19901 BROSCHAT:POTASSIUM DEFICIENCY l5l

Principes,34(3), 19S0, pp. 151-155

PotassiumDeficiency of Palmsin South Floridal

Truornv K. Bnoscuer Uniaersity of , Fort Lauderdale Research and Education Center 32OS College Auenue, Fort Lauderdale, FL 33314

Potassiumdeficiency symptoms in palms Deficiency symptomsof N, P, and Mg are have been documented for economically well known in palms and do not include important food such as coconut flecking on the foliage (Broeshart et al. palm(Cocosnucifera) and African oil palm 1957,Broschat i984, Bull i958, Manciot (Elaeisguineezsls) (Broeshart et al. I 957, et al. 1979). The K deficiencysymptoms Bull 1961, Manciot et al. 1979) and for described by Broschat (1984) for five someornamental palms (Broschat l9B4). species of ornamental palms included Yet even with this information on K defi- necrotic spotting and streaking, but no ciency symptomology available, the exis- translucent yellow flecking. Potassium tence of widespreadK deficiency in south deficiencysymptoms of most consist Florida palms has gone undetected for of a marginal necrosisof the oldestleaves, decades.Marlatt (1980), Dickey (I977), although Broeshart et al. (I957), B,rll and Street and Gamon (1983) point out (1961), and Manciot et al. (1979) have that south Florida soils are extremely defi- described spotting symptoms similar cient in K, yet they do not report K defi- to those describedin this paper associated ciency on any ornamental plants in south with potassium deficiency in C. nucifera Florida, much less on palms. and E guineensis. Palm growers have often wondered about Close examination of palms growing the cause of the translucent yellow or under field conditions at the Fort Lauder- orangg flecking they observeon the oldest dale Research and Education Center of palms. Pathologistshave never showed a wide range of symptoms which been able to isolate pathogensfrom these varied among species.For some species, spotsand unlike most biotic diseases,these only translucent yellowishflecking in vary- symptomsare confinedto the oldestleaves ing degreesof severity was observedand of the palm. Many people believed these marginal and tip necrosiswere rarely seen symptoms were the result of natural leaf (upper left, Back Cover). In other species senescenceand were therefore not pre- necrotic streaks, spots, or flecks exist, but ventable.However, palms growing in other chlorotic areas were not present (upper parts of the world often do not show these right, Back Cover). In still other species symptoms. This fact, plus the restriction no flecking or streaking of any kind was of these symptoms to the oldest leaveso observed,but marginal and/ or tip necrosis suggeststhat the problem may be caused were the primary symptoms (lower left, by a nutritional toxicity or a deficiency of Back Cover). In most species,however, a mobile element such as N, P, K, or Mg. translucent yellow flecking appears to be the earliest symptom of K deficiency and occurs on mildly affectedleaves or towards I Florida Agricultural Experiment Stations Journal the base of more severely affected leaves. SeriesNo. 9893. As the deficiencyprogresses, the spotsmay r52 PRINCIPES lVoL. 34 coalesce and marginal necrosis may appear forsteriana, and Chamaedorea seifrizii on the leaflets. This intermediate stage with standardsestablished for those species appears on moderately affected leaves or showedall were deficient in K (H. Poole, on the middle leaflets of more severely pers. comm.) Establishedminimum K con- affected leaves. The most severely affected centrationsfor recently matured leavesare leaves (the oldest on the palm) will often I.2To for C. seifrizii, I.27o for C. lutes- have entire leaflets withered and frizzled cens,0.597o for H. for sterianaoand' 0.7 4% in appearance (lower right, Back Cover). for E. guineensis.Leaf samplesfrom palms These symptoms somewhat resemble those showing symptoms averaged 0.457o, of Mn deficiency except for the lack of O.BBTa,0.5570, and O'487oK, resPec- size reduction in affected leaves and the tively for these species. Since specific fact that these symptoms occur on the symptomology varies widely among palrn oldest leaves first rather than the newest. speciesosymptoms for 52 speciesof palms As with Mn deficiency, K deficiency is grown in south Florida are listed in the capable of killing palms if not treated. appendix. Severely affected palms of most species As an element, K is highly soluble and also tend to hold fewer leaves than healthy is readily leached from the sandy soils of oalms. south Florida. Container media or soils Potassium deficiency, like Mg defi- having higher cation exchange capacities ciency, occurs on the margins of the oldest can retain K against leaching and for this leaves of palms and from a distance the reason,K deficiency is much less common two deficiencies may sometimes be con- in container-grownpalms and in other palm fused. However, Mg-deficient palms never growing regions of the United States. show any flecking or marginal necrosis and Imbalancesbetween K and other nutrient symptoms usually appear as a distinct broad elementssuch as N, Ca, and Mg can also yellow band around the periphery of an causeK deficiency(Dickey I977). In south otherwise green leaf. The discoloration Florida the problem of K deficiency is sometimes associated with K deficiency accentuatedby the use of landscapefer- may occur throughout the leaf, or if not, tilizers having slow release N fertilizer is never sharply delimited from a green sourcesthat last up to three or four months, leaf center as is the case with Mg defi- but water-solubleK sourceswhich can be ciency. Unfortunately, both Mg and K completely leached through a sandy soil deficiencies are widespread in south Flor- with one or two heavy irrigationsor rains. ida and symptoms of both may occur on At the FLREC, where such fertilizers have the same leaf, thereby making diagnosis been used for years, the problem of K more difficult. deficiency is much more severe than in Potassium deficiency was confirmed by landscapeswhich received no fertilizer at leaf nutrient analysis for some of the species all. Iisted in this article. Comparisons of sim- Unlike Mg deficiency which is difficult ilar-aged leaves with and without symp- to correct in palms, K-deficient palms toms for Dictyosperma album Yar. con- respondrapidly to K fertilization. Addition jugatum, Chrysalidocar pus lutescerus, of resin-coatedcontrolled-release potas- severely deficient Howea forsteriana, Elaeis guineensis, sium sulfate to Cocos nucifera, and Neodypsis decaryi Hyophorbe oerschafeltii and Chrysali- showed that leaves showing symptoms had docarpus lutescensresulted in a signifi- less than half the K concentration of cant increasein the number of greenleaves apparently healthy leaves. Comparison of on the plants within four or five months. K concentrations in leaves showing symp- Controlledrelease K fertilizers are the best toms of E. guineensis, C. lutescens, H. materials for preventing and correcting K r9901 BROSCHAT:POTASSIUM DEFICIENCY r53

