Control of grape root borer

Final Report for FNE08-639

Project Type: Farmer
Funds awarded in 2008: $3,182.00
Projected End Date: 12/31/2009
Region: Northeast
State: Pennsylvania
Project Leader:
R. Martin Keen
Landey Vineyards
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Project Information

Summary:

Note to readers, attached is the complete final report for FNE08-639

Grape root borer is one of the most serious insect pests of grapes in the eastern United States. The goal of this project is to find a sustainable method of control using pheromone traps. A total of 81 traps were placed in the experimental area of 2.41 acres in the three acre vineyard using a randomized complete block design. Three different colors (standard-yellow with green and white, all green and all white) of traps placed at three different heights were located in the vineyard in 2003 and 2004. The standard traps captured the greatest number of moths and were usually the best statistically in both 2003 and 2004. The white traps had consistently caught the lowest number of moths and were the least effective statistically. With the removal of the all white traps and the addition of all yellow traps, no statistical significance was found in the color treatments in 2005, 2006 or 2007. In 2008, the standard traps were statistically better than the yellow traps using Tukey’s studentized range (hsd ) test, but not with the AgStats02 program.

Based on statistical analysis in 2005, 2006 and 2007 height treatments are significant. A difference in height of just 13 inches can be statistically significant. In 2007, the new medium placement of 57 inches was significantly better than the high placement of 70 inches with the AgStats02 program and Tukey’s studentized range (hsd ) test. In 2008 no significant difference was found in the height treatments, although the same height treatments utilized in 2007 were repeated. Grape root borer traps should be placed in the vine canopy between 44 and 70 inches above the ground.

Mating disruption still appears to be a possibility, although the total number of moths captured has not decreased since the initiation of the project in 2003. Since the first trapping began in 2003, the total number of grape root borers captured has remained relatively constant until 2007 when a 50% increase occurred in male moths captured. In 2008 the total number of males captured increased again, this time by 22% over the 2007 total. The production of grapes indicates trapping has been helpful in reducing the total possible number of grape root borers in the vineyard. Production and vigor of the vines has increased during the first four years of the project showing the beneficial aspects of the pheromone trapping. A drop in production and vigor occurred in 2007 that can be attributed to 2,4-D exposure in 2006. Production and vigor in 2008 were very similar to 2007.

Introduction:

Goals, Farm profile and Participants

Little work has been done on grape root borer (Vitacea polistiformis) in Pennsylvania. Several methods are available to trap and enumerate the adult male grape root borer with pheromone lures. We have worked with different trapping methods in our vineyard. This project continues five previous SARE grants, FNE03-471, FNE04-520, FNE05-550, FNE06-576 and FNE07-610. One of the main goals of this project has been to determine if the color and placement of moth traps are significant variables. Results from 2003 and 2004 revealed the color of the trap is a significant parameter in the number of moths captured. In 2003 the standard (yellow with green and white) and all green traps were significantly more effective than the white traps and in 2004 the standard traps were significantly better than the green or white traps. With the removal of the white traps from the experiment and the addition of all yellow traps in 2005, trap color was no longer a significant variable until 2008.

In 2003 and 2004, the placement of the traps was rarely significant. Each year the data is evaluated using two different statistical programs. The high placement of traps was significantly better than the medium or low placement in 2004 with one statistical program , but not the other. When the white traps were removed from the experiment in 2005, placement became a significant variable. Depending on the statistical program used, the high and medium placement or just the high placement were significantly better than the low placement. In 2006, similar results were recorded with the same trap placements as in 2005. Depending on the statistical program used, high and medium placement or just the medium placement were significantly better than the low placement. In 2007 the trap placements were modified due to the statistically significant results from the previous two years.

The current SARE project will continue to build on the previous work. Trap colors utilized in 2007 were repeated to ascertain if those colors continue to be no longer significant. Trap placements from 2007 were repeated due to the medium placement of 57 inches being statistically more efficient than the high placement of 70 inches in 2007. Another main goal of this project is to determine if mating disruption is possible with high numbers of pheromone traps in a vineyard. Because of the multiple year life cycle (at least three years) of the grape root borer, an extended testing period is required. If mating disruption is possible as a control measure, the need for pesticides would be eliminated.

