Cycocel sprays have been the traditional growth retardant used on poinsettias. Foliar sprays of PGRs are more likely to reduce bract size than drenching. oz. The first treatment of 2000 ppm B-Nine and 1000 ppm Cycocel was applied 10 September when the lateral shoots were about two inches long. Normally PGRs are applied during cloudy weather. Treatment effects on plant height were similar with one or two doses. Growers can try to control late season stretch by applying a very dilute drench of A-Rest or Bonzi. Proper spacing is a key. GrowerTalks. Traditionally it has been recommended that plant growth regulators (PGRs) not be applied after mid-October or the start of short days (Hartley and Wilfret, 1992). Therefore, it is probably worthwhile to leave at least 10 representative plants untreated to evaluate the effectiveness of the low concentration drench treatments. Most of the poinsettia cultivars introduced within the last 10 years require less PGR than earlier types. Several Massachusetts growers have been making these treatments for a number of years and are pleased with the results. Plant size. Although there are a number of things that can go wrong from now until December 25, there are a few of these that seem to reoccur each year. Bract internode length (measured from the top of the cyathia to the lowermost bract showing red color) was also measured at the end of the experiment to determine how treatments affected bract spacing. Ohio Florists' Assoc., Columbus, OH., 60(7):52. generally cortez varieties are resistant to late-season stretch. Subscribe. However, smaller plant diameter resulted from increases in Bonzi concentration or drench volume, but not number of doses. Hammer, P.A. The objective of this study, supported by the Massachusetts Flower Growers' Association, was to test Bonzi for late season height control by studying the effects of Bonzi concentration, drench volume applied, and number of doses. The amount of active ingredient applied in each dose are shown in Table 1. after the Bonzi drench the plants generally grow an additional ½ – 1"/1.27 – 2.54 cm depending on the drench rate used. One dose of Bonzi at 2 ppm applied at 5 fl. apply a late-season Bonzi drench one to two weeks before shipping when the plants are almost at finished height with at least two to three bracts in full color. No bract distortion was evident in any of the other treatments. Drench applications are made on the basis of volume per pot (i.e., fl. Tall cuttings, early planting and pinching, too close spacing, and inadequate light are the major causes of poinsettias finishing too tall. This can be done when the plants are about ½ to 1 inch below the desired height and/or one to two weeks (up to three weeks in the south) before shipping. ©2020 University of Massachusetts Amherst • Site Policies, Greenhouse Best Management Practices (BMP) Manual, New England Greenhouse Floriculture Guide, Pesticide Information (Labels, MSDS, WPS), Pesticide Licensing (Certification, Exams, Workshops), Soil and Plant Nutrient Testing and Diagnostics, Center for Agriculture, Food, and the Environment, Center for Agriculture, Food and the Environment. He even has the ability to compare prices on the products you love and help you save money! of A-Rest or Bonzi. It's like Ficus times 10 - white milky sap everywhere.... they look pretty cool though - good ramification. Cared-for properly, the poinsettia will give weeks of color and pleasure to its owner. Thus it isn't necessary to use the high levels of active ingredient which led to the reduced bract diameter recorded in this experiment. Starting in late October, higher drench rates can be used to provide stronger hold if needed, with a slight reduction in bract size. GENERAL INFORMATION BONZI is a plant growth regulator for greenhouse use on container grown poinsettias and geraniums. Growth medium drench treatments were 1, 2, or 3 ppm Bonzi applied in volumes of 3, 4, or 5 fl. However, foliar sprays of 25-50 ppm on poinsettia were nearly as effective as drenches and provided reasonable growth control. An unexpected outcome was that differences in height among Bonzi-treated plants did not result from different concentrations, drench volumes or number of doses. Based on my results, the use of two doses of Bonzi drench or any combination of Bonzi concentration and drench volume resulting in a level of active ingredient above 0.24 mg a.i./pot risks a reduction in bract diameter and bract distortion. Hammer, T.J. Read on for common pitfalls and how to avoid them. Poinsettias Bonzi for regulation of poinsettia growth: Bonzi has shown growth retarding activity on a wide range of ornamental species and at very low dosage rates. oz./pot) so results are normally uniform. This site is maintained by Center for Agriculture, Food and the Environment in the College of Natural Sciences. My results demonstrate that Bonzi applied as a drench at low concentrations during the early stages of bract expansion and coloring is effective at suppressing the height and diameter of poinsettia. He will explore the Internet with you as your very own friend and sidekick! Email: firstname.lastname@example.org . When used as directed, Bonzi produces no phytotoxic effects. Drench applications of PGRs are laborious and mistakes in mixing or applying solutions could be disastrous in terms of too much growth control, uneven results, or bract injury. Roll, Eds. Production de poinsettias – Phase 4. Table 2. First, poinsettias begin to grow at their most rapid pace during this period, evident by the sigmoidal shape of poinsettia growth curves (some cultivars can be more vigorous during this time than others). Welcome to the world of BonziBUDDY! Florida has demonstrated that applying growth retardants as a drench provides excellent height control and is safer than sprays. green leaves and stems), not reproductive (red bracts and cyathia). When used as … However, you should not reuse any containers that were used to treat ornamentals with Bonzi. Plants potted in July and early August often end up too tall because of the extra time for vegetative growth between planting, pinching, and the initiation of flower buds. For example, Bonzi (paclobutrazol, Syngenta Professional Products) is often used as a drench during poinsettia production to reduce unwanted stem elongation late in the crop. Sprays should be applied on the basis of volume of spray per square foot of bench (generally 1 gal./200 sq.ft.) Bract diameter of Bonzi-treated plants was not different from the control treatment when one dose of PBZ was applied at 1 ppm at all drench volumes and 2 ppm at 3 and 4 fl.oz. If Bonzi (or another growth-retarding chemical) is applied too early in the crop schedule, or at … PGRs are very useful tools for controlling the height of poinsettias, but overeliance on PGRs is potentially costly in terms of material and labor. PGRs must be applied uniformly in order to cause uniform inhibition to plant growth. Micro drenches of Bonzi can be used at any stage of production, and it will not decrease the bracts to an unsellable state. Date d'acquisition. Now that poinsettias are safely tucked into their prop trays and the threat of Erwinia (Pectobacterium) is almost over, it's time to think about other Poinsettia issues. We want to suppress vegetative growth Fig. Got itchy last night and started pruning - never realized Poinsettias are so sappy! Par Brian Cantin, Conseiller sénior aux producteurs. Rooted cuttings of 'Red Sails' poinsettia were potted on 29 July 1999 in 6-inch azalea pots of Fafard 3B. PGR use can be reduced or eliminated by the starting with good quality cuttings, use of a tighter schedule, and by providing the plants with as much light as possible by proper spacing and maximizing light transmission. A desirable level of plant size reduction without a reduction in bract diameter and no bract distortion resulted from one dose of 1 ppm Bonzi (all drench volumes) and 2 ppm (3 and 4 fl.oz.).