The predicted water uptake for each plant species is tive amount of shade, if any, and seasonal variation over compared with the observed water uptake in Table 2. more than one growing season are other factors that con Overall, among the 15 plant species, the predicted water ceivably affect water uptake but were beyond the scope of uptake ranged from -46% to +123% of the observed the present study. A comprehensive water uptake model values. Examination of the data, however, revealed that must take these factors into account if it is to have utility on the greatest variation between observed and predicted up a broad scale. Further work is being conducted in these areas take rates occurred in plants that consumed less than 2 with the goal of developing a multiple regression, predictive liters/container/month (Table 2). When only the species model for water uptake in container grown ornamental that consumed more than 2 liters/container/month were plants. considered, the variation between predicted and observed water uptake reduces to -33% to +27% of the observed Literature Cited values. This range is not particularly extreme when one considers the relatively modest data necessary to generate 1. Bailey, H. P. 1979. Semi-arid climates: their definition and distribu tion, in Hall, A. E., G. H. Cannell, and H. W. Lawton (eds.). 1979. the prediction: the Thornthwaite evapotranspiration esti Agriculture in semi-arid environments. Springer-Verlag, New York. mate, which is ultimately based only on ambient air 2. Dunne, T. and L. B. Leopold. 1978. Water in environmental temperature, and size index of the plant. Both of these planning. W. H. Freeman, San Francisco. parameters can be quickly and easily determined, and then 3. Rogers, J. S. and D. S. Harrison. 1977. Irrigation water requirements for agronomic crops in Florida. University of Florida, IFAS, Water be used to generate a relatively accurate prediction of Resources Council publication WRC-5. actual water uptake. 4. and G. A. Marlowe, Jr. 1977. Water needs of Florida There are, nonetheless, limitations to the general ap vegetable crops. University of Florida, IFAS, Water Resources plication of this method of predicting water uptake in Council publication WRC-2. container-grown plants. The size of the container, the rela Proc. Flo. State Hort. Soc. 93:168-169. 1980. CONTROL OF THE OLEANDER CATERPILLAR ON OLEANDER1 James A. Reinert rell); the oleander aphid, Aphis nerii Fonscolombe; 2 species University of Florida, IFAS, of defoliating caterpillars—the oleander moth, Syntomeida Agricultural Research Center, epilasia jucundissima Dyar, and Empyreuma pugione L.; 3205 S.W. 70 Ave., Ft. Lauderdale, FL 33314 and the witches' broom disease, Sphaeropsis sp. The oleander moth is common throughout Florida including Additional index words. Syntomeida epilais jucundissima, the Keys and Dry Tortugas (3), Mexico, northern Southern Nerium, acephate, azinphosmethyl, bendiocarb, carbaryl, America, and the Caribbean (2). Its larvae may defoliate fenvalerate, methidathion, methomyl, oxamyl, permethrin, oleander plantings several times a year and control measures resmethrin, malathion, Bacillus thuringiensis. are required to prevent severe damage. Larvae are present all year, but highest densities occur during the warmer Abstract. Twenty insecticides were evaluated for control months. I have received several complaints that diazinon and of the oleander caterpillar, Syntomeida epilais jucundissima dimethoate were not providing satisfactory control of Dyar, on container-grown oleander, Nerium oleander L. One oleander moth larvae as had been experienced in previous spray application of either acephate, azinphosmethyl, seasons. The present study was conducted to evaluate bendiocarb, carbaryl, fenvalerate, methidathion, methomyl, currently registered insecticides as well as several new com oxamyl, permethrin, or resmethrin provided 100% control pounds for efficacy against the larvae and to determine if of larvae at 24 hr post application. Malathion and izasofos resistance is developing. treatments resulted in 98 and 88% control, respectively. Treatment with Bacillus thuringiensis Berliner resulted in 84% mortality at 24 hours, but all larvae remaining were Materials and Methods unable to feed and thus were considered moribund. One hundred ten oleander plants, each 1.2-1.5 m high and growing in 25 cm diam. plastic posts, were divided for Oleander, Nerium oleander L.y is used widely as an orna use in 2 experiments. At the beginning of each experiment, mental plant throughout the southern states from Florida plants were randomly assigned to 5 replicates and infested to California, throughout the Caribbean Islands, and by individually introducing 10 late instar larvae on each Mexico. Oleander plants are used particularly in roadside plant. Larvae for these studies were collected from field and street plantings, in parks, and in the landscape around plantings of oleander. buildings and residential dwellings. For each experiment, insecticide