With the development of an effective pheromone blend for grape root borer attraction in 1986, the possibility of mating disruption seemed viable. [Note: In this section and others the pheromone E,Z-2,13-octadecadien-1-ol acetate will be written as EZ and Z,Z-3,13-octadecadien-1-ol acetate will be written as ZZ. The secondary compound in Isonet® Z and Isomate® GRB, E,Z-3,13-octadecadien-1-ol acetate, will be written as EZ-3.]
In 1986 and 1987, vineyards in Arkansas were treated with either EZ or ZZ alone, but not as a pheromone blend. The pheromones were released from Shin-Etsu twist ties at 100 per acre. Each twist tie contained 40 milligrams of the pheromone and were placed 4 feet above the ground. Tests were run at three different locations with three vineyards at each location. At each location one vineyard was a control, one vineyard received EZ and the other vineyard, ZZ. The distance between the vineyards at each location varied from 650 feet to 1.2 miles. Of the nine vineyards, only two had vines that were over nine years of age. A majority of the vineyards were from 3 to 6 years of age. The six vineyards with pheromones were from 0.6 to 2.5 acres, while the three control vineyards were 3.2 to 4.7 acres. Three white paper wing traps with a 99:1 EZ:ZZ pheromone lure were placed in each vineyard to monitor the presence of male grape root borers. No counts of grape root borer populations were done previous to the testing.
The wing traps in pheromone treated vineyards captured significantly fewer moths than the control vineyards. Half of the vineyards had total trap shutdown, meaning no moths were captured. Pupal cases were also counted in each vineyard at 100 preselected vines during the treatment and two years later. The vineyards treated with ZZ had significantly fewer pupal cases than the control vineyards, while the pupal cases in the EZ treated vineyards were reduced but not at a significant amount. 1
The effect of mass trapping was tested in 2007 to 2009. Two separate commercial Concord vineyards, each with a 16 acre treatment plot, had one green bucket trap per acre with a pheromone lure, for a total of 16 traps. In one vineyard, the total counts decreased from 158 to 39, but in the other plot the numbers increased over the three years from 3 to 77. 2
In 1988, tests were run utilizing EZ:ZZ, ZZ alone, and a combination of EZ:ZZ and ZZ in several vineyards in different counties of North Carolina. In the EZ:ZZ and ZZ combination trial, the perimeter of the vineyard was treated with EZ:ZZ and the interior had only ZZ. The pheromones were contained in Shin-Etzu twist-ties with 80 milligrams per tie. Twist ties were placed in the vineyards at a rate of 100 per acre and hung at approximately 6.5 feet above the ground. Each test and control vineyard was in a different county. The two control vineyards were 0.25 and 3 acres each and vine age was from 5 years to over 10 years. Three treatment vineyards were from 0.5 to 1.5 acres in size and vine age was from 5 to 14 years. Each treatment vineyard received a single type of pheromone treatment. Three white paper wing traps with a 99:1 EZ:ZZ pheromone lure were placed in each vineyard to monitor the presence of male grape root borers. Three additional white paper wing traps were placed outside of the treatment vineyards to estimate populations outside of the vineyards. The distance these traps were located from the vineyards was not disclosed. No counts of grape root borer populations were done previous to the testing. Pupal case counts were also done at each of the vineyards. In the treatment vineyards, 50 to 103 vines were checked for pupa, while in the two control vineyards only 10 or 20 vines were surveyed.
