaking the foliage 10 times. Citrus cutworm larvae falling on the canvas were counted and recorded, then returned to the foliage. Pre-treatment larval counts involved sampling the Northeast and Southwest corners of the trees at Exeter Farms on 7 Apr and at Lind-cove on 4 Apr. All four tree quadrants were sampled for post-treatment larval counts on 15 Apr and 22 Apr at Exeter Farms; and on 18 Apr and 25 Apr at Lindcove.


1995 ◽  
Vol 20 (1) ◽  
pp. 57-57
Author(s):  
E. E. Grafton-Cardwell ◽  
C. A. Reagan

Abstract Insecticides for the control of citrus cutworm were evaluated on 29 yr old ‘Washington navel’ orange trees at the Lindcove Research and Extension Center, Exeter, CA. The insecticide applications were made on 28-29 Apr with a Bean hand-sprayer at 450 psi and approximately 300 gpa (3—4 gal/tree). Lorsban was applied after sunset to reduce the detrimental impact of the insecticide on honey bees in the orchard. The 14 treatments were assigned based on pretreatment sampling of larvae and each of the treatments were applied to single trees, replicated 8 times. Larval collections were accomplished by placing a canvas beating sheet (112 cm × 75 cm) beneath the outside foliage of the tree and vigorously shaking the foliage 10 times. Citrus cutworm larvae which fell onto the canvas were counted and recorded by instar, then returned to the foliage. Pretreatment larval counts were made on 20 Apr by sampling the northeast and southwest quadrants of each tree. Post treatment counts were made on 9 May by sampling all four quadrants of each sample tree, again recording each instar. Percentage of scarred fruit due to citrus cutworm feeding was evaluated on 7 Sept on each of the sample trees within a 2 m vertical swath around the tree beginning approximately 20 cm above ground level and extending approximately 40 cm into the tree interior. In 1994, late Apr and early May temperatures at Lindcove ranged from relatively cool to warm, with daily maximums between 61°F and 90°F (mean of 72.5°F).


1997 ◽  
Vol 22 (1) ◽  
pp. 69-70
Author(s):  
E. E. Grafton-Cardwell ◽  
C. A. Reagan

Abstract Acaricides for control of citrus red mite were evaluated in the spring of 1995 and 1996 on ≈20 year old ‘Washington navel’ orange trees at the Lindcove Research and Extension Center, Exeter, CA. The acaricides were compared for efficacy against citrus red mite as well as their impact on populations of a predatory mite, which feeds on citrus red mite in San Joaquin Valley orchards. The acaricides were applied on 19 May in 1995; and on 8 Apr in 1996 using a Bean hand-sprayer at 300 psi and approximately 300 gpa (3^1 gal/tree). Single tree treatments were assigned based on pretreatment sampling of citrus red mite conducted on 9 May 1995 and 7 Apr 1996. Samples consisted of five leaves from the periphery of four quadrants of each tree (20 leaves per tree). The number of all active stages of citrus red mite and predatory mites per leaf were recorded weekly.


1996 ◽  
Vol 2 (4) ◽  
pp. 325-331 ◽  
Author(s):  
M. Zettlitzer ◽  
W. Schuhbauer ◽  
N. Kohler

BioControl ◽  
2007 ◽  
Vol 53 (4) ◽  
pp. 579-587 ◽  
Author(s):  
Stephanie M. Rill ◽  
Elizabeth E. Grafton-Cardwell ◽  
Joseph G. Morse

1993 ◽  
Vol 44 (4) ◽  
pp. 349-353 ◽  
Author(s):  
Hitoshi KAWADA ◽  
Yoshinori SHONO ◽  
Takaaki ITO ◽  
Yasuo ABE

1994 ◽  
Vol 19 (1) ◽  
pp. 51-51
Author(s):  
E. E. Grafton-Cardwell ◽  
C. A. Reagan ◽  
S. L. Vehrs ◽  
A. E. Eller ◽  
J. McClain

Abstract Insecticides for the control of citrus cutworm were evaluated in a commercial orchard on 28 year old navel orange trees (‘Washington’ on Troyer rootstock) in Terra Bella, California. The insecticides were applied on 21 and 22 Apr when citrus cutworm larvae were first emerging. Treatment applications were made with a Bean hand-sprayer at 450 psi, and approximately 300 gal/acre (3-4 gal/tree). Lorsban was applied after sunset to reduce the detrimental impact of the spray on honey bees in the orchard. ATI 720 F (Azadirachtin) was applied with a spray adjuvant (Kinetic). Each of 19 treatments were applied to 8 single tree replications. Treatments were assigned to trees based on pretreatment levels of citrus cutworm and the insecticide applications were made to alternate trees along three rows of citrus. All larval collections were accomplished by placing a canvas beating sheet (112 cm × 75 cm) under the outside foliage of the tree and vigorously striking the foliage with PVC pipe. Citrus cutworm larvae which fell on the canvas were counted and recorded by instar, then returned to the foliage. Pretreatment citrus cutworm larvae counts were made on 20 Apr by sampling the northwest and southeast quadrants of the tree. Post treatment counts were made on 29 Apr and 5 May by sampling all four quadrants of the tree, again recording each instar. Percentage of scarred fruit due to citrus cutworm feeding was evaluated on 1 Sep on each experimental tree within a 2 meter swath around the tree beginning 20 cm from the ground and extending 40 cm into the tree interior. In 1993, late April and early May temperatures ranged from relatively cool to warm, with daily maximums between 70 and 91° F (mean of 82.4° F).


2007 ◽  
Vol 58 (4) ◽  
pp. 342 ◽  
Author(s):  
A. M. Grieve ◽  
L. D. Prior ◽  
K. B. Bevington

Citrus is regarded as a salt-sensitive crop, but its yield response to salinity is affected by variety, rootstock, duration of salt exposure, irrigation management, soil type, and climate. This study quantified the yield response of mature Valencia [Citrus sinensis (L. Osbeck)] orange trees on sweet orange (C. sinensis) rootstock to increased levels of sodium chloride in irrigation water in the Sunraysia area of the Murray Valley in south-eastern Australia. The orchard was planted on a loamy sand and trees were irrigated and fertilised with a well-managed under-tree microsprinkler system. Four levels of salt, ranging from the river-water control (0.44 dS/m) to 2.50 dS/m, were applied over a 9-year period. Overall yield effects were smaller than expected, and did not conform well to the often used bent-stick model. Relative to the control, yield was initially higher (by up to 9%) in the intermediate salt treatments, and 3% lower in the highest treatment. However, relative yields of salinised trees decreased with time, and in the final year of the experiment, yield of the highest salt treatment was 9% lower than the control. Yield increases in the intermediate treatments resulted from increases in fruit number. All 3 salt treatments decreased average fruit weight by 4% and decreased juice content but increased juice sugar and acid content. Salt treatment strongly reduced trunk growth, and the effect increased with time. Our results show that with appropriate irrigation management, soils, and rootstocks, citrus trees can maintain productivity at salinity levels of 2.0 dS/m or more, but fresh fruit profitability is likely to be lower because of a reduction in average fruit size.


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