,,mp-#cac ,,november #aieh ,,pecan ,,diseases ,,and ,,insects ,,and ,,their ,,control ,,texas ,,agricultural ,,experiment ,,station 444 ,,texas ,,agricultural ,,extension ,,service ,college ,station1 ,texas ,key to ,pecan ,diseases ,,diseases ,,of ,,the ,,leaves ,olive spots on underside page #e ,scab ,downy1 buff1 or greenish-yellow lesions page #g ,downy ,spot ,small1 reddish-brown to gray spots on page #f ,brown ,leaf ,spot underside ,dark brown to black lesions on veins page #f ,vein ,spot and stems ,tiny white tufts of fungal growth on page #i ,articularia ,leaf ,mold underside ,small olive green velvety spots4 ,by page #g ,leaf ,blotch midsummer1 black pimple-like dots appear in the spots ,leaflets yellowish1 mottled1 narrowed page #h ,rosette and crinkled with reddish-brown spots1 may be perforated ,broomy type of twig growth1 bunching of page #h ,bunch ,disease leaves ,,diseases ,,of ,,the ,,nuts ,small black sunken or raised spots page #e ,scab which may fuse to cover entire surface of shuck ,pink spore masses on shuck surface page #i ,pink ,mold ,,diseases ,,of ,,the ,,roots ,galls of various sizes on larger roots page #g ,crown ,gall ,splitting and deterioration of bark of page #aj ,cotton ,root ,rot infected roots1 strands of buff-colored fungal growth may be present ,,nonparasitic ,,plants ,,on ,,the ,,limbs ,,and ,,bark ,whitish-gray mosslike masses on the bark page #i ,lichens ,accumulations of grayish strands page #i ,spanish ,moss1 ,ball ,moss hanging from limbs and twigs or ball-like growth on limbs and branches ,key to ,pecan ,insects ,,insects ,,attacking ,,the ,,nuts ,olive-green caterpillars up to inch page #aj ,pecan ,nut ,casebearer long feeding in the nuts1 or later in the season1 in the shucks ,white caterpillars up to inch long page #aa ,hickory ,shuckworm tunneling in the shucks ,white legless grubs feeding in the nuts page #ab ,pecan ,weevil in late summer ,green or brown bugs sucking the sap page #ab ,stink ,bugs and ,plant from the nuts ,bugs ,,insects ,,attacking ,,the ,,foliage ,soft-bodied yellow insects producing page #ac ,aphids honeydew or small black insects causing yellow blotches on the foliage ,tiny green arthropods in webs near the page #ac ,mites midrib1 leaves appear scorched ,caterpillars feeding in gray cases page #ad ,pecan ,leaf ,casebearer about inch long in the spring2 small winding blotches produced in the leaves in the summer ,olive-green caterpillars tunneling in page #aj ,pecan ,nut ,casebearer the shoots in the early spring ,tiny caterpillars in light brown page #ae ,pecan ,cigar ,casebearer cigar-shaped cases about inch long ,galls on the leaves1 twigs and nuts page #ad ,pecan ,phylloxera ,leaves eaten in the early spring by a page #ad ,sawfly light green caterpillar which leaves the midribs and veins intact ,beetles feeding on the foliage at night page #ae ,may ,beetles ,caterpillars in large white webs page #ae ,fall ,webworm encasing entire branches ,caterpillars with long soft hairs page #af ,walnut ,caterpillar feeding in colonies on the foliage without producing webs ,dark gray1 active caterpillars up to #c page #af ,pecan ,catocala inches long feeding on the foliage in early spring ,masses of frothy white foam enclosing page #af ,pecan ,spittlebug tiny1 light green insects in the spring ,tiny greenish caterpillars feeding in page #af ,pecan ,bud ,moth the terminals and axils of the buds on young pecan trees ,,insects ,,attacking ,,the ,,limbs1 ,,trunk ,,and ,,twigs ,beetle girdling twigs and limbs in late page #ag ,pecan ,twig ,girdler summer and fall ,holes about inch in diameter in dying page #ag ,red-shouldered limbs ,shot-hole ,borer ,white borers with an enlargement behind page #ag ,flatheaded ,borers the head tunneling underneath the bark of trunk and limbs ,limbs encrusted with scales1 which page #ah ,obscure ,scale closely resemble the color of the bark ,,contents ,key to ,pecan ,diseases #b ,key to ,pecan ,insects #b ,spray ,schedule for the ,control of ,pecan ,diseases and ,insects #d ,introduction #e ,pecan ,diseases and ,their ,control #e ,scab #e ,brown ,leaf ,spot #f ,vein ,spot #f ,leaf ,blotch #g ,crown ,gall #g ,downy ,spot #g ,bunch ,disease #h ,rosette #h ,lichens #i ,articularia ,leaf ,mold #i ,pink ,mold #i ,spanish and ,ball ,moss #i ,cotton ,root ,rot #aj ,pecan ,insects and ,their ,control #aj ,pecan ,nut ,casebearer #aj ,hickory ,shuckworm #aa ,pecan ,weevil #ab ,stink and ,plant ,bugs #ab ,aphids #ac ,mites #ac ,pecan ,leaf ,casebearer #ad ,pecan ,phylloxera #ad ,sawflies #ad ,may ,beetles #ae ,pecan ,cigar ,casebearer #ae ,fall ,webworm #ae ,walnut ,caterpillar #af ,pecan ,catocala #af ,pecan ,spittlebug #af ,pecan ,bud ,moth #af ,twig ,girdler #ag ,red-shouldered ,shot-hole ,borer #ag ,flatheaded ,borers #ag ,obscure ,scale #ah ,application of ,fungicides and ,insecticides #ah ,spray ,equipment #ah ,literature ,cited #ai ,,spray ,,schedule ,,for ,,the ,,control ,,of ,,pecan ,,diseases ,,and ,,insects ,name of spray and ,insect or ,spray materials1 ,remarks time of application disease to be per #ajj gallon controlled ,prepollination ,scab1 downy ,zineb1,a #b pounds ,if phylloxera is a spray1 when first spot1 vein spot problem1 see page leaves are #ad4 one-third grown ,first cover spray1 ,scab1 downy ,zineb1 #b pounds when tips of small spot1 vein nuts have turned spot1 leaf brown and nut blotch1 brown casebearer eggs are leaf spot observed ,pecan nut #c pounds #ej percent casebearer1 wettable ,,ddt1 or #a pecan leaf pound #be percent casebearer wettable parathion1 or #a pint nicotine sulfate plus #b quarts summer oil1 or #e pounds #dj percent wettable toxaphene1 or #c pounds #be percent wettable malathion ,rosette ,zinc sulfate1 #b ,if rosette is a pounds problem1 include zinc sulfate in spray4 ,second cover spray1 ,scab1 downy ,zineb1 #b pounds #c to #d weeks after spot1 vein ,zinc sulfate1 #b first cover spray spot1 leaf pounds blotch1 brown leaf spot ,rosette ,third cover spray1 ,scab1 brown ,zineb1 #b pounds ,if aphid or mite #c to #d weeks after leaf spot1 infestations are second cover spray liver spot1 severe1 use aphids1 mites insecticides recommended on page #ac4 ,walnut ,if walnut caterpillar1 caterpillars or fall webworm fall webworms are a problem1 use insecticides recommended on pages #ae and #af4 ,rosette ,zinc sulfate1 #b pounds ,fourth cover spray ,pecan weevil #f pounds #ej percent ,for control of wettable ,,ddt weevils1 apply spray when as many as three weevils can be jarred from a tree4 ,if scab is present add #b pounds zineb to ,,ddt spray4 ,a,zineb4 ,zinc ethylene bis dithiocarbamate4 ,manufactured by ,rohm ,haas ,co41 trade name ,dithane ,z-#gh3 ,e4 ,i4 ,du,pont ,co41 trade name ,parzate4 ,pecan ,diseases and ,insects and ,their ,control ,david ,w4 ,rosberg and ,d4 ,r4 ,king ,respectively1 associate professor1 ,department of ,plant ,physiology and ,pathology1 and associate professor1 ,department of ,entomology4 ,the pecan tree must be protected from attack by the many destructive