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Effect of Rate and Timing of Biorational Materials for Control of Second Generation White Apple Leafhopper Nymphs, 1995

Effect of Rate and Timing of Biorational Materials for Control of Second Generation White Apple... Downloaded from https://academic.oup.com/amt/article-abstract/21/1/6/4639806 by DeepDyve user on 02 August 2020 6 Arthropod Management Tests, Vol. 21 A: POME FRUITS WALH nymphs/leaf Rate form/ Compound acre" Timing 9 May 12 May 19 Ma y 25 May' 29 May 2 Jun 8 Jun 16 Jun 23 Jun Orchex 796 2% Std. 2.96 ab 2.40 bed 0.70 efg 1.25 defg 0.94 e 0.75 bed 0.70 a 0.48 a 0.01 a Orchex 692 2% Std. 2.88 ab 1.43 de 0.26 g 0.55 hi 0.66 e 0.58 cd 0.46 a 0.41 a 0.00 a WS-2928 2% Std. 3.16 ab 1.53 ab 0.36 g 0.48 i 0.78 e 0.58 cd 0.63 a 0.56 a 0.00 a Neemix 4.5% 7 fl oz Std. 2.81 ab 2.56 abed 1.76 de 1.23 efgh 1.34 cde 0.89 bed 0.66 a 0.33 a 0.01 a Orchex 796 1% Std. 2.68 ab 2.18 bed 1.06 ef 1.50 def 1.16 cde 1.11 abc 0.91 a 0.43 a 0.04 a Orchex 692 1% Std. 2.80 ab 1.25 de 0.50 fg 0.61 ghi 0.81 e 0.86 bed 0.65 a 0.44 a 0.00 a WS-2928 1% Std. 2.79 ab 2.50 abed 0.60 fg 1.13 defg 1.06 de 0.94 abed 0.66 a 0.49 a 0.03 a Neemix 4.5% 3.5 fl oz Std. 3.64 a 2.10 bed 2.11 bde 2.20 bed 2.18 ab 1.50 a 0.68 a 0.54 a 0.00 a Orchex 796 2% EOG 2.98 ab 3.06 abc 2.34 abed 2.60 abc 0.95 de 0.64 bed 0.45 a 0.41 a 0.00 a Orchex 692 2% EOG 2.48 b 1.68 cde 2.40 abed 2.66 abc 0.78 e 0.43 d 0.71 a 0.39 a 0.00 a WS-2928 2% EOG 2.75 ab 2.50 abed 3.00 ab 2.66 abc 0.98 de 0.83 bed 0.63 a 0.35 a 0.00 a Neemix 4.5% 7 fl oz EOG 3.15 ab 3.45 ab 3.71 a 3.98 a 1.96 abc 1.09 abc 0.65 a 0.53 a 0.01 a Orchex 796 1% EOG 3.26 ab 2.35 bed 2.89 ab 3.51 a 1.78 bed 1.09 abc 0.35 a 0.39 a 0.03 a Orchex 692 1% EOG 2.72 ab 3.84 a 3.23 ab 3.26 ab 1.21 cde 0.74 bed 0.30 a 0.41 a 0.00 a WS-2928 1% EOG 2.99 ab 3.11 ab 3.38 ab 2.89 ab 1.41 bede 0.71 bed 0.36 a 0.41 a 0.00 a Neemix 4.5% 3.5 fl oz EOG 2.40 b 2.05 bed 1.54 cde 1.68 cde 1.44 bede 1.09 abc 0.60 a 0.45 a 0.00 a Sevin 4F 1 pt Std. 3.20 ab 0.30 e 0.24 g 0.74 fghi 0.80 e 0.68 bed 0.48 a 0.40 a 0.00 a Check 2.70 ab 2.18 bed 2.90 abc 2.83 abc 2.63 a 1.19 ab 0.63 a 0.30 a 0.00 a Means within columns followed by the same letter are not significantly different (Waller-Duncan &-ratio f-test, k = 100). Data transformed to log (x+0.5) before analysis due to unequal variances (Levene's test). Std. timing; 90% in instars I, II, 111(9 May); EOG (end of generation); when adults first begin to emerge (26 May). "Orchex 796, Orchex 692, and WS-2928 are percentage by volume of water. APPLE: Malus domestica Borkhauser 'Delicious' E. H. Beers (7A) White apple leafhopper (WALH); Typhlocyba pomaria McAtee Tree Fruit Res. & Ext. Ctr. 1100 N. Western Ave. Wenatchee, WA 98801 (509) 663-8181 ext. 234 EFFECT OF RATE AND TIMING OF BIORATIONAL MATERIALS FOR CONTROL OF SECOND GENERATION WHITE APPLE LEAFHOPPER NYMPHS, 1995: The test was conducted in a mature apple orchard (several strains of 'Delicious') at the Tree Fruit Research & Extension Center, Wenatchee, WA. Treatments were replicated 4 times, with each replicate consisting of a single tree. The experimental design was a RCB, using pre-treatment WALH populations as the blocking factor. The experimental treatments (three types of horticultural mineral oil and Neemix, a neem product) were applied at various rates and timings. The timings were