Farm Profile

I am a part-time farmer currently farming 5 acres with my brother. The land is rented from our mother. The total size of the present farm is only 7.8 acres, although it has been cultivated by our family for seven generations. There is no house on the premises, only a 40′ by 60′ tobacco barn. My brother and I first planted wine grapes on the farm in 1974. Today a total of 3.5 acres is planted in wine grapes and includes the French hybrids: seyval, vidal and chambourcin and pinot noir, a vinifera. The vidal was planted in 1976, chambourcin in 1980, seyval in 1984 and 1986 and pinot noir in 2007, 2008 and2009. Vines are grown with unilateral or bilateral cordon training on the bottom wire. A standard three wire system with wires at 36, 54, and 72 inches is used for the trellis. The vines are trained using vertical shoot positioning. Vineyard spacing is 9 foot wide rows with 6 feet between the vines in the row. An area of approximately one half acre is used for the growing and production of grafted vines and other varieties. Since 1989 I have also grown one half acre of saffron on the farm. Previously I was the only commercial grower of saffron in the United States. The saffron was harvested, dried, packaged and sold directly to retail outlets under the label of Greider’s Lancaster County Saffron. Since 2004 the saffron harvest has been dramatically reduced to the point we no longer have a sufficient quantity for sales.

The farm is composed entirely of Duffield silt loam with a 0 to 3% slope on the top of a small hill. The location provides excellent air drainage with no frost pockets. The surrounding area is almost entirely in farmland and is located in an agricultural security area. There have been no changes in the operation since the initiation of the SARE project.

Participants

The technical advisor for this project is Mark Chien of Pennsylvania State University . Since 1999, Mark has been the wine grape agent for Penn State Cooperative Extension. Currently he is serving all of Pennsylvania. Another advisor on the project is Dr. Michael Saunders of the entomology department at Pennsylvania State University. One area of his research involves the ecology and pest management of arthropods affecting vineyards and refining existing grape management practices. His extension work covers integrated pest management in viticulture. Dr. Saunders will provide expertise in experimental design and statistical analysis of the data.

Project Objectives:
Project Activities

Results from the 2003 and 2004 SARE projects revealed the color of the trap can be a significant variable in the number of moths captured. A complete statistical analysis of the data revealed the standard and green traps were significantly more effective than the white traps in 2003. In 2004, the standard traps were more effective than the green or white. In 2003 and 2004 the white traps were the least effective of the three colors. The following year, in 2005, the white traps were removed from the study and replaced with a completely yellow trap. With the removal of the white traps in 2005, trap color was no longer statistically important, but trap placement became statistically important. Depending on the statistical program used, the high and medium placement or just the high placement were significantly better than the low placement. In 2006, similar results were recorded with the same trap placements as in 2005. Depending on the statistical program used, high and medium placement or just the medium placement were significantly better than the low placement. In 2007 the trap placements were modified due to the statistically significant results of the previous two years. A new trap placement was selected, because the low placement of 18 inches was statistically inferior to the high and medium placements in 2005 and 2006. The low placement of 18 inches was removed from the experiment and replaced with a new placement of 57 inches in 2007.

The goals of the project have been to maximize the capture rate by determining the best color and placement of traps and to ascertain if mating disruption is possible with a high number of traps. The experiment was designed to attempt capture of all male moths with sufficient replicates for statistical analysis. In 2003 and 2004, 31% of the traps caught no root borers at all. When the white traps were removed in 2005, the number of traps catching no root borers decreased to 9% in 2005,12% in 2006 and 6% in 2007. The experimental design from 2003, 2004, 2005, 2006 and 2007 was repeated in 2008 using the same plots and blocks with the traps placed in a new random selection. The variables tested were trap color and placement. A randomized complete block design was developed for each variable. The experimental area covered 80% of the vineyard.

