The title of the project: From Beneficial Insect to Economic Pest: a Sustainable Management to the Asian Lady Beetle in Midwestern Grapes

Final Report for GNC04-034

Project Type: Graduate Student
Funds awarded in 2004: $9,633.00
Projected End Date: 12/31/2005
Grant Recipient: Univeristy of Minnesota
Region: North Central
State: Minnesota
Graduate Student:
Faculty Advisor:
William Hutchison
Univeristy of Minnesota
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Project Information

Summary:

This research provided significant contributions to our knowledge of the Harmonia axyridis-wine grape system. Adult beetles feeding on wine grapes appeared to increase their overwintering survival. Also, yellow jackets and beetles were not able to break the skins of grape berries directly. For growers, we developed practical sampling plans based on six potential action thresholds. We also examined the efficacy of biorational and conventional insecticides for managing H. axyridis. The combination of a sampling plan and the use of effective insecticides proved useful to growers in 2005; both will be essential components of sustainable management plans for this new pest.

Introduction:

The multicolored Asian lady beetle, Harmonia axyridis (Pallas) has become a significant pest of fall ripening fruit in Minnesota and the Midwestern U.S., including infestations in grapes. Live or dead beetles, crushed with grapes during the wine making process, create an unpleasant odor and taste. Economic consequences of this pest include complete losses to growers, or increased costs from additional time and labor needed to wash and process grapes before juicing. Given the potential for continuing economic impacts by this pest, and a lack of research-based management alternatives, this project will assess new approaches to minimize beetle infestations and guidelines to reduce insecticide use. Project outcomes, including the use of on-farm research and rapid web-based delivery methods, will increase grower awareness regarding new management tactics, including the potential for floating row covers, chemical control, and the possibility of using trap cropping to attract and kill beetles outside of the primary vineyard. In addition, this project will explore possible reasons for H. axyridis feeding on ripening grapes and the role of wasps in this process.

Project Objectives:

1 -- Evaluate floating row cover barriers to exclude H. axyridis from grapes near ripening.
This objective will compare the efficacy of row cover in protecting grapes from H. axyridis with the efficacy of insecticides and an untreated check. To be a practical management tactic, the mesh must not alter the quality of grapes for wine production. Potential negative effects from shade induced by the row cover will be evaluated through measuring sugar, pH and time to ripening of grapes.

2 -- Spatial distribution of H. axyridis infestations in vineyards.
This objective will evaluate the spatial distribution of H. axyridis in vineyards, and develop a sampling plan for H. axyridis in wine grapes.

3 -- Biological impetus and mechanisms for H. axyridis feeding on fall ripening grapes.
This objective will determine how H. axyridis utilizes simple sugars obtained from grapes. Sub-objective 3A evaluate the survival of males and females of H. axyridis adults after feed on a 25% sucrose solution, fresh squeezed grape juice, or water alone for 48 h. Sub-objective 3B will determine the amounts of body sugars and lipids of males and females of H. axyridis adults after feed on the aforementioned diets.

4 -- Interaction among H. axyridis, wasps, and grapes: source of initial fruit damage?
This objective will determine if wasps cause direct damage that subsequently allows H. axyridis feeding.

Cooperators

Click linked name(s) to expand
  • Nan Bailly
  • John Falconer
  • Anna Mansfield

Research

Materials and methods:

