Antirrhinum ma/us L. Seedling Growth Decreased from Fungicide Drenches T. C. Weiler and T. I. Kirk 1. Holland Bulb Planting Chart 3

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1 _ Horticulture Department Cooperative xtension Service Purdue University West Lafayette, Indiana Vol. 8, No. 2 dited by P. Allen Hammer August 1980 CONTNTS Page Antirrhinum ma/us L. Seedling Growth Decreased from Fungicide Drenches T. C. Weiler and T. I. Kirk 1 Holland Bulb Planting Chart 3 New Publications 4 The Light That Wouldn't Go Off: Improper Switching An lectrical Hazard L. Art Spomer 5 Questions 7 The Way I See It P. Allen Hammer 9 ^ Cooperative xtension Work in Agriculture and Home conomics, State of Indiana, Purdue University and U.S.Department of Agriculture Cooperating. H.G.Diesslin, Director, West Lafayette, Ind. Issued in furtherance of the Acts of May 8 and June 30,1914. It is the policy of the Cooperative xtension Service of Purdue University that all persons shall have equal opportunity and access to its programs and facilities without regard to race, religion, color, sex or national origin.

2 ttqutr t * * * ** ** Antirrhinum majus L. Seedling Growth Decreased from Fungicide Drenches T.C. Weiler and T.I. Kirk1 Susceptibility of Anti rrhinum majus, snapdragon, to Phytophthora cactorum stem rot (2) has encouraged the application of preventive fungicide solutions to the soil immediately after seedlings are trans planted. Some producers have suspected that growth is reduced by treat ment and have ascribed blame to particular fungicides or combinations of fungicides. ight-week-old 'White Butterfly1 and 'Christina' snapdragon seedlings were transplanted from seed flats February 13, 1979, to 10 cm clay pots with a growing medium of silt loam, peatmoss, and perlite (1:2:2 by volume) amended to optimum nutrient levels and ph (3). The same day the growing medium was drenched with various fungicides at commercially used rates (1,k). Treatments were as follows: mg ai/10 cm potz d iazoben ethazol1 PCNB benomyl Treatment (Dexon WP) (Truban C) (Terraclor WP) (Benlate WP) Control D P DP B B DB Rates of application were: diazoben 0.6 gm/1 (8 oz/100 gal), ethazol 0.31 ml/1 (k fl oz/100 gal), PCNB, 0.3 gm/1 (4 oz/100 gal), benomyl 1.8 gm/1 {2k oz/100 gal). The plants were grown in a 12 C (55 F) greenhouse under natural photoperiod. Growth was measured k weeks after transplanting. Data were averaged over the 2 cultivars since no differences were observed between them. Plant height, fresh weight, and dry weight were less than the control after all fungicide applications (Figure l). Drenches containing benomyl or diazoben severely reduced growth, and when used in combination, growth was most restricted. Thus greatest productivity probably can be expected from a growing medium during early growth free of pathogens as well as free of preventive fungicides. Associate Professor and Research Technician, Department of Horticulture.

3 2. o. 300 LSD (Q«Q05) or n LSD(a«o.05) CO UJ or 1 16 o r- 14 LSD(a*0.05) UJ n P DP B B DB TRATMNT Figure 1. Growth of snapdragon seedlings with and without (C) various soil-applied fungicide applications.

4 LITRATUR CITD 1. Bing, A.J., W. Boodley, C.F. Gortzig, R.W. Langhans, J.G. Seeley, R.K. Horst, C.. Williamson, R.G. Halgesen, D.R. Price, and G. Johnson. 197^- Cornell Recommendations for Commercial Floriculture Crops. Part II. Disease, Pest, and Weed Control. New York Agric. xt. Publ. ML 5M. ^8pp. 2. Forsberg, J-L Diseases of Ornamental Plants. Special Publ. 3, University of Illinois, Urbana. 220pp. 3. Mastalerz, J.W The Greenhouse nvironment. Wiley, New York. 629pp. k. Powell, C.C Disease Control Chart. Ohio Florists' Assn. Bui. 58O. supplement. 2pp. ^^ ^^»^^**^*^T*^^* ^^*^^^^^*^^*^^*^^*^^*^^*^R^^*^^ ^^ ^^ #^* ^^fc ^^%^^S#^%^^*^^*^^*^^*^^*^^*^^*^^*^^^^^*^^^^^* ^^^^^^ ^^^^^^^^*^^^ ^^^^^^^^*^^^ ^^^^^^^^* InThe Fall...

5 NW k. NW PUBLICATIONS Cornell Recommendations for Commercial Floriculture Crops. The new editions, Part I - Cultural Practices and Production Programs ($1.50) and Part II - Pest Control - Diseases, Insects, and Weeds ($2.50), are highly recommended. They are well written, useful references for the greenhouse grower. Available from: Cornel 1 University Distribution Center, Seven Research Park, Ithaca, NY Introduction to Floriculture. This book only took 3 years to complete from when it was conceived to when it came off the press. Published by Academic Press, edited by Roy Larson, and written by 20 different flori culturists, it covers the culture of commerical flower crops. The book was written for college students and commercial flower growers. The chapters and authors are as follows: Cut Flowers Chrysanthemums A.M. Kofisiantk Poinsettias JameA SkankA Carnations SewaAcL BeAemoA aster Li 1ies HaAold OJiZklyiA Roses Ray HaA2.k Snapdragons WojiLIvi Rog&iA Orchids TkomaA Sktdmn Gladiolus GaAy WiZfyiQA. Minor Cut Crops ChAUtlna Auman Potted Plants Bulbous Plants Augiut VoMQJvtOQh Azaleas Roy LaAAon Pot Mums G. VouglaA Q.njxtVi Gloxinias, etc. R. Ke.yvt KhnmlnA Hydrangeas Tom WeteA Cyclamen RichaAcL WtdmoJi Begonias Roy La/iAon Kalanchoes Joe Lovz. Other Flowering Pot Plants P. AULqm HammoA Bedding Plants WaIZ CanlAon and d RowloAy Hanging Baskets 3am Ratkmdtl Foliage Plants CkanZoA ConoveA The 624 page book, costing $29-50, is available from: Academic Press, 111 Fifth Ave. New York, NY