Research Bulletin Fluctuating Temperatures: Comparison of Linear Smith,O

Page 6 — Viticulture and Enology Research Center February 1991 component from the western grapeleaf skeletonizer, of western grapeleaf skeletonizer (Lepidoptera: Harrisina brillians. Tetrahedron Lett. 23: 2757-2760. Zygaenidae). Environ. Entomol.19:1689-1697. Roltsch, W. J., M. A. Mayse & K. Clausen. 1990. Tem SAS Institute. 1985. SASuser's guide: statistics.SAS perature dependent development under constant and Institute, Gary, N.C. Research Bulletin fluctuating temperatures: Comparison of linear Smith,O. J.,K.M. Hughes, P. H. Dunn & 1. M. Hall. versus nonlinear methods for modeling development 1956. A granulosis virus disease of the western grapeleaf skeletonizer (Lepidoptera: Zygaenidae). California State University, Fresno J. Econ. Entomol. 78: 799-801. About CATI... Soderstrom, E. L.,D. G. Brandl, J. Myerson, R. G. Buttery &B. E. Mackey. 1985. Sex pheromone for Asa permanent research arm ofCalifornia State attractingwestern grapeleafskeletonizer (Lepidop Seasonal Patterns of Western Grapeleaf University, Fresno's School ofAgricultural Sciences tera; Zygaenidae). J. Econ. Entomol. 8: 799-801. and Technology, the California Agricultural Tech Steinhaus,E. A.& K. M.Hughes. 1952. A granulosisof nology Institute (CATI) is committed toimproving the western grapeleaf skeletonizer. J. Econ. Entomol. Skeletonizer (Lepidoptera: Zygaenldae) the profitability ofCalifornia's foundation 45:744-745. industry-agriculture. Stern, V. M.,D. L. Raherty &W. L.Peacock.1983. Pheromone Trap Catch Theaddress is asfollows: Control of the western grapeleaf skeletonizer (Lepi doptera: Zygaenidae), a newgrapepestin theSan California Agricultural Technology Institute Joaquin Valley, California. J. Econ. Entomol. 76:192- By William J. Roltsch, Wesley 0. Carr Jr., and Mark A. Mayse California State University, Fresno 195. Fresno, CA 93740-0115 Stern, V. M. & B.A. Federici. 1990.Granulosis virus: Introduction pheromone trap catch data can be useful in describing Phone: (209) 278-4869. biological control forwestern grapeleaf skeletonizer. the general seasonal occurrence pattern of a species, California Agriculture 44:21-22. The Western Grapeleaf Skeletonizer (WGLS) particular care must be taken when attempting to use {Harrisina brillians Barnes & McDunnough) was first such data to reflect relative population abundance on a detected in San Diego County, California during 1941 daily basis. Such information can only be interpreted (Lange, 1944). It is now established in the southern and within the context of a detailed knowledge of the central regions of California and may ultimately become biology of the organism. The field dynamics of competi established in the northern viticultural regions of the tion involving synthetic pheromone and female moth state. Larvae are primarily grapevine defoliators. pheromone attractiveness to male moths are often quite However, they will feed on fruit clusters on extensively complex . For example, pheromone trap catch of WGLS defoliated vines, which often leads to Botrylis bunch rot. frequently declines during the middle of a generation Research on WGLS biology, biological control, chemical curve, while at the same time visual count data of flying control, and pheromone attractants has been conducted moths signify peak male and female moth abundance intermittently for more than 40 years since Lange's (W. C. Carr Jr., unpublished). (1944) report on this insect as a new California grape pest (Steinhaus & Hughes, 1952; Barnes et al, 1954a&b; The primary objective of this project was to investi Hall, 1955;Smith et al, 1956;Clausen, 1961;Myerson et gate WGLS moth seasonal activity patterns within and al., 1982; Stem et al., 1983; Soderstrom et al., 1985; Curtis between years in vineyards in the Fresno County region et al., 1989;Stern & Federici, 1990;Clausen, 1989;Mayse of California's San Joaquin Valley. Furthermore, two & Carr, 1990; Roltsch et al., 1990). commonly used trapping devices were compared for their relative effectiveness. Results would demonstrate Pheromone systems of pest insects have been of particular interest to practitioners of integrated pest TheVilicullureand Enology Research Center is one management because these monitoring tools can greatly ofthemajor research centers comprising the reduce the time and labor involved in sampling. Sex pheromone traps can be very