deficiency in south Florida since they are Bnoscser, T. K. 1984. Nutrient deficiency symp- not readily leached by heavy rainfall or toms in frve species of palms grown as foliage irrigation. Both sulfur-coated and resin- plants. Principes28:6 14. Burr, R. A. 1958. Symptoms of calcium and phos- coated potassium sulfate are produced phorus deficiency in oil palm seedlings.Nature commercially and should be suitable for 182: 1749-175O. use on south Florida's sandy soils. Foliar BULL, R. A. 196I. Studieson the deficiencydis- sprays with potassiumnitrate, potassium eases of the oil palm. 2. Macronutrient defi- ciency symptoms in oil chloride, potassiumsulfate, potassiumace- palm seedlingsgrown in sand culture. J. West African Inst. Oil Palm tate, and potassium citrate on severely Res.3: 254-264. deficient C. lutescensdid not significantly Dtcrny, R. D. 1977. Nutritional deficiencies of increase leaf K concentrations over that woody ornamental plants used in Florida land- of control plants. Thus it appearsthat soil scapes.Univ. Fla. Agr. Exp. Sta. Bull. 79I. Mancror, E., M. OrrecNrEn, eNo R. OCHS. 1979. application of controlled-releaseK fertil- Mineral nutrition and fertilization of the coconut izers is the most effective treatment for K around the world. Oleagineaux 34: 576-580. deficiency in south Florida palms. As with Menrerr, R. B. 1980. Noncontagiousdiseases of Mg deficiency,however, old affectedleaves tropical foliage plants. Univ. Ela. Agr. Exp. Sta. Ext. will never recover from their symptoms. Bull. 8I2. Srnrrr, J. J. eNo N. GelroN. 1983. nutrient deficiencysymptoms. Univ. Fla. Coop. Ext. Serv. Lrrnnerunu Crrno Circ.435. BnonsneRr,H., J. D. Frnwnnoe,aNo W. G.Kove- cHIcH. 1957. Mineral deficiency symptoms o{ the oil palm. Plant Soil 8: 289 300.

Appendix

Potassium deficiency symptoms for 52 speciesof palms. All symptoms described pertain to oldest leaves on palms. Relative susceptibility is based on observationsof palms growing under similar conditiom at the FLREC.