The same trap trap colors utilized in 2006 and 2007, yellow, standard (yellow with green and white) and green, were retested in 2008. Standard and green plastic universal moth traps are available from Great Lakes IPM (Vestaburg, Michigan). The all yellow traps were purchased from Advanced Pheromone Technologies, Inc. in Marylhurst, Oregon. A total of 81 traps were placed in the vineyard or 27 of each color – yellow, standard and green.

The vineyard was divided into 27 blocks of 72 feet by 54 feet or 3888 square feet per block. Each block was divided into three plots of 18 feet by 72 feet or 1296 square feet per plot. A trap was suspended on the trellis at the center of each plot. Every block received the three different colors. The color of each trap placed in the plots of each block was selected using a ten thousand random digit table.

The three different trap height placements utilized in 2007 were selected for retesting in 2008. Traps were placed 44 inches above the ground in the canopy close to the fruiting zone, 57 inches above the ground in the middle of the vine canopy and 70 inches above the ground or at the top of the vine canopy. The distance from ground level was based on the position of the pheromone lure.

For trap height the vineyard was divided into 9 blocks of 162 feet by 72 feet or 11,664 square feet per block. Each block was divided into three plots of 72 feet by 54 feet or 3888 square feet per plot. Each plot for the trap height experiment was the same as a block for trap color. Within each plot for trap height, the three traps received the same height. For each of the three trap heights there were 27 replicates, three in each plot. The height of the traps in the plots of each block were selected using a ten thousand random digit table.

The traps were placed in the vineyard on June 19th according to the experimental design. A 10% DDVP toxicant insecticide PVC tape measuring 1 inch by 4 inches was placed inside each trap to kill any moths that entered. A pheromone lure for grape root borer was place in the lure holder of each trap. The traps were checked every three or four days or twice a week from June 21st until September 7th with the moths captured recorded on data sheets.

Cooperators

Click linked name(s) to expand
  • Mark Chien

Research

Research results and discussion:
Results

In our vineyard, the first male grape root borer moths were recorded on July 5th (3 moths) and the last August 26th (1 moth), with the highest catch on July 15th with 127 moths. A total of 444 moths were captured in 2008, a 21.6% increase from the total captured (365 moths) in 2007. In 2006 a total of 243 male grape root borer moths were captured, in 2005 a total of 266 male moths were captured and in 2004 a total of 144 moths, while in 2003, 224 moths. This variability in the total number of male grape root borers captured each year is not unexpected. There is a very high mortality of eggs and newly hatched larvae that can vary significantly from year to year depending on many factors such as the weather and the presence of predators during egg development and hatching. In the northern regions of the grape root borer range (Pennsylvania) most of the larvae probably have a three year or longer life cycle.

Table 1. Major Catch Dates for 2008

Date Total moths captured
7-5 3
7-8 13
7-12 64
7-15 127
7-19 101
7-22 69
7-26 33
7-29 12
8-2 8
8-5 2
8-9 5
8-12 2

The initiation of moth emergence, date of highest catch and the end of moth emergence can also vary from year to year. During the six years of this project, the date of first capture has been from June 28th to July 5th. For five of the six years the date of the highest catch has been in mid-July with the other year being in early August. The date of last capture has varied from August 7th to August 30th.

Statistical analysis was performed on the data with two different methods in 2008. The first was the agricultural statistics analysis program (AgStats02) provided by the Pacific Northwest Conservation Tillage Systems Information Source at http://pnwsteep.wsu.edu/agstatsweb. This program allows up to 16 treatments and 16 replicates and performs an analysis of variance. The level of significance can be selected at 1%, 5%, 10% or 20%. All data entered with this program utilized the randomized complete block design option. The other statistical method was Tukey’s studentized range (hsd ) test. This test is also called the honestly significant difference (hsd ) procedure.

The height treatment data in the statistical program has been entered as low (44 inches above ground level), medium (57 inches above ground level) and high (70 inches above ground level).

