Efficacy of Soil and Foliar-Applied Azadirachtin in Combination with and in Comparison to Soil-Applied Imidacloprid and Foliar-A
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is indicative of a trend that will spread Efficacy of Soil and Foliar-applied Azadirachtin to the pyrethroids, there will be a in Combination with and in Comparison to strong need to look for alternatives to broad-spectrum foliar-applied pes- Soil-applied Imidacloprid and Foliar-applied ticides. Studies that evaluate the abil- ity of pesticides to reduce damage Carbaryl Against Japanese Beetles on Roses on flowers and leaves could provide simultaneous estimates of efficacy on 1,2,3 1 highly preferred and somewhat less Justin M. Vitullo and Clifford S. Sadof preferred plant substrates. Imidacloprid is one of the most ADDITIONAL INDEX WORDS. Popillia japonica, Rosa, systemic insecticide commonly used materials in land- scapes because of its activity against SUMMARY. This study evaluated azadirachtin and imidacloprid for their ability to leaf beetles (Chrysomelidae) and reduce injury by Japanese beetles [Popillia japonica (Coleoptera: Scarabaeidae)] on floribunda-type roses (Rosa sp. ‘Acadia Sunrise’), either applied to foliage or as a soil its long residual toxicity (Sclar and drench. Roses were arranged in field plots and exposed to resident adult beetle Cranshaw, 1996; Webb et al., 2003). A populations. Insecticides were evaluated in field and laboratory trials. Laboratory single systemic application of imid- assays of leaves collected from plants 14 days after soil applications of azadirachtin acloprid reduced adelgid (Adelgidae) were less preferred by adult beetles than those collected from untreated controls. populations to zero on healthy east- Plants in field trials that received soil treatments of either imidacloprid or ern hemlock trees (Tsuga canadensis) azadirachtin had defoliation levels that were <8% throughout the entire season, up to 816 d after the application whereas untreated control plants were 20% defoliated. Addition of foliar sprays to (Webb et al., 2003) and provided soil applied insecticides provided no added protection to foliage. Rose blooms were control of aphids (Aphididae) and more difficult to protect with both foliar and soil-applied insecticides. Bloom injury elm leaf beetle (Pyrralta luteola)on of untreated controls varied between 20% and 30%, while plants receiving soil applications of azadirachtin varied between 0.2% and 18%. Soil applications of American elm (Ulmus rubra)for imidacloprid provided somewhat better protection of blooms with injury ranging 1–2 years (Lawson and Dahlsten, between 0.2% and 8%. Foliar applications of azadirachtin gave no added protection 2003; Sclar and Cranshaw, 1996). to blooms of plants treated with imidacloprid. Adding carbaryl foliar treatments When systemically applied to poplar every 2 weeks improved control to <2% injury, a level that was comparable to weekly (Populus deltoides and nigra) and application of carbaryl. The potential for using soil-applied azadirachtin to reduce silver maple (Acer saccharinum), the need for foliar applications of carbaryl in rose gardens is discussed. imidacloprid was toxic to adult Asian long-horned beetles (Anoplophora he Japanese beetle is an eco- flowers are even more preferred glabripennis) (Wang et al., 2005). nomically important pest to by beetles than foliage (Held and Although soil applications of Tgrowers, landscape managers, Potter, 2004). Due to the long flight imidacloprid do not protect Transvaal and homeowners who rely on insecti- period of adult beetles (usually >8 daisy (Gerbera jamesonii) blooms cides to manage the adult beetle and weeks), multiple foliar applications from western flower thrips (Frankli- its grubs. Adults feed on foliage, of persistent insecticides like carbaryl niella occidentalis) injury (Cloyd and fruits, or flowers of >300 species of are typically used to attain satisfactory Sadof, 1998), its outstanding ability wild and cultivated plants in 79 fam- control of adult beetles on blooms to protect foliage makes it a good ilies (Potter and Held, 2002), includ- and foliage (Potter and Held, 2002). candidate for adult Japanese beetle ing Rosaceae. Roses provide a useful With the implementation of control on rose leaves. system for exploring new ways of the Food Quality Protection Act Despite its utility as a foliar pro- controlling adult Japanese beetles (FQPA), the U.S. Environmental Pro- tectant, soil applications of imidacloprid because both flowers and leaves are tection Agency (EPA) has revoked often result in pest outbreaks of tet- highly susceptible to adult feeding. the registration of some of the com- ranychid mites (Tetranychidae) and Due to the attraction of floral scents, mon insecticides homeowners used armored scales (Diaspididae) (Raupp to control Japanese beetles on roses et al., 2004; Rebek and Sadof, 2003; Funding was provided by the USDA IR-4 project, (U.S. EPA, 2003). If the recent can- Sclar et al., 1998). Some of these out- Bayer Environmental Science, PBI Gordon, and cellation of diazinon for homeowners breaks can be explained by reported Valent corporations. Roses were donated by Bailey Nurseries (St. Paul, MN). This is paper 2005-17819 of the Indiana Agricultural Research Program. Units We thank R. Arcinas, M. Pannich, J. Young, and To convert U.S. to SI, To convert SI to U.S., L. Knoblock for technical assistance. Thanks also to multiply by U.S. unit SI unit multiply by R. Foster and T. Gibb (Dept. of Entomology, Purdue 0.3048 ft m 3.2808 University) and M. Jenks (Dept. of Horticulture, Purdue University) for reviewing this manuscript. 