FLORIDA COOPERATIVE EXTENSION SERVICE INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES, UNIVERSITY OF FLORIDA. GAINESVILLE i e0?/14dda godiaye !69ioWe4 Th~ Volume 12, Number 6 June, 1975

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Flowering of Bromeliads R. T. Poole and C. A. Conover

Bromeliads are an attractive group of plants well adapted to interior environments, although over-watering and over-fertilizing shorten the life of many plants. Even though they grow best under bright light, they will endure the low light levels found in most indoor locations. Bromeliads are attractive without flowers, but even more beautiful with flowers. As most bromeliads take 2 or more years to flower, methods have been examined which may induce earlier flowering.

Pineapples, commercially the most important bromeliad, have been induced to flower by treatment with v rious ethylene releasing compounds for many years. More recently, EthreO, (ethephon) has been shown to be a very effective ethylene releasing compound. Ethrel can be sprayed on the plant or poured into the vase formed by the leaves to force bromeliads into bloom. The Florida Foliage Grower, Volume 11, Number 12, reported 80% blooming in January of 18 mo. Aechmea fasciata from a media and watering experiment 2 mo. after being treated with EtTreT, 100 mg ethephon per plant. Of the 20% that did not bloom, almost all were plants of small size and poor quality.

1Associate Professor, Plant Physiology and Associate Professor and Center Director, Agricultural Research Center, Apopka, respectively.

IN THIS ISSUE PAGE Flowering of Bromeliads 1 Aphelandra Flowering 2 Control of Solanum Mealybug on Zebra Plant 4 News Release 5 Calendar of Events 5

COOPERATIVE EXTENSION WORK IN AGRICUL-TURE AND HOME ECONOMICS. STATE OF FL.ORIDA IFAS. UNIVERSITY OF FL-ORIDA. U. S. DEPARTMENT OF AGRICUL-TURE. AND BOARDS OF COUNTY COMMISSIONERS, COOPERATING -2-

One hundred mg of ethephon can be obtained by mixing one tablespoon of 21.3% Ethrel in one quart of water and adding 2 tablespoons of this solution to the vase of the bromeliads. The Ethrel-water solution should be applied to bromeliads innediately after mixing, as Ethrel begins to lose its effectiveness when added to water.

An experiment was initiated April 30, 1974 to investigate effects of 3 levels of Ethrel, 25, 75 and 125 mg/plant at 4 application times, April 30, June 11, July 31 and September 3 on blooming of Aechmea fasciata. Plants were one year old April 1974. At time of application, the vases contained water as a result of over-head irrigation. After the April treatment, approximately 50% of the plants flowered within two months but flowers were small and did not present an attractive appearance. Approximately 50% of the plants treated June and July bloomed and were of a more satisfactory appearance. Aechmea fasciata normally bloom during the late summer. The only satisfactory treatment, 83% bloom, was 25 mg/plant applied September 3, 1974 when plants were approximately 1 1/2 years old. None of the untreated plants flowered at this time.

Guzmania manostachia, Guzmania flamea and Vriesia splendens in different research plots that were I 1/2 to 2 years old also bloomne approximately 2 months after treatment with 25 mg ethephon. About 10% of the non-treated plants bloomed in these tests, but approximately 90% of treated plants bloomed. SUMMARY: Results from these studies indicate that 25 mg of ethephon applied to the vase of bromeliads 1 1/2 to 2 years old should cause bromeliads to flower within 2 months without damaging leaves of plants.

Aphelandra Flowering1 2 Wesley P. Hackett, Anton M. Kofranek, and Chrystal Arnold

Aphelandra squarrosa is grown as an ornamental plant for both its foliage and its flowers. Production of uniform flowering plants is difficult because plants propagated from tip cuttings often flower sporadically over quite a long time span. This complicates the marketing of the plants. It has been shown that Aphelandra flower development is little affected by long or short days but is promoted by high light intensity, i.e., 1000 to 1200 foot-candles, when grown at a high night temperature (700 F). Based on these reports, an experiment was set up to determine if uniform flowering could be obtained by manipulating the light intensity of stock plants and rooted cuttings.

