Progress 08/01/04 to 07/31/06
Outputs
Obj. 1 Aphid Survey 51 aphid infestations were detected in spring floral crops in 40 greenhouses in MA and NY in 2004. 52.9%) were M. persicae. 5.9% were A. gossypii. 27.5% were A. solani. Obj. 2. Greenhouse trials at UMASS. 1. Banker plants did not consistently suppress both aphids on both plants in all four replicates. In the second replicate in 2005 (June 16-July 7), parasitoids appeared to die from high greenhouse temperatures. 2. Margarite daisy (a chrysanthemum), in controls, was consistently a better host than pansy, for both aphids. However, the ratio of improvement (D/P) was only 1.97 (doubling) for green peach aphid, while it was 24.9 for cotton aphid. 3. Aphids in controls increased in density to the final count. Therefore, final counts, not peak counts, could be used to assess biological control impacts. 4. Parasitoids suppressed cotton aphid to 1-6% of control values, but had less effect on green peach aphid (13-34% of control values), both in single aphid
treatments. 5. Aphids of both species were more strongly suppressed by parasitoids on daisy, the better host plant of both aphids, than on pansy. 6. The presence of a second species of aphid was not in general a positive influence on biological control. Obj. 3. Commercial greenhouse trials. Outcomes varied among locations and are being analyzed. In MA, of three greenhouse, use of banker plants was successful in two cases, but one of these was largely due to natural control by syrphid larvae that invaded the plot. One had so little aphid suppression and the trial had to be terminated. The third experienced good control. In NY, of four locations, one had good control, with aphids placed on uncaged plants remaining scarce; one location experienced a high peak of aphids that dropped back quickly (one week) to levels initially placed on plants; and two locations failed to control aphids, which increased to unacceptable numbers. In NY, problems prevented us from having an abundance of
parasitized aphids on the banker plants at the start of the trial. Growers were inattentive to irrigating banker plants so that the plants and thus the aphid host numbers as well as any developing parasitoids were severely affected. Finally, in some locations, the aphid present in the greenhouse was foxglove aphid, a non-host for the parasitoid being assessed. Obj. 4. Compatibility of two pesticides with Aphidius colemani. Partial data are presented in Table 3 and 4 Table 3. Numbers of live Aphidius colemani at various times after exposure to freshly dried residues of two pesticides, versus a water control. No. live wasps (of 10/replicate) at three times post treatment(n = number of replicates) Pesticide 2h 6h 12h water control 9.7 (25) 9.3 (10) 8.7 (11) pymetrozine 8.9 (30) 6.8 (12) 4.6 (10) pyriproxyfen 8.8 (30) No data 7.6 (10) Table 4. Emergence of adult Aphidius colemani from mummies treated with either of two pesticides, versus a water control. Pesticide Number of emerging
adults (of 10 mummies) (n= no. of replications) water control 5.9 (18) pymetrozine 5.0 (21) pyriproxyfen 5.8 (12) Tested materials did not affect emergence of wasps from mummies, but do affect adult survival.
Impacts
1. Safeguarding human health. In theory, if banker plants are adopted as replacement for aphicides, this might reduce worker exposure to pesticides. However, this project is at an earlier phase, assessing whether this technology works well enough to be recommended. Therefore we cannot say at this time that it has had any effect on human health, although future adoption, based on this work, might. 2. Economic benefits. Aphids can be cheaply controlled with pesticides. It is likely that biological control will be at least as costly, if not more so. Therefore no economic benefits are claimed from this work. 3. Implementation of IPM. This project assessed one new IPM strategy (banker plants for aphids). This is the first data set in North America for use of banker plants in greenhouse flower crops for aphid control. While the project did not find a high and consistent level of control with treatments as applied, it did find that the method can suppress some aphids under
some conditions. The next step is to develop more information that can make the approach work over a wider set of conditions. Interestingly, the approach is currently being adopted and is commercially available. No fact sheets or websites have yet been generated from this research. However, after analysis is complete, an extension article for Floral Notes (a MA newsletter for flower growers) will be prepared. 4. Enhanced collaboration among stakeholders. I am not aware that these trials have change collaboration among stakeholders in any way.
Publications
- No publications reported this period
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Progress 10/01/04 to 09/30/05
Outputs
Obj. 1. Aphid/Crop Survey in MA and NY Greenhouses. This survey was completed in the first year of the project as proposed. Aphids identification is pending, but broadly, greenpeach aphid and cotton aphid were the dominant species found, as expected, in both MA and NY. Obj. 2. Assess the Efficacy of Banker Plants Systems for Biological Control of Aphids in Spring Flower Crops. In the spring of 2005, two trials were run using banker plants in greenhouses at UMASS as proposed. Plants used were magarita daisy and pansy, because we were unable to find aphid strains that would feed on both geranium and impatiens as proposed. Otherwise, the trials were run as proposed. Trials differed greatly in temperature, due to seasonal timing. The earlier trial (in late winter, early spring) showed excellent control from Aphidius colemani wasps introduced on a banker plant (more than 99% control). Control was poor in the second trial (late spring and early summer) because of high
temperatures (above 35 C) early in the trial. While parasitism did subsequently rise, it did not greatly suppress aphid populations as these had increased significantly during the early part of the trial. Analysis is deferred until completion of the two further replicates to be run in spring of 2006 Obj. 3. Compatibility of Selective Aphicides and A. colemani. In the laboratory, we will measure the effect of pyretrozine and pyroproxifen on adults and mummies of Aphidius colemani. This work is planned for spring of 2006 Obj. 4. Efficacy under Commercial Greenhouse Conditions. After the previous work, we will examine the efficacy of A. colemani in commercial growers in MA and NY. This trial will be run in spring of 2006
Impacts
Initial results suggest that banker plants are highly effective in suppressing aphids before greenhouses become hot. This implies that growers will likely be able to use the approach effectively in New England because the normal period for spring flower and bedding plants is in April and May, which preceeds the onset of hot weather in most years at this location.
Publications
- No publications reported this period
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Progress 10/01/03 to 09/30/04
Outputs
Objectives for 2004 (the award year) were to conduct a survey of aphids in the spring bedding crop season and establish colonies of both green peach aphid and cotton aphid in preparation for the first trials in spring of 2005. Twenty greenhouses were checked for aphids in spring of 2004 in both MA and NY. Indentification of aphids is not completed yet, as this requires the help of an aphid taxonomist in Florida, whose schedule was affected by hurricanes. Aphids will be identified in the winter of 2005, when Suzanne Lyon, my technician, travels to Florida to work with the taxonomist. Colonies of both aphid species have been obtained and we are now in the process of switching the aphids onto the desired plant species (impatiens and ivy geranium) to be used in the future greenhouse trials. Plant material for the spring trials has been donated by Ball Horticulure.
Impacts
Planned trials will provide information on whether or not biological control of aphids in spring bedding plants works and is cost effective. Assuming the answer to each of these questions is yes, the impact of this project will be to reduce pesticide use and increase use of biological control in this crop.
Publications
- No publications reported this period
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