Mating disruption treatments for the tufted apple bud moth (TABM), Platynota idaeusalis (Walker), were .... supplied the rope dispensers and Scentry Inc. (Buck-.
105
Entomologia Experimentalis etApplicata 74: 105-114, 1995. (~) 1995 Kluwer Academic Publishers. Printed in Belgium.
Small plot mating disruption trials for tufted apple bud moth, Platynota idaeusalis, in Pennsylvania apple orchards C. M. Felland I , L. A. Hull 1, B. A. Barrett z, A. L. Knight 3, J. W. Jenkins 4, R A. Kirsch 5 & D. R. T h o m s o n 6
1Penn State University, Fruit Research Laboratory, Biglerville, PA 17307, USA 2Dept. Entomol., Univ. of Missouri, Columbia, MO 652111, USA 3 USDA-ARS, Yakima, WA 98902, USA 4Ecogen Inc., Goodyear, AZ 85338, USA 55219 Neko Circle, West Linn, OR 97068, USA 6pacific Biocontrol Corp., Davis, CA 95616, USA Accepted: May 18, 1994
Key words: Lepidoptera, Tortricidae, Platynota idaeusalis, mating disruption, leafroller, apple
Abstract Mating disruption treatments for the tufted apple bud moth (TABM), Platynota idaeusalis (Walker), were tested in small plot trials in apple orchards in Pennsylvania. Treatments were evaluated by fruit injury and by capture of male TABM in traps baited with synthetic pheromone sources or virgin females. The TABM pheromone is a two component isomeric blend of E- 1 l-tetradecen- 1-ol (E 11-14:OH) and E- 11 -tetradecenyi acetate (E 11-14:Ac). A 50:50 ratio of these two components was used in standard monitoring septa and in mating disruption treatments released from either hollow fibers ('fiber') or PVC tubes ('PVC'). Other pheromone blends tested included a 90:10 ratio of E11-14:Ac and E11-14:OH ('EAc') and its reverse ('EOH'), mixture 'EAc' with 30% of the Z-isomers ('low EAc'), and a blend similar to the preceding with 2% Z9-12:Ac ('generic'). These other blends were released from multi tube tape ('tape') or Shin-Etsu type rope ('rope') dispensers. Seasonal dispenser release rate in mg ha -j h -1 was ca. 30 for the 'rope' dispensers, 14 for 'PVC' and 6 for 'fiber'. 'EAc-tape' and 'EOH-tape' were equally effective in reducing catches of males in traps baited with synthetic lures and in traps baited with virgin females. Both treatments also reduced fruit injury. 'EAc-rope', 'fiber' and 'PVC' also were generally effective; whereas, the 'low EAc' and 'generic' treatments reduced trap capture less than 90% and did not reduce fruit injury. Dispenser density was positively correlated with reduction in trap capture for the 'low EAc-rope' and 'genericrope' treatments. Traps loaded with 'fiber' dispensers captured more male TABM than the other treatments in non-pheromone permeated environments. Trap capture of other tortricids was reduced in pheromone treatments. 'EAc-rope' and the 'TABM' treatments provided mean (s.e.) percent reduction in trap catch of 99.5 (0.4) and 42.9 (10.1), respectively, for the redbanded leafroller, Argyrotaenia velutinana (Walker), and 90.4 (6.8) and 90.4 (1.3), respectively, for the obliquebanded leafroller, Choristoneura rosaceana (Harris).
Introduction Tufted apple bud moth (TABM), Platynota idaeusalis (Walker) (Lepidoptera, Tortricidae), is a key pest of apples in much of the Cumberland-Shenandoah region of eastern USA (Weires & Riedl, 1991). In Pennsylvania annual losses attributed to TABM are in excess of $2 million even with $60-100 per acre per season spent
on insecticides primarily targeted for this pest (L.A.H., unpubl.). Resistance to the organophosphate insecticide azinphosmethyl is widespread (Knight et al., 1990b) and is thought to contribute substantially to these economic losses. This resistance has resulted in increased use of carbamate and pyrethroid insecticides which threaten the successful biological control of the European red mite, Panonychus ulmi (Koch), by
106 the coccinellid predator Stethorus punctum (LeConte). Further, cost of insecticide registration plus increased regulatory and environmental concerns highlight the need to pursue alternative control measures for TABM and other orchard pests. Mating disruption is a control tactic that can fit well in apple pest management (Kirsch, 1988). Commercial introduction of mating disruption technology for codling moth, Cydia pomonella (L.) (Barnes et al., 1992; Pfeiffer et al., 1993b) in the USA is rapidly expanding, with an excess of 5000 ha treated in 1993. Mating disruption with reduced insecticide use has been used to manage resistance in the light brown apple moth, Epiphyas postvittana (Walker), in New Zealand (Suckling etal., 1990). In addition, mating disruption for variegated leafroller, Platynota flavedana (Clemens) is being investigated in the midAtlantic USA (Pfeiffer et al., 1993a). Optimization of pheromone blend and dispenser technology are crucial to the success of mating disruption. TABM pheromone is primarily a two component isomeric blend of E- 11-tetradecen- 1-ol (E 1114:OH) and E-I l-tetradecenyl acetate (El 1-14:Ac). Sex pheromone gland extracts have been reported as a 2:1 alcohol:acetate ratio with 0.05; Fisher's Protected LSD); 1990 trials are unreplicated, s.e. based on traps within treatment blocks I Treatments described in Table 1 2 Not available because trial initiated for brood 2 only 3 Primarily obliquebanded and redbanded leafrollers.