selected based on previous experience of WALH phenology. The late Jul timing (27 Jul) coincides with the appearance of the 4th instars, while the mid-Aug timing (14 Aug) coincides with the first appearance of adults of the second generation. Pesticides were applied with a handgun sprayer to the point of drip. WALH populations were sampled ca. weekly by counting in situ all live nymphs on 20 leaves per tree, distributed throughout the tree canopy. Among the late Jul timing treatments, there were no differences among the treatment means of the plots before the treatments were applied or on the first post-treatment count (28 Jul). On 4 Aug, the three oils (2% rate), Orchex 692 (1%), and WS-2928E (1%) treatments had means significantly lower than the check. For a given oil, there were no differences between the 1% and the 2% rate, and for a given rate, there were no differences among the oils. The treatment mean for Neemix at either rate was not lower than mean in the check through the end of the test. For the mid-Aug timing treatments, all three oils at both rates significantly reduced WALH populations relative to the check during the primary part of the post-treatment period (18 Aug-1 Sep), with the exception of WS-2928E (1%) on 1 Sep; all treatment means were equivalent on the 11 Sep count date. The oils at 2% were not different from the standard insecticide, Sevin, on 25 Aug and 1 Sep; the oils at 1% were not different from Sevin on 1 Sep (again with the exception of WS-2928E). There were no differences between the 1 % and 2% rates of the individual oils. In general, Neemix (both rates) did not suppress WALH relative to the check with the exception of the 3.5 oz rate on 25 Aug, when the treatment mean was significantly lower than the check. Overall, the oils did a fair job of suppressing leafhopper populations. For the late Jul timing, initial suppression was good, but populations rose again, presumably as newly eclosed nymphs appeared. Suppression of nymphs at the later timing was generally equivalent to that of the early timing, thus either timing would be sufficient. Timing the treatments for mid-Aug might eliminate more larger instars, thus minimizing damage. Neemix does not appear to provide usable levels of mortality of WALH. WALH nymphs/leaf Rate v/v or 4 Aug 11 Aug 18 Aug Treatment Timing 26 Jul 28 Jul 25 Aug 1 Sep 11 Sep form/acre 0.71 c 0.44 f 0.64 a Orchex 796 2% late July 0.83 a 0.26 be 1.48 de 1.54 cdefg 1.08 defg Orchex 692 2% late July 0.78 a 0.16 c 0.64 c 1.06 def 1.51 de 1.55 cdefg 1.54 bede 0.88 a 2% 0.19 be 0.71 c 1.05 def 1.50 de 1.09 fghi 1.03 defgh 0.40 a WS-2928E late July 0.85 a Neemix 4.5% 7 fl oz late July 0.79 a 0.31 be 1.10 abc 2.31 abc 2.89 a 3.45 a 2.24 a 0.54 a 1.26 abc 1.00 ef 2.41 abc 2.29 b 1.81 abc 0.61 a Orchex 796 1% late July 0.78 a 0.33 be Continued Downloaded from https://academic.oup.com/amt/article-abstract/21/1/6/4639806 by DeepDyve user on 02 August 2020 A: POME FRUITS Arthropod Management Tests, Vol. 21 7 Rate v/v WALH nymphs/leaf or Treatment from/acre Timing 26 Jul 28 Jul 4 Aug 11 Aug 18 Aug 25 Aug 1 Sep 11 Sep Orchex 692 1% late July 0.83 a 0.31 be 0.68 c 1.38 bedef 2.39 abc 2.34 b 1.93 ab 0.60 a WS-2928E 1% late July 0.71 a 0.43 abc 1.00 be 1.35 cdef 1.96 bed 1.76 bedef 1.78 abc 0.61 a Neemix 4.5% 3.5 oz late July 0.68 a 0.28 be 1.09 abc 2.20 abed 2.75 ab 2.16 be 1.93 ab 0.55 a