useful for monitoring various characteristics of a species' occurrence. For example, they can be used to monitor the seasonal occurrence of a species. Also, they may be useful in providing seasonalinf5rmationregarding the approxi California Agricultural Technology Institute mate time of first appearance, which is often used as a Publication No. 910202 "biofix" for phenology model initialization. While sex Page 5 Page 2 for each of the two trap types. However, examination of heat accumulation from maximum and minimum how patterns of WGLS activity may vary or coincide checked, moths were counted and removed from the the raw field data indicated that during one 28 day temperatures. Ecology 50:514-517. among vineyards and years in the central San Joaquin inserts so that the sticky surface would remain effective period in 1987, delta traps caught ca. 60% of that cap Curtis C. E., P. J. Landolt, R. R. Heath &R. Murphy. Valley. This research is part of a broader research in capturing moths attracted the next day. tured by wing traps. No certain explanation can be 1989.Attraction of western grapeleaf skeletonizer program investigating WGLSecology, with the ultimate provided for this one-time deviation from comparative males (Lepidoptera: Zygaenidae) to S-(+)-2-Butyl- goal of helping growers improve the ways they manage Pheromone traps were monitored in the early trap catches that were typically much closer. In general, (Z)-7-Tetradecenoate. J. Econ. Entomol. 82: 454-457. WGLS populations. afternoon on a daily basis. In 1986,monitoring began on the wing traps' higher daily moth totals probably Clausen, C. P. 1961. Biologicalcontrol of western June 1, prior to the start of the second moth flight of the involved several factors associated with the two trap grapeleaf skeletonizer (Harnsina brillians). Hilgardia Materials and Methods season. In 1987,monitoring began during the first week types differing designs. Most notably, the wing trap 31:613-638. of March, well before the spring emergence from the sticky insert had 338cm^ of surface area compared to Clausen, K. 1989. Mortality patterns of western ^ape- Studies during 1986-87 were conducted on the overwintering population of pupae. For all years, 214cm^ of surface area for the delta trap sticky insert leafskeletonizer on grapesin central California. M.S. California State University, Fresno (CSUF) farm vine monitoring continued into November, by which time (i.e., delta area = 63%of wing trap area). Thesis, California State University, Fresno. yard. Counts were made of male moths collected from moths were rarely caught. Hall, I. M. 1955. The use of Bacillus thurinqiensis Berliner pheromone traps located within each division of a six- Conclusion to control the western grapeleafskeletonizer. J.Econ. quadrant grid. The 1 ha (2.5 acres) grid was situated During 1988,single traps were placed in the same Entomol. 48: 675-677. within a 2.5ha (6.2 acres) plot of 30-year-oldThompson area of the CSUFvineyard, as well as in six commercial First, second and third seasonal moth flights dem Lange, W. H.Jr. 1944. The western grapeleaf skeleton seedless grapevines{Vitis vinifera L.). One wing trap and or abandoned Thompson seedless vineyards in the onstrated similar patterns of occurrence among vine izer, Harrisina brillians in California. Calif. Dept. one delta trap containing sticky bottom inserts were Fresno vicinity. During 1989-90,trapping was continued yards within a year. However, greater differences Agric. Bui. 32:98-104. located in each quadrant (Fig. 1).Each trap contained in the CSUF vineyard and in two of the six additional occurred in moth flight duration among years. Using Mayse, M. A. &W. C. Carr Jr. 1990. Alternative chemical the same type and amount of the 1cm x 0.5 cm lami vineyards used in 1988. The two additional sites were 17 pheromone traps to determine the approximate time control of western grapeleaf skeletonizer on grapes in nated lure (Hercon Environmental Corp., Emigsville, km (10.5 miles) east and 12 km (7.4 miles) west of the that WGLS moths first occur in a vineyard during the central California. Res. Bui. 900506, Calif. Agric. Pa.). TheWGLS lure contained thesynthetic analogof CSUF site.Traps were placed in each vineyard prior to springseems reasonable. In everyvineyard forall years, Technol. Inst., Calif. State Univ., Fresno. female pheromone (sec-butyl-(Z)-7-tetradecenoate), spring emergence in March and checked at three- to traps initially caught oneor two moths. Thereafter, each Myerson, J., W. F. Hadden &F. L. Soderstrom. 