p e n s e r s p e r h a r e s u l t e d in o n l y 3 6 , 6 a n d 3 4 . 6 % r e d u c -
Logit
analysis
was
applied
to
the
three
dis-
t i o n in t r a p c a t c h f o r first a n d s e c o n d b r o o d T A B M , r e s p e c t i v e l y , in t h e o r c h a r d in w h i c h d i s p e n s e r d e n s i t y
penser density studies. Good
was not increased.
(g = 0 . 0 2 7 ) t r e a t m e n t s ( T a b l e 5). N o fit w a s p o s s i b l e
the
'generic-rope'
(g=0.424)
fits w e r e o b t a i n e d f o r and
'low
EAc-rope'
111 for the 'EAc-rope' treatment (g>>0.4). 'Low EAcrope' was more effective than 'generic-rope' at the 90% reduction level. However, the predicted dispenser density needed to achieve 99% level of reduction in trap capture is ca. four times that of the recommended rate for both treatments. Blend~dispenser studies. In 1989 the 'fiber' treatment resulted in greater reduction in trap catch than the 'generic-rope' treatment during both broods of TABM (Table 6). Fruit injury also tended to be low in the 'fiber' treatment. In 1990 the 'fiber' and 'PVC' treatments resulted in excellent reduction in trap catch compared with the 'EAc-rope' treatment. Fruit injury was lowest in the 'fiber' treatment; whereas, injury in the 'EAc-rope' treatment was greater than in the untreated control. Impact on other tortricids. In two trials in 1990 trap captures of other species of leafrollers were also affected by the pheromone permeated environment (Table 7). Over the entire season in the two trials the 'EAc-rope' treatment resulted in mean (s.e.) percent reduction in trap catch of 99.5 (0.4), 90.4 (6.8) and 100 (0.0) compared to total numbers in the untreated plots of 102, 29 and 10 for redbanded leafroller, obliquebanded leafroller and variegated leafroller, respectively. The 'TABM' treatments resulted in mean (s.e.) percent reduction in trap catch of 42.9 (10.1), 90.4 (1.3) and 100 (0.0) based on total density in the untreated plots of 7, 26 and 7 for redbanded leafroller, obliquebanded leafroller and variegated leafroller, respectively. Codling moth pressure was low. Only five codling moths were captured in both 1990 trials for the entire season. Treatment summary. Overall, treatment (F = 4.9, df = 2, 12, P=0.0274) and log dispenser density (F= 15.4, dr= 1, 12, P=0.0020) were both significant for percent reduction in trap catch during the second brood (Table 8). The treatment by log dispenser density interaction was not significant (F=3.08, df=2, 12, P = 0.0833). Trap catch reduction with the 'fiber' treatment was consistently high. The 'generic-rope' treatment did not perform as well as the similar 'low EAcrope' treatment. Fruit injury was highly variable. However, the 'fiber' and 'EAc-rope' treatments had relatively low injury.