Table 2. Height Treatments 2008

high 70” 189 moths
medium 57” 128 moths
low 44” 127 moths

At a 5% level of significance, no significant difference was found in the 2008 height treatments with the AgStats02 program. The same result also occurred using Tukey’s studentized range (hsd) test for statistical analysis. At a 5% level of significance, no significant difference was found in the 2008 height treatments. This was the first year since 2004 and the removal of the white traps from the study, that no significant difference was found in the height treatments.

Color treatments are entered in the statistical program as yellow, standard (yellow with green and white) and green.

Table 3. Color Treatments 2008

standard 221 moths
green 118 moths
yellow 105 moths

The experimental design for each color treatment (yellow, standard and green) contained 27 replicates. Unfortunately the AgStats02 program allows only 16 replicates. To run this program the three replicates of each color in each height block were combined. The three treatments (yellow, standard and green) were entered with nine replications. At a 5% level of significance, no significant difference was found in the 2008 color treatments with the AgStats02 program. The same result occurred in 2005, 2006 and 2007.

A different result occurred using Tukey’s studentized range (hsd) test with 27 replicates for statistical analysis. At a 5% level of significance, a significant difference was found in the 2008 color treatments. The standard (yellow with green and white) traps were significantly better than the yellow traps.

Table 4. Tukey’s studentized range (hsd ) test Color Treatment 2008

LSD (least significant difference) 3.8532

Treatment Name Mean
standard 8.1852 a treatments with different letters
green 4.3704 ab are significantly different
yellow 3.8889 b
5% level of significance

An analysis of variance (AgStats02) for the combined treatments (height and color) was performed. For this statistical analysis, nine treatments were entered with nine replications. Within each height treatment block (162 ft. by 72 ft.) there were all nine possible combinations of height and color treatments. Using AgStats02 at a 5% level of significance, no significant statistical difference was found in the 2008 combined treatments of height and color.

Based on statistical analysis in 2008, only the color treatments were significant. With Tukey’s studentized range (hsd ) test, the standard (yellow with green and white)traps were significantly better than the yellow traps. This was the first year since 2004 the color treatments were found to be significant. In 2004 white traps were utilized instead of the current yellow traps. The white traps were removed from the testing in 2005 and replaced with the yellow traps. No statistical significance was found in the color treatments using the AgStats02 program.

The height treatments of 44 inches, 57 inches and 70 inches had no statistical significance in 2008. This was the first time since 2004 that no statistical significance was found in the height treatments. Every year since the white traps were removed from the experiment the height treatments had been significant.

Three varieties of French hybrid grapes; seyval, vidal and chambourcin are planted in the vineyard. The experimental design was developed primarily to test if adult male grape root borer moths would have a preference for different pheromone traps based on color and location. The initial plan called for an attempt to determine if grape root borers have a preference among the three varieties planted in our vineyard. Unfortunately the experimental design only allows a comparison to be made between the seyval and vidal.

In an analysis of variance (AgStats02) based on variety preference, two treatments were entered with eight replicates. No significant difference was found between the two varieties, even at a 20% level of significance. The same result occurred in 2003, 2004, 2005, 2006 and 2007.

7. Conditions

On May 30, 2006, the adjoining 37 acre farm was sprayed entirely with a herbicide mix containing the amine form of 2,4-dichlorophenoxyacetic acid (2,4-D) because of its enrollment in the Conservation Reserve Enhancement Program (CREP) administered by the Farm Service Agency of the USDA. Grapevines are extremely sensitive to small amounts of phenoxy-type herbicides through both spray drift and volatilization of the chemical due to high temperatures. That day the high temperature reached 93°F for over one hour. By June 8th, herbicide damage due to 2,4-D was visible on the grapevines. On June 22nd, employees of the Pennsylvania Department of Agriculture took samples of grape tissue for herbicide testing. Analysis of the grape leaves found 2,4-D present at a concentration of 0.009 parts per million. A trace amount of 2,4,5-trichlorophenoxypropionic acid (2,4,5-TP), which was banned in 1985, was also found in the grape leaves. Damage from the herbicide exposure was more apparent in 2007, but still visible in 2008. Vine vigor and production of the chambourcin and vidal are below levels seen previous to the 2,4-D exposure. The seyval has rebounded to a vigor and production level equal to that found before the herbicide exposure.