1 -- Evaluate floating row cover barriers to exclude H. axyridis from grapes near ripening.
A field experiment was conducted in 2004 at the Alexis Bailey Vineyard, Hastings, Minn. The insecticide trial was set up in an established vineyard of ‘Leon Millot’. Eight treatments were arranged in a randomized complete block design with four replications each. Each plot consisted of one trellis by four vines in length. A single untreated trellis separated plots. Standard production practices were followed for tilling, pruning, and fungicide sprays. Treatments included: carbaryl (Sevin® XLR Plus, Bayer CropScience) at 1.71 Kg AI/ha (1.54 lb AI/ac); bifenthrin (Capture® 2EC, FMC Corporation) at 0.045 Kg AI/ha (0.040 lb AI/ac); malathion (Malathion® 5, Agriliance) at 1.90 Kg AI/ha (1.70 lb AI/ac), pyrethrin (Pyganic® EC 1.4, MGK Company) at 0.031 Kg AI/ha (0.028 lb AI/ac); and an untreated check. All insecticides were applied within 16 days of anticipated harvest (begin 1 Sept.), and within theirs respective pre-harvest intervals. Carbaryl was applied 16 and 10 days before harvest (DBH; Sept. 1st and 7th); bifenthrin at 7 DBH (Sept. 10th); malathion at 10 and 7 DBH (Sept. 7th and 10th); pyrethrin at 1 DBH (Sept. 16th). Insecticides were applied using a CO2-pressurized backpack sprayer with a 0.91-m (3-ft) boom with 2 nozzles (XR-Teejet 8002 flat fan, with no screen). The sprayer was calibrated to deliver 467.74 liters/ha (50 gal/ac) at 242.32 kPa (35 psi). Plots were sampled for insect pests 6 times before harvest on 31 August, 2, 6, 9, 14, and 17 September 2004. On each sample date, 10 randomly selected clusters from each plot were sampled using visual whole-cluster inspection; counts of H. axyridis adults were recorded for each cluster. Counts of H. axyridis were averaged within plots for each sample date, giving a mean density per cluster for each plot on each sample date. Mean density was then transformed using √ x + 1. Transformed H. axyridis densities were analyzed by date using analysis of variance and the protected Fisher’s Least Significant Difference test (LSD) (SAS 2000).

A field experiment was conducted in 2005 at the Alexis Bailey Vineyard, Hastings, Minn. The insecticide trial was set up in an established vineyard of ‘Leon Millot’. Seven treatments were arranged in a randomized complete block design with four replications each. Each plot consisted of one trellis by four vines in length. A single untreated trellis separated plots. Standard production practices were followed for tilling, pruning, and fungicide sprays (Winkler et al. 1974). Treatments included: carbaryl (Sevin® XLR Plus, Bayer CropScience, Kansas City, MO) at 64.0 oz/ac or 1.97 Kg AI/ha (1.76 lb AI/ac); bifenthrin (Capture® 2EC, FMC Corporation, Philadelphia, PA) at 6.4 oz/ac or 0.112 Kg AI/ha (0.1 lb AI/ac); imidacloprid (Provado® Solupak 75% WP, Bayer CropScience, Kansas City, MO) at 1.0 oz/ac or 0.053 Kg AI/ha (0.047 lb AI/ac), thiamethoxan (Actara® WG, Syngenta Crop Protection, Inc., Greensboro, NC) at 3.5 oz/ac or 0.061 Kg AI/ha (0.055 lb AI/ac); zetacypermethrin (Mustang Max®, FMC Corporation, Philadelphia PA) at 4.0 oz/ac or 0.027 Kg AI/ha (0.024 lb AI/ac); and an untreated check. All insecticides were applied within 30 days of anticipated harvest (beginning 9 August), and within the respective pre-harvest intervals. Carbaryl, thiamethoxan, and zetacypermethrin were applied 7 days before harvest (DBH; August 24th); bifenthrin at 30 and 7 DBH (August 9th and 24th, respectively); and imidacloprid at 1 DBH (August 30th). Insecticides were applied using a CO2-pressurized backpack sprayer with a 0.91-m (3-ft) boom with 2 nozzles (XR-Teejet 8002 flat fan, with no screen). The sprayer was calibrated to deliver 467.74 liters/ha (50 gal/ac) at 242.32 kPa (35 psi). Plots were sampled for insect pests 4 times before harvest on 23, 26, 29, and 31 August 2005. On each sample date, 15 randomly selected clusters from each plot were sampled using visual whole-cluster inspection; counts of H. axyridis adults were recorded for each cluster. Counts of H. axyridis were averaged within plots for each sample date, giving a mean density per cluster for each plot on each sample date. Mean density was then transformed using √ x + 1. Transformed H. axyridis densities were analyzed by date using analysis of variance and the protected Fisher’s Least Significant Difference test (LSD) (SAS 2004).