Orchex 796 2% mid-Aug 0.75 a 0.49 abc 1.00 be 1.71 bede 1.19 de 0.54 hi 0.74 fgh 0.46 a Orchex 692 2% mid-Aug 0.83 a 0.49 abc 1.35 abc 1.75 bede 0.96 e 0.66 hi 0.58 gh 0.33 a WS-2928E 2% mid-Aug 0.79 a 0.53 abc 1.63 ab 2.48 abc 1.18 de 0.85 ghi 0.89 efgh 0.49 a Neemix 4.5% 7 fl oz mid-Aug 0.81 a 0.50 abc 0.96 be 1.60 bedef 1.79 cd 1.84 bede 1.39 bedef 0.55 a Orchex 796 1% mid-Aug 0.80 a 0.40 abc 1.06 be 2.26 abc 0.94 ef 0.96 ghi 0.71 fgh 0.46 a Orchex 692 1% mid-Aug 0.74 a 0.61 ab 1.14 abc 3.39 a 1.28 de 1.18 efgh 0.79 fgh 0.68 a WS-2928E 1% mid-Aug 0.68 a 0.48 abc 1.23 abc 2.56 ab 1.39 de 1.39 defg 1.18 cdefg 0.41 a Neemix 4.5% 3.5 oz mid-Aug 0.78 a 0.79 a 1.03 be 1.68 bede 1.88 cd 1.19 efgh 1.51 bede 0.43 a Sevin 4F 1 pt mid-Aug 0.79 a 0.56 abc 1.36 abc 2.19 bede 0.15 f 0.41 i 0.39 h 0.23 a Check 0.86 a 0.40 abc 1.83 a 1.69 bede 2.53 abc 2.09 bed 1.69 abed 0.46 a — — Means within columns followed by the same letter are not significantly different different (Waller-Duncan 4-ratio r-test, 4-ratio = 100). APPLE: Malus domestica Borkhauser 'Delicious' and 'Fuji' J. F. Brunner, M. D. Doerr and L. O. Smith (8A) Obliquebanded leafroller (OBLR); Choristoneura rosaceana Washington State University (Harris) Tree Fruit Research and Extension Center 1100 N. Western Avenue Wenatchee, WA 98801 509-663-8181 APPLE, OBLIQUEBANDED LEAFROLLER CONTROL WITH AZADIRACHTIN, BACILLUS THURINGIENSIS AND CHLORPYR- IFOS IN SPRING, 1995: Neemix, Dipel 2X, and Lorsban 4E were evaluated for their ability to control OBLR larvae of the overwintering generation. The test was conducted in apple orchards at Milton-Freewater, OR and Mattawa, WA. Trees were 3-yr-old Fuji on dwarfing roots at Milton-Freewater and 3-yr-old Delicious on dwarfing roots at Mattawa. Treatments were applied to 3-tree plots replicated 5 times at Milton-Freewater and 12-tree plots replicated 5 times at Mattawa in a RCB design. All treatments were applied with a handgun sprayer at 300 psi to the point of drip, simulating a dilute spray of approximately 400 gpa. Application dates at Milton-Freewater were 5 Apr (pink) and 25 Apr (petal fall), and at Mattawa they were 5 Apr (pink) and 9 May (petal fall). The approximate application timings with regard to plant development stage are shown in the table. The post-treatment evaluation was made on 8 May in Milton-Freewater and the total number of live OBLR larvae found in a 2-min timed sample recorded. The post- treatment evaluation was made on 24 May in Mattawa and total number of live OBLR larvae on all trees of a treatment replication counted and collected to observe sublethal effects. Surviving larvae were reared on artificial leafroller diet in 3.25 oz portion cups until death or adult emergence. Any deformities possibly resulting from exposure to an insect growth regulator were recorded. A significant rainfall occurred less than 2 h after the pink application at Milton-Freewater. Weather was good during and after the other applications; however, spring weather in general was cooler and wetter than normal. Leafroller populations at these sites were moderate. The only treatment that had significantly fewer OBLR larvae than the untreated check in both tests was Lorsban. No significant rate response was noted with either the Neemix or the Dipel 2X treatments. It is unusual that there was no rate response noted with these rates of Dipel 2X, and