107 l95Bl WOLFENBARGER: PalmInsects and Their Confrol.

D. O. WoITENBARGER Sub-T ropical Experiment Station, H onzestead,

Well-kept palm trees enhance the can the degree of harmfulness be fore- .i beauty, and lend interest to the Florida told. landscape and make real estate more Palms are comparatively slow in re- valuable. Many insects inhabit palm acling to severeinsect in[estations. As trees, however. It requires vigilance a result great damageor evendeath may to detect and control them before ex- occur before there is any manifestation tensive damage occurs. A brief discus- of injury by the plant. The scaleinsect sion is presented of some of the most infestation of the palms in important pests, with considera- 1956 is an example. In this instancethe tion of somefactors affecting their abun- scale populations infesting the fronds danceand management. reached their peak before most people realized that the palms were heavily in- A few general comments are given fested. Hordes of ladybeetles {eeding concerning insect pest infestations. All on the scale insects were observed by parts o{ the trees are susceptibleto at- many and occasionallywere blamed for iack by one to many species' Many in- the premature yellowing and death of sects present on palms are harmless to the fronds. The ,author observed the the plants and to man; some are bene- onset of this epidemic about May, 1956, {icial. Most of the species which are its peak about August, and the decline damaging to the plants are held in check through Septemberand October. Time by their enemies. Occasionally condi' for chemical control measures would tions become favorable for the rapid have been early multiplication of a species. Then many June. trees may be injured and some killed. Many speciesof insects infest palms. Scaleinsects, Aspid,iotus ilestructo'r Sign A total of 59 coconut palm pests was and,Chrysomphalus aonid'ium (L.) on listed by Capco (1950) in the Philip- coconut leaves in 1956 and the royal pines.Two ende,micand 30 non-endemic palm bug, Xylastod'orisluteolus (Barb'), species were listed by Simmerman in 1957 are examples of insects that re' (i948) as inhabitants of the cently reached and passed epidemic Pr.itchardia in the Hawaiian Islands. abundance. Epidemic populations of Bruner, et aI. (1945) listed 23 insect insects develop and occur periodically' speciesas those which attack the coco- Apparently there is great irregularity in nut palm in , while 13 insectswere the appearanceof theseepidemics which named as pests of the royal palm. No compilation of palm infesting insect appear to be non-cyclic, dependent on pests,other than that of scaleinsects by conditions favoring reproduction of a Riddick (1955), has been made for species. Epidemic populations of harm- Florida. not now predictable, nor ful insectsare Scale Insects *Florida Agricultural Experiment Station Most palms in Florida are in{estedby Journal Series, No. 748. Presented at the the coconut scale,Aspid,iotus destructor Fairchild Tropical Garden, Palm Conference, Sign.; Florida red scale,Chrysompkalus April 18, 1958. W *@ ti * .]

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Fig. 58. Insects that attack palms: a, royal palm bug, much enlarged; b, termites in royal palm trunk, enlarged; c, palmetto weevil {rom Phoenix with adults at top and larvae at bot- tom, all slightly reduced; d, ambrosia beetles, much enlarged; e, Florida red scale on coco- nut palm, top of leaflet at leit, bottom at right, all much enlarged; f, ambrosia beetle bur- rows, about natural size, 19581 WOLFENBARGER:INSECTS I09 aoni.diwn (Linn.), (Fig. SBe); latania from a residence or arterial highway. scale, Aspid,iotus lataniae Sign. Scale Malathion, which is safer than para- insects are probably more injurious to thion, may be used for scalecontrol but Florida palms year after year than any is less effective. A combination of one other group of insects. A total of 22 gallon of oil emulsion concentrate and scale insect species is listed, Riddick four pounds o{ 25 per cent wettablepow- (f955), as infesting the coconut palm der of malathion may be used. and the same number the royal palm. Above rec,ommendationsare for treat- A total of 20 scale insects is listed, ing a few treLs. Chemicalcontrol appli- Capco (1956), as pestsof the coconut cations for trees on streetsor other pub- palm in the Philippines. A list of eight lic property are considered impractical scale insect pests was given by Bruner at this time for the following reasons: et al. (1945) as those which attack the ( 1) size of trees which makes cover- coconut palm in Cuba, while six scale age difficult becausetoxicant must con' insects were named as those which at- tact each insect, (2) drift of spray mix- tack the royal palm. tures to nearby objects and adjoining Many coconut, Florida red, and la' properties, (3) cost of treatment would tania scale insects infested the fronds of be rather high for preservationof some treesin Florida in 1956. This epidemic green fronds, since trees are not killed was concurrent with the application of by infestations. malathion-bait sprays for eradication Pahn Leal Slteletonizer measures against the Mediterranean P,almfronds of severalspecies are at' fruit fly, Ceratitis capitata (Wied.). As tacked by the palm leaf skeletonizer, a result the sprays were frequently Homaleilra sabalella (Chamb.), accord- blamed for the scale infestations. Ob- ing to Creighton(1937). It was a major servationsof palm trees on New Provi- pest in the decade 1930-1940, and is dence Island, Bahamas,however, where very common today but the populations no malathion-bait spray was applied, are sparse. Larvae feed on the leaflets showed that deterioration of the fronds and usually go unnoticed until there is from insect infestationswas about equal much injury. Most of the larvae are to that in Florida. Conditions were parasitized and perish without having favorable in 1956 for the scale increase been observedor of imPortance. and are believedto account for the epi- Conditions may become favorable demic. again for increase of the skeletonizer Homeownerswho wish to treat Palms and make application of chemical con- for scale insect control will get most ef' trol measuresdesirable. Three pounds fective results from spray applications. of lead arsenate per I00 gallons of An oil emulsion spray containing lla water may be used,but a visible residue to II/3 per cent actual oil in water is may remain. Nicotine sulfate (one pint effective. Parathion at 0.15 to 0.30 of 40 per cent nicotine sulphate per pounds active ingredient per 100 gallons 100 gallons of water) was reported by o{ water is probably more effective than Wolcott (1933) to control the insect in oil emulsion. Trees may be injured by . Emulsion {ormulation of applications of oil. Parathion is very some of the newer insecticides-chlor- toxic to man and other . It dane, dieldrin, lindane and malathion- should be usedwith caution and extreme may be used, applied according to sug' care and only on trees some distance qestions on the container. 1I0 PRINCIPES [Vol. 2