1982. Sec- which is highly attractive to male moths (Soderstrom et four-day intervals during each flight cycle and weekly trapcount gradually increased. This would beexpected butyl-(Z)-7-tetradecenoate. Anovel sexpheromone a)., 1985; Curtiset al., 1989). Both trap designs received between cycles. Bucketstyle traps (Fig. 1) were used iftraps were catching moths at levels representative ofa new lures every six weeks. Thestickybottom inserts during 1988-90 because of theirability to trap large gradually increasing moth population emerging from an werereplacedon an individual basis depending on each numbers of moths without the diminished effectiveness overwintering population of pupae. About the Authors... trap's condition. Each day whenthe 12 traps were expected froma sticky typetrap.Sticky traps required Although in the majority ofcases moths were first William }. Roltsch isa lecturer and caught inFresno County vineyards from the 16th to 25th research scientist for the Department ofPlant Figure 1. Pheromone trap styles used tomonitor male WGLS moths in this study. ofMarch, first trapcatch islikely to occur earlier or later Science andMechanized Agriculture, California in counties south or north of Fresno respectively. State University, Fresno. He obtained his Ph.D. Results clearly indicate thatWGLS hasthree distinct degree in entomology from Michigan State I Bucket Trap generations per year, and moth trap counts suggest that University. During the last two years he has a small fourth generation may occur. However, positive participated in a variety of research projects confirmation ofa distinct fourthgeneration ofWGLS through CSU, Fresno's integrated pest Wing Trap will require retaining pupae from the second and third generations, and observing their fate under ambient management (IPM) program. conditions throughout the remainder of the season. 8 cm X 2.5 cm Wesley C. Carr Jr. is aformer graduate entrance holes 22 cm References research assistant for CSU, Fresno's Department of Plant Science and Mechanized Agriculture. He Anonymous. 1987. IMPACT (Integrated Management has a master's degree inentomology. ofProduction inAgriculture using Computer Tech nology) Manual. Univ. of Calif. 1PM Implementation Mark A. Mayse is a professor of entomology 10 cm 26 cm Group. Davis,CA. in CSU, Fresno's Department of Plant Science 27 cm Barnes, M. M., D.W. Robinson &A. G. Forbes. 1954a. and Mechanized Agriculture. As director of Attractants for moths of thewestern grapeleaf skele- CSU, Fresno's integrated pest management tonizer. J. Econ. Entomol. 47: 58-63. (IPM) program, he has led research activities in Barnes, M. M., C. Gammon &D. W. Robinson. 1954b. the areas of IPM and agricultural sustainability. Insecticide dusts for control ofthe western grapeleaf Delta Trap skeletonizer inCalifornia. J. Econ. Entomol. 47; 54- He has a Ph.D. in entomolgy from the University ofIllinois. cm 12 cm 57. Baskerville, G. L. &P. Emin. 1969. Rapid estimation of Pages Page 4

MOTH FLIGHTS -- MAiTRE 88 -- MAITRE 88 — CSUF 88 — MAITRE 89 — MAITRE 89 I -- BELMONT 88 MAITRE 90 I — MAITRE 88 CSUF 1986 CSUF 1987 \\

50 1' "I o -- BELMONT 88- BFLMONT 88 — BELMONT 89" BELMONT 89- 0 1 . 1 1 1 1 1 1 1 1 1 ... 1 ..•. 1 . . •• I •• (r \ — MUSCAT 88 SELMONT 90 LU 250 " 'V -- SELMA 88 CL 200 CL -i ' 1 — STANFORD 8J O «0- (/) LU J GOLF 88 X CL 150 I- o 100 r"' I " ' I f' 200- CSUF 87 50 CSUF 87 'd K -- CSUF 88 • -- CSUF 88 80 100 120 MO ISO 180 200 220 2^0 260 280 300 — CSUF 89 I I 111 — CSUF 89 500 1000 1500 2000 2500 (10 April) (9 June) (8 Aug.) (17 Sept.) (27 Ocl.) " --- CSUF 90 DEGREE DAYS JULIAN DATE

MOTH FLIGHTS -- MAiTRE 88 -- MAITRE 88 — CSUF 88 — MAITRE 89 — MAITRE 89 I -- BELMONT 88 MAITRE 90 I — MAITRE 88 CSUF 1986 CSUF 1987 \\