A change in nozzle type in our vineyard sprayer during the first half of the season in 2008 resulted in an outbreak of powdery mildew.

8. Economics

Although the project was not structured for economic analysis, some trends are apparent. Since the introduction of universal moth traps to the vineyard production has increased with some yearly fluctuations. Many other variables, such as weather or lack of disease pressure, could account for the increase, instead of the presence of moth traps. With the increase in production, total farm income has also increased. The production of chambourcin, our most valuable variety, peaked in 1996 at 5.5 tons total production. By 2002 when two universal moth traps were placed in the vineyard, production had declined to 1.4 tons. Over the next two years, when 81 traps were in the vineyard each year, production increased 184% to 3.97 tons. Since 2004, the production of chambourcin has remained relatively constant with minor fluctuations until 2007. Production of vidal increased each year since the project started until 2006. The decrease in vidal and chambourcin production can be attributed to the 2,4-D exposure in late May 2006. Vidal, with its reduced vigor, appeared to be the variety most affected by the exposure. Along with the decrease in fruit production, the chambourcin and vidal vines were less vigorous in 2007 and 2008 with decreased shoot growth and leaf production.

Table 5. Grape Production in Tons 2002-2008

Variety 2002 2003 2004 2005 2006 2007 2008

chambourcin 1.4 2.8 3.97 3.7 3.8 2.6 2.7
vidal 3.9 6.2 7.4 9.2 7.8 5.7 5.3

 

Research conclusions:
Assessmemt

Results from 2008 did not confirm the results of 2007. The placement of traps was found to be not significant in 2008. With both the AgStats02 statistical program and Tukey’s studentized range (hsd ) test in 2007, the medium placement (57 inches) was significantly better than the low placement (44 inches). No statistical significance was found in the placement of the traps with either the AgStats02 program or Tukey’s studentized range (hsd )test in 2008.

In 2007 no significant difference was found in the color treatments. For the first time since 2004, a significant difference was found in 2008 in the color treatments. Utilizing Tukey’s studentized range (hsd ) test, the standard color traps were significantly better than the yellow traps. This was the first year since 2004 when the all white traps were removed and replaced with all yellow traps that any statistical significance has been found in the color treatments. No statistical significance was found in the color treatments with the AgStats02 program.

Distribution of grape root borers in a small area can be very random. In the experimental test area of 2.41 acres, there were plots with no root borers and other areas of higher concentrations. In both 2003 and 2004, 25 traps or 31% caught no root borers during the 2.5 months of trapping. The number of traps catching no root borers in 2005 decreased to just 7 or 9% of the total traps. In 2006, 10 traps or 12% of the total traps caught no root borers. The number of traps catching no root borers in 2007 decreased to just 5 or 6% of the total traps. In 2008 the number of traps catching no root borers decreased again to 4 or 5% of the total traps, the lowest number since the initiation of the project. The lower number for 2008 could be due to the increased number of grape root borers captured and or the improved placement of the traps that was initiated in 2007.

Plots with high concentrations of captured moths decreased in the early years and then remained almost constant in terms of the percentage of moths captured, until 2008. In 2003, 4 traps or 5% of the total traps captured 25% of the moths. The four highest trap catches in 2003 were 17, 15, 14 and 10. In 2004, 4 traps or 5% captured 20% of the moths and the two highest trap counts were 8, followed by 7 and 6. Four traps or 5% captured 16% of the moths in 2005 and the four highest trap catches were 14, 11, 9 and 8. This trend continued in 2006 with 4 traps or 5% capturing 14% of the moths and the four highest trap catches were 10, 9, 8 and 8. In 2007, 4 traps or 5% captured 14.8% of the moths and the four highest trap counts were 16, 13, 13 and 12. This downward trend was reversed in 2008. Four traps or 5% of the total traps captured 21.2% of the moths. The four highest trap catches in 2008 were 42, 18, 17 and 17. The previous highest trap catch was 17 in 2003 and in 2008 the highest trap catch (42) was nearly 2.5 times greater. A possible explanation for this greatly increased single trap catch will be researched this year.