diseases and insects that affect it to produce a bountiful nut crop4 ,the diseases that affect the pecan1 especially those caused by fungi1 are rapidly spread throughout the trees in an orchard in the early spring4 ,during this season of frequent rains1 the spores of the disease fungi germinate and invade the young tender tissues of the shoots1 leaves and nuts4 ,under conditions of prolonged damp weather1 when the humidity remains high1 the disease organisms reproduce at a rapid rate and cause severe shedding of leaves and nuts4 ,pecans are attacked by more than #bj species of insects that cause damage to leaves1 nuts1 twigs1 buds1 branches and even the bark4 ,the development of commercial pecan acreages has provided ideal conditions for the increase in severity of both disease and insect damage because of the abundant food supply in a concentrated planting of pecans4 ,in its natural habitat the pecan is less subject to the devastations of diseases and insects4 ,the many destructive insects and diseases must be controlled for successful pecan production4 ,the pecan grower must also understand the nature and habits of the various disease and insect pests that threaten his crop and use certain cultural practices which help to reduce damage from diseases and insects4 ,pecan ,diseases and ,their ,control ,the diseases which affect the pecan are of four different types3 namely fungus1 bacterial1 virus and physiological4 ,the fungus diseases1 the most numerous and widespread1 are caused by small microscopic molds4 ,approximately #ab different fungus organisms cause harmful diseases of the pecan4 ,the bacterial disease organisms1 unlike the disease producing fungi1 are single celled and can be seen only under a microscope4 ,bacterial diseases are fewer and of less economic importance than fungus diseases4 ,virus diseases are caused by extremely small agents which can be seen only under special ultra-microscopes such as the electron microscope4 ,plant viruses are protein substances1 but their exact nature is unknown4 ,physiological disorders 7sometimes called physiological diseases7 are caused by a variety of environmental conditions4 ,a physiological disorder in a pecan tree may result from infertile soil1 excessive moisture1 or the absence or degree of available nutritional mineral elements to the growing tree4 ,these various environmental factors have special adverse effects1 manifested by specific symptoms caused by insufficient levels of a given nutritional mineral element or elements1 which are easily corrected by supplying the tree the necessary mineral elements either through soil application or foliage sprays4 ,,scab ,pecan scab1 caused by the fungus ,cladosporium effusum 7,wint47 ,demaree1 is the most destructive disease of pecans in ,texas4 ,the fungus invades the young rapidly growing shoots and leaves and later the developing nuts4 ,severely infected nuts on highly scab-susceptible varieties fall or fail to develop1 resulting in a total nut crop loss4 ,early season defoliation often occurs in seasons of frequent rains and high humidity which facilitate the rapid development and spread of the scab fungus4 ,the scab fungus overwinters in infected shoots and in old shucks and leaves in the trees4 ,in the spring when temperature and moisture conditions become favorable1 the fungus begins to grow in the shoot lesions1 old leaves and shucks1 and within a few days produces great numbers of spores4 ,these spores are spread by wind and rain to newly developed leaves where they germinate and invade the tender tissues1 initiating primary infection4 ,the fungus produces a great abundance of spores on the surface of these primary infection sites and spreads throughout the tree and infects young shoots1 leaves and nuts4 ,on the leaves1 primary infection lesions occur on the lower leaf surfaces and are characteristically olive brown1 somewhat elongated in shape and vary in size from a barely discernible dot to lesions one-fourth inch or more in diameter4 ,frequently1 adjacent lesions coalesce1 forming large very dark lesions4 ,primary scab lesions commonly occur on or along the leaflet veins but often may be found between the veins on the underleaf surface4 ,on the nuts1 scab lesions appear as small black dots1 which are elevated or sunken in older infections4 ,adjacent lesions on the nuts may coalesce forming large sunken black lesions1 ,figure #a4 ,when infection is severe1 the entire nut surface is black in appearance1 development is arrested and the nuts drop prematurely4 ,illustration3 ,figure #a4 ,scab lesions on leaves and nuts of ,delmas variety4 ,note concave lesions and overall scabby appearance of severely infected nuts4 ,illustration3 ,figure #a4 ,infected nuts4 ,pecan varieties vary in their susceptibility to scab disease4 ,among the highly susceptible varieties are3 ,burkett1 ,delmas1 ,schley1 ,moore1 ,halbert and most western varieties4 ,moneymaker1 ,success and ,curtis are moderately resistant4 ,mahan1 ,stuart and ,desirable varieties are highly resistant to the scab fungus4 ,however1 this character of resistance varies1 depending on the area of the state1 local environmental conditions and the particular strain of the scab fungus present4 ,scab disease development is favored by rainy periods and cloudy days when the humidity remains high and leaf surfaces are wet4 ,under these conditions1 spores of the fungus in contact with the wet leaf surface of a pecan leaflet or nut germinate rapidly1 invade the tender tissues and initiate infection within #f hours4 ,lesions resulting from these infection sites1 become visible to the naked eye within #g to #ad days1 depending on environmental conditions4 ,a period of warm dry weather after infection occurs may retard lesion development4 ,control4--,the control of pecan scab disease depends primarily on the protection of tender leaf1 nut and shoot surfaces with proper application of an effective fungicide4 ,a protective film of fungicide chemical prevents scab fungus infections by killing the spores immediately after their germination1 thereby preventing invasion of susceptible tissues4 ,unfortunately1 once the fungus has invaded the tissues it becomes protected from chemical attack and produces spores in great abundance4 ,therefore1 thorough coverage of leaf1 nut and shoot surfaces with a fungicide chemical must be maintained to prevent secondary infections1 7#f1 #aj1 #aa74 ,sanitation measures1 such as removal of old attached shucks and leaf stems in trees and plowing or disk harrowing under fallen leaves and shucks help reduce primary infections4 ,see spray schedule1 page #d1 for scab disease control4 ,,brown ,,leaf ,,spot ,the brown leaf spot disease fungus ,cercospora fusca 7,heald and ,walf7 ,rand affects only mature leaves and usually does not appear until the latter part of ,may or mid-,june4 ,primary lesions develop on the lower leaf surfaces as small dots1 which gradually enlarge and become reddish brown with a grayish cast4 ,the