Very few male grape root borers were captured in the white wing traps within the treatment vineyards. In the treatment with EZ:ZZ, only one moth was captured in the vineyard, while 684 were captured in the perimeter traps. Trap shutdown occurred with each of the pheromones tested. Two years later trap counts were made again at each of the vineyards. The EZ:ZZ treated vineyard showed a decrease of 28%. During the same time period the two control vineyards also showed decreases of 22 and 13%. The pupal cases in the EZ:ZZ treatment decreased 47% from 1988 to 1990. Similar results were found in the other treatments. No pupal cases were found in the control vineyard. 3
Pheromone trials for mating disruption were done in Florida in 1989 and 1990. A 3.7 acre vineyard known to have grape root borer was used as the test vineyard. Twist tie dispensers containing the EZ:ZZ blend were placed in the vineyard at a rate of 100 per acre. The concentration of the EZ:ZZ blend was not reported. Three white paper wing traps containing the EZ:ZZ pheromone lures were also placed in the vineyard for monitoring. A vineyard 50 miles away was used as the control. The presence of pupal cases around the base of 100 vines at each of the vineyards was used as a method to determine the efficacy of the pheromone twist ties. Female moths were also captured at each vineyard and the fertility of their eggs were determined.
Total trap shutdown occurred both years in the test vineyard. Male moths were captured at the control vineyard, but the number captured was not given. The presence of pupal cases was reduced. In the test vineyard, 112 pupal cases were found in 1989. In 1991, 78 pupal cases were reported. The difference was significant at a 10% level, but not at a 5% level. In the control vineyard the number of pupal cases was much less, eight in 1990 and only four in 1991. The fertility of female moths in the test vineyard was also reduced. None of the 21 females captured in 1989 had mated and of the 43 captured in 1990, 11.6% had mated. In the control vineyard, 70.6% of the females captured in 1989 had mated and 87.5% in 1990. 4
The use of Isonet® Z twist ties was tested in Florida in 2003 and 2004. The pheromones in Isonet® Z are based on those secreted by the female European leopard moth (Zeuzera pyrina L.)and the currant clearwing (Synanthedon tipuliformis Clerck), not the grape root borer. Active ingredients are EZ and EZ-3 in a ratio of 95:5. The major pheromone for the grape root borer, European leopard moth and currant clearwing is the same but the secondary compound is different. Isonet® Z twist ties were placed in the vineyards at a rate of 257 per acre and hung 3.3 feet to 5 feet above the ground.
The effectiveness of Isonet® Z was compared to Lorsban 4E, another pheromone system and no control at all. Four separate vineyards were divided into four 1 acre treatment plots with 49 feet between each treatment plot in a randomized complete block design. No other vineyards were within 10 miles of each of the treatment vineyards. Two paper wing traps ( color not reported), each with an EZ:ZZ pheromone lure were placed in each test vineyard at 3.3 feet to 5 feet above the ground.
Success of the treatment method was based solely on the number of male moths captured in the paper wing traps. No male moths were captured in the Isonet® Z treated sections in 2003 or 2004. The trap catches for the Isonet® Z in 2003 were significantly lower than the Lorsban 4E and the control at a 5% level of significance. In 2004 the Isonet® Z was significantly better than the control but not the Lorsban 4E treated plots at a 5% level. 5
Additional testing with Isonet® Z was done in 2011. The efficacy of the standard grape root borer pheromone lure to the Isonet® Z twist ties was compared in a commercial vineyard. Pherocon® VI delta traps baited with a pheromone lure captured significantly more moths than traps with an Isonet® Z twist tie at a 5% level of significance with Tukey’s studentized range test. The standard pheromone lure baited traps caught an average of about 12 moths per trap while the Isonet® Z baited traps captured an average of about 7 moths per trap. The color of the traps was not reported.
The efficacy of Isonet® Z at various concentrations of twist ties was also tested in 2011. In two different commercial vineyards, Isonet® Z twist ties were placed at densities of 300/acre, 150/acre and 51/acre, along with control plots. Each treatment had 4 replicates of 1 acre apiece. Each plot also contained a wing trap with a standard grape root borer pheromone lure. No moths were captured in the plots with Isonet® Z twist ties, but moths were caught in the control plots. 6 The color of the wing trap was not reported.
In 2003, 2004 and 2005 Isonet® Z twist ties were placed in a commercial vineyard that had a severe infestation of grape root borer at a rate of 200 twist ties per acre. High numbers of nematodes were also used simultaneously to aid in the reduction of grape root borers. The numbers of grape root borer was reduced.