Participation Summary

Education & Outreach Activities and Participation Summary

Participation Summary

Education/outreach description:

A large poster presentation on the 2003, 2004, 2005, 2006 and 2007 SARE projects was presented at the Pennsylvania Association for Sustainable Agriculture’s 18th annual Farming for the Future conference on February 5-7, 2009. This conference held in State College, PA was attended by 1900 people from 30 states and six countries.

A 45 minute power point presentation on the 2007 and 2008 SARE projects was presented at the 2009 Mid-Atlantic Fruit and Vegetable Convention on February 3, 2009 in Hershey, Pennsylvania. A ten minute question and answer session followed the talk. The meeting is sponsored by the State Horticultural Society of Pennsylvania, Pennsylvania Vegetable Growers Association, Maryland State Horticultural Society and New Jersey Horticultural Society. Approximately 100 people attended the talk, with attendees from Pennsylvania, Maryland, New Jersey and Ontario.

Project Outcomes

Assessment of Project Approach and Areas of Further Study:

Potential Contributions

Adoption

The results after six years of the project are barely encouraging. Since 2005 no statistical difference had been found with the trap colors being used until 2008. The standard (yellow with green and white) traps were significantly better than the yellow traps utilizing Tukey’s studentized range (hsd ) test. No statistical significance was found using the AgStats02 program. The results from 2008 would indicate the best color to use for grape root borer capture would be the standard color.

Height placement was statistically significant in 2007, but not in 2008. This was the first year since 2004 that height placement was not statistically significant. Results from 2008 did not verify the results from 2007 that height placement can be statistically significant. Testing over the six years of the project has shown the traps should be placed in the vine canopy between 44 and 70 inches above the ground.

Mating disruption still appears to be a possibility, although the total number of moths captured each year has not been reduced and has even increased the last two years.

Table 6. Total Male Grape Root Borers Captured

2003 2004 2005 2006 2007 2008

224 144 266 243 365 444

Although the number of male grape root borers captured increased 22% from 2007 to 2008 in our vineyard, this was a lower rate of increase than the previous year increase of 50%.

The relatively stable number of male moths captured does not mean mating disruption is unattainable. During the first two years of the study, all variables remained the same and the number of moths captured decreased 36%. White traps were used in the first two years and they were proven to be statistically ineffective at capturing moths. The white traps were removed from the study in 2005 and the total number of moths captured increased, but the effectiveness of all the colors also increased with no statistical difference being present.

During the third and fourth years of the study all variables remained the same and the number of moths captured decreased 8.6%. The low placement of traps was proven to be statistically ineffective at capturing moths. Removal of the low placement (18”) in 2007 increased the effectiveness of the traps at capturing grape root borers in 2007 and 2008. The total number of moths captured increased during those years.

The grape root borer in the northern portion of its range (Pennsylvania, New Jersey, Maryland) can have a three year or possibly even longer larval stage feeding on grape roots. During the six years of the study, the total number of male moths captured has not increased substantially until 2007, but the trapping methods have improved overtime. If no trapping had been done in the vineyard, the number of grape root borers would be expected to be much higher by 2008 as is evident in other local vineyards.

Grape production indicates trapping has been helpful in reducing the total number of grape root borers in the vineyard. Production and vigor of the vines has increased during the project. Chambourcin production went from 1.4 tons in 2002 to 3.8 tons in 2006 and vidal increased from 3.9 tons to 7.8 tons during the same time period. Production decreased in 2007, but that can be attributed to 2,4-D exposure in 2006. Production in 2008 was very similar to 2007. Chambourcin production increased slightly while vidal dropped slightly in production. The slight drop in vidal can be attributed to fruit loss due to the presence of powdery mildew. Infected vidal fruit was removed throughout the season. Just the increase in production has shown trapping to be beneficial.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.