Project Overview
Annual Reports
Information Products
Commodities
- Additional Plants: ornamentals, trees, Christmas trees
Practices
- Education and Training: demonstration, extension, farmer to farmer, participatory research, workshop
- Pest Management: biological control, integrated pest management
- Production Systems: holistic management, organic agriculture
Proposal abstract:
In 2009, an estimated 30.8 million live Christmas trees were purchased in the US, valued at $1.1 billion. Almost 34% of the plantations are in the Northeast, where Christmas tree production provides critical income that preserves the working landscape and small family farms. Christmas tree plantations are monocultures, and several insect pests, such as spider mites and balsam twig aphid occur, for which chemical pesticides are commonly applied. Root aphids surfaced regionally as a persistent Christmas tree problem. Because they feed on tree roots, they often go undetected until populations are high and tree health is impacted. Infested seedlings are stunted, chlorotic and susceptible to root rot. Growers came to us several years ago complaining of root aphid problems and asking for solutions. They said they preferred to avoid chemical pesticides, knowing they are not good for the environment or human health (theirs and their customers). However, to date, pesticides are the only option available. Until research is done to demonstrate the potential of biocontrol, growers will continue to rely on chemical approaches, despite their recognized drawbacks.The goal of this project is to determine reliable methods for surveying root aphids in Christmas trees and test two biological control agents for root aphid management. . One trial will involve release of predatory mites, Stratiolaelaps scimitus. The second study treatment is an an insect-killing fungus (Beauveria bassiana). Both will be compared to an untreated control.Outreach will be at state christmas tree association meetings in the region.
Project objectives from proposal:
The specific research objectives of this project are:
1) Conduct studies to develop grower-friendly survey methods for root aphids;
2) Test the efficacy of predatory mites and fungal drenches of BotaniGard, a registered insect-killing fungus, against conifer root aphids. In addition, information to Christmas tree growers on effective detection methods for root aphids and options for non-chemical based management, will be disseminated.
Performance Targets:
1. The efficacy of two biological control agents will be evaluated against conifer root aphids.
2. Detection methods appropropriate for growers will be developed and tested.
3. Technical information on conifer root aphids will be transfered to 100 New England growers at educational workshops.
4. Technical information on conifer root aphids will be transfered to 500 New England growers through articles in newsletters.
5. Three publications or factsheets will be developed and disseminated to growers.
This project includes two objectives to address root aphid management in Christmas tree plantations. Research will be conducted primarily at two Vermont plantations heavily infested with conifer root aphids.
Obj. 1. Conduct studies to develop grower-friendly survey methods for conifer root aphids.
According to literature from Washington state, these root aphids have two host tree species, a primary host, believed to be Fraxinus spp., (Ash), and alternate hosts which are various fir species (Abies spp.).3 They are thought to have two flight periods, one in the spring when they migrate from the primary to the secondary host, the other in the fall when they leave conifer trees to return to ash trees. Despite this migratory behavior, some young aphids remain on the roots throughout the year. Based on our observations in Vermont this year, these aphids have a significant flight period in the fall though their destination is unclear. To date there has been no evidence of aphids on ash trees located around root aphid-infested plantations. This year migration occurred in late September, though the precise time likely varies from year to year. We have not observed adult flights in the spring in Vermont when the aphids are believed to return to the plantation, though it is logical that it does occur.
Yellow sticky traps will be tested as a means of detecting root aphids in Christmas tree plantations. These traps may not be the most precise survey method in that they can only provide a general indication of the population, and may not reflect population levels of aphids feeding on roots or the risk to the trees. However, these traps are commercially available at low cost and should provide evidence of the presence or absence of the pest, and a relative estimate of population levels. Our experience has been that at this point many growers are unaware if their trees are infested with root aphids. If a simple method of detection could be devised, growers could monitor their plantations and increase their knowledge of their current pest problems.