Work with the Isonet® Z twist ties continued in 2007. The same vineyard utilized in the previous testing was again treated with Isonet® Z twist ties at a rate of 100 dispensers per acre. The control area from the previous study was used as the treatment area this time and vice versa. Pupal counts were done in the vineyard in 2009. The number of pupal cases was reduced in the treatment area as compared to the control but the reduction was not significant. Two other commercial vineyards in different areas of Virginia were also selected for testing with Isonet® Z at the same rate. In one vineyard the reduction in grape root borers was significant at the 5% level, while in the other vineyard the reduction had a 1% level of significance in the number of pupal cases. 7
The effect of mass trapping was tested in 2007 to 2009. Two separate commercial vineyards, each with a 16 acre treatment plot, had one standard green trap with a pheromone lure placed in each acre for a total of 16 traps. In a Vidal vineyard, the total counts decreased from 218 to 43, but in the other vineyard (Chardonel) numbers increased over two years from 899 to 1361. In 2009 the Chardonel vineyard was removed.
In 2011, the effectiveness of mating disruption with Isonet® Z and mass trapping with standard pheromone lures was tested. Two treatments of 6 acres and 8 acres each received 200 Isonet® Z twist ties per acre, along with 4 green bucket traps with pheromone lures in each treatment plot. Total trap shutdown occurred with the Isonet® Z with no trap captures.
Five different areas of 5, 5. 8, 8. and 10 acres each were utilized for mass trapping. Each treatment plot had one green bucket trap per acre with a standard pheromone lure. The number of male grape root borers captured varied from 11 to 102. Two plots of 6 and 8 acres were used as a control with a total of four traps per plot. Grape root borer captures in the control plots were 17 and 9. 8
The success of mass trapping has been varied. In our own vineyard, using 33 standard traps per acre between 2003 and 2008, the total captures of male moths increased from 224 to 444, an increase of 98%. The number of male grape root borers captured per acre increased from 93 to 185. Although various trap colors and positions were being tested, from 2003 to 2006 at least 7 traps per acre were the proper colors and position.
After 2006, all the traps in our vineyard were the proper colors and positions to maximize the capture of male grape root borers. In 2009 the number of standard traps per acre was reduced to eleven. All were the proper color and height. The total number of grape root borers captured continued to increase to 525 in 2011 or 219 per acre. After 2011 the number captured decreased to 388 in 2013 or 162 per acre.
In Arkansas, with one green bucket trap per acre for three years in a 16 acre vineyard, counts decreased from 10 per acre to 2.4 per acre, while another vineyard of the same variety and size increased from 0.2 per acre to 5 per acre. In Missouri, similar results occurred with mass trapping. Sixteen green bucket traps were placed in a 16 acre French hybrid vineyard for three years and counts decreased from 14 per acre to 2.7 per acre. In another Missouri 16 acre hybrid vineyard, the counts increased from 56 per acre to 85 per acre in 2 years using one green bucket trap per acre. A year later this vineyard was removed. Although the number of grape root borers per acre are much higher in our vineyard, it remains productive to the present.
The influence of mass trapping has been variable. Sometimes it has resulted in reductions and other times the number of grape root borers has actually increased. In our own tests, with high numbers of traps per acre as compared to others, no significant reduction in grape root borers has been seen. Mass trapping may be more successful if the initial number of grape root borers are fairly low per acre.
The success of mating disruption has also been varied. Various different pheromones have been utilized as a single chemical or in blends. Mating disruption has been measured by both trap shutdown and reduction in pupal cases. In Arkansas EZ and ZZ twist ties with 40 milligrams of either chemical were used at a rate of 100 per acre. Success was measured by the captures of males in white wing traps. The reduction with ZZ was significant while the reduction with EZ was not significant.
Research in North Carolina used three different combinations: EZ:ZZ, ZZ, and a combination of EZ:ZZ and ZZ. The pheromone twist ties contained 80 milligrams each and were used at a density of 100 per acre. Using white paper wing traps, trap shutdown occurred for all the tests. Two years later, both the treatments and control had decreases in trap captures. Pupal cases also decreased in the treatment areas, but no pupal cases were found in the control.