the 113 g/100 treatment was not significantly better than the check. This may indicate that rain affected the efficacy of the treatments at Milton-Freewater, and the petal fall application at Mattawa may have been too late. Spring weather conditions were not conducive to control of leafrollers using "soft" insecticides that have to be consumed to be effective. While the timing of treatment applications was made during periods when weather conditions were as good as possible, the low level of control was not unexpected. The sublethal effects study indicates that survivors exposed to Neemix may had have higher mortality due to deformities in the larval and pupal stage than the untreated check and therefore resulted in a lower percentage emerging as adults. The sublethal effects from the Lorsban 4E survivors were not included because of the low number of subjects available. Avg. no. of live OBLR larvae per 2 min per 12 trees Treatment Rate/100 Timing M-F» Mattawa Neemix 4.5% 104 ml Pink, petal fall 5.2ab 8.0bc Neemix 4.5% 207 ml Pink, petal fall 6.2bc 8.6bc Neemix 4.5% 104 ml Pink, petal fall 8.6bc 9.6bc +Dipel 2X 21 g Dipel 2X Pink, petal fall 7.2bc 11.2bc 21 g Dipel 2X 113 g Pink, petal fall 8.2bc 5.0ab Lorsban 4E 475 ml Pink 0.0a 0.6a Untreated None 11.6c 11.8c Means in the same column followed by the same letter not significantly different (P = 0.05, Fisher's Protected LSD). •Milton-Freewater orchard m-f http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Arthropod Management Tests Oxford University Press

Effect of Rate and Timing of Biorational Materials for Control of Second Generation White Apple Leafhopper Nymphs, 1995

Beers, E., H.
Arthropod Management Tests , Volume 21 (1) – Jan 1, 1996
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Oxford University Press
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© Entomological Society of America.
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2155-9856
DOI
10.1093/amt/21.1.6
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Abstract

Downloaded from https://academic.oup.com/amt/article-abstract/21/1/6/4639806 by DeepDyve user on 02 August 2020 6 Arthropod Management Tests, Vol. 21 A: POME FRUITS WALH nymphs/leaf Rate form/ Compound acre" Timing 9 May 12 May 19 Ma y 25 May' 29 May 2 Jun 8 Jun 16 Jun 23 Jun Orchex 796 2% Std. 2.96 ab 2.40 bed 0.70 efg 1.25 defg 0.94 e 0.75 bed 0.70 a 0.48 a 0.01 a Orchex 692 2% Std. 2.88 ab 1.43 de 0.26 g 0.55 hi 0.66 e 0.58 cd 0.46 a 0.41 a 0.00 a WS-2928 2% Std. 3.16 ab 1.53 ab 0.36 g 0.48 i 0.78 e 0.58 cd 0.63 a 0.56 a 0.00 a Neemix 4.5% 7 fl oz Std. 2.81 ab 2.56 abed 1.76 de 1.23 efgh 1.34 cde 0.89 bed 0.66 a 0.33 a 0.01 a Orchex 796 1% Std. 2.68 ab 2.18 bed 1.06 ef 1.50 def 1.16 cde 1.11 abc 0.91 a 0.43 a 0.04 a Orchex 692 1% Std. 2.80 ab 1.25 de 0.50 fg 0.61 ghi 0.81 e 0.86 bed 0.65 a 0.44 a 0.00 a WS-2928 1% Std. 2.79 ab 2.50 abed 0.60 fg 1.13 defg 1.06 de 0.94 abed 0.66 a 0.49 a 0.03 a Neemix 4.5% 3.5 fl oz Std. 3.64 a 2.10 bed 2.11 bde 2.20 bed 2.18 ab 1.50 a 0.68 a 0.54 a 0.00 a Orchex 796 2% EOG 2.98 ab 3.06 abc 2.34 abed 2.60 abc 0.95 de 0.64 bed 0.45 a 0.41 a 0.00 a Orchex 692 2% EOG 2.48 b 1.68 cde 2.40 abed 2.66 abc 0.78 e 0.43 d 0.71 a 0.39 a 0.00 a WS-2928 2% EOG 2.75 ab 2.50 abed 3.00 ab 2.66 abc 0.98 de 0.83 bed 0.63 a 0.35 a 0.00 a Neemix 4.5% 7 fl oz EOG 3.15 ab 3.45 ab 3.71 a 3.98 a 1.96 abc 1.09 