shape of the lesions may be circular or irregular1 especially where two or more lesions develop adjacent to one another1 ,figure #b4 ,in seasons favorable for brown leaf spot development pecan trees may be completely defoliated within #c to #d months if the disease is not controlled4 ,most pecan varieties which are maintained in a vigorous state of growth are resistant to brown spot disease4 ,control4--,see spray schedule1 page #d4 ,,vein ,,spot ,vein spot disease is caused by the fungus ,gnomonia nerviseda4 ,the symptoms of the disease are similar to the leaf lesion symptoms of scab disease1 but vein spot disease1 unlike scab disease1 affects only the leaves4 ,lesions of vein spot disease develop on the veins or stems of leaflets and leaves1 are usually less than one-fourth inch in diameter and are characteristically dark brown to black4 ,leaflets and leaf stems which are severely affected drop1 resulting in premature defoliation4 ,the fungus lives in fallen leaves over the winter4 ,the following spring when temperature and moisture conditions are favorable1 spores formed in special structures called perithecia are forcibly discharged into the air and carried by wind currents to the newly formed spring foliage1 initiating primary infections4 ,control4--,see spray schedule1 page #d4 ,,leaf ,,blotch ,leaf blotch disease is caused by the fungus ,mycosphaerella dendroides 7,cke47 ,demaree and ,cole4 ,the disease occurs mainly in trees of poor vigor1 which may be due to neglect1 infertile soil1 rosette or overcrowding4 ,nursery trees are particularly susceptible to the disease4 ,the fungus overwinters in fallen leaves4 ,in the early spring1 large numbers of spores produced in the old leaves on the ground are carried by wind currents to the young leaves in the tree1 where they germinate and rapidly invade the tender leaf tissue4 ,the disease symptoms first appear on the undersurface of mature leaves in early summer1 as small olive-green velvety spots4 ,by midsummer black pimplelike dots become especially noticeable in the leaf spots after the surface spore masses have been removed by wind and rain1 giving the diseased areas of the leaves a black1 shiny appearance4 ,when the disease is severe1 infected leaflets are killed1 which causes defoliation of the trees in late summer or early fall and results in reduced tree vigor and increased susceptibility to disease and insect attack4 ,control4--,leaf blotch disease can be controlled effectively in the early spring by disking under old fallen leaves that harbor the fungus pathogen4 ,in areas where a spray program for the control of scab disease is carried out1 leaf blotch usually is not a damaging disease4 ,in localities where leaf blotch disease occurs in the absence of other pecan diseases1 two applications of fungicide will control the disease effectively4 ,the first spray should be applied after pollination when the tips of the nutlets have turned brown and the second spray application should be made #c to #d weeks later4 ,see spray schedule1 page #d4 ,,crown ,,gall ,crown gall disease1 caused by the bacterium ,agrobacterium tumefaciens 7,e4 ,f4 and ,town47 ,conn41 often is damaging to pecan trees4 ,nursery trees as well as trees in bearing pecan orchards are susceptible to the disease4 ,illustration3 ,figure #b4 ,brown leaf spot diseased pecan leaflet showing typical symptoms4 ,lesions are circular to irregular in shape4 ,the development of galls is confined primarily to larger roots near the base of the tree trunk1 although small roots may become infected and galls develop on them4 ,the smaller galls are under the soil surface and cannot be detected unless the soil is carefully removed from around the roots1 ,figure #c4 ,large galls1 often #aj to #ah inches in diameter1 develop on larger roots and may protrude well above the surface of the soil4 ,illustration3 ,figure #c4 ,crown gall disease symptoms on young infected pecan tree4 ,galls on nursery trees develop at or below the soil surface on the taproot and larger secondary roots4 ,control4--,all infected nursery trees should be dug and immediately burned4 ,crown gall-diseased orchard trees sometimes can be saved by digging the soil from around large roots and removing the exposed galls4 ,where galls were removed1 the damaged root surfaces should be painted with a creosote-coal tar mixture 7one part creosote to three parts coal tar7 to prevent spread of the disease#i4 ,cultivation of the soil around the trunk base of infected trees should be avoided to prevent root wounds and spreading of the crown gall pathogen4 ,,downy ,,spot ,downy spot disease1 caused by the fungus ,mycosphaerella caryigena 7,ell4 and ,ev47 ,damaree and ,cole1 attacks all pecan varieties4 ,only leaves are susceptible to the disease4 ,primary infection of new leaves in the spring occurs from spores produced in specialized fruiting bodies in old overwintered leaves4 ,the downy spots appear usually during the summer months on the lower surfaces of leaflets4 ,the downy character of the lesions is due to the production by the fungus of thousands of minute spores on the surface of each spot4 ,the spores are spread by wind and rain to adjacent leaves and to neighboring trees4 ,after spore dissemination is complete1 the lesions visible from both leaf surfaces are one-eighth to one-fourth inch in diameter and greenish yellow4 ,later in the season the lesions turn brown due to the death of the leaf cells in the diseased area4 ,moneymaker and ,stuart varieties are most susceptible to downy spot disease although all pecan varieties are moderately to slightly susceptible4 ,control4--,disk under old fallen leaves in the early spring before the leafbuds begin to swell4 ,this practice covers the leaves with soil and prevents the discharge of spores into the air1 thereby controlling primary infection of new leaves4 ,in seasons when heavy rains make early spring disking impossible1 downy spot disease can be controlled by spraying the trees as indicated in the spray schedule on page #d4 ,,bunch ,,disease ,although the cause of bunch disease is not known1 evidence indicates it is an infectious disease1 which suggests that the causal agent may be a virus4 ,trees affected with bunch disease show the bunching symptom1 which is due to excessive growth of slender succulent twigs from lateral buds that normally remain dormant4 ,in moderately affected trees one or several branches will show the 8bunch0 growth symptom4 ,bunching in severely affected trees may involve all main branches which produce thick masses of sucker-like growth and few1 if any1 nuts4 ,observations indicate that the ,stuart variety is the most resistant to bunch disease4 ,illustration3 ,figure #d4 ,rosette die-back symptoms of pecan tree showing severe zinc deficiency4 ,control4--,there is no known effective control for bunch disease4 ,early detection of the first symptom of bunch and pruning out of the affected branch may prevent spread of the disease throughout the tree4 ,when