Arnbrosia Beetles production (correspondence Fransisco Very small beetles about l/10 inch Sein, Jr.). The larvae feed among the long frequently burrow into trunks of flowers, spinning some webbing which coconut palms. (One specieswas ten- produces unsightly masses. This insect, tatively determined by Howard V. although present, has not been a prob- Weems as Xyleborus alJinis Eich.). lem in Florida. The may benefit These burrows are usually constructed man by preventing fruit production on .in logs.of,reeentlycut or.killed trees and trees in p,arks and on streets. Liability in trees of low vitality. (Fig. 5Bd, f). for infuries from falling fruits necessi- Trees having low vitality lack pressure tates removal of fruits before they fall. o'sap of flow" to repulse attacks. Am- Royal Palrn Bug brosia beetles are contaminated with Jnfestationsof the royal palm, Roy- fungi which grow in the burrows. Lar- stonea.,had not been observedfor years. vae which hatch from eggs depositedby In 1957, however, the royal palm bug, the beetles grow and develop by feed- Xylastod,orisluteolus Barb. (Fig. 5Ba), ing on mycelia of the fungus. The fungi infested royal p,alm trees throughout also extend beyond the insect burrows Florida. Leaves of larger trees were into the tree trunk tissues and frequently affected more noticeably than those on causethe tree to perish. It is frequently smaller trees. Fronds became yellow, impractical or impossible, however, to then brown colored, and died earlier determine whether the beetle infesta- than is usual,making the treesunsightly. tions, fungal invasions or the low tree No tree is known to have been killed by vitality was the most important factor the insect. Some interesting life history in the death of individual trees. Ttees studies on this bug are reported, Bara- that appear vigorous are sometimesin- nowski {1958). fested. Sometimes a nearby pile or dump of removed trees may be the Control was achieved by sprays of source of an unusually densepopulation chlordane and dieldrin. Emulsion and of beetles. Injured trees or those of ,wettable powder formulations were Iow vitality which often cannot be de- equally effective at one pound technical tected are attacked by ambrosia beetles. chlordane or one-quarter pound techni- cal dieldrin. Successful sprays were Control of the beetles generally is those applied by power sprayers. Air- achieved by keeping trees in vigorous plane applications were not satisfactory condition and destroying or removing in reducing bug populations. infested logs or trees. Those who wish to spray for control of the beetlesmay Termites use benzene hexachloride or lindane. Infestations of the smooth-headed. Two pounds of I0 per cent gamma- powder-posttermite, Cryptotermescaui- isomer of benzenehexachloride or one frozs Banks (determination by F. Gray pound of 25 per cent gamma-isomerof Butcher), (Fig. 58b) occur in tree lindane per five gallons of water for each trunks. These infestations occur ap- tree trunk is suggested. parently in trees of low vitality where the tissues have become lifeless. Un- Coconut Flower Moth sightly trunk scars occur from termite A small grayish colored moth l,arva, infestations and decomposition of the Batrached,ramathesoni Busck. feeds on fibers. coconut bloom and destroys much fruit The best control is achievedbv main- 1es8l WOLFENBARGER: INSECTS taining healthy trees. Applications of aldrin, chlordane, dieldrin or h"P- tachlor to the initially infested areas mieht reduce the cavities in the trees. Pahnetto V eeail The palmetto weevil, Rhynchophorus uuentatus Fab. (Fig. SBc), occasionally kills trees of Phoenix canariensis. Early infestation indications are reclining and falling fronds (Fig. 59). Such fronds are often looseenough to be pulled from the tree trunk. At the bases of these loose fronds