2 -- Spatial distribution of H. axyridis infestations in vineyards.
Vineyards were sampled in 2004 and 2005 in Stillwater, Afton, Hastings, and Red Wing in Minnesota, and Somerset in Wisconsin. Samples were taken 4 weeks before harvest. Each year, grape clusters were sampled eight times over the four weeks preceding harvest. On each date, 40 to 220 randomly selected clusters were sampled using visual, whole-cluster inspection. For each cluster, data were recorded for the presence or absence of at least one H. axyridis adult and/or one freshly injured berry. Freshly injured berries were defined as an opening in the berry that exposes the pulp. Causes of injury to berries were primarily splitting, followed by birds or insects. Resampling software was used to develop enumerative and binomial sequential sampling plans.

3 -- Biological impetus and mechanisms for H. axyridis feeding on fall ripening grapes.
Harmonia axyridis were collected during October 2004 on the outside walls of Hodson Hall, University of Minnesota, Saint Paul, MN. Forty males or females were sexed, and placed in a 190 x 80 mm Petri dish. Bottom of one 100 x 15 mm Petri dish containing one of the diets were placed in the center of a 190 x 80 mm Petri dish. The diets included: i) 12 injured grape berries; ii) sucrose solution 25 % (i.e., 3.5 g of sugar in 14 ml of water embedded in a cotton ball); iii) 14 ml of water embedded in a cotton ball; and iv) nothing. Petri dishes with adults and diet were held at 25 ± 1°C and a photoperiod of 16:8 (L:D) h. After six days, mortality was recorded, live individuals were transferred to clean plastic Petri dishes (150 x 15 mm), and held at 5 ± 1°C and a photoperiod of 16:8 (L:D) h through the winter. Mortality was evaluated on 11/08/04, 12/21/04, 01/28/05, 02/23/05, and 04//04/05.

4 -- Interaction among H. axyridis, wasps, and grapes: source of initial fruit damage?
Three treatments were used in this trial: i) grape berries with intact skin and yellow jackets; ii) grape berries with intact skin and H. axyridis adults; and iii) grape berries with intact skin alone. For each treatment, 3-4 grape berries of ‘Frontenac’ with intact skin were set in a 150 x 80 mm Petri dish with one yellow jacket (i), one H. axyridis adult (ii), or nothing (iii). The treatment with yellow jackets was replicated 21 times, and the other two treatments were replicated 10 times. After 24 h, insects were removed from the Petri dishes, and each berry was carefully inspected for injury.

Research results and discussion:

1 -- Evaluate floating row cover barriers to exclude H. axyridis from grapes near ripening.
In 2004 field trials, the density of H. axyridis adults at harvest in plots treated with bifenthrin applied 7 d before harvest (DBH) and in plots covered with netting was statistically lower than untreated plots. The density of H. axyridis adults in plots treated with carbaryl 10 DBH (2.50 ± 1.19) and malathion 7 DBH (3.25 ± 2.29) did not differ significantly from untreated plots (15.50 ± 5.07) even though the densities in the treated plots were lower than in the untreated plots. The proportion of clusters infested at harvest with H. axyridis adults in plots treated with bifenthrin applied 7 DBH, carbaryl 10 DBH, and malathion 7 DBH, and in plots covered with netting was statistically lower than untreated plots.
In 2005, the density of H. axyridis adults and the proportion of clusters infested with H. axyridis adults at harvest in plots treated with bifenthrin 7 DBH, bifenthrin 30 DBH, zeta-cypermethrin 7 DBH, and imidacloprid 1 DBH was statistically lower than untreated plots.
In 2004 and 2005, levels of sugar, titratable acidity, and pH in the grape juice did not differ statistically across the treatments.
In 2004 and 2005, levels of alcohol, titratable acidity, and pH in the wine did not differ statistically across the treatments.