Figure 5. Estimated daily trap catch counts for male west Figure 2. Average daily pheromone trap catch counts for male 65 85 105 125 145 165 185 205 225 245 265 285 305 325 1—^ ern grapeleaf skeletonizer moths in seven vineyards in 1988. western grapeleaf skeletonizer moths during 1986 and 1987 in 1000 1500 2000 1 I I I i I Note that counts are plotted against degree-days (i.e., phy CSUF vineyard. Averages calculated daily from 12 traps for all (26 March) (5 Moy) (14 June) (24 July) (2 Sept.) (12 Oct.) DEGREE DAYS siological time). dates except from March 26 to April 10 during 1987, at which JULIAN DATE time four traps were used. Number values designate dates of pheromone lure replacement for each year (6 = 1986, 7 = 1987). Figure 4. Estimated daily trap catch counts for male western Figure 3. Estimated daily trap catch counts for male west grapeleaf skeletonizer moths in the CSUF vineyard from 1987 ern grapeleaf skeletonizer moths in the CSUF vineyard from to 1990, and in two additional vineyards during 1988 to 1990. traps in the vineyard until April 11, compared with 12 1987 to 1989, and in two additional vineyards during 1988 Note that counts are plotted against degree-days (i.e., phy traps through the remainder of the 1987 season. daily removal of moths during peak flight periods when and 1989. Counts plotted against Julian dates. Number siological time). an accurate assessment of moth flight activity was values designate dates of pheromone lure replacement for Trap catch data plotted against degree-days im necessary. The bucket portion of each bucket trap con each year (8 = 1988, 9 = 1989). proved the correspondence of seasonal flights among tained a small piece of insecticidal strip material {a.i.= years within vineyards (Fig. 4.). This was most evident dichlorvos). On several occasions a trap was noted as Throughout this study, the earliest date on which by comparing second moth flight overlap between the being approximately one-third full while containing yards were located within 13km (8miles) east, west and moths were caught in a trap in any given vineyard was 1988 and 1989 seasons (Figs.3 & 4). Figure 4 illustrates nearly 500 moths. south of CSUFin 1988,one vineyard was approximately March 13,1988. The latest date on which the first moth the degree of variation observed among years for each 29 km (18miles) south of CSUF. Temperature data from of the season was caught in a given vineyard was April of the three vineyards monitored for three or four Trap catch data for 1986-87are presented as daily a second CIMIS station (within 6.5 km or 4 miles) were 3,1990. The majority of first seasonal trap catches consecutive years. Relative to 1988 and 1990, trap catch trap catches. Those collected during 1988-90are pre used in relation to that field. occurred between the 16th and 25th of March. Periods of for the second flight in 1989 differed in two ways. The sented as the estimated daily trap catch, which equals moth flight activity during each generation commonly duration of trap catch was shorter during 1989,and the the number of moths caught between check dates Results and Discussion lasted as long as 20-30days. Generation trap catch curve shifted to the left. Figure 5 illustrates that within a divided by the number of days between check dates. curves commonly exhibited several peaks (i.e., bimodal) year, moth flight occurrence was fairly consistent from These data were then plotted against the Julian date or The presence of four distinct WGLS moth flights (Figs. 2 and 3). This was particularly true of the third vineyard to vineyard. This is of particular significance accumulated degree-days accrued midway between was demonstrated in 1986,1987 and 1989,suggesting moth flight occurring in August of each year. because vineyard management differed greatly. Four of dates that traps were checked. that as many as four generations can occur in the San the seven sites monitored in 1988 were abandoned Joaquin Valleyin a given year (Figs. 2 &3).Relatively However, decline in trap catch resulting in bimodal vineyards. Degree-day accumulations began on the first day low trap counts during the fourth moth flight indicated curves did not reflect a decline in moth abundance. that moths were caught during spring emergence within that the majority of moths emerging in the spring are Studies of WGLSmoth flight behavior conducted at Wing and delta trap data collected in 1987 were each vineyard. Degree-days were calculated using the from pupae that entered diapause during the third CSUF have shown that both male and female flight analyzed for similarity of trap catch using a paired t-test Baskerville and Emin (1969) single-sine approximation generation(i.e., the offspringfrom moth flight III; Fig.2), activity is often very high during this time. These with each trap type paired at each of the six locations in method with a lower (9.0°C)and upj'er (28.2®C) thresh and perhaps evenduring earliergenerations. Compari