Discussion These results suggest that the natural blend may be the best disruptant for this tortricid as it appears to be for some other moth species (Minks & Card6, 1988). Roelofs (personal communication) has established pheromone emission of TABM to be approximately 50:50 E11-14:Ac and E11-14:OH. The 'fiber' treatment resulted in excellent reduction in trap catch even at low release rates and at high population pressure. Because more male TABM were able to orient to the 'fiber' dispensers, the mode of action of these dispensers may have involved false trail-following to a greater extent than the 'EAc-rope' treatment (Card6, 1990). Poor results occurred with the pheromone blends with low isomeric purity, especially atthe lowest density. High levels of the Z-isomer in these treatments may have reduced their effectiveness (Hill et al., 1974), although the relatively high release rates may have overcome the inhibition to some extent (Roelofs & Novak, 198 l). The 'generic-rope' treatment provided 73% reduction in trap catch of TABM in this study compared with 51.0 and 89.7% reduction under lower moth density in Virginia (Pfeiffer et al., 1993a). Further evaluations should standardize blend and dispenser type (i.e. load hollow fibers with the EAc blend, etc.). Additional direct comparisons of the 'fiber' and 'PVC' treatments are also needed. The 'PVC' treatment is currently favored over 'fiber' treatment because of its ease of application and its single application per year. However, the 'PVC' treatment has not consistently provided full season release (Felland, unpubl, data). Sprayable formulations of hollow fibers are being investigated for other species, but face registration hurdles in tree fruits (Knight, unpubl, data). The high initial population of TABM in many of the orchards tested probably attributed tO the high levels of injury in some mating disruption treatments (Kirsch, 1988). Overall, the level of fruit injury varied widely, even in the insecticide treatment. Moderate levels of fruit injury are often tolerated for processing fruit where moderate (< 10%) TABM injury does not result in lower returns for the grower (Hull & Rajotte, 1988). Factors that affect injury levels include crop load, resistance levels, along with insecticide timing, rates and coverage (Knight et al., 1988). The 'PVC' and 'EAc-rope' treatments in large plots over three years with no insecticide cover sprays after petal fall have provided levels of injury by TABM approaching that of a full insecticide schedule (Hull
112
Table 5. Logit analysis of dispenser density for two mating disruption treatments on percent reduction in trap catch of second brood of tufted apple bud moth, Adams County, PA, USA, 1989 and 1990 Dispenser density (95% CI) Treatment I
Slope (4- s.e.)
90% trap catch reduction
99% trap catch reduction
Generic-rope
5.165 4- 0.226
1519.8(1169.7-3858.4)
4429.7 (2364.9-78,499.8)
Low EAc-rope
3.786 4- 0.316
1036.4(951.2-1153.0)
4458.8 (3415.4-6439.2)
I Treatments described in Table 1.
Table 6. Effect of various pheromone treatments on male captures of tufted apple bud moth (TABM) in pheromone monitoring traps and fruit injury at harvest, Adams County, PA, USA, 1989 and 1990 Mean 4- s.e. injuries per 100 fruit Treatment I
Plot size
Mean • s.e. males per trap
TABM
(dispensers/ha)
(ha)
Brood 1
Blood 1
Brood 2
Brood 2
Other leafrolIers 2
Low isomeric purity trial, 1989 Generic-rope (988)
0.4
86.8 4- 5.8b
260.5 4- 37.0bc
4.2 + 2.3a
7.3 -1- 5.0a
0.0 4- 0.0a
Low EAc-rope (988)
0.4
30.3 4- 10.8b
66.5 4- 71.4ab
4.8 4- 1.9a
4.6 4- 2.3a
0.0 4- 0.0a
Fiber (988)
0.4
8.0 -4- 4.0a
17.5 5: 5.0a
2.7 4- 0.5a
3.6 4- 0.7a
0.0 4- 0.Oa
Insecticide
0.4
286.8 4- 110.3bc
641.8 4- 157.8c
2.5 4- 1.3a
2.2 4- 0.7a
0.0 4- 0.0a
High isomeric purity trial, 1990 EAc-rope (988)
0.8
31.04-3.7
57.34-35.4
15.64- 1.2
22.24- 1.0
1.24-0.4
PVC (988)
0.8
2.84-0.8
5.3+0.9
8.94-0.9
21.84-1.8
1.14-0.4
Fiber (988)
0.7
8.8 4- 2.2
2.5 4- 1.0
6.2 q- 0.7
14.4 4- 1.2
1.7 4- 0.5
Insecticide
0.6
323.3 4- 84.9
440.8 4- 107.1
4.3 4- 0.8
10.8 4- 0.8
0.8 4- 0.2
Untreated
0.4
516.0 4- 245.0
534.0 4- 307.0
9.2 4- 1.3
18.6 4- 1.6
2.4 + 0.7
Means within a column in 1989 test followed by the same letter are not significantly different (P>0.05; Fisher's Protected LSD) I Treatments described in Table 1 Primarily obliquebanded and redbanded leafrotlers.
