Propagation Pests and Diseases
Transcription
Propagation Pests and Diseases
Wax myrtle, Southern bayberry Myrica cerifera Propagation Wax myrtle may be propagated by seed or cutting. Seeds are collected in the autumn, stratified at 40 F for 2-3 months and sown in the spring. Alternatively, the seed can be sown in the fall and covered with ¼ inch mulch for natural stratification. Seed moisture is essential. Germination should occur in 3-6 weeks. Semi-hardwood stem tip cuttings taken in early summer and dipped in IBA Quick Dip 5000 ppm can be rooted under intermittent mist. Problems with fungal diseases during rooting make propagation difficult. Pests and Diseases The current Insect Management Guide for Commercial Foliage and Woody Ornamentals can be found at http://edis.ifas.ufl.edu/IG012. The current Professional Disease Management Guide for Ornamental Plants can be found at http://edis.ifas.ufl.edu/PP123. Eriophyid mites (bud mites) Recognition: Leaf symptoms include leaf curling or folding, abnormal shape or distortion, galls, discoloration or bronzing, russeting, blisters and withering. These problems are caused by a microscopic wormlike mite with only two pairs of legs. The symptoms can be confused with symptoms of viruses or herbicide damage. Symptoms produced by eriophyid mites may persist for several weeks after the mites have disappeared. Contributing factors: unknown Management recommendations: Most bud mite damage can be tolerated on wax myrtle. Eriophyid mites are host specific, so will not spread to other plant species. For localized infestations, prune and dispose of infested plant parts. Only a few specific miticides are effective against eriophyid mites. Fusaarium wiltt (Fusarium m oxysporuum) Recoognition: Loss of vigor, stunting, andd curled, willted and/or off-color o foliiage results from Fuusarium wiltt. Individuall branches orr the whole plant may m die. A diistinctive broown-purple discoloration d n of the xylem x can bee seen when looking at a cross sectionn of the base of an infecteed stem. Contributing factoors: The funngus is soil-bborne. Nematoodes or root wounds mayy allow entryy of the pathogeen. The probblem is concentrated in Central C and South Florida. F Managgement recoommendatioons: Minimizze root damagee during plannting and maaintenance. Inspect I all plants beffore acceptinng them for installation. i There is no treatment foor infected plants and d they will eventually die. Remove infected treess and replannt with nonsusceptiblle species. Soil S fumigation is necessary only if replanting r wiith wax myrtle. Inon notus hearrtrot; Ptycchogaster wood w rot (Inonotus rickii r or Ptychog gaster cubeensis) Reccognition: External E sym mptoms very similar to those caused byy Fusarium; i.e., loss of vigor v and diebback. Additiionally, sap exudation e annd bark staiining are diaagnostic. Cinnnamon brow wn, beardlikee sporulatingg structures may m be evideent near wouunds or brannch stubs on the trunk. Branches B mayy breaak easily. Innternally, thee decay will be b spongy, yelllow-brown or o red-brownn, often fleckked with whiite streaks (m mycelium), and a borderedd by a dark purrplish zone of o stained xylem. Con ntributing factors: f Thiss fungus spreads throughh air--borne spores which enteer the plant through t wouunds in the wood. w It is asssociated moost often witth mannicured, heaavily pruned wax myrtle but also occcurs in naturaal stands. Maanagement recommend r dations: Prevvention is based on soundd maintenancce practices. Minimize pruuning and othher causes off bark injuryy. Do not pruune when spoorulating struuctures are noticed n in thee areaa. Avoid plaanting infecteed plants; plants dug from m the wild may m come froom infected stands and shoould be inspeected carefullly. There is no treatmennt for infected plaants except reemoval and replacement r t. Sinnce the funguus is not soil borne, fumiigation is not neccessary. Botrryosphaeriia canker and a dieback Recognitiion: Externaal symptoms include cannkers, wiltingg and diebacck of a brancch or branchhes of a tree or o shrub. Dark streaaks may be seen s in the wood w under the bark. Cankers may m be dark or sunken annd may be suurrounded byy wound calllus. The funngi attack plaant tissue thrrough wounds, growth g crackks, leaf scars and lenticells. Under magnificaation, the small black funngal fruiting bodies may be seen errupting throuugh the bark. The fruitingg bodies aree white insidde when slicced open. Contributing factorss: This disease organism m attacks stressed pllants and is spread s by prruning, air movement m annd splashing water. Managem ment recomm mendations: There are no n effective fungicide controls. Preevention is the t best defense. Keep o culttural conditiions, avoid stress s and plants in optimum wounds, and a maintainn sanitation. Root knot nem matodes Reecognition: Nematodes N i impair the rooots, causingg pooor growth, plant p declinee and thinninng of the folliage. Infesteed roots mayy be brown and a stunted and have obvioous galls. Coontributing factors: Higghest populaations of nematodes occcur in well-ddrained sandyy soils wherre preevious cropss have suppoorted populattions. Management recommend dations: Keep plants as healthy as possible with addequate wateer and ferrtilizer to suppport new rooots. No chemical controls are avvailable for use u on existinng plants. When replacinng plants, rem move all rooots and repplace soil. Avoid A replantting with sussceptible speecies, or fum migate beforee replanting.. Sources 1. Elizabeth Bush. Botryosphaeria Canker and Dieback of Trees and Shrubs in the Landscape. Virginia Cooperative Extension. http://pubs.ext.vt.edu/450/450-726/450726.html 2. Cathy Neal, Celeste White and Eleanor Foerste. Key Plant and Key Pests in Central Florida Landscapes. University of Florida Extension slide set. 3. University of Florida Landscape Plant Propagation Information. http://hort.ufl.edu/lppi/ Prepared by: Juanita Popenoe, PhD, Commercial Horticulture Lake County Extension, 1951 Woodlea Rd., Tavares, FL 32778-4052 Tel.: (352) 343-4101, FAX: (352) 343-2767 May 2010 The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information, and other services only to individuals and institutions that function with nonâdiscrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions, or affiliations. U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A&M University Cooperative Extension Program, and Boards of County Commissioners Cooperating.