abc 0.65 a 0.53 a 0.01 a Orchex 796 1% EOG 3.26 ab 2.35 bed 2.89 ab 3.51 a 1.78 bed 1.09 abc 0.35 a 0.39 a 0.03 a Orchex 692 1% EOG 2.72 ab 3.84 a 3.23 ab 3.26 ab 1.21 cde 0.74 bed 0.30 a 0.41 a 0.00 a WS-2928 1% EOG 2.99 ab 3.11 ab 3.38 ab 2.89 ab 1.41 bede 0.71 bed 0.36 a 0.41 a 0.00 a Neemix 4.5% 3.5 fl oz EOG 2.40 b 2.05 bed 1.54 cde 1.68 cde 1.44 bede 1.09 abc 0.60 a 0.45 a 0.00 a Sevin 4F 1 pt Std. 3.20 ab 0.30 e 0.24 g 0.74 fghi 0.80 e 0.68 bed 0.48 a 0.40 a 0.00 a Check 2.70 ab 2.18 bed 2.90 abc 2.83 abc 2.63 a 1.19 ab 0.63 a 0.30 a 0.00 a Means within columns followed by the same letter are not significantly different (Waller-Duncan &-ratio f-test, k = 100). Data transformed to log (x+0.5) before analysis due to unequal variances (Levene's test). Std. timing; 90% in instars I, II, 111(9 May); EOG (end of generation); when adults first begin to emerge (26 May). "Orchex 796, Orchex 692, and WS-2928 are percentage by volume of water. APPLE: Malus domestica Borkhauser 'Delicious' E. H. Beers (7A) White apple leafhopper (WALH); Typhlocyba pomaria McAtee Tree Fruit Res. & Ext. Ctr. 1100 N. Western Ave. Wenatchee, WA 98801 (509) 663-8181 ext. 234 EFFECT OF RATE AND TIMING OF BIORATIONAL MATERIALS FOR CONTROL OF SECOND GENERATION WHITE APPLE LEAFHOPPER NYMPHS, 1995: The test was conducted in a mature apple orchard (several strains of 'Delicious') at the Tree Fruit Research & Extension Center, Wenatchee, WA. Treatments were replicated 4 times, with each replicate consisting of a single tree. The experimental design was a RCB, using pre-treatment WALH populations as the blocking factor. The experimental treatments (three types of horticultural mineral oil and Neemix, a neem product) were applied at various rates and timings. The timings were selected based on previous experience of WALH phenology. The late Jul timing (27 Jul) coincides with the appearance of the 4th instars, while the mid-Aug timing (14 Aug) coincides with the first appearance of adults of the second generation. Pesticides were applied with a handgun sprayer to the point of drip. WALH populations were sampled ca. weekly by counting in situ all live nymphs on 20 leaves per tree, distributed throughout the tree canopy. Among the late Jul timing treatments, there were no differences among the treatment means of the plots before the treatments were applied or on the first post-treatment count (28 Jul). On 4 Aug, the three oils (2% rate), Orchex 692 (1%), and WS-2928E (1%) treatments had means significantly lower than the check. For a given oil, there were no differences between the 1% and the 2% rate, and for a given rate, there were no differences among the oils. The treatment mean for Neemix at either rate was not lower than mean in the check through the end of the test. For the mid-Aug timing treatments, all three oils at both rates significantly reduced WALH populations relative to the check during the primary part of the post-treatment period (18 Aug-1 Sep), with the exception of WS-2928E (1%) on 1 Sep; all treatment means were equivalent on the 11 Sep count date. The oils at 2% were not different from the standard insecticide, Sevin, on 25 Aug and 1 Sep; the oils at 1% were not different from Sevin on 1 Sep (again with the exception of WS-2928E). There were no differences between the 1 % and 2% rates of the individual oils. In general, Neemix (both rates) did