observations suggest that an increased proportion of the test plot. The wing trap mean (x=21.28moths-per- old (Roltsch et al. 1990). Temperature data were ac son of WGLSdegree-day requirements for development male moths may be attracted to actual pheromone- trap-per-day) was significantly (t=2.69, df=234, P<0.01) cessed through the University of California IMPACT (Roltsch et al., 1990) with the 1986-89 degree-day accu emitting females rather than to the synthetic lure traps greater then the delta trap mean (x=19.06). A Pearson program (Anonymous, 1987).Temperature data from a mulations during late summer and fall strongly suggests at these times (W. C. Carr Jr., unpublished). Relative to correlation test was f>erformed on the trap means. A California Irrigation Management Information System that larvae which are not fourth or fifth instars by mid- the remainder of the season during 1987,spring emer correlation coefficient (r) of 0.89 was obtained (SAS (CIMIS)station located on the CSUF campus were used October are likely to encounter insufficient cumulative gence trap data may have been artificially high until Institute 1985,pp. 415-416),indicating a relatively high for all vineyards, with one exception. While five vine- degree-days to complete development. April 11. This probably resulted from having only four degree of correlation of moth activity recorded by date Page 5 Page 2 for each of the two trap types. However, examination of heat accumulation from maximum and minimum how patterns of WGLS activity may vary or coincide checked, moths were counted and removed from the the raw field data indicated that during one 28 day temperatures. Ecology 50:514-517. among vineyards and years in the central San Joaquin inserts so that the sticky surface would remain effective period in 1987, delta traps caught ca. 60% of that cap Curtis C. E., P. J. Landolt, R. R. Heath &R. Murphy. Valley. This research is part of a broader research in capturing moths attracted the next day. tured by wing traps. No certain explanation can be 1989.Attraction of western grapeleaf skeletonizer program investigating WGLSecology, with the ultimate provided for this one-time deviation from comparative males (Lepidoptera: Zygaenidae) to S-(+)-2-Butyl- goal of helping growers improve the ways they manage Pheromone traps were monitored in the early trap catches that were typically much closer. In general, (Z)-7-Tetradecenoate. J. Econ. Entomol. 82: 454-457. WGLS populations. afternoon on a daily basis. In 1986,monitoring began on the wing traps' higher daily moth totals probably Clausen, C. P. 1961. Biologicalcontrol of western June 1, prior to the start of the second moth flight of the involved several factors associated with the two trap grapeleaf skeletonizer (Harnsina brillians). Hilgardia Materials and Methods season. In 1987,monitoring began during the first week types differing designs. Most notably, the wing trap 31:613-638. of March, well before the spring emergence from the sticky insert had 338cm^ of surface area compared to Clausen, K. 1989. Mortality patterns of western ^ape- Studies during 1986-87 were conducted on the overwintering population of pupae. For all years, 214cm^ of surface area for the delta trap sticky insert leafskeletonizer on grapesin central California. M.S. California State University, Fresno (CSUF) farm vine monitoring continued into November, by which time (i.e., delta area = 63%of wing trap area). Thesis, California State University, Fresno. yard. Counts were made of male moths collected from moths were rarely caught. Hall, I. M. 1955. The use of Bacillus thurinqiensis Berliner pheromone traps located within each division of a six- Conclusion to control the western grapeleafskeletonizer. J.Econ. quadrant grid. The 1 ha (2.5 acres) grid was situated During 1988,single traps were placed in the same Entomol. 