the tree is severely affected1 and limbs are involved1 the tree should be destroyed to protect nearby healthy trees from infection4 ,for propagation purposes1 all bud or scion wood should be taken only from bunch disease-free trees4 ,,rosette ,rosette is a nutritional deficiency disease caused by certain soil conditions which make zinc unavailable to the pecan tree4 ,all pecan trees require zinc for growth4 ,trees showing the first symptom of zinc deficiency have yellowed tops4 ,the individual leaflets when examined are yellowish and mottled4 ,the next season the foliage may be yellowish and the leaflets narrowed and crinkled4 ,more severely affected trees produce foliage which is a yellowish to reddish-brown overall color1 and the leaflets are very narrow with reddish-brown spots and may be perforated4 ,shoots are much shortened and the leaves are produced in compact bunches of dense foliage4 ,trees affected by rosette for several seasons have many dead shoots and small branches from the dying-back of each season's growth1 ,figure #d4 ,such trees are greatly stunted1 of poor vigor and produce few1 if any1 nuts4 ,control4--,rosette is controlled readily by applying zinc sulfate to the tree either as a foliage spray or in the dry form as a soil application4 ,where a disease and insect spray control program is being carried out1 zinc sulfate may be added to the spray mixture4 ,foliage spray4 ,two pounds zinc sulfate 7#cf percent7 per #ajj gallons of water4 ,first application3 after pollination when tips of nutlets turn brown4 ,second application3 #c to #d weeks later4 ,third application3 #c to #d weeks later4 ,soil application4 ,application of zinc sulfate to the soil1 particularly in a large orchard is a more expensive operation1 but it provides longer protection against rosette4 ,in highly alkaline soils1 or soils that readily fix zinc and make it unavailable to the tree1 foliage spray applications of zinc sulfate are more economical because of the excessive rates required to supply available zinc through the soil4 ,rate of application of zinc sulfate3 ,mildly rosetted trees--apply #e pounds zinc sulfate 7#cf percent7 annually for #b to #c years4 ,severely rosetted trees--apply #e to #aj pounds zinc sulfate 7#cf percent7 annually until rosette symptoms disappear4 ,time and method of application3 ,apply zinc sulfate to the soil around trees in late ,february or early ,march4 ,broadcast zinc sulfate under the tree from the trunk to several feet beyond the limb canopy4 ,disking1 harrowing1 or any operation that mixes the zinc sulfate with the soil1 is desirable to prevent washing away and surface soil fixing of zinc4 ,,lichens ,lichens commonly are found growing on the branches and trunks of pecan trees1 especially in humid areas and river bottom orchards having poor air drainage4 ,lichens are nonparasitic to the pecan tree1 but merely attach themselves to the bark surfaces4 ,lichens grow equally well on rocks1 fence posts1 bricks and other objects4 ,there are several types of lichens that occur on pecan trees1 none of which are damaging except perhaps in appearance to the trees in cases of extremely heavy infestations1 ,figure #e4 ,illustration3 ,figure #e4 ,lichens commonly found on the bark of pecan trees4 ,left1 a fan-shaped type4 ,right1 an erect-branched type4 ,control4--,the occurrence of lichens in trees regularly sprayed with copper-containing fungicides is rare4 ,,articularia ,,leaf ,,mold ,articularia leaf mold caused by the fungus ,articularia quercina 7,,pk7 ,hoehn is a disease of minor occurrence and importance4 ,the disease occurs most commonly following rainy periods and in areas of high relative humidity in the leaves of trees of poor vigor4 ,the fungus produces on the lower surfaces of the leaves a conspicuous growth of white tufts which contain masses of spores1 ,figure #f4 ,illustration3 ,figure #f4 ,articularia leaf mold fungus1 showing white tufts on lower leaf surfaces of pecan leaflets4 ,control4--,articularia leaf mold does not occur in trees or in orchards which have been sprayed for disease control4 ,a single application of fungicide such as zineb at #b pounds per #ajj gallons of water when the disease is first detected is usually sufficient to control ,articularia leaf mold disease4 ,,pink ,,mold ,pink mold1 ,cephalothecium roseum ,corda1 usually occurs on nuts infected with the scab fungus4 ,the pink mold fungus apparently enters the nuts through scab lesions on the shucks and continues to produce masses of pink spores on shuck surfaces until late fall4 ,the fungus sometimes invades the kernel of thin-shelled pecan varieties causing 8pink rot0 which is characterized by an oily appearance of the nut shell and a rancid odor4 ,control4--,pink mold rarely occurs on the shucks of nuts in the absence of scab disease4 ,in areas where scab disease control is regularly practiced pink mold is not a problem4 ,,spanish ,,and ,,ball ,,moss ,spanish moss1 ,tillandsia usneoides1 and ,ball moss1 ,tillandsia recurvata ,l41 are not parasitic to the pecan tree and are similar to lichens in that they both derive their food from the air1 rain or atmospheric moisture4 ,neglected orchards in areas of high humidity or poor air drainage are most troubled with ,spanish moss and ,ball moss4 ,when large and excessive growths of ,spanish moss develop in pecan trees1 the shading effect to the leaves is detrimental to tree vigor1 bearing and growth1 ,figure #g4 ,control4--,the ,spanish moss plant like the pecan tree requires sunlight for vigorous growth4 ,a pecan tree kept in a vigorous state of growth produces dense foliage that effectively shades accumulations of ,spanish moss and retards its growth4 ,spanish moss is not a problem in pecan trees in orchards which are sprayed with fungicide for disease control4 ,both ,spanish moss and ,ball moss can be controlled by spraying pecan trees with #f pounds of lead arsenate per #ajj gallons of water#c4 ,do not allow livestock to graze in orchards sprayed with lead arsenate4 ,,cotton ,,root ,,rot ,cotton root rot disease is caused by the fungus ,phymatotrichum omnivorum 7,shear7 ,dvgg41 a soil-inhabiting pathogen that attacks a wide range of host plants including the pecan4 ,the roots of the pecan tree are invaded during the summer when growth of the fungus in the soil is most active4 ,the infected roots are killed1 disrupting the transportation of water to the leaves1 ,figure #h4 ,trees diseased by cotton root rot produce yellow foliage1 and shedding of leaflets occurs during dry periods4 ,diseased trees usually die #a to #c years after becoming infected4 ,illustration3 ,figure #g4 ,spanish moss accumulation in pecan trees reduces vigor from excessive shading4 ,illustration3 ,figure #h4 ,cotton root infected with cotton root rot fungus4 ,note the splitting and general deterioration of the root4 ,control4--,an effective control for cotton root rot disease has not been developed4 ,new orchards should not be planted in soil having a history of cotton