2 -- Spatial distribution of H. axyridis infestations in vineyards.
Taylor’s power law parameters a = 3.28 and b = 1.24 were determined by a regression analysis of the log-mean and log-variance of 34 data sets (slope = 1.24 ± 0.04 (SE), intercept = 0.52 ± 0.06, and R2 = 0.96). The b value greater than 1 suggests that an aggregated dispersion for H. axyridis in the vineyards. In addition, we did not notice any edge effect of H. axyridis distribution, suggesting that a trap cropping would not be a feasible control tactic.
We developed eight sampling plans to assess adult density or infestation level. The sampling plans were developed using 49 data sets collected from commercial vineyards sampled in 2004 and 2005. The two enumerative plans covered two precision levels (0.10 and 0.25), and the six binomial plans covered six action thresholds (3, 7, 12, 18, 22, and 31 % of cluster samples infested with at least one H. axyridis). The average sample number (ASN) for each sampling plan was determined through analyses using resampling software. For research purposes, with a precision level of 0.10 (SE/ ), the enumerative plan resulted in an ASN of 552 clusters. For IPM applications, the enumerative plan with a precision level of 0.25, resulted in an ASN of 184 clusters. By contrast, the binomial plans resulted in much lower ASNs, and should be more practical for IPM purposes. At a tally threshold of 1 adult per cluster, the operating characteristic curve, and the six action thresholds provided binomial plans where the ASN ranged from only 19 to 26 clusters. We also develop decision stop lines for each action threshold. In addition, the percentage of correct decisions ranged from 83 to 96, and the percentage of incorrect decision to not treat was always smaller than incorrect decision to treat.

3 -- Biological impetus and mechanisms for H. axyridis feeding on fall ripening grapes.
Sub-objective 3A in 2004: Survival of H. axyridis males in all diets (83.24 ± 6.59 to 92.45 ± 1.18) was significantly higher than in the untreated check (39.39 ± 10.73). Survival of H. axyridis males fed on a solution of sucrose 25 % was the highest, and it was followed by H. axyridis males fed on water, and on grape juice. Survival of H. axyridis females was significantly higher than males (F = 14.47, P = 0.0003, and df = 1, 96). Survival of H. axyridis females fed on grape juice (92.05 ± 1.49) was significantly higher than in the untreated check (75.46 ± 3.18).
Sub-objective 3A was repeated in 2005, and the mortality of H. axyridis adults still being evaluated.
Sub-objective 3B: due to difficulties with the methodology, sub-objective 3B has not been started.

4 -- Interaction among H. axyridis, wasps, and grapes: source of initial fruit damage?
Three treatments were used in this trial: i) grape berries with intact skin and yellow jackets; ii) grape berries with intact skin and H. axyridis adults; and iii) grape berries with intact skin alone. For each treatment, 3-4 grape berries of ‘Frontenac’ with intact skin were set in a 150 x 80 mm Petri dish with one yellow jacket (i), one H. axyridis adult (ii), or nothing (iii). The treatment with yellow jackets was replicated 21 times, and the other two treatments were replicated 10 times. After 24 h, insects were removed from the Petri dishes, and each berry was carefully inspected for injury. All berries, for all treatments, did not have any injury. These results showed that neither yellow jackets, nor H. axyridis adults can cut off the grape berry skin under laboratory conditions.

Participation Summary

Educational & Outreach Activities

Participation Summary:

Education/outreach description:

Results of this research were published and presented in refereed journals, proceedings, extension bulletins, and at research and extension meetings (see Appendix). During the 2005 season, three newsletters were published in the Minnesota Fruit and Vegetable IPM News (Volume 2; numbers 6, 13, and 15), to update grape growers on the management of H. axyridis. The Minnesota Fruit and Vegetable IPM News (http://www.mda.state.mn.us/pestsurvey/pestreports/pestreport.html) is a web-based newsletter funded by the Minnesota Department of Agriculture and the USDA Risk Management Agency.

Appendix
Publications
Refereed Journals:
1. Galvan, T.L., E. C. Burkness and W.D. Hutchison. Influence of berry injury on infestations of the multicolored Asian lady beetle in wine grapes. Research Brief in Plant Health Progress (submitted).
2. Galvan, T.L., R.L. Koch and W.D. Hutchison. 2006. Toxicity of indoxocarb and spinosad to the multicolored Asian lady beetle (Coleoptera: Coccinellidae) via three routes of exposure. Pest Management Science (in press).
3. Galvan, T.L. R.L. Koch and W.D. Hutchison. 2005. Effects of spinosad and indoxacarb on survival, development and reproduction of the multicolored Asian lady beetle (Coleoptera: Coccinellidae). Biological Control, 34: 108-114.

Proceedings:
Galvan, T. L., R. L. Koch, E. C. Burkness, S. J. Wold Burkness, and W. D. Hutchison. 2005. Research Updates on Multicolored Asian Lady Beetle Management in Minnesota Grapes. In: Proceedings of the Upper Midwest Regional Fruit and Vegetable Growers Conference, St. Cloud, MN, February 3-4.