48: 675-677. within a 2.5ha (6.2 acres) plot of 30-year-oldThompson area of the CSUFvineyard, as well as in six commercial First, second and third seasonal moth flights dem Lange, W. H.Jr. 1944. The western grapeleaf skeleton seedless grapevines{Vitis vinifera L.). One wing trap and or abandoned Thompson seedless vineyards in the onstrated similar patterns of occurrence among vine izer, Harrisina brillians in California. Calif. Dept. one delta trap containing sticky bottom inserts were Fresno vicinity. During 1989-90,trapping was continued yards within a year. However, greater differences Agric. Bui. 32:98-104. located in each quadrant (Fig. 1).Each trap contained in the CSUF vineyard and in two of the six additional occurred in moth flight duration among years. Using Mayse, M. A. &W. C. Carr Jr. 1990. Alternative chemical the same type and amount of the 1cm x 0.5 cm lami vineyards used in 1988. The two additional sites were 17 pheromone traps to determine the approximate time control of western grapeleaf skeletonizer on grapes in nated lure (Hercon Environmental Corp., Emigsville, km (10.5 miles) east and 12 km (7.4 miles) west of the that WGLS moths first occur in a vineyard during the central California. Res. Bui. 900506, Calif. Agric. Pa.). TheWGLS lure contained thesynthetic analogof CSUF site.Traps were placed in each vineyard prior to springseems reasonable. In everyvineyard forall years, Technol. Inst., Calif. State Univ., Fresno. female pheromone (sec-butyl-(Z)-7-tetradecenoate), spring emergence in March and checked at three- to traps initially caught oneor two moths. Thereafter, each Myerson, J., W. F. Hadden &F. L. Soderstrom. 1982. Sec- which is highly attractive to male moths (Soderstrom et four-day intervals during each flight cycle and weekly trapcount gradually increased. This would beexpected butyl-(Z)-7-tetradecenoate. Anovel sexpheromone a)., 1985; Curtiset al., 1989). Both trap designs received between cycles. Bucketstyle traps (Fig. 1) were used iftraps were catching moths at levels representative ofa new lures every six weeks. Thestickybottom inserts during 1988-90 because of theirability to trap large gradually increasing moth population emerging from an werereplacedon an individual basis depending on each numbers of moths without the diminished effectiveness overwintering population of pupae. About the Authors... trap's condition. Each day whenthe 12 traps were expected froma sticky typetrap.Sticky traps required Although in the majority ofcases moths were first William }. Roltsch isa lecturer and caught inFresno County vineyards from the 16th to 25th research scientist for the Department ofPlant Figure 1. Pheromone trap styles used tomonitor male WGLS moths in this study. ofMarch, first trapcatch islikely to occur earlier or later Science andMechanized Agriculture, California in counties south or north of Fresno respectively. State University, Fresno. He obtained his Ph.D. Results clearly indicate thatWGLS hasthree distinct degree in entomology from Michigan State I Bucket Trap generations per year, and moth trap counts suggest that University. During the last two years he has a small fourth generation may occur. However, positive participated in a variety of research projects confirmation ofa distinct fourthgeneration ofWGLS through CSU, Fresno's integrated pest Wing Trap will require retaining pupae from the second and third generations, and observing their fate under ambient management (IPM) program. conditions throughout the remainder of the season. 8 cm X 2.5 cm Wesley C. Carr Jr. is aformer graduate entrance holes 22 cm References research assistant for CSU, Fresno's Department of Plant Science and Mechanized Agriculture. He Anonymous. 1987. IMPACT (Integrated Management has a master's degree inentomology. ofProduction inAgriculture using Computer Tech nology) Manual. Univ. of Calif. 1PM Implementation Mark A. Mayse is a professor of entomology 10 cm 26 cm Group. Davis,CA. in CSU, Fresno's Department of Plant Science 27 cm Barnes, M. M., D.W. Robinson &A. G. Forbes. 1954a. and Mechanized Agriculture. As director of Attractants for moths of thewestern grapeleaf skele- CSU, Fresno's integrated pest management tonizer. J. Econ. Entomol. 47: 58-63. (IPM) program, he has led research activities in Barnes, M. M., C. Gammon &D. W. Robinson. 1954b. the areas of IPM and agricultural sustainability. Insecticide dusts for control ofthe western grapeleaf Delta Trap skeletonizer inCalifornia. J. Econ. Entomol. 47; 54- He has a Ph.D. in entomolgy from the University ofIllinois. cm 12 cm 57. Baskerville, G. L. &P. Emin. 1969. Rapid estimation of Page 6 — Viticulture and Enology Research Center February 1991 component from the western grapeleaf skeletonizer, of western grapeleaf skeletonizer (Lepidoptera: Harrisina brillians. Tetrahedron Lett. 23: 2757-2760. Zygaenidae). Environ. Entomol.19:1689-1697. Roltsch, W. J., M. A. Mayse & K. Clausen. 1990. Tem SAS Institute. 