root rot disease4 ,pecan ,insects and ,their ,control ,,pecan ,,nut ,,casebearer ,the pecan nut casebearer1 ,acrobasis caryae ,grote1 is the major pest of pecans in ,texas4 ,early in the spring1 the overwintered generation feeds first in the buds and then in the developing shoots1 causing them to wilt and die4 ,succeeding generations feed on the nuts during the late spring and summer1 ,figure #i4 ,severe infestations may destroy the entire crop of pecans4 ,the adult is a light gray moth which is about one third inch in length4 ,the wings are gray1 and the forewings have a ridge of dark scales across them about one-third the distance from the base4 ,the moths fly at night and spend the day in concealment4 ,the young larvae are white to pink1 but later become olive gray to green and attain a length of about one-half inch4 ,this insect passes the winter as a partially grown larva in a tiny silken cocoon called a hibernaculum1 which is usually attached to a bud1 ,figure #aj4 ,in the spring1 the larvae feed for a short time on the buds1 after which they tunnel in the developing shoots until they reach maturity1 ,figure #aa4 ,pupation usually occurs in these burrows1 and the moths emerge in late ,april and ,may4 ,two or #c days after the adults emerge1 they deposit eggs on the tips of the nuts1 ,figure #ab4 ,each female may deposit from #ej to #aej eggs4 ,the eggs1 which are just visible to the naked eye1 are greenish white when they are deposited but assume a reddish appearance a few days later4 ,the first-generation larvae hatch from the eggs in #d or #e days and migrate to the buds below the nuts to feed4 ,after a day or two1 they enter the nuts1 usually at the base1 and feed in them1 each larva frequently destroying an entire cluster4 ,bits of frass and webbing may be observed projecting from the injured nuts4 ,upon reaching maturity1 the larvae pupate in the nuts and emerge as adults in ,june and early ,july4 ,illustration3 ,figure #i4 ,injury to nuts caused by first generation larvae of the pecan nut casebearer4 ,the adults deposit eggs in grooves on the tips or bases of the nuts4 ,second-generation larvae which hatch from these eggs also feed in the nuts4 ,less injury is produced by this generation because the nuts are larger and each larva requires only one or two nuts to complete its development4 ,pupation takes place in the hollowed out nuts1 ,figure #ac1 and the moths emerge from late ,july to early ,september4 ,a third generation usually follows1 but the shells of the nuts have become hard1 and only a few of them are penetrated by the larvae4 ,instead1 they feed in the shucks4 ,a number of third-generation larvae construct hibernacula1 while the remainder pupate and appear as adults1 emerging from late ,august to ,october4 ,these adults deposit eggs1 which hatch into fourth-generation larvae4 ,if nuts are available1 their shucks constitute the principal food of the larvae of this generation4 ,in the absence of nuts1 the larvae feed on buds and leaf stems4 ,overwintering hibernacula are constructed by the partially grown larvae by the middle of ,november#b4 ,control4--,the necessity for control of this pest may be determined by examination of the trees when the shoots appear in the spring4 ,if a number of them are wilted1 the following control measures probably will be required4 ,a spray application should be made when eggs of the first generation appear on the tips of the young nuts in late ,april or ,may4 ,the period of egg deposition usually coincides with the completion of pollination1 at which time the tips of the nuts turn brown4 ,satisfactory control may be obtained by using any of several insecticides4 ,see spray schedule1 page #d4 ,ordinarily1 only one application of spray is required to control the nut casebearer4 ,however1 if trees surrounding the treated area are not sprayed1 moths may enter the sprayed area and a serious infestation of second-generation larvae may develop4 ,under these circumstances1 a second spray may be required in ,june or early ,july when second-generation eggs are deposited#f1 #aa4 ,,hickory ,,shuckworm ,the hickory shuckworm1 ,laspeyresia caryana 7,fitch71 frequently causes severe injury to pecans4 ,in the late summer and fall the shucks are tunneled out4 ,as a result1 the nuts are slower to mature and the kernels do not develop properly4 ,the shucks stick to the nuts and fail to open1 thus increasing the difficulty of harvest4 ,the adult shuckworm is a dark1 grayish-black moth with a wing span of a little over one-half inch4 ,the larva is white with a light brown head4 ,it attains a length of three-eighths inch at maturity4 ,the winter is passed by the larvae in fallen pecan or hickory shucks4 ,they pupate in late winter and emerge as adults during the spring4 ,the adults deposit eggs principally on hickory trees on the leaves and young nuts1 and the larvae feed in developing nuts in early summer4 ,succeeding generations develop in pecan shucks4 ,before pupating1 the larvae cut a hole to the outside1 and then spin a cocoon4 ,when the moth emerges1 the empty pupal skin is left projecting from the hole and can be seen afterward on the shuck4 ,as many as five generations may be completed each year before the last generation larvae go into hibernation4 ,control4--,no economical chemical control for the shuckworm has been developed4 ,cultural measures will aid in reducing populations4 ,plowing during ,july and ,august to turn under the infested shucks is relatively effective4 ,the larvae are unable to mature in the decaying shucks1 and the adults cannot emerge from the soil4 ,care should be taken to completely cover the fallen shucks1 but the depth of plowing should be regulated or damage to the roots will result4 ,illustration3 ,figure #aj4 ,location of overwintering cocoons1 or hibernacula1 of the pecan nut casebearer4 ,,pecan ,,weevil ,the pecan weevil1 ,curculio caryae 7,horn71 is a late-season pest of pecans in ,texas4 ,in years when severe infestations occur1 this insect may destroy a large portion of the pecan crop4 ,the kernels are eaten out by the larvae4 ,the adult is a brownish weevil which is about three-eighths inch long4 ,the female has a snout which is as long as the body2 the male's is somewhat shorter4 ,the weevil appears in late ,august and early ,september4 ,after the nut kernels have hardened1 the female chews a hole in the shell and deposits her eggs in little pockets in the nuts4 ,creamy white grubs hatch from the eggs and feed inside the nuts during the fall1 attaining a length of about three-fifths inch4 ,when they reach maturity1 the grubs chew a hole about one-eighth inch in diameter in the shell1 emerge from the nut and drop to the ground in late fall and early winter4 ,they burrow in the soil to a depth of #d to #ab inches and construct a cell4 ,some individuals remain in the larval stage until the following fall when pupation occurs4 ,other larvae do not transform to pupae until the succeeding year4 ,the adults appear during