3.7854 gal L 0.2642 2.5400 inch(es) cm 0.3937 1 Purdue University, Entomology Department, West 25.4000 inch(es) mm 0.0394 Lafayette, IN 47907-2089. 1.6093 mile(s) km 0.6214 2Current address: Tropical Research and Education 28.3495 oz g 0.0353 Center, Homestead, FL 33031. 305.1517 oz/ft2 gÁm–2 0.0033 3Corresponding author. E-mail: justin.vitullo@ 7.4892 oz/gal gÁL–1 0.1335 gmail.com. 6.8948 psi kPa 0.1450 316 • July–September 2007 17(3) toxicity of imidacloprid to lady bee- Agriculture Plant Hardiness Zone 5), baited with a mixture of 3 phenethyl tles (Coccinelidae), predatory mites 10 miles southeast of the Purdue propionate : 7 eugenol : 3 geraniol (Phytoseiidae), predatory plant bugs University campus in West Lafayette, (floral lure) and (R,Z)-5-(1-decenyl)- (Miridae), and parasitic wasps (Braco- Ind., during Summer 2004. Bare- dihydro-2(3H)-furanone (sex lure). nidae) (James and Coyle, 2001; James root floribunda-type roses (Bailey Traps were placed 25 m outside the and Vogele, 2001; Sclar et al., 1998; Nurseries, St. Paul, Minn.) were north and south side of the field Smith and Krischik, 1999). In con- planted on 15 Apr. 2004 in four rows on 2.5-m-tall stands to determine trast, azadirachtin extracted from the of 25 plants each in 1-ft-deep and 1.5- first beetle flight. Traps were removed neem tree (Azadirachta indica) have ft-wide augered holes. Within each after the first beetle was caught. fewer documented impacts on non- row, roses were placed 2 m apart, each Visual estimates of defoliation target beneficial insects, reducing row was 3 m apart and separated by and floral bloom damage were likelihood of secondary pest out- a 2-m-wide strip of fescue turfgrass recorded by the same three observers breaks (Schmutterer, 1990). The pri- planted medially and mowed weekly throughout the season. Estimates mary activity of azadirachtin is to to 4 inches. Plants received a mini- were made to the nearest 5% of the inhibit the development of immature mum of 1 inch of water each week total leaf area or bloom tissue con- insects to adulthood by interfering from either rain or drip-line irriga- sumed and the mean from all observ- with molting (Ladd et al., 1984). tion. Drip irrigation and bare soil ers has been reported. Estimates Azadirachtin also has repellent and between turf strips were covered with occurred twice weekly after the ini- antifeedant properties that are effec- a 2- to 4-inch layer of shredded hard- tiation of adult beetle flight. Each tive deterrents of >200 insect species, wood mulch. Roses were maintained week, the height and width of each including adult Japanese beetles in accordance with standard growing shrub was measured and a qualita- (Duthie-Holt et al., 1999; Held practices (Lerner et al., 2003). It tive estimate of plant fullness was as- et al., 2001; Ladd et al., 1978). was unnecessary to apply fungicides signed. Fullness was visually estimated Systemic applications of azadirachtin to newly planted roses. 3.5 g of by looking at a plant profile and extracts have been shown to affect Garden Mate 10N–8.8P–8.3K fertil- determining the amount of light that a variety of pests on different hosts izer (Greenview Lebanon Seaboard was blocked by the foliage. Fullness (Arpaia and van Loon, 1993; Nisbet Corp., Lebanon, Penn.) was applied ranks were based on percentage of et al., 1993). The systemic activity of under the mulch of each rose bush the canopy that was filled with leaves azadirachtin can control sucking and once new growth reached 6 inches using a 1 to 5 scale (1 £ 20%, 2 = 21% root-feeding insects (Isman et al., (5 May). Senesced blooms were dead- to 40%, 3 = 41% to 60%, 4 = 61% to 1991) as well as reduce boring insects, headed (removed) weekly to stimu- 80%, 5 > 80%). such as the pine engraver beetle late bloom production during the Means and standard errors of (Ips pini) and the mountain pine course of the season. The number of injury and size measurements were beetle (Dendroctonus ponderosae)on blooms removed was recorded each calculated for each treatment. Effects lodgepole pine (Pinus contorta) week. of the pesticide treatment, mode of (Duthie-Holt et al., 1999; Naumann FIELD INSECTICIDE TRIALS. Field pesticide application (foliar, soil, et al., 1994). Effective translocation grown roses were grouped into a both, and untreated) and timing of of azadirachtin, low toxicity to fixed-factor completely randomized foliar application on these measures nonphytophagous natural enemies, design with six replicates.