In May, 20 sticky traps will be put up vertically at each of the two test sites where aphids are known to occur at high levels at 1,000 sq ft-intervals. Traps will be labeled to identify the cardinal direction of their position so the direction of the flight of the aphid into or out of the plantation can be determined. In addition, 10 traps will be positioned horizontally adjacent to symptomatic trees to catch aphids as they emerge from the soil. Traps will also be put up in two additional plantations where it is unknown if aphids are present. Every 2 wk for two months, traps will be inspected for winged conifer aphids. They are easily distinguished from other winged aphids by their bluish color and the presence of white wool attached to their abdomen. Ten small trees (
Obj. 2. Test the efficacy of predatory mites and fungal drenches of BotaniGard, a registered insect-killing fungus against conifer root aphid. In mid-May, at each plantation, 70 test trees (~1-2 m tall) with symptoms of root aphids will be selected. The experiment will include three treatments: 1) release of H. miles, a soil-dwelling predatory mite; 2) drench with Mycotrol®O (an organic Beauveria bassiana formulation from Bioworks, Inc.); 3) untreated control. Twenty test trees will be randomly assigned to each treatment; 10 trees will be used to estimate pretreatment aphid populations. Predatory mites (~500/tree) will be distributed around the bole of each tree, as recommended by B. Spencer, Applied Bio-nomics (pers. com.). The fungal treatment will be made at the rate of 2 liters of Mycotrol/378 liters water (recommended rate for root aphids, Bioworks). The fungal suspension will be applied with a hand-held hydraulic sprayer around the tree trunk at a rate of 0.5 liters/tree. A second spray will be made after 3 days, as recommended. No treatment will be made to control trees. Half of the treatment trees will be sampled 4 wk after treatment; the remaining trees will be sampled after 8 wk. Aphid population levels will be determined as described above. In addition, the presence of predatory mites, ants and other predators will be determined by visual inspection of the root balls. A subsample of aphids will be collected and plated to assess fungal infection. The trial will be repeated in mid-August. Aphid density data from both trials will be subjected to ANOVA (Proc GLM, P<0.05) to determine the following significant differences: among treatments, between sites, between sample times within trials and between trials.
Literature Cited:
1. USDA 2007 Census of Agriculture. Census of Horticultural Specialties: Christmas Trees on Operation. http://www.agcensus.usda.gov/Publications/2007/Online_Highlights/Census_of_Horticulture_Specialties/hortic_2_016_016.pdf
2. Burden, D. 2012. Christmas Tree Profile. http://www.agmrc.org/commodities__products/forestry/christmas-tree-profile/
3. DeAngelis, J.A. Conifer root aphid, Prociphilus americanus (Walker) in true fir.
http://entomology.oregonstate.edu/system/files/u1473/Root_Aphid_Handout.pdf
4. Straw, N.A., N.J. Fielding, G. Green & J. Price. 2000. Impact of green spruce aphid, Elatobium abietinum (Walker), and root aphids on the growth of young Sitka spruce in Hafren Forest, Wales: effects on height, diameter and volume. Forest Ecology & Management 134: 97-109.
This project includes two objectives to address root aphid management in Christmas tree plantations. Research will be conducted primarily at two Vermont plantations heavily infested with conifer root aphids.
Obj. 1. Conduct studies to develop grower-friendly survey methods for conifer root aphids.
According to literature from Washington state, these root aphids have two host tree species, a primary host, believed to be Fraxinus spp., (Ash), and alternate hosts which are various fir species (Abies spp.).3 They are thought to have two flight periods, one in the spring when they migrate from the primary to the secondary host, the other in the fall when they leave conifer trees to return to ash trees. Despite this migratory behavior, some young aphids remain on the roots throughout the year. Based on our observations in Vermont this year, these aphids have a significant flight period in the fall though their destination is unclear. To date there has been no evidence of aphids on ash trees located around root aphid-infested plantations. This year migration occurred in late September, though the precise time likely varies from year to year. We have not observed adult flights in the spring in Vermont when the aphids are believed to return to the plantation, though it is logical that it does occur.
Yellow sticky traps will be tested as a means of detecting root aphids in Christmas tree plantations. These traps may not be the most precise survey method in that they can only provide a general indication of the population, and may not reflect population levels of aphids feeding on roots or the risk to the trees. However, these traps are commercially available at low cost and should provide evidence of the presence or absence of the pest, and a relative estimate of population levels. Our experience has been that at this point many growers are unaware if their trees are infested with root aphids. If a simple method of detection could be devised, growers could monitor their plantations and increase their knowledge of their current pest problems.