the summer1 following pupation4 ,the entire life cycle requires from #b to #c years1 most of this time being spent in the soil4 ,illustration3 ,figure #aa4 ,overwintered larva of the pecan nut casebearer and characteristic injury to the developing shoots4 ,control4--,frequently1 certain trees in the orchard are more heavily infested than others1 since the adults usually do not go far from the tree upon which they developed4 ,the time at which insecticide applications should be made to control this insect can be determined by jarring the trees4 ,begin checking the first week in ,august4 ,a large sheet should be placed under a tree and the limbs jarred with a padded pole4 ,the weevils drop to the ground and remain motionless for a short period1 at which time they may be counted4 ,when three or more weevils are jarred from each tree1 an application of spray containing #f pounds of #ej percent ,,ddt wettable powder per #ajj gallons of water should be made#h4 ,illustration3 ,figure #ab4 ,eggs of the first generation pecan nut casebearer deposited on the tips of the young nuts4 ,,stink ,,and ,,plant ,,bugs ,the adults of several species of stink bugs and plant bugs suck the sap from young pecan nuts causing an injury known as black pit1 in which the interior of the nuts turns black4 ,the injured nuts fall from the trees before the shells harden4 ,feeding by the insects after shell hardening1 ,figure #ad1 produces brown or black spots on the kernels4 ,areas affected taste bitter1 but the remainder of the kernel is unaffected4 ,stink bugs are familiar to everyone4 ,plant bugs resemble them and are usually shades of brown1 smaller and narrower in body outline4 ,plant bugs and stink bugs overwinter in the adult stage in debris on the ground4 ,in the spring1 the adults are attracted to growing vegetation such as cover crops or weeds1 where they deposit their eggs4 ,the immature bugs develop on low-growing vegetation4 ,when they reach maturity1 their wings are fully developed and they fly to pecan trees4 ,a few eggs may be deposited on pecan trees1 but the young bugs apparently are unable to develop on them4 ,only the adults are present in sufficient number to inflict economic injury4 ,there may be as many as four generations each year4 ,control4--,although certain insecticides will control these pests1 the number and frequency of spray applications necessary for control would not be economical4 ,care should be taken to keep weeds down in the orchard during the growing season4 ,winter cover crops should be plowed down early in the spring so they will not be attractive to the adults coming out of hibernation4 ,if this operation is delayed1 the bugs will leave the cover crop when it is removed and migrate to the trees in large numbers4 ,,aphids ,these soft-bodied insects appear during the summer and fall4 ,they suck the sap from the leaves1 causing them to turn yellow or brown and fall to the ground4 ,heavy infestations may cause defoliation in the late summer reducing the nut crop in the current and succeeding year4 ,the black pecan aphid1 ,melanocallis caryaefoliae 7,davis71 is about one-sixteenth inch long when full grown1 robust and greenish black4 ,its back is decorated with tubercles4 ,bright yellow blotches up to one-fourth inch in diameter appear around the punctures produced by the feeding of this insect4 ,the yellow aphids1 ,monellia spp41 which attack pecans inflict injury similar to that caused by the black pecan aphid4 ,however1 the large yellow blotches on the leaves do not result from their feeding4 ,a sticky substance called 8honeydew0 is secreted by these insects creating an ideal medium for sooty mold fungus to develop#e4 ,both black and yellow aphids overwinter in the egg stage in crevices in the bark4 ,in the spring the eggs hatch1 and the aphids begin feeding on the leaves4 ,many generations are completed each year4 ,only females1 which may be wingless or winged1 are produced during the growing season4 ,the winged individuals fly to different parts of the tree or to other trees4 ,in the fall1 males and females appear and eggs are deposited under the bark4 ,illustration3 ,figure #ac4 ,pupa of the second generation of the pecan nut casebearer in a hollowed out nut4 ,usually1 these insects are not present in sufficient numbers to cause serious injury until mid or late summer4 ,infestations earlier in the season rarely assume damaging proportions4 ,as is the case with mites1 aphid populations may increase1 following the application of certain insecticides applied for the control of the pecan nut casebearer or following treatment with bordeaux mixture for pecan scab disease control4 ,illustration3 ,figure #ad4 ,southern green stink bug on developing nuts4 ,control4--,when damaging infestations appear1 the trees should be sprayed with either #a pound of #ab percent gamma ,,bhc wettable powder2 or #a pint of #dj percent nicotine sulfate plus #c pounds of soap2 or #a pound of #be percent parathion wettable powder#i4 ,,mites ,these tiny pests attack the leaves usually on the underside causing irregular brown areas to appear4 ,trees which are heavily infested appear scorched and may lose their leaves in late summer or fall4 ,mites usually are light green and are just large enough to be seen without the aid of a hand lens4 ,they are wingless and feed principally on the underside of the leaves along the midrib4 ,colonies of them produce webs in which molted skins and eggs may be found4 ,the life cycle of mites is very short and several generations occur each year4 ,large populations may develop during the late summer and fall4 ,the use of certain insecticides for the control of the pecan nut casebearer or bordeaux mixture for scab control frequently contributes to increases in mite populations later in the season4 ,control4--,mites may be controlled in three ways when damaging infestations develop4 ,an application of #b pounds of wettable sulfur per #ajj gallons of water may be made2 #f pounds of wettable sulfur per #ajj gallons of water may be added to the spray applied for the control of the nut casebearer2 and repeated applications of zineb included in a regular spray schedule for pecan scab control will effectively control mites4 ,however1 a single application of zineb is not effective#g4 ,,pecan ,,leaf ,,casebearer ,on occasion1 this insect1 ,acrobasis juglandis 7,le,b471 develops to damaging numbers and causes economic injury4 ,early in the spring the larva feeds on unfolding leaves and buds4 ,it may prevent leaf development for weeks1 resulting in a greatly decreased yield of nuts4 ,the adult is a dark gray moth marked with brown4 ,its forewings1 which have a spread of about two-thirds inch1 are gray with black blotches4 ,there is a reddish mark near the base of the forewings4 ,the immature larva is brown1 but changes to dark green as it develops to a length of one-half inch4 ,it has a shiny1 brownish black head and is enclosed in a gray case which completely covers the body and is