1Adapted from Flower and Nursery Report, University of California, January, 1973. 2Associate Professor and Professor, Department of Environmental Horticulture, Davis; and Horticulturist, Neiden's Hillside Floral, Inc., Encinitas, Calif., respectively. -3-

Single-stem plants of the cultivar 'Brockfield', which had been cut back to two pairs of mature leaves, were grown at a light intensity of 300 to 400 foot-candles in a 70*F greenhouse. Cheesecloth was used to control light intensity. Ten weeks after cutback, 4-inch tip cuttings from the new shoots that had developed were rooted under mist. After rooting, plants were potted in 4-inch pots and placed in three different light intensities (Table 1) at a 70*F night temperature. Twenty-five plants were used in each treatment. Flowering uniformity was assessed by noting the date of full bloom for each plant and determining the number of days from earliest full bloom date until 80% of the plants were in full bloom. We have called this time span the FB80 - Table 1 shows that plants that received 750 to 850 foot-candles of light flowered earliest with fewest nodes and were the shortest. Flowering at this light intensity was quite uniform, as indicated by the FBO of 5 days. Plants in the intermediate light intensity (500 to 600 foot-candTes) flowered later and much less uniformly. At this light intensity, the FB8 0 was 37 days. Plants receiving 300 to 400 foot-candles flowered very late, with the largest number of nodes, and were the tallest plants. However, the flowering date was more uniform at 300 to 400 foot-candles than it was at 500 to 600 foot-candles, as indicated by the FB80 of 21 days.

Table 1. The influence of light intensity on vegetative growth and flowering of Aphelandra squarrosa 'Brockfield'. (Treatments started on March 1).

Light Intensity Plant Height Number Nodes Mean Date of FB80 Treatments (cm) at Flowering Full Bloom (Days)

High 750 to 800 foot-candles 45.2 8.6 July 2 5

Medium 500 to 600 foot-candles 50.0 9.5 July 18 37

Low 300 to 400 foot-candles 56.3 10.3 August 21 21

1Time span from earliest full bloom date until 80% of the plants were in full bloom.

These data show that low light suppresses flowering and high light promotes it. In order to obtain uniform flowering, it is necessary to have cuttings that are uniformly vegetative or uniformly reporductive. Vegetative cuttings can be obtained by maintaining the stock plants under low light intensity (300 to 400 foot-candles), and cuttings with uniform flower bud development can be obtained by pruning the stock plants and growing them under high light intensity (750 to 850 foot-candles). Pruning ensures the production of shoots of the same age that bud uniformly under high light intensity. Regardless of whether low or high light is used for growing stock plants, high light intensity should be used during rooting and subsequent growth of rooted cuttings to obtain the fastest and most uniform flowering. -4-

Control of Solanum Mealybug on Zebra Plant R. A. Hamlen and R. W. Henley1

Foliar mealybugs are pests of greenhouse grown ornamentals. The solanum mealybug, Phenacoccus solani, is a persistent pest of numerous tropical foliage plants, in particular Zebra pl t, A hel dra squarrosa. Control of overlapping generations with Meta-Systox-Oor ygo UfoViar sprays has been difficult and often unsatisfactory. Infestations in stock production areas frequently escape detection until entire ranges have become established with cuttings populated with only immature stages of this pest. Heavily infested plants result in reduced sales and potential quarantine restrictions. This study was designed to determine the most effective and non-phytotoxic material for control of solanum mealybugs on Zebra plants.