Acoelorrhaphe urightii oldest leaves generally off-color with raised necrotic spots feeling like pustules. Some necrotic streaking. Moderately susceptible. Allagoptera arenaria-some orange and necrotic flecking near leaflet tips followed by tip necrosis. Slightly gusceptible. alexandrae light yellow flecking becoming generally chlorotic with necrotic spotting and marginal and tip necrosis on most severely affected leaves. Slightly susceptible. Areca catechu translucent whitish flecking in longitudinal bands becoming necrotic with necrotic portions often falling out of leaf leaving holes or tears in leaflets. Moderately susceptible. Arenga autralasica-some very fine translucent light green flecking and very fine necrotic flecking. Considerable tip and marginal necrosis and necrotic streaking. Moderately susceptible. Bismarckia nobilis tips of leafletshave chlorotic streaks or longitudinal bands with broad necrotic bands within chlorotic areas. Slightly susceptible. Butia capitata-oldest leaves generally off-color. Some translucent orange spotting, necrotic flecking, and marginal and tip necrosis. Moderately susceptible. Carpentaria acuminata-oldest leaves generally off-color. Extensive yellow spotting and necrotic spotting with extensive tip necrosis giving frizzled appearance. Moderately susceptible. Caryota mitis-foliage slightly off-color. Necrotic spotting with some marginal and tip necrosis. Moderately susceptible. C. rumphiana-oldest leaves off-color with tip necrosis and some necrotic flecking. Slightly susceptible. Chamaedorea elegans-slight discoloration of leaves, some minor chlorotic and necrotic flecking. Tip and marginal necrosis. Slightly susceptible. C. seifrizii-slight mottling of leaflets, but generally just tip necrosis. Slightly susceptible. Chamaerops humilis fine translucent flecking coalescingto encompassentire leaf. Chlorotic areashave necrotic flecking within. Most severely affected leaves have marginal and tip necrosis. Moderately susceptible. sp.-Extensive marginal and tip necrosis surrormded by slight chlorotic halo. No spotting present. Moderatelv susceptible. 154 PRINCIPES lVoL. 34

Extensive marginal Chrysalidocarpus cabad.ae-rranslucent yellow flecking interspersed with necrotic flecking. and tip necrosis giving frizzled appearance to older leaves' Very susceptible' spotting with C. lutesceis leaves becming off-coLred to orange. Translucent orange flecking and necrotic extensive marginal and tip necrosis. Very susceptible. necrotic. Marginal *ioguo*o-y.llow to orange flecks or elongated streaks. Streaks becoming and tip necrosis. Moderately susceptible. as severity increases' Coro, ,.urif"ro translucent orange flecking becoming interspersed with necrotic_spotting Exten;ive marginal and tip necrosis giving withered appearance to leaf tip. Very susceptible. Moderately sus- Corypha elata-vJ.ry fine translucent yellow flecking followed by marginal and tip necrosis. ceptible. Moderately Dictyosperma album uniform translucent yellow flecking throughout leaves. No necrosis observed. susceotible. and tip necrosis Elaeis gui.neensis-translucent orange and light green flecking near leafiet tips with marginal resulting in frizzled aPpearance. Moderately susceptible. necrotic spotting. Gaussia malyrr-olrler lewes light yellowish-green. Some light green translucent flecking and Some marginal and tip necrosis. Slightly susceptible' necrotic streaking Heterospathe iloro-l^rL" becoming off-color. Necrotic flecking and tip necrosis with some evident. Slightly suscePtible' slightly discolored with necrotic tips. Occasional orange flecking near Houea forsteriina-leaflei" becoming leaflet tips. Slightly susceptible. orange translucent flecking with entire leaf eventually becoming orange. Hyophorbe' 'E"t"r.it" i"rtrhl6"'ltti-biight -u.gi.al and tip necrosis giving oldest leaf frizzled appearance. Fxtremely susceptible. necrosis. Moderately Hyphaene.p.-firi necrotic ilecks coul"""ing to form large necrotic blotches. Some tip suscentible. followed by marginal Latania lontaroides general discoloration with extensive chlorotic and necrotic streaking, and tip necrosis of leaflets. Moderately susceptible. of the leaf. Moderately Licuala giand,is translucent yellow flecking with ,ome tip necrosis around the margin susceptible. a tattered appear- Liuistona australis Extensive necrotic streaking and marginal and tip necrosis giving leaves ance. No flecking or discoloration evident. Extremely susceptible' in the center of the L. chinensis-Necrotic flecking with narrow orange halos surrounding flecks concentrated Moderately leaflets. Leaflet centers beciming necrotic rather than marginal or tip necrosis as in other species. susceptible. necrosis. Moderately L. mariai very fine translucent yellow flecking with some necrotic streaking and tip susceptible. necrotic streaking. L. ,otun1ifolio-older leaves off-color. No flecking, but extensive marginal and tip necrosis and