borne in a position nearly perpendicular to the leaf on which the larva is feeding4 ,the pecan leaf casebearer overwinters as an immature larva in a hibernaculum around a bud4 ,it emerges in late ,march or early ,april as the buds open4 ,the larvae mature in ,april1 ,may and ,june and transform into pupae within their gray cases1 ,figure #ae4 ,the moths are present from ,may until early ,august4 ,eggs are deposited during this period on the underside of the leaves4 ,the larvae which hatch from these eggs develop slowly1 and do not attain a length of more than one-sixteenth inch during that season4 ,they construct little winding cases in which they live4 ,their feeding produces irregular blotches on the leaf surface1 ,figure #af4 ,before the leaves drop in the fall1 the larvae migrate to the buds1 and construct their overwintering hibernacula4 ,only one generation is completed each year4 ,control4--,control of this insect is accomplished by spraying for the pecan nut casebearer4 ,see spray schedule1 page #d4 ,the insecticides recommended for nut casebearer control also reduce infestations of the leaf casebearer4 ,illustration3 ,figure #ae4 ,overwintered larvae of pecan leaf casebearer in their cases4 ,illustration3 ,figure #af4 ,summer injury to the leaves by the pecan leaf casebearer4 ,,pecan ,,phylloxera ,the pecan phylloxera1 ,phylloxera devastatris ,perg41 and the pecan leaf phylloxera1 ,p4 notabilis ,perg41 produce galls on the new growth of pecans4 ,leaves1 twigs and nuts may be affected4 ,the galls are conspicuous swellings1 ,figure #ag1 which attain a size of from one-tenth to #a inch in diameter4 ,they are caused by a soft-bodied insect which is closely related to aphids4 ,the winter is passed in the egg stage in crevices in the bark4 ,in the spring1 the egg hatches and the tiny nymph feeds on the tender1 young growth1 apparently secreting a substance which stimulates the plant tissues to develop into galls4 ,after the nymph reaches maturity1 a number of eggs are deposited inside the gall4 ,the young nymphs of the succeeding generation develop within the gall1 which splits open in #a to #c weeks1 liberating them4 ,several generations follow during the summer and fall1 as long as there is fresh young growth on the tree4 ,from #d to #e weeks are required for each generation#d4 ,control4--,the dormant oil spray recommended for obscure scale control will prevent the development of phylloxera4 ,if dormant oil is not applied1 use #b pints of nicotine sulfate plus #f pounds of soap2 #c pounds of #be percent malathion wettable powder2 or two and a half pounds of #aj percent gamma isomer ,,bhc wettable powder per #ajj gallons of water when the leaves are one-third grown4 ,,sawflies ,sawfly larvae1 ,periclista sp4 and others1 feed on the foliage of pecans during ,april and early ,may4 ,the larvae1 which are light green1 chew holes in the leaves4 ,usually the midrib and veins are left intact1 giving the leaflets a lacy appearance1 ,figure #ah4 ,the adults closely resemble wasps1 except that they are not 8wasp-waisted40 ,illustration3 ,fig4 #ag4 ,developing galls of the pecan phylloxera4 ,note the open gall on the lower leaf4 ,control4--,the larvae may be controlled with an application of #b pounds of #ej percent ,,ddt wettable powder or #a pound of #be percent parathion wettable powder per #ajj gallons of water4 ,illustration3 ,figure #ah4 ,sawfly injury to pecan foliage4 ,,may ,,beetles ,many species of ,may beetles may damage pecans early in the spring4 ,the beetles appear only at night and spend the day concealed beneath the surface of the soil4 ,they feed on the young leaves and prevent the foliage from developing4 ,beetles of the most common species are one-half to three-fourths inch long and shiny dark brown4 ,they are attracted to lights and are observed commonly on porches or screen doors at night4 ,the larvae are the grubworms1 or white grubs1 which feed in the soil on the roots of many plants4 ,the female beetle deposits eggs in the soil1 where the larva develops4 ,most species require two summers for the larva to mature4 ,pupation is accomplished in a cell which is constructed in the ground in the fall of the second year4 ,the beetles emerge the following spring4 ,both larvae and adults may be found in the soil during the winter4 ,control4--,may beetles are usually a problem in orchards which are not cultivated because the larvae feed on the roots of the sod cover4 ,cultivation of the orchard periodically will reduce the food supply of the grubs1 and smaller infestations of adults will appear the following year4 ,where cultivation is not feasible1 sprays will control the adults4 ,apply #b pounds of #ej percent ,,ddt wettable powder2 #d pounds of lead arsenate2 or #a pound of #be percent parathion wettable powder per #ajj gallons of water when damage by this insect is severe#i4 ,,pecan ,,cigar ,,casebearer ,the pecan cigar casebearer1 ,coleophora caryaefoliella 7,clem71 may be damaging in some years4 ,the larva feeds on the leaves1 producing tiny holes4 ,it constructs a light brown1 cigar-shaped case about one-fourth inch in length which encases it throughout development4 ,control4--,the spray applied for control of the nut casebearer will usually prevent significant injury by the cigar casebearer4 ,see spray schedule1 page #d4 ,,fall ,,webworm ,the webs produced by the fall webworm1 ,hyphantria cunea 7,drury71 are familiar to everyone4 ,leaves are eaten by the larvae which live in loosely woven1 dirty white webs1 ,figure #ai4 ,the adult is a white moth which may have black or brown spots on the forewing4 ,its wings have a span of about #a inch4 ,the larvae are pale yellow spotted with black4 ,they attain a length of #a inch when full grown and are covered with long black and white hairs4 ,the insect overwinters as a pupa in lightly woven cocoons in debris on the soil or under the bark4 ,in the spring the adults emerge and lay masses of greenish white eggs on the leaves4 ,the caterpillars which hatch from the eggs feed on the leaves in colonies under webs which they construct4 ,after feeding for a month to #f weeks1 the larvae crawl down the tree and pupate in loose cocoons in debris1 under bark1 or in loose soil4 ,adults appear during the summer and deposit eggs for the second generation4 ,the larvae of this generation feed extensively until fall1 crawl down the tree and pupate for the winter4 ,control4--,light infestations on a few trees can be eliminated by pruning out the affected branches and burning them4 ,if this method of control is not practicable1 the trees should be sprayed with #b pounds of #ej percent ,,ddt wettable powder2 #a pound of #be percent parathion wettable powder2 or #c pounds of lead arsenate per #ajj gallons of water#i4 ,illustration3 ,figure #ai4 ,web of the fall webworm on a pecan limb4 ,,walnut ,,caterpillar ,during the spring and summer1 the walnut caterpillars1 ,datana integerrima ,g4 ,r4 and others1 may strip the leaves from branches or entire small