2011 Annual Report
1a.Objectives (from AD-416)
#1: Develop improved techniques for managing scarabs and ambrosia beetles in nurseries by determining the biology and ecology of exotic scarabs and ambrosia beetles in relation to the nursery ecosystem, the response of nursery crops to root herbivory by exotic scarabs and potential relationship to attacks by ambrosia beetles, and by examining interactions between exotic ambrosia beetles and the nursery ecosystem including factors leading to attacks on nursery trees by ambrosia beetles, especially as it relates to abiotic and biotic stress.
#2: Evaluate sustainable, environmentally-friendly alternatives to conventional insecticides, including reduced-risk chemicals, microbial products, and botanical extracts for control of ambrosia beetles and scarabs.
#3: Develop new application methods and strategies for ambrosia beetle and scarab control and to prevent their distribution to uninfested parts of the United States and abroad.
1b.Approach (from AD-416)
The development and survival of Anomala orientalis (oriental beetle, OB) larvae will be evaluated on a variety of woody ornamental species. The relationship between constitutive and induced defensive compounds in the roots, along with total carbon and nitrogen levels, and development and survival of OB will be determined. OB larvae have caused considerable damage to trees and shrubs in ornamental nurseries and in production of small fruits such as blueberries and cranberries. Despite the damage this species causes in woody nursery and small fruit crops, there has been very little research evaluating trees and shrubs as hosts for OB. Species and varieties of trees and shrubs that are poor or marginal hosts would either not need protection from OB or acceptable levels of protection might be achieved by lower rates of insecticides.
Data will be analyzed each season and adjustments will be made to experimental design if necessary. If we identify species that are especially good or poor hosts for OB, we will conduct additional testing on varieties within those species and closely related species to see if their quality as hosts is similar (good or poor). This information will be used to identify suites of characteristics (chemical compounds, nutritional, etc.) that make a woody plant a viable host for larval OB. This data could then be used by plant breeders to develop varieties resistant to OB.
This project began in December, 2010 replacing 3607-21000-010-00D, Management of Invasive Scarabs, Root Weevils and Other Beetles of Quarantine Significance in Horticultural, Turf and Nursery Crops. In 2011, we started or continued research projects on interactions of oriental beetle larvae (invasive scarab) and ornamental nursery crops as hosts; growth-response of nursery trees to root-herbivory by scarab larvae; monitoring ambrosia beetles with ethanol-baited traps and ethanol-injected trap trees; began developing a temperature-based model for predicting activity of the ambrosia beetle Xylosandrus germanus to help growers synchronize their controls with its activity; testing conventional and botanical insecticides and entomopathogens for control of ambrosia beetles; evaluating response of ambrosia beetles to different tree species injected with ethanol; optimizing an odor-based trap-tree tactic for inducing attacks on trees by ambrosia beetles; evaluating verbenone as a repellent to ambrosia beetles in the field; evaluating synergism between ethanol in injected trees and volatiles emitted from those trees; identifying host-derived volatile cues used by X. germanus to locate hosts; evaluated the impact of flood stress on the attractiveness and susceptibility of hosts to ambrosia beetles; assessed the role of random landing vs. volatile attractants in the host-finding behavior of ambrosia beetles.
Optimization of ethanol-baited bottle-traps for monitoring ambrosia beetles in nurseries. Xylosandrus germanus is an invasive ambrosia beetle and a serious pest in ornamental tree nurseries. In order to synchronize their control treatments with this beetle’s seasonal activity, growers need a reliable monitoring system. We demonstrated that bottle-traps baited with 2 low-release ethanol lures were more effective at detecting the initial emergence of overwintered adult beetles than traps baited with 1 lure. This research enables nursery growers to more reliably monitor the emergence of overwintered X. germanus and accurately synchronize their sprays with its activity.
Comparing the efficacy of plant essential oils for managing ambrosia beetles and their corresponding analysis. Due to adverse environmental and non-target effects associated with conventional insecticides, the pursuit of botanically-based materials is warranted. The efficacy of commercially-available botanical materials for controlling ambrosia beetles was evaluated. This research showed that some botanical insecticides reduced attacks compared to untreated trees. Gas chromatography-mass spectrometry (GC-MS) was used to identify volatile compounds associated with the botanical insecticides. GC-MS analyses identified allyl isothiocyanate as the predominant compound in one the most effective botanical insecticides. These results will assist with developing improved botanical formulations and alternatives to conventional insecticides, with future research focusing on developing improved formulations containing allyl isothiocyanate.
Influence of alpha-pinene on attraction of ambrosia beetles to ethanol-baited traps. Certain species of ambrosia beetles are increasingly recognized as pests of ornamental nursery trees. Ethanol is the most attractive compound known for these beetles and is commonly used for monitoring purposes. In order to optimize monitoring and detection programs, field-based trapping experiments were conducted to assess the influence of alpha-pinene on attraction of ambrosia beetles to ethanol-baited traps. Alpha-pinene increased the attraction of certain ambrosia beetles to ethanol, but reduced the attraction of other species. These experiments demonstrate that traps baited with ethanol alone and a combination of ethanol and alpha-pinene are useful for monitoring and detecting ambrosia beetles in ornamental nurseries. This information will help refine monitoring techniques that enable growers synchronize their control treatments with ambrosia beetle activity.
Identification of the compound in zonal geraniums responsible for paralyzing the Japanese beetle. We isolated and identified quisqualic acid from flower petals of zonal geranium, and demonstrated its role in paralyzing adult Japanese beetles. Prior to our study, the chemical basis for paralysis of Japanese beetles following consumption of geranium flowers had remained unknown since the phenomenon was first described in the 1920s. We are currently assessing the commercial ability of using zonal geraniums as a source of plant-derived controls for Japanese beetles and other insects. Understanding the chemical basis for resistance of zonal geraniums could also assist greenhouse growers with managing important pests.
Reding, M.E., Ranger, C.M. 2011. Systemic insecticides reduce feeding, survival and fecundity of adult black vine weevils (Coleoptera: Curculionidae) on a variety of ornamental nursery crops. Journal of Economic Entomology. 104(4):405-413.
Ranger, C.M., Winter, R.E., Singh, M.E., Reding, M.E., Frantz, J., Locke, J.C., Krause, C.R. 2011. A rare excitatory amino acid from flowers of zonal geranium responsible for paralyzing the Japanese beetle. Proceedings of the National Academy of Sciences. 108(4):1217-1221.
Ranger, C.M., Reding, M.E., Gandhi, K., Oliver, J., Schultz, P., Canas, L., Herms, D. 2011. Species dependent influence of (-)alpha pinene on attraction of ambrosia beetles (Coleoptera: Curculionidae: Scolytinae) to ethanol-baited traps in nursery agroecosystems. Journal of Economic Entomology. 104(2):574-579.