The use of EZ:ZZ twist ties at a rate of 100 per acre was tested in Florida for two years. Total trap shutdown occurred using white paper wing traps. A year later both the treatment and control had decreases in pupal cases. The reduction in the treatment area was significant at the 10% level. Far fewer pupal cases were found in the control but the reduction in pupal cases was actually greater, 50% versus 30% in the treatment area.
Beginning in 2003, all mating disruption studies were done with Isonet® Z. The concentration of pheromones in each Isonet® Z twist tie is less than the concentration found in Isomate® GRB, 70 milligrams versus 80.43 milligrams. Various different densities of twist ties per acre have been tested. In most of the studies, trap shutdown deemed the experiment a success.
In Florida in 2003 and 2004, 257 Isonet® Z twist ties per acre were placed in the test vineyards. Total trap shutdown occurred both years in the treated sections. Further study was done in 2011 when various densities of Isonet® Z were tested. Total trap shutdown occurred in the treated areas with 300 twist ties per acre, 150 twist ties per acre and 51 twist ties per acre. The trapping ability of Isonet® Z as compared with standard pheromone lures for grape root borer was also tested. Standard bucket traps were utilized and standard pheromone lures captured significantly more male moths than Isonet® Z at a 5% level of significance with Tukey’s studentized range test.
In Virginia in 2007, Isonet® Z at a density of 100 twist ties per acre was tested in three vineyards. In 2009, pupal counts were done in each vineyard. In one vineyard the pupal cases were reduced but not at a significant level. In the other two vineyards, the reduction in pupal cases was significant, one at 5% and the other at a 1% level of significance.
Total trap shutdown also occurred in Missouri in 2011 when 200 Isonet® Z twist ties were used per acre in two test vineyards
Various tests at different locations show that trap shutdown occurs with Isonet® Z at different densities. The minimum required for mating disruption has not been determined. When pupal cases were counted after treatment with Isonet® Z, one vineyard did not have a significant reduction while two other vineyards did have significant reductions.
Johnson, Donn T., Barbara A. Lewis, and J. Wendell Snow. 1991. Control of grape root borer (Lepidoptera: Sesiidae) by mating disruption with two synthetic sex pheromone compounds. Environ. Entomol. 20(3): 930-934.↩︎
Johnson, D. T., C. R. Roubos, T. W. Nyoike, L. L. Stelinski, and O. E. Liburd. 2013. Lures, Mating Disruption and Mass Trapping of the Grape Root Borer. Acta Hortic. 1001:129-137.↩︎
Pearson, G. A. 1992. Pheromone effects on mating success and female behavior in the grape root borer. Thesis, North Carolina State University, Raleigh.↩︎
Webb, S. E. 1991. Management of grape root borer in Florida with a pheromone. Proc. Fla. State Hort. Soc. 104:3-5.↩︎
Weihman, S. W., and O.E. Liburd. 2006. Mating disruption and attract-and-kill as reduced-risk strategies for control of grape root borer Vitacea polistiformis (Lepidoptera: Sesiidae) in Florida vineyards. Fla. Entomol. 89(2): 245-250.↩︎
Johnson, D. T., C. R. Roubos, T. W. Nyoike, L. L. Stelinski, and O. E. Liburd. 2013. Lures, Mating Disruption and Mass Trapping of the Grape Root Borer. Acta Hortic. 1001:129-137.↩︎
Pfeiffer, D. G., C. A. Laub, T. A. Jordan, A. K. Wallingford, and M. Cassel. 2010. Control of grape root borer using mating disruption – 2009. Proceedings of 85th Cumberland-Shenandoah Fruit Workers’ Conference, 19-20 November 2009, Winchester, VA. pp. 35-36.↩︎
Johnson, D. T., C. R. Roubos, T. W. Nyoike, L. L. Stelinski, and O. E. Liburd. 2013. Lures, Mating Disruption and Mass Trapping of the Grape Root Borer. Acta Hortic. 1001:129-137.↩︎