very large white grubs may be found. (The same or a closelY re- 'ogru-gru" lated species is called in Puerto Rico and is an item of food.) These larvae hatch from eggs, develop Fig. 59. Phoenix with reclining fronds in the tree, pupate and give rise to loosened by larvae of palmetto weevil adults in the tree. The coconut palm, feeding in area producing fronds. with Cocos nucifera, is also infested given excellentthrips control on mangos the beetle. and avocadosand is suggestedfor use The beetlehas been controlled by "p- on palms. plying DDT and lindarle to the center of Mites the palm where new fronds are emerg' The tumid mite, Septanychus tumidus irg. Lindane or benzenehexachloride (Banks), has been taken from royal scale in- is preferred to DDT, since palm fronds. Th"y have been observed sects do not increase following their in low populations without having been the application. Liberal amounts of serious. Breoipalpus sp. also has been aqueoussuspension, mixed according to found on the coconut palm and not been the maximum recommendationslisted, serious. Other species are probably are suggested. present but have not been recognized. GreenhouseThrips On mite infested fronds the leaves ap- Greenhousethrips, Heliothrips haem' pear dry and powdery in early stages rnonhoid,alis (Bouche), were found of infestations. In later stages of mite feeding on royal palm fronds. Other injury dead brown leaf tissues are thrips speciesmay be found. These in' evident. sects remove or destroy the green color Sulfur is suggested if control is in leaves by rasping leaf tissue and needed. If sulfur is ineffective, one of the plant juices. Infestations sucking the newer miticides. such as Kelthane or begin in the newly opened frond and Chlorobenzilate,may be tried. soon the frond is yellow, then brown insects af- colored. Death of the leaf occurs earlier A number of destructive than usual. Thrips have not been nu- fecting palms are not known to be pres- merouson palms in Florida. ent in Florida. The coconut rhinocerus Dieldrin, four ounces technical per beetle, Strategus quadlifoueatus (Pali- 100 gallons of water from wettable sot de Beauvois), is very destructive in powder or emulsion formulations, has Puerto Rico, accordingto Plank (I94'B), It2 PRINCIPES [Vol. 2 where larvae and adults feed principally uegetables. 100 pp. Mimeo. Philip- in the trunk. It is significant to note pine Bureau of Plant Industry. 1956. that most infestationsin Puerto Rico Creighton, John T. sabalella are observedabout years two after hur- Chambers,the major pest of palms in ricanes. Two other beetles,Oryctes rhi- Florida. Iournal o't' Economic Ento- nocerus Lind. and Rhina oblita Duval, mology 30: 590-595. 1937. harmful to coconuttrees in other parts Plank, Harold K. of the world, are not known to exist in Life history, habits Florida. and c6ntrol of the coconut rhinoceros beetle in Puerto Rico. Fed,eral Ex- periment Station in Pu,erto Ri,co Lrrnnarunn Crrno (Mayaguez) Bulletin 45: 1-35. 1948. Baranowski, R. M. The royal palm bug. Riddick, Eloise. Check list of hosts of Principes 2, 72-73. 1958. scale insects of Florida. State Plnnt Bruner, S. C., L. C. Scaramuzza,y A. R. Board, Florid,a, Bulletin 7: 1-78. Otero. Catalogo de los insectos que 1955. atacan a las plantas economicas de Wolcott, George N. An economic en- Cuba. Estarion Experimental Agron- tornology ot' the West Indies. 688 pp. 6mica, Santiagod,e las Vegas (Cuba). illus. The Entomological Society Boletin 63: I-246. 1945. of Puerto Rico, San Juan, 1933. Capco, Santiago R. A list ot' plant pests Zimmerman, Elwood C. Insects ot' Ha- of the Philippines, with sp'ecial refer- waii L: 110. 1948. University of ence to t'ield, crops, fruit trees and, Hawaii Press. Honolulu. 1948.

ClassifiedSecfion

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