Proc. Fla. State Hort. Soc. 91: 250-253. 1978. RESPONSE OF FLOWER CROPS AND THEIR INSECT PESTS TO THE SYNTHETIC PYRETHROID INSECTICIDE, PERMETHRIN1 James F. Price and David J. Schuster ducted during 1978 (Table 1). All greenhouse and open IFAS, University of Florida, field studies were conducted at the Agricultural Research Agricultural Research & Education Center, and Education Center (AREC) in Bradenton, Fla. With Bradenton, Florida 33508 the exception of Experiment 10 conducted at AREC, all ex periments in a saran house environment (25% shade) were Additional index words, chrysanthemum, African violet, conducted within the facilities of cooperating flower grow exacum, episcia, caladium, carnation, gladiolus, gypsophila, ers. Flower beds in saran houses were 36 inches (91.4 cm) leafminer, mealybug, cabbage looper, aphid. wide and those in the field were 32 inches (81.3 cm) wide. Experiments 7, 9, and 10 were conducted on beds mulched Abstract. The synthetic pyrethroid insecticide, permethrin with black polyethylene. Beds in all other tests were not (3-phenoxybenzyl (±)-3-(2f2-dichIorovinyl)-2,2-dimethyl = mulched. All treatments appeared once in 4 complete blocks. cyclopropanecarboxylate), formulated as SBP 1513 and Am Pesticidal sprays were applied weekly and notations of bush(R), was evaluated as an insecticidal spray on chrysan phytotoxic reactions were made as the reactions became themum (Chrysanthemum morifolium Ramat.), carnation evident. (Dianthus caryophyllus L.)/ African violet (Saintpaulia ionan- Mines of L. sativae from 10 randomly selected chrysanthe tha Wendl), caladium (Caladium hortulanum Birdsey), episcia mum stems per plot were counted 8 and 9 weeks ('Dignity,' (Episcia cupreata (Hooker) Hans.), exacum (Exacum affine standard) or 9, 10, and 11 weeks ('Darkchip,' pompon) after Balfour), statice (Limonium sinuatum (L.) Mill.), gladiolus initial chemical applications in Experiment 1. Data from (Gladiolus grandiflorus Hort.), gypsophila (Gypsophila pani- all evaluations were totaled for each cultivar and trans culatum L), and poinsettia (Euphorbia pulcherrima Wild.). formed yx + 0.5 before analysis of variance and mean In chrysanthemums treated with permethrin at as low as separation by Duncan's multiple range test. In Experi 0.125 Ib ai/100 gal, populations of chrysanthemum aphid ment 4, leafmines from 25 chrysanthemum leaves ran (Macrosiphoniella sanborni (Gillette)), cabbage looper (Tri- domly selected from the middle 1/3 stratum of stems in choplusia ni Hubner) and its damage, and vegetable leaf- each plot of the 2 cultivars were counted 5 and 6 weeks miner (Liriomyza sativae Blanchard) mines were significantly following treatments. Data from those 2 evaluation periods reduced below levels that occurred when water alone was were totaled, transformed, and analyzed. Numbers of leaf- applied. Populations of the striped mealybug (Ferrisia vir- mines present and feeding holes of lepidopterous larvae on gata (Cockerel!)) were reduced up to 100% when SBP 1513 10 randomly selected chrysanthemum stems from Experi was applied at 0.125 Ib ai/100 gal to African violets, cala ment 3 were counted at flower harvest. Also evaluated at dium, episcia, and exacum. SBP 1513 was highly toxic to that time were cabbage loopers (Trichoplusia ni (Hubner)), foliage of gypsophila but that formulation and Ambush dis observed in entire plots, and flower thrips (Frankliniella played little phytotoxicity to foliage of the other plants tritici (Fitch)), collected by the method of Poe and Green evaluated. No phytotoxic reaction to chrysanthemum and (2). In that experiment, chrysanthemum aphid (Macro carnation flowers occurred when SBP 1513 was applied at siphoniella sanborni (Gillette)) populations were deter 0.25 Ib ai/100 gal, but discoloration of flowers occurred in mined 3 weeks after the first aphids appeared on plant African violet, exacum, and gladiolus. terminals. Entire plots were sampled for aphids and numbers of terminals that hosted more than 5 aphids Many of pyrethrum's benefits, such as rapid action, ex were recorded. cellent activity against adult dipterans, and low acute Caladium tubers infested with striped mealybugs human hazard became readily available to plant protec (Ferrisia virgata (Cockerell)) were placed onto 2 groups of tionists following the introduction of synthetic pyrethroids. caladium, African violet, episcia, and exacum (Experiments These compounds have a wide spectrum of insecticidal 11-14). SBP 1513 applications were initiated on 1 group of activity, degrade less in ultraviolet light, and cost about plants when mealybugs first began to transfer to their new the same as naturally derived pyrethrums. However, few hosts and to the second group 6 weeks later when plants of these new compounds have been registered for orna were heavily infested. Mealybugs on the 5 most heavily mental plants. Resmethrin is the only synthetic pyrethroid colonized caladium petioles and from all leaves and stems registered for more than one crop. Only in the past year of the other plants