Peach Twig Borer

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Peach Twig Borer Control in Almonds - Dormant Trials 1999 Nickels Soil Laboratory

John Edstrom
UCCE Farm Advisor

Stan Cutter
NSL Farm Manager

Field trials were conducted on almonds to evaluate unregistered compounds for the control of the overwintering generation of Peach Twig Borer, Anarsia lineatella, when applied as a dormant spray. Treatments were applied 2-2-99, delayed dormant as dilute handgun sprays (200 psi) at 2 gallons of spray solution per tree (including 6 gallons of dormant oil per 400 gallons). Six single tree replicates were used in a randomized complete block design at two locations at the Nickels Soil Laboratory, Arbuckle, CA. Vigorous third leaf Carmel and Aldrich ctvs almonds were sprayed in these two tests. Conditions at the time of application were clear, sunny and cool, 45 degrees F with a north wind at 4 mph. Coverage was considered satisfactory but not optimal given the wind and drift considerations. Treatments were evaluated by determining the number of damaged shoot tips ("strikes") per tree on April 26, 1999. Data presented from the Carmel trial appears to show good efficacy of Dimilin 2L® when applied at the higher rates evaluated. This level of control would be commercially acceptable but slightly below the level typically obtained with the widely used synthetic pyrethroid, Asana®. Significant reductions in the overwintering larvae were also obtained at the lower rates but performance was erratic between reps and probably not commercially acceptable. Data from the Aldrich test is of limited use given the lower insect pressure at this location but generally supports our interpretation of the Carmel data. No phytotoxicity from any treatment was observed nor were any spray mixing/ application problems evident.

University of California Cooperative Extension
Nickels Soil Lab

PTB Test #1
Carmel ctv almonds

Shoot strikes per tree

Treatments & Amount/Acre	Rep						Total	Mean
Treatments & Amount/Acre	1	2	3	4	5	6	Total	Mean
Untreated	13	18	9	11	11	23	85	14.17 a
Asana @ 12 oz.	0	0	2	0	0	2	4	0.67 c
Avaunt 30WG @ 0.055 lb. a.i.	8	5	0	5	7	6	31	5.17 b
Avaunt WG @ 0.11 lb. a.i.	2	0	0	0	5	2	9	1.50 c
Dimilin @ 12 oz.	2	2	4	0	9	8	25	4.17 b
Dimilin @ 16 oz.	0	0	0	1	3	1	5	0.83 c

PTB Test #1
Aldrich ctv almonds

Treatments & Amount/Acre	Rep						Total	Mean
Treatments & Amount/Acre	1	2	3	4	5	6	Total	Mean
Untreated	2	6	5	9	5	6	33	5.50 a
Asana @ 12 oz.	3	0	0	0	1	2	6	1.00 b
Avaunt 30WG @ 0.055 lb. a.i.	5	0	0	0	0	1	6	1.00 b
Avaunt WG @ 0.11 lb. a.i.	2	0	0	0	0	0	2	0.33 b
Dimilin @ 16 oz.	2	0	1	1	0	0	4	0.67 b

*square root trans - Duncan MRT P = 0.05

Dormant oil @ 6 gal./400 gallons added to all sprays.
Applied 2-2-99 by dilute handgun spray at 2 gal./tree.
Evaluated 4/26/99 by counting number of shoot tip strikes per single tree rep.

Send mail to jlschmierer@ucdavis.edu with questions or comments about this web site. Copyright © 1999 Colusa County Cooperative Extension, Univ. of California Last modified: September 01, 2000

Send mail to jlschmierer@ucdavis.edu with questions or comments about this web site.
Copyright © 1999 Colusa County Cooperative Extension, Univ. of California
Last modified: September 01, 2000