Extension/Outreach articles:
1. Galvan, T. L., E. C. Burkness, and W. D. Hutchison. 2006. Wine grapes in the Midwest: reducing the risk of the multicolored Asian lady beetle. Public. 08232. Univ. of Minnesota Extension Service, St. Paul, MN.
2. Galvan, T. L., E. C. Burkness, and W. D. Hutchison. 2005. Multicolored Asian Lady Beetle Management in Minnesota Grapes: Preliminary Results and Ongoing Research. Minnesota Grape Growers Association Newsletter (in press).

Presentations
Research--Submitted:
1. Galvan, T. L., E. C. Burkness, and W. D. Hutchison. 2006. Enumerative and binomial sequential sampling plans for the multicolored Asian lady beetle in wine grapes. 10-minute paper presentation, student competition, Meeting of the North Central Branch of the Entomological Society of America, Bloomington, IL.
2. Galvan, T. L., E. C. Burkness, and W. D. Hutchison. 2006. Efficacy of insecticides for management of the multicolored Asian lady beetle on wine grapes under field and laboratory conditions. 10-minute paper presentation, Meeting of the North Central Branch of the Entomological Society of America, Bloomington, IL.
3. Galvan, T. L., R. L. Koch, E. C. Burkness, S. J. Wold Burkness, and W. D. Hutchison. 2005. Phenology and management of the multicolored Asian lady beetle in Minnesota Grapes. 10-minute paper presentation, student competition, Meeting of the North Central Branch of the Entomological Society of America, West Lafayette, IN.

Extension--Invited:
1. Galvan, T. L., R. L. Koch, E. C. Burkness, S. J. Wold Burkness, and W. D. Hutchison. 2005. Research Updates on Multicolored Asian Lady Beetle Management in Minnesota Grapes. Upper Midwest Regional Fruit and Vegetable Growers Conference, St. Cloud, MN, February 3-4, 30-minute presentation
2. Hutchison, W. D. and T. L. Galvan. 2005. The multicolored Asian lady beetle as a new pest of grapes: 1st year research update. Annual Minnesota Grape Grower Association Conference, Rochester, MN (Feb.), 60-minute presentation.

Project Outcomes

Project outcomes:

Outcomes from this research have improved the basic knowledge of the wine grape-H. axyridis system and contributed to a more sustainable approach for managing H. axyridis in wine grapes. Regarding basic knowledge, we found that feeding on wine grapes (i.e., uptake of sugar) during the fall (Sept.), may increase the survival of H. axyridis through the winter. We also found that survival rate of males is more dependent on sugar uptake before overwintering than the survival rate of females. In addition, we observed that yellow jackets and H. axyridis adults are not able to directly break grape berry skins. This result indicates that control of yellow jackets in vineyards may not affect H. axyridis feeding, and that H. axyridis feeding on wine grapes depends on previous injury in grape berries (e.g., injury caused by birds of physiological splitting). For pest management, we developed six practical binomial sampling plans based on six potential action thresholds for H. axyridis in wine grapes. The use of sampling has prevented growers to spray their vineyards with insecticide. For example, in 2005, only one out of five vineyards that were sampled required insecticide spray. This represents less environmental contamination, lower insecticide exposure to farmers, and more consistent economic returns for wine grape production. In addition to sampling, we also examined the efficacy of possible insecticides to be used in wine grapes to manage H. axyridis. Based on insecticide efficacy, pre-harvest intervals for currently labeled insecticides, and the late-season influx of H. axyridis infestations, chemical control is presently limited to carbaryl at 7 days before harvest (DBH), malathion at 3 DBH, or imidacloprid 1 at DBH. The combination of a sampling plan and the use of effective insecticides are new, essential components for the sustainable management of this exotic beetle pest.

Economic Analysis

Remove beetles by shaking clusters and covering bins where clusters are held. Float clusters in buckets of water and vacuum clusters. Some growers have done one or both. However, each method has resulted in significant increases in time and labor, and increased the costs of harvest. According to these estimates, growers that use sampling as a strategy in the management of MALB in wine grapes will save at least $200.00 per acre when compared with growers that will rely on the mechanical removal strategy only.

Farmer Adoption

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Recommendations:

Areas needing additional study

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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.