Table 7. Summary of variegated leafroller (VLR), redbanded leafroller (RBLR) and obliquebanded leafroller (OBLR) captures in mating disruption trials, Adams County, PA, USA, 1990 High isomeric purity trial
'EAc-rope' trial
VLR
RBLR
OBLR
VLR
RBLR
OBLR
Fiber
0
3
2
_2
_
_
PVC EAc-rope
0 0
5 0
3 5
0
l
0
Insecticide
5
1
5
3
96
3
Untreated
7
7
26
3
95
3
Treatrnent j
I Treatments described in Table 1, all at 988 dispensers per ha 2 Not tested.
113 Table 8. Summary of effects of pheromone treatments on second brood of tufted apple bud moth (TABM), Adams County, PA, USA, 1989-1990
Treatment I
Replicates
Mean 4- s.e. second brood TABM data Trap catch reduction (%) Injuries per 100 fruit2
Fiber EAc-rope Low EAc-rope Generic-rope
3 4 5 7
98.6 95.5 88.7 72.5
4- 0.5a 4- 2.2ab 4- 4.3bc 4- 7.5c
7.2 4- 3.6a 7.5 4- 4.9a 9.7 4- 2.2a 13.5 4- 4.0a
Means within columns followed by the same letter are not significantly different (P>0.05; Fisher's Protected LSD) I Treatments described in Table 1 2 Mean (s.e.) injury 7.1 (2.7) and 14.8 (4.5) in the insecticide treatment and untreated control, respectively.
& Felland, 1994). However, injury by other leafroller species has increased in these orchards as was observed by Pfeiffer et al. (1993a). These other species may be able to be controlled by a selective insecticide program (i.e. Bacillus thuringiensis products) (Kirsch, 1988). Alternatively, a generic leafroller or leafroller/codling moth pheromone could be investigated (van Deventer & Blommers, 1992). The leafroller complex in the mid-Atlantic region includes species with either E (TABM and variegated leafroller) or Z-isomer dominant pheromone blends (redbanded and obliquebanded ieafrollers) (Pfeiffer et al., 1993a). The 'generic-rope' treatment examined in this trial did not work well for TABM; whereas, the 'EAc-rope' treatment provided relatively high percent reduction in trap catch for TABM, redbanded leafroller (3% E 11-14:Ac, 37% Z11-14:Ac and 60% 12:Ac) and variegated leafroller (90% E11-14:OH and 10% Z11-14:OH). The natural pheromone blend was effective for TABM and variegated leafroller but provided minimal reduction in trap capture of redbanded leafroller. None of the treatments were successful against obliquebanded leafroller (4.8% E11-14:Ac, 90.2% Z11-14:Ac and 5.0% Z1114:OH). Two new generic leafroller blends were tested in the eastern USA in 1993. These contained the components of the pheromone blends of the four common ieafrollers. One of these blends appears promising and testing with this and a modified blend are planned (Hull & Felland, 1994). The reduction of insecticide in orchards treated with mating disruption for TABM has opened up the investigation of second-stage integrated management (Prokopy et al., 1990) in the Pennsylvania apple IPM program. Mating disruption has been found to comple-
ment the existing IPM strategy of reducing acaracide applications by conserving S. puncture along with the predatory mite Zetzellia mali (Ewing). These predators have controlled mites in pheromone plots in which the insecticide program is reduced (Hull & Felland, 1994). Parasitism of TABM and other leafroilers has been high in mating disruption trials (Hull et al., 1993).
Acknowledgments We appreciate the assistance rendered by the staff at the Fruit Research Laboratory at Biglerville and the cooperation ofE. Etter, P. Hall, J. Oyler, and H. Schulteis in the use of their orchards. The contribution of pheromone dispensers from Biocontrol Ltd., Pacific Biocontrol, and Scentry (Ecogen Inc.) is appreciated. We thank J. White of Scentry (Ecogen Inc.) for residual analysis of pheromone dispensers. This work was supported in part by Pennsylvania Department of Agriculture Grants 448150 and 449217 and by grants from the State Horticulture Association of Pennsylvania.