not suppress WALH relative to the check with the exception of the 3.5 oz rate on 25 Aug, when the treatment mean was significantly lower than the check. Overall, the oils did a fair job of suppressing leafhopper populations. For the late Jul timing, initial suppression was good, but populations rose again, presumably as newly eclosed nymphs appeared. Suppression of nymphs at the later timing was generally equivalent to that of the early timing, thus either timing would be sufficient. Timing the treatments for mid-Aug might eliminate more larger instars, thus minimizing damage. Neemix does not appear to provide usable levels of mortality of WALH. WALH nymphs/leaf Rate v/v or 4 Aug 11 Aug 18 Aug Treatment Timing 26 Jul 28 Jul 25 Aug 1 Sep 11 Sep form/acre 0.71 c 0.44 f 0.64 a Orchex 796 2% late July 0.83 a 0.26 be 1.48 de 1.54 cdefg 1.08 defg Orchex 692 2% late July 0.78 a 0.16 c 0.64 c 1.06 def 1.51 de 1.55 cdefg 1.54 bede 0.88 a 2% 0.19 be 0.71 c 1.05 def 1.50 de 1.09 fghi 1.03 defgh 0.40 a WS-2928E late July 0.85 a Neemix 4.5% 7 fl oz late July 0.79 a 0.31 be 1.10 abc 2.31 abc 2.89 a 3.45 a 2.24 a 0.54 a 1.26 abc 1.00 ef 2.41 abc 2.29 b 1.81 abc 0.61 a Orchex 796 1% late July 0.78 a 0.33 be Continued Downloaded from https://academic.oup.com/amt/article-abstract/21/1/6/4639806 by DeepDyve user on 02 August 2020 A: POME FRUITS Arthropod Management Tests, Vol. 21 7 Rate v/v WALH nymphs/leaf or Treatment from/acre Timing 26 Jul 28 Jul 4 Aug 11 Aug 18 Aug 25 Aug 1 Sep 11 Sep Orchex 692 1% late July 0.83 a 0.31 be 0.68 c 1.38 bedef 2.39 abc 2.34 b 1.93 ab 0.60 a WS-2928E 1% late July 0.71 a 0.43 abc 1.00 be 1.35 cdef 1.96 bed 1.76 bedef 1.78 abc 0.61 a Neemix 4.5% 3.5 oz late July 0.68 a 0.28 be 1.09 abc 2.20 abed 2.75 ab 2.16 be 1.93 ab 0.55 a Orchex 796 2% mid-Aug 0.75 a 0.49 abc 1.00 be 1.71 bede 1.19 de 0.54 hi 0.74 fgh 0.46 a Orchex 692 2% mid-Aug 0.83 a 0.49 abc 1.35 abc 1.75 bede 0.96 e 0.66 hi 0.58 gh 0.33 a WS-2928E 2% mid-Aug 0.79 a 0.53 abc 1.63 ab 2.48 abc 1.18 de 0.85 ghi 0.89 efgh 0.49 a Neemix 4.5% 7 fl oz mid-Aug 0.81 a 0.50 abc 0.96 be 1.60 bedef 1.79 cd 1.84 bede 1.39 bedef 0.55 a Orchex 796 1% mid-Aug 0.80 a 0.40 abc 1.06 be 2.26 abc 0.94 ef 0.96 ghi 0.71 fgh 0.46 a Orchex 692 1% mid-Aug 0.74 a 0.61 ab 1.14 abc 3.39 a 1.28 de 1.18 efgh 0.79 fgh 0.68 a WS-2928E 1% mid-Aug 0.68 a 0.48 abc 1.23 abc 2.56 ab 1.39 de 1.39 defg 1.18 cdefg 0.41 a Neemix 4.5% 3.5 oz mid-Aug 0.78 a 0.79 a 1.03 be 1.68 bede 1.88 cd 1.19 efgh 1.51 bede 0.43 a Sevin 4F 1 pt mid-Aug 0.79 a 0.56 abc 1.36 abc 2.19 bede 0.15 f 0.41 i 0.39 h 0.23 a Check 0.86 a 0.40 abc 1.83 a 1.69 bede 2.53 abc 2.09 bed 1.69 abed 0.46 a — — Means within columns followed by the same letter are not significantly different different (Waller-Duncan 4-ratio r-test, 4-ratio = 100). APPLE: Malus domestica Borkhauser 'Delicious' and 'Fuji' J. F. Brunner, M. D. Doerr and L. O. Smith (8A) Obliquebanded leafroller (OBLR); Choristoneura rosaceana Washington State University (Harris) Tree Fruit Research and Extension Center 1100 N. Western Avenue Wenatchee, WA 98801 509-663-8181 APPLE, OBLIQUEBANDED LEAFROLLER CONTROL WITH AZADIRACHTIN, BACILLUS THURINGIENSIS AND CHLORPYR- IFOS IN SPRING, 1995: Neemix, Dipel 2X, and Lorsban 4E were evaluated for their ability to control OBLR larvae of the overwintering generation. The test was conducted in apple orchards at Milton-Freewater, OR