Naturally infested Zebra plants approximately 12 inches (30 centimeters) high, in 6-inch (15 centimeter) diameter plastic containers, in a soil mixture of 2 peat, 1 pine bark and 1 cypress shavings by volume were maintained in a greenhouse at 72-90*F (22-320C). Mid-day light intensity at plant height was approximately 900 fc (9,000 lux) and plants were fertilized weekly with 2 lbs/ 100 gals of 20-5-30 liquid fertilizer, including minor elements. Plants received either 3 systemic drenches at 3-week intervals or a single application of systemic granular materials. Drench treatments were applied as 8 fl. oz. (236 milliliters) of chemical solution per container with granular materials added to the soil surface in acre equivalents computed from the container surface area. Both containers treated with granular formulations and control plants received 8 fl. oz (236 milliliters) of water. Materials, lb AI (active ingre ient)/100 gal or lb AI/acre rates and methods of application were: Temi 210 G, 10 lb, soil urface; Vydat 10 G, 10 lb, soil surface; Vydate 0 0.25 lb, drench; Furadad10 G, 10 lb, soil surface; frada &4 F, 0.25 lb, drench; CygorU 267 C, 0.25 lb, drench; Meta-Systox- IV25% EC, 0.25 lb, drench; and Dacamo)9 10 G, 10 lb, soil surface. Numbers of mealybugs were counted per 3 leaves from the basal, mid and upper portions of each plant.

Table 1. Effect of drench and granular applications with systemic insecticides on number of living adult and nymph solanum mealybugs infesting Zebra plant foliage. Rate of Avg. no. mealybugs/leaf Pesticide and formulated material after initial treatmenta formulation lb/Acre pt/100 galb 6 weeks 9 weeks TemikeiG 100 --- 0.04 0.0 Furada ,4F--- 1/2 0.00 0.0 Funrdanl10G 100 --- 0.10 0.1 CygoRf267 EC --- 1 0.04 0.0 DacamoO 0G 100 --- 0.20 1.7 VydatE2L --- 1 0.00 0.0 Vydat4010G 100 --- 2.90 8.6 Meta-Systox-25EC --- 1 2.20 5.7 Control ------18.60 29.4 0 aOne application of granular formulations, 3 drench applications at 3 week intervals with liquid formulations. bEight fl. oz. of drench solution was applied per 6-inch container. -5-

Summary

Table 1 indicates all chemicals were effective in reducing s lanum mealybug populations compared to controls. In this study Furada D4F drenches (using 1/2 pt of formulated product per 100 gal) produced interveinal necrosis of older foliage which was undesirable. The effectiveness of drench applications of systemic chemicals was impressive. Liquid formulations can be applied through the various types of container or bed surface irrigation systems that are currently used for watering and fertilization in the tropical foliage industry.

Assistant Professor and Associate Professor, Foliage Extension Specialist, Agricultural Research Center,.Apopka, respectively.

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News Release Plans are underway for the 1976 National Tropical Foliage Short Course. With its excellent accommodations, the Sheraton-Towers Hotel, Orlando will house the short course, January 25 through 28, 1976. The 1976 National Tropical Foliage Short Course will provide lectures and discussions, educational exhibits, a banquet and hospitality functions. By adding a section and dividing portions of the porgram into split sessions, the number of speaker hours will be approximately twice that of previous short courses. Subjects to be covered will be of concern to all segments of the foliage industry including: plant producers, brokers, retailers, designers, interiorscape contractors, maintenance experts and others.

Calendar of Events 1975 July 19-23 Society of American Florists Annual Convention, Orlando Hyatt House - Orlando FL October 3-5 1975 Florida Nursery and Allied Trades Show, Inc. Curtis Hixon Convention Center, Tampa FL 1976 January 21-24 Tropical Plant Industry Exhibition, Diplomat Hotel, Hollywood FL

January 25-28 1976 National Tropical Foliage Short Course, Sheraton-Towers Hotel, Orlando FL -6-

Florida Foliage Grower Monthly Newsletter - Edited By 0

Richard W. Henley Associate Professor Foliage Extension Specialist Agricultural Research Center - Apopka

This public document was promulgated-at an annual cost of $ 295.65 or .05 cents per copy to inform county and state extension personnel, foliage growers, marketers and allied trades of research results and improved practices in ornamental horticulture.

To simplify information in the "Florida Foliage Grower" it is sometimes necessary to use trade names of products, equipment and firms. No endorsement of named products is intended nor is criticism implied of similar products which are not mentioned.

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