References Abacus Concepts, 1989. SuperANOVA Accessible general linear modeling. Abacus Concepts, Berkeley, CA., 316 pp. Barnes, M. M., J. C. Millar, P. A. Kirsch & D. C. Halks, 1992. Codling moth (Lepidoptera: Tortricidae) control by dissemination of synthetic sex pheromone. Journal of Economic Entomology 85: 1274-1277. Carde, R. T., 1990. Principles of mating disruption. In: Ridgway, R. L., R. M. Silverstein & M. N. lnscoe (eds). Behaviormodifying chemicals for insect management, applications of
114 pheromones and other attractants. Marcel Dekker Inc., New York, NY, pp. 47-71. David, P. J. & R. L. Horsburgh, 1989. Effects of pheromone trap design, placement, and pheromone dispenser and load on male Platynota flavedana and P. idaeusalis (Lepidoptera: Tortricidae) catches in Virginia apple orchards. Environmental Entomology 18: 145-149. Deventer, P. van & L. Blommers, 1992. Mating disruption of several leaf-feeding orchard leaf-roller species with a single sex pheromone component. Acta Phytopathologica et Entomologica Hungarica 27:615-620. Hill, A., R. Card6, A. Comeau, W. Bode & W. Roelofs, 1974. Sex pheromones of the tufted apple bud moth (Platynota idaeusalis). Environmental Entomology 3: 249-252. Hull, L. A. & E. G. Rajotte, 1988. Effects of tufted apple bud moth (Lepidoptera: Tortricidae) injury on quality and storageability of processing apples. Journal of Economic Entomology 81: 17321736. Hull, L. A., D. J. Biddinger & C. M. Felland, 1993. Tufted apple bud moth par~sitoid diversity, relative effectiveness and temporal distribution in conventional and pheromone disruption apple orchards in Pennsylvania. Pennsylvania Fruit News 73: 19-23. Hull, L. A. & C. M. Felland, 1994. Tufted apple bud moth behavior in a pheromone environment and the use of mating disruption to reduce insecticide input in Pennsylvania apple orchards. Pennsylvania Fruit News 74: 42-59. Kirsch, P., 1988. Pheromones: Their role in control of agricultural insect pests. American Journal of Alternative Agriculture 3: 8397. Knight, A. L. & L. A. Hull, 1988. Area-wide population dynamics of Platynota idaeusalis (Lepidoptera: Tortricidae) in southcentral Pennsylvania pome and stone fruits. Environmental Entomology 17: 1000-1008. Knight, A. L., L. A. Hull & E. G. Rajotte, 1988. Resistance management strategies for tufted apple budmoth. Pennsylvania Fruit News 68: 28-34. Knight, A. L, L. A. Hull & E. G. Rajotte, 1990a. Patterns of Platynota idaeusalis (Lepidoptera: Tortricidae) egg mass deposition within an apple orchard. Environmental Entomology 19: 648-655.
Knight, A., L. Hull, E. Rajotte, H. Hogmire, D. Horton, D. Polk, J. Walgenbach, R. Weires & J. Whalon, 1990b. Monitoring azinphosmethyl resistance in adult male Platynota idaeusalis (Lepidoptera: Tortricidae) in apple from Georgia to New York. Journal of Economic Entomology 83: 329-334. LeOra Software, 1987. POLO-PC. A user's guide to Probit Or LOlit analysis. LeOra Software, Berkeley, CA., 22 pp. Minks, A. K. & R. T. Card6, 1988. Disruption of pheromone communication in moths: is the natural blend really most efficacious? Entomologia experimentalis et applicata 49: 25-36. Pfeiffer, D. G., W. Kaakeh, J. C. Killian, M. W. Lachance & P. Kirsch, 1993a. Mating disruption for control of damage by leafrollers in Virginia apple orchards. Entomologia experimentalis et applicata 67: 47-56. Pfeiffer, D. G., W. Kaakeh, J. C. Killian, M. W. Lachance & P. Kirsch, 1993b. Mating disruption for control of damage by codling moth in Virginia apple orchards. Entomologia experimentalis et applicata 67: 57-64. Prokopy, R. J, M. Christie, S. Johnson & M. O'Brien. 1990. Transitional step toward second-stage integrated management of arthropod pests of apple in Mossachusetts orchards. Journal of Economic Entomology 83: 2405-2409. Roelofs, W. L. & M. A. Novak, 1981. Small-plot disorientation test for screening potential mating disruptants. In: E. R. Mitchell (ed.). Management of Insect Pests with Semiochemicals. Plenum Press, New York, NY, pp. 229-242. Smart, K. J., 1985. Phenology of the tufted apple budmoth, Platynota idaeusalis (Walker) (Lepidoptera: Tortricidae), in western North Carolina. M.S. Thesis. North Carolina State University, 38 pp. Suckling, D. M., P. W. Shaw. J. G. I. Khoo & V. Cruickshank, 1990. Resistance management of light brown apple moth, Epiphyas postvittana (Lepidoptera: Tortricidae) by mating disruption. New Zealand Journal of Crop and Horticultural Science 18: 89-98. Weires, R. & H. Riedl, 1991. North American species. In: L. P. S. van der Geest & H. H. Evenhuis (eds.). World Crop Pests. vol. 5. Tortricid Pests: Their Biology, Natural Enemies and Control. Elsevier, New York, NY, pp. 413-434.