and Mattawa, WA. Trees were 3-yr-old Fuji on dwarfing roots at Milton-Freewater and 3-yr-old Delicious on dwarfing roots at Mattawa. Treatments were applied to 3-tree plots replicated 5 times at Milton-Freewater and 12-tree plots replicated 5 times at Mattawa in a RCB design. All treatments were applied with a handgun sprayer at 300 psi to the point of drip, simulating a dilute spray of approximately 400 gpa. Application dates at Milton-Freewater were 5 Apr (pink) and 25 Apr (petal fall), and at Mattawa they were 5 Apr (pink) and 9 May (petal fall). The approximate application timings with regard to plant development stage are shown in the table. The post-treatment evaluation was made on 8 May in Milton-Freewater and the total number of live OBLR larvae found in a 2-min timed sample recorded. The post- treatment evaluation was made on 24 May in Mattawa and total number of live OBLR larvae on all trees of a treatment replication counted and collected to observe sublethal effects. Surviving larvae were reared on artificial leafroller diet in 3.25 oz portion cups until death or adult emergence. Any deformities possibly resulting from exposure to an insect growth regulator were recorded. A significant rainfall occurred less than 2 h after the pink application at Milton-Freewater. Weather was good during and after the other applications; however, spring weather in general was cooler and wetter than normal. Leafroller populations at these sites were moderate. The only treatment that had significantly fewer OBLR larvae than the untreated check in both tests was Lorsban. No significant rate response was noted with either the Neemix or the Dipel 2X treatments. It is unusual that there was no rate response noted with these rates of Dipel 2X, and the 113 g/100 treatment was not significantly better than the check. This may indicate that rain affected the efficacy of the treatments at Milton-Freewater, and the petal fall application at Mattawa may have been too late. Spring weather conditions were not conducive to control of leafrollers using "soft" insecticides that have to be consumed to be effective. While the timing of treatment applications was made during periods when weather conditions were as good as possible, the low level of control was not unexpected. The sublethal effects study indicates that survivors exposed to Neemix may had have higher mortality due to deformities in the larval and pupal stage than the untreated check and therefore resulted in a lower percentage emerging as adults. The sublethal effects from the Lorsban 4E survivors were not included because of the low number of subjects available. Avg. no. of live OBLR larvae per 2 min per 12 trees Treatment Rate/100 Timing M-F» Mattawa Neemix 4.5% 104 ml Pink, petal fall 5.2ab 8.0bc Neemix 4.5% 207 ml Pink, petal fall 6.2bc 8.6bc Neemix 4.5% 104 ml Pink, petal fall 8.6bc 9.6bc +Dipel 2X 21 g Dipel 2X Pink, petal fall 7.2bc 11.2bc 21 g Dipel 2X 113 g Pink, petal fall 8.2bc 5.0ab Lorsban 4E 475 ml Pink 0.0a 0.6a Untreated None 11.6c 11.8c Means in the same column followed by the same letter not significantly different (P = 0.05, Fisher's Protected LSD). •Milton-Freewater orchard m-f

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Arthropod Management Tests – Oxford University Press

Published: Jan 1, 1996

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