treatments were Major pests of oleander include: 2 species of scales-the randomly assigned to plants within replicates. Test plants false oleander scale, Pseudaulacaspis cockerelli (Cooley), were sprayed to the point of runoff with the respective in and the oleander pit scale, Asterolecania pustulans (Cocke- secticides on August 28, 1979 (Test 1) and August 29 (Test 2) using a 7.6 liter compressed air sprayer. Insecticides and iFlorida Agricultural Experiment Stations Journal Series No. 2585. the rates evaluated in each experiment are given in Tables Appreciation is expressed to Mr. David Demmery for technical as 1 and 2. A wetting agent, Triton 1956®, was added to sistance. Use of a trade name does not constitute a guarantee of the Bacillus thuringiensis Berliner (Dipel®). product by the University of Florida and does not imply its approval to the exclusion of other products that may also be suitable. As each plant was sprayed, usually all the larvae would Proc. Fla. State Hort. Soc. 93: 1980. 168 drop to the ground. Larvae were immediately placed back Table 2. Percentage control of oleander caterpillars on oleander follow on the oleander foliage. This procedure was repeated as ing insecticidal treatments on August 29, 1979 (5 replicates). needed for a period of ca. 1 hr posttreatment. Larvae which fell to the ground and appeared dead or moribund were % controlz.y simply placed on the soil in the container. In this way, an Insecticides g Al/liter 4hr 24 hr exact mortality rating could be made, since fallen larvae will often fail to climb back up the same plant. Mortality Acephate 75SP 1.2 100a 100a of larvae was recorded at 4 and 24 hr posttreatment. Data Bendiocarb 76WP 0.6 100a 100a were adjusted to the untreated check by Abbott's formula Carbaryl 80WP 1.2 100a 100a (1), analyzed by analysis of variance and means separated Fenvalerate 2.4EC 0.24 100a 100a Permethrin 2EC 0.24 100a 100a by Duncan's multiple range test. A phytotoxicity evaluation Resmethrin 2EC 0.24 100a 100a was made on each plant 2 weeks following the treatments. Malathion 57% EC 1.44 92a 98a Bacillus thuringiensis -{- 0.61 24b 84ax Triton 1956 +0.6 RESULTS AND DISCUSSION Pfimiphos-etyl 4EC 0.6 26b 56b Dioxathion 8EC 0.6 14b 30c The percent control of larvae treated with each in Untreated Check — 0c Od secticide is presented in Tables 1-2. The single spray treat ments of either acephate (Orthene®), azinphosmethyl zMeans in a column not followed by same letters are significantly (Guthion®), bendiocarb (Ficam®), Carbaryl (Sevin®), different (P<0.01) by Duncan's multiple range test. fenvalerate (Pydrin®), methomyl (Lannate®), oxamyl yPercentage control computed by Abbott's formula. (Vydate®), permethrin (Ambush®), or resmethrin (SBP- ^Larvae were alive but not feeding, therefore, considered as 100% 1382) provided 100% control within 4 hr after treatment control. were made. Methidathion (Supracide®) and malathion each reduction at 24 hr. Treatment with B. thuringiensis, pre gave 92% control at 4 hr with 100 and 98%, respectively, viously shown to provide effective control of larvae (4), Table 1. Percentage control of oleander caterpillars on oleander follow killed 84% of the larvae by 24 hr. However, all larvae re ing insecticidal treatments on August 28, 1979 (5 replicates). maining on these plants were unable to feed and were considered moribund. No new feeding by B. thuringiensis treated larvae was observed the following day, therefore, !% controls y 100% control was obtained. Isazofos (CGA-12223) provided Insecticide g AI/liter 4hr 24 hr 88% control at 24 hr. None of the other 7 chemicals were judged to provide an acceptable level of control. No 100a Azinphosmethyl 2EC 0.6 100a phytotoxicity was observed on any of the treated plants Methomyl 1.8EC 0.6 100a 100a Oxamyl 2EC 0.6 100a 100a when they were evaluated 1 day and 2 weeks after insecti Methidathion 2EC 0.6 92a 100a cides were applied. Izazofos 2EC 0.6 60b 88a Chlorpyrifos 2EC 0.6 14c 31b Dimethoate 2.67EC 0.6 20c 20bc Literature Cited Diazinon 4EC 0.6 6c 23bc 1. Abbott, W. S. 1925. A method of computing the effectiveness of an Fenitrothion 8EC 0.6 10c 13c insecticide. /. Econ. Entomol. 18:265-267. Oxydemetonmethyl 2EC 0.6 8c 8c 2. Bratley, H. E. 1932. The oleander caterpillar Syntomeida epilais, Untreated Check 0c 0c — Walker. Fla. Entomol. 15:57-64. 3. Kimbal, C. P. 1965. Lepidoptera of Florida. Arthropods of Florida, zMeans in a column not followed by same letters are significantly Vol. 1. Fla. Dept. Agr., Div. Plant Ind. 363 pp. different (P<0.01) by Duncan's multiple range test. 4. Reinert, J. A. 1974. Bacillus thuringiensis for control of the oleander yPercentage control computed by Abbott's formula. caterpillar. Proc. South. Nurs. Assoc. Res. Con]. 19:44-45. Proc. Fla. State Hort. Soc. 93:169-171. 1980. EFFECT OF ATMOSPHERIC SULFUR DIOXIDE ON 'BLUECHIP' AND ICEBERG' CHRYSANTHEMUMS1 T. K. Howe and S. S. Woltz Abstract. 'Bluechip' and Iceberg7 cultivars of Chrysanthe University of Florida, IFAS, mum morifolium Ram at.