*",#;l;J;:"j[l:T:iijl transrucentflecks coarescing to form largerchlorotic spors. Extensive marginal and iip t""ro.it givitg olde"t leaves a frizzled appearance. Moderately susceptible' followed phoen.ix dactylifera some discoloration towards the tips of leaflets with very fine translucent flecking by marginal and tip necrosis. Moderately susceptible. marginal p. reciirata" rips of leaves off-color. Some tianslucent yellow and necrotic flecks followed by extensive and tip necrosis. Moderately susceptible. susceptible. p. roe.beleiii-1ips of leaflets becoming off-"olo, and then orange followed by tip necrosis..Moderately necrosis. Moderately Pritchardia beccariana-rrarsluceniyellow flecking, off-color foliage and extensive tip susceptible. ptrchospir^a elegons older leaves off-color. Coalescing orange spots with extensive necrotic spotting inter- Moderately susceptible. spersed. Some tip necrosis. _ necrosis. Slightly p. micarthurii necrotic spots with narrow yellowhalos. Some necrotic streaking and marginal susceptible. susceptible. p. nicolai-older leaves off-color with slight mottling of foliage. Extensive tip necrosis. Moderately streaks with some Rauen.ea riuularis-old.er leaves slightly off-color. Fine necrotic flecking becoming necrotic Moderately tip and marginal necrosis. S"t".!ly affected leaves have only necrotic veins remaining on leaves. susceptible. and tip necrosis. Rhapis excelsa-older leaves off-color with very fine necrotic flecking and extensive marginal Moderately susceptible. giving older leaves Roystonea r"gio-so^" translucent yellow flecking, but extensive marginal and tip necrosis a frizzled appearance. Moderately susceptible. and tip necrosis. Sabal mauritiifoimis-translucent y;Iow spotting, leaves off-color towards tips with marginal Slightly susceptible. r9901 BROSCHAT:POTASSIUM DEFICIENCY r55

S-. palmetto-translucent yellow-orange flecking followed by marginal and tip necrosis. Slightly susceptible. Scheelea rostrata-lranslucent fine light green streaking, necrotic spotting, truncation of leaf tip, and extensive marginal necrosis. Moderately susceptible. Syagrus amara-rranslucent yell;w-orange flecking and necrotic flecking surrounded by chlorotic halo. Marginal and tip necrosis. Slightly susceptible. S. pseudococos -Highly resistant. S. romanzofiana-clusters of translucent yellow flecks near leaflet tips with some marginal and tip necrosis. .Severely affected leaves appear frizzled and orange in color. Moderately susceptible. S. schizophylla general discoloration of older leaves with light green translucent flecks coalescing into spots up to 3 mm in diameter. Moderately susceptible. radiata-translucent yellow and necrotic flecking. No significarlt marginal or tip necrosis. Moderately suscentible. Trachycaipus martidnus minor yellow flecking on slightly off-color leaves. Some tip necrosis. Fairly resistant. acanthocoma-translucent light green flecks usually appearing in longitudinal bands along the leaflets. Some tip necrosis and necrotic streaking. Fairly resistant. Veitchia macdanielsii - slight tip necrosis. Very resistant. Wodyetia bifurcata interveinal chlorotic streaking with necrotic spots surrounded by narrow yellow halo. Some marginal and tip necrosis. Moderately susceptible.

NOTICE "Palms in tropical rain forests." A symposiumin IQUITOS, , 18-24 September l99l-to include a field trip in the I.ower Ucayali River Basin. For information write: FRANCISKAHN, ORSTOM,Apartado 18-1209, LIMA, PERU.

Back Cover Potassiumdeficiency in palmsof southFlorida. Upper left, old leaflersof potassiumdeficient Dictyosperrna a_lbumheld up to the light to show translucent yellow flecking. Upper right, Caryota_rniti.sshowing the necrotic flecking characteristic of potassiumdehciency inihis species.Lower left, old leaf of Roystonea regia showinemarginal and tip necrosii caused by potassiumdeficiency in the species.Lower right, Hyophorbe uerschffittiiwithreduced leaf number and characteristic frizzling of the oldest most severely affected leaf. Less severely affected leaves have extensive orange translucent flecking, not apparent in this photograph.See pp. 151-155.