in both groups were counted 1 week was ICI, Inc. granted an emergency registration for Am following the last chemical application to the respective bush (R> for vegetable leafminer (Liriomyza sativae Blan group. chard) control in chrysanthemums (Chrysanthemum mori- folium Ramat.). Results and Discussion Previous information indicates that the synthetic py Significantly fewer leafmines were observed on chry rethroids are effective in management of insect pests santhemums where Ambush was applied at 0.10 and 0.20 common in ornamentals (1, 3, 4). To more accurately assess Ib ai/100 gal than on plants treated with water alone the potential of permethrin for management of ornamental (Table 2). SBP 1513 controlled leafminers as well as did pest populations, Ambush 2EC and SBP 1513 1 TEC Vydate<R' (oxamyl). These tests were conducted on small (Penick Corporation) were tested for impact on selected plots that allowed adults to move from areas in which arthropods and ornamental plants. treatments had not killed adult leafminers and into areas Materials and Methods in which adults had been killed. Thus adulticidal effects could not be fully evaluated. Unpublished data (Mellinger Fifteen experiments involving permethrin were con- 1978) from large plot trials indicate that substantial reduc tion in leafminers resulted from adulticidal effects of Am iFlorida Agricultural Experiment Stations Journal Series No. 1526. bush. 250 Proc. Fla. State Hort. Soc. 91: 1978. Table 1. Summary of experiments evaluating the efficacy of 2 permethrin formulations for insect control and phytotoxicity on several orna mental crops. Expt. Chemicals Lb. ai/ Gal./ No. weekly Insectz Plot Crop no. Crop Cultivar(s) tested 100 gal. acre treatments evaluated size environment Chrysanthemum: Dignity Ambush O.ly 225 8 Leafminer 8 ft bed Saran house Darkchip 0.2 10 (2.44 m) Vydate 1.0 Chrysanthemum: Golden Polaris Ambush 0.1 225 10 None 8 ft bed Saran house Statesman 0.2 Darkchip 0.4 Yellow Albatross Albatross Yellow Dignity Dignity Promenade Donlope's White Spider Onward Yellow Knight May Shoesmith Fuji Mefo Chrysanthemum: Yellow Manatee SBP 1513 0.125y 225 7 Chrysanthe 8 ft bed Saran house Iceberg 0.25 mum aphid Cabbage looper Flower thrips Leafminer 4 Chrysanthemum: Yellow Manatee Ambush O.ly 225 5 Leafminer 8 ft bed Saran house Iceberg 0.2 5 Chrysanthemum: Accent Ambush 0.1 225 5 None 8 ft bed Saran hnnse Jackstraw 0.2 Florida Marble 0.4 Beloved Firepower White Marble Carnation: Starfire SBP 1513 0.125 225 None 4 ft bed Saran house White Elegance 0.25 0.50 Statice: Kampf Js Blue SBP 1513 0.125 75 None 4 ft bed Field 0.25 0.50 Gladiolus: Manatee Rose SBP 1513 0.125 143 None 5 ft bed Field 0.25 0.50 Gypsophila: Bristol Fairy SBP 1513 0.125 122 None 6 ft bed Field 0.25 0.50 10 Gypsophila: Bristol Fairy SBP 1513 0.125 122 None 6 ft bed Saran house 0.25 0.50 Ambush 0.1 0.2 11 Caladiumx: Candidum SBP 1513 0.125 N/A Mealybug 2 pots Greenhouse 12 African violet: Meta SBP 1513 0.125 N/A Mealybug 2 pots Greenhouse 13 Episciax: Acajou SBP 1513 0.125 N/A Mealybug 2 pots Greenhouse Frosty 14 Exacumx Elfin SBP 1513 0.125 N/A 4 Mealybug 2 pots Greenhouse 15 Poinsettia: Annette Hegg Diva SBP 1513 0.125 N/A 6 None 1 pot Greenhouse 0.25 0.50 zPhytotoxic reactions of test plants to each chemical compound and each rate of application were also evaluated. yln addition to those rates indicated, a rate 4 times that of the lowest rate tested was applied as a treatment for phytotoxic evaluation only. xTwo similar tests were conducted-one upon an initially low mealybug population (Group 1) and one upon an initially dense population (Group 2). Proc. Fla. State Hort. Soc. 91: 1978. 251 Table 2. Total numbers of Liriomyia sativae mines observed in samples In another small plot test on chrysanthemums, SBP from chrysanthemum plots sprayed with 2 insecticides at varying 1513, applied at 0.125 and 0.25 lb ai/100 gal, significantly rates. reduced numbers of leaf mines (Table 3). In that test SBP 1513, even at the lower rate, provided excellent control of Rate the chrysanthemum aphid (97% reduction), and cabbage Expt. (lbs ai/ Avg. mines looper larvae (91% reduction), and reduced numbers of no. Cultivar Treatment 100 gal) per plotz holes in leaves apparently caused by cabbage looper larvae (93% reduction). SBP 1513 had no significant effect on 1 Dignity Water check 37.5a Ambush 0.10 8.3b flower thrips populations. No phytotoxicity occurred on Vydate 1.00 4.3b foliage or flowers of the chrysanthemum cultivars treated Ambush 0.20 3.5b with Ambush or SBP 1513. In greenhouse tests on African violet (Saintpaulia 1 Darkchip Water check 79.3a Ambush 0.10 19.3b ionantha H. Wendl.), caladium (Caladium hortulanum Ambush 0.20 12.5b Birdsey), exacum (Exacum affine Balfour), and episcia Vydate 1.00 10.8b (Episcia cupreala (Hooker) Hans.) for control of the striped 4 Manatee Water check 49.0a mealybug at initially low densities (experiments 11-14) SBP Iceberg Ambush 0.10 8.5b 1513 maintained mealybug populations 94-100% below the Ambush 0.20 4.5b checks (Table 4, Group 1).