1985. SASuser's guide: statistics.SAS perature dependent development under constant and Institute, Gary, N.C. Research Bulletin fluctuating temperatures: Comparison of linear Smith,O. J.,K.M. Hughes, P. H. Dunn & 1. M. Hall. versus nonlinear methods for modeling development 1956. A granulosis virus disease of the western grapeleaf skeletonizer (Lepidoptera: Zygaenidae). California State University, Fresno J. Econ. Entomol. 78: 799-801. About CATI... Soderstrom, E. L.,D. G. Brandl, J. Myerson, R. G. Buttery &B. E. Mackey. 1985. Sex pheromone for Asa permanent research arm ofCalifornia State attractingwestern grapeleafskeletonizer (Lepidop Seasonal Patterns of Western Grapeleaf University, Fresno's School ofAgricultural Sciences tera; Zygaenidae). J. Econ. Entomol. 8: 799-801. and Technology, the California Agricultural Tech Steinhaus,E. A.& K. M.Hughes. 1952. A granulosisof nology Institute (CATI) is committed toimproving the western grapeleaf skeletonizer. J. Econ. Entomol. Skeletonizer (Lepidoptera: Zygaenldae) the profitability ofCalifornia's foundation 45:744-745. industry-agriculture. Stern, V. M.,D. L. Raherty &W. L.Peacock.1983. Pheromone Trap Catch Theaddress is asfollows: Control of the western grapeleaf skeletonizer (Lepi doptera: Zygaenidae), a newgrapepestin theSan California Agricultural Technology Institute Joaquin Valley, California. J. Econ. Entomol. 76:192- By William J. Roltsch, Wesley 0. Carr Jr., and Mark A. Mayse California State University, Fresno 195. Fresno, CA 93740-0115 Stern, V. M. & B.A. Federici. 1990.Granulosis virus: Introduction pheromone trap catch data can be useful in describing Phone: (209) 278-4869. biological control forwestern grapeleaf skeletonizer. the general seasonal occurrence pattern of a species, California Agriculture 44:21-22. The Western Grapeleaf Skeletonizer (WGLS) particular care must be taken when attempting to use {Harrisina brillians Barnes & McDunnough) was first such data to reflect relative population abundance on a detected in San Diego County, California during 1941 daily basis. Such information can only be interpreted (Lange, 1944). It is now established in the southern and within the context of a detailed knowledge of the central regions of California and may ultimately become biology of the organism. The field dynamics of competi established in the northern viticultural regions of the tion involving synthetic pheromone and female moth state. Larvae are primarily grapevine defoliators. pheromone attractiveness to male moths are often quite However, they will feed on fruit clusters on extensively complex . For example, pheromone trap catch of WGLS defoliated vines, which often leads to Botrylis bunch rot. frequently declines during the middle of a generation Research on WGLS biology, biological control, chemical curve, while at the same time visual count data of flying control, and pheromone attractants has been conducted moths signify peak male and female moth abundance intermittently for more than 40 years since Lange's (W. C. Carr Jr., unpublished). (1944) report on this insect as a new California grape pest (Steinhaus & Hughes, 1952; Barnes et al, 1954a&b; The primary objective of this project was to investi Hall, 1955;Smith et al, 1956;Clausen, 1961;Myerson et gate WGLS moth seasonal activity patterns within and al., 1982; Stem et al., 1983; Soderstrom et al., 1985; Curtis between years in vineyards in the Fresno County region et al., 1989;Stern & Federici, 1990;Clausen, 1989;Mayse of California's San Joaquin Valley. Furthermore, two & Carr, 1990; Roltsch et al., 1990). commonly used trapping devices were compared for their relative effectiveness. Results would demonstrate Pheromone systems of pest insects have been of particular interest to practitioners of integrated pest TheVilicullureand Enology Research Center is one management because these monitoring tools can greatly ofthemajor research centers comprising the reduce the time and labor involved in sampling. Sex pheromone traps can be very useful for monitoring various characteristics of a species' occurrence. For example, they can be used to monitor the seasonal occurrence of a species. Also, they may be useful in providing seasonalinf5rmationregarding the approxi California Agricultural Technology Institute mate time of first appearance, which is often used as a Publication No. 910202 "biofix" for phenology model initialization. While sex