In May, 20 sticky traps will be put up vertically at each of the two test sites where aphids are known to occur at high levels at 1,000 sq ft-intervals. Traps will be labeled to identify the cardinal direction of their position so the direction of the flight of the aphid into or out of the plantation can be determined. In addition, 10 traps will be positioned horizontally adjacent to symptomatic trees to catch aphids as they emerge from the soil. Traps will also be put up in two additional plantations where it is unknown if aphids are present. Every 2 wk for two months, traps will be inspected for winged conifer aphids. They are easily distinguished from other winged aphids by their bluish color and the presence of white wool attached to their abdomen. Ten small trees (
Obj. 2. Test the efficacy of predatory mites and fungal drenches of BotaniGard, a registered insect-killing fungus against conifer root aphid. In mid-May, at each plantation, 70 test trees (~1-2 m tall) with symptoms of root aphids will be selected. The experiment will include three treatments: 1) release of H. miles, a soil-dwelling predatory mite; 2) drench with Mycotrol®O (an organic Beauveria bassiana formulation from Bioworks, Inc.); 3) untreated control. Twenty test trees will be randomly assigned to each treatment; 10 trees will be used to estimate pretreatment aphid populations. Predatory mites (~500/tree) will be distributed around the bole of each tree, as recommended by B. Spencer, Applied Bio-nomics (pers. com.). The fungal treatment will be made at the rate of 2 liters of Mycotrol/378 liters water (recommended rate for root aphids, Bioworks). The fungal suspension will be applied with a hand-held hydraulic sprayer around the tree trunk at a rate of 0.5 liters/tree. A second spray will be made after 3 days, as recommended. No treatment will be made to control trees. Half of the treatment trees will be sampled 4 wk after treatment; the remaining trees will be sampled after 8 wk. Aphid population levels will be determined as described above. In addition, the presence of predatory mites, ants and other predators will be determined by visual inspection of the root balls. A subsample of aphids will be collected and plated to assess fungal infection. The trial will be repeated in mid-August. Aphid density data from both trials will be subjected to ANOVA (Proc GLM, P<0.05) to determine the following significant differences: among treatments, between sites, between sample times within trials and between trials.
Literature Cited:
1. USDA 2007 Census of Agriculture. Census of Horticultural Specialties: Christmas Trees on Operation. http://www.agcensus.usda.gov/Publications/2007/Online_Highlights/Census_of_Horticulture_Specialties/hortic_2_016_016.pdf
2. Burden, D. 2012. Christmas Tree Profile. http://www.agmrc.org/commodities__products/forestry/christmas-tree-profile/
3. DeAngelis, J.A. Conifer root aphid, Prociphilus americanus (Walker) in true fir.
http://entomology.oregonstate.edu/system/files/u1473/Root_Aphid_Handout.pdf
4. Straw, N.A., N.J. Fielding, G. Green & J. Price. 2000. Impact of green spruce aphid, Elatobium abietinum (Walker), and root aphids on the growth of young Sitka spruce in Hafren Forest, Wales: effects on height, diameter and volume. Forest Ecology & Management 134: 97-109.
A wide range of educational materials will be developed based on results obtained through this research. The following two are specifically anticipated: 1) a fact sheet describing the life cycle and pest status of conifer root aphids, with images of the different life stages and symptomatic trees; 2) a fact sheet on how to survey for root aphids in Christmas tree plantations; 3) a handout on biological control options for managing root aphids in Christmas tree plantations, and advantages and disadvantages of using predatory mites and insect-killing fungi. These publications will be uploaded to the UVM Entomology Research Laboratory website for access to growers nationwide (http://www.uvm.edu/~entlab/. In addition, presentations will be made at grower meetings of several regional Christmas tree associations. Almost every northeastern state has its own association and each holds meetings for its members at different times. We will contact representatives from each association to inform them of our research and request an opportunity to share the information at their meetings. Some of these associations have newsletters and/or websites. We will offer to supply articles or links to our website. Some of the potential associations and the timing of their meetings and other outreach options include: Massachusetts Christmas Tree Association: annual meeting in January, has a website;
NH/VT Christmas Tree Association has 3 meetings/year (June, September, January), publishes a newsletter (Tree Line) and has a website; Maine Christmas Tree Association meets in early January; Connecticut Christmas Tree Growers Association meets in March and has a website;
Rhode Island Christmas Tree Growers Assoc. meets in May and has a website; New York Christmas Tree Farmers Association of NY meets in July and the National Christmas Tree Association: publishes a newsletter (Tree Talk); coordinates an electronic newsletter (The Leader); and publishes the American Christmas Tree Journal.