trees4 ,the adult is a moth with a wingspan of #a to #b inches4 ,the forewings are light brown with darker wavy lines4 ,the hindwings are lighter in color without lines4 ,the immature larva is reddish brown with narrow yellowish lines that extend the length of the body4 ,the full-grown larva is almost black with two grayish lines on the back and two on the sides4 ,many long1 soft gray hairs are distributed over the body4 ,this insect overwinters in the pupal stage in the soil4 ,the adult emerges in the spring and deposits eggs in masses on the underside of the leaves1 ,figure #bj4 ,the larvae feed in colonies on the leaves for about #c weeks4 ,at periodic intervals1 the groups of larvae move to the trunk to molt and1 after shedding their skins1 they return to the leaves to feed until the next molt4 ,they do not encase themselves in webs4 ,there are two generations each year1 the first appearing in late spring and early summer1 the second in later summer and fall4 ,larvae of the second generation complete development and crawl down to pupate in the soil4 ,control4--,when these insects become abundant enough to defoliate portions of the tree1 they may be controlled by applying a spray containing #b pounds of #ej percent ,,ddt wettable powder2 #c pounds of lead arsenate2 or #a pound of #be percent parathion wettable powder per #ajj gallons of water4 ,illustration3 ,figure #bj4 ,walnut caterpillar adults and egg mass on a pecan leaflet4 ,,pecan ,,catocala ,several species of catocalas1 ,figure #ba1 among them ,catocala maestosa ,hlst41 may strip the leaves of pecans in the spring leaving only the midribs4 ,the caterpillars are very dark gray and attain a length of about #c inches when full grown4 ,they are very active when disturbed and move with a looping motion4 ,both the caterpillars and the moths are well camouflaged4 ,when they rest on the trees during the day1 their color so harmonizes with the color of the bark that they are frequently indistinguishable4 ,control4--,one application of #b pounds of #ej percent ,,ddt wettable powder per #ajj gallons of water controls this pest4 ,although the majority of catocala larvae reach maturity before the time to spray for the nut casebearer1 a number of them will be killed when the recommended spray is applied for the latter insect4 ,,pecan ,,spittlebug ,in the spring and early summer a number of buds and small nuts may be covered with foamy white masses4 ,inside these masses are several small insects called spittlebugs1 ,clastoptera obtusa 7,say74 ,the white froth is produced probably to maintain an artificial high humidity1 which is required for development4 ,the adults resemble leafhoppers and fly actively during the summer4 ,this insect has not been known to cause any significant injury on pecans in ,texas4 ,,pecan ,,bud ,,moth ,the pecan bud moth1 ,gretchena bolliana 7,sling471 damages nursery stock and freshly top-worked pecans4 ,the greenish larvae feed in the axils of the newly set buds and in the terminals of young trees1 causing extensive branching4 ,there are several generations each year4 ,illustration3 ,figure #ba4 ,moth of the pecan catocala4 ,control4--,this insect may be controlled by applying a spray containing #b pounds of #ej percent ,,ddt wettable powder per #ajj gallons of water4 ,,twig ,,girdler ,the adult twig girdler1 ,oncideres cingulata 7,say7 7,o4 texana of some authors71 girdles twigs and branches1 weakening them so that they fall off or die on the tree1 ,figure #bb4 ,this insect is active during the late summer and early fall4 ,many twigs may be found on the ground under a severely infested tree4 ,secondary branching may occur and the number of bearing twigs is reduced4 ,the twig borer is a grayish brown beetle one-half to five-eighths inch in length with a broad gray band over the middle of the wing covers4 ,its head is reddish brown and bears a pair of long antennae1 which extend beyond the abdomen on the male4 ,the larva is a white legless grub about three-fourths inch long when it reaches maturity4 ,this insect overwinters as a partially grown larva in a twig on the tree or ground4 ,it develops rapidly in the spring feeding in the twig4 ,following pupation1 the adult emerges in late ,august or early ,september4 ,the female systematically girdles twigs and deposits eggs in the severed portion since the larva is unable to develop in healthy sapwood4 ,the eggs hatch in a few weeks into larvae which remain small until the following spring when they complete development1 pupate and emerge as adults in the late summer and fall4 ,there is one generation annually1 although some individuals require #b years to mature#a4 ,control4--,infestations may be reduced by removing girdled branches from the trees and the ground and burning them4 ,chemical control is also effective4 ,the trees should be sprayed with #d pounds of #ej percent ,,ddt wettable powder per #ajj gallons of water when the first injured branches are observed in late ,august or early ,september4 ,two or three applications at #b-week intervals may be required for most effective control#i4 ,,red-,,shouldered ,,shot-,,hole ,,borer ,the red-shouldered shot-hole borer1 ,xylobiops basilare 7,say71 and other shot-hole borers also injure trees in a devitalized condition4 ,the larvae feed in wood1 pupate and emerge as adults through round holes about one-eighth inch in diameter in the bark4 ,many of these holes may be observed in close proximity to each other4 ,control4--,since this insect feeds on dying or dead wood1 prunings and dead limbs should be removed from the orchard and burned4 ,adequate fertilizer and water will keep trees in a healthy condition and prevent injury by this pest4 ,,flatheaded ,,borers ,the flatheaded apple tree borer1 ,chrysobothris femorata 7,oliv471 and other species of flatheaded borers attack unhealthy or recently transplanted pecan trees by burrowing in the bark and sapwood of the large branches and trunk4 ,their presence is indicated by the appearance of darkened1 depressed areas in the bark from which traces of frass may protrude4 ,when these portions of the bark are removed1 shallow winding burrows packed with sawdust may be observed4 ,the burrows usually are on the sunny side of the trunk or branch1 but may extend completely around and penetrate the wood to a depth of #b inches4 ,young trees may be girdled by this insect4 ,the adult beetle is about one-half inch long1 broad and blunt at the head end and tapering to a point posteriorly4 ,its wing covers1 which have a metallic sheen1 are dark colored and corrugated4 ,the larva1 or borer1 which is legless and yellowish white1 attains a length of #a inches when full grown4 ,immediately behind the head is a broad1 flattened expanded area from which the insect takes its name4 ,the winter is passed by larvae in varying stages of development within the tree4 ,in the spring1 they change to pupae in their burrows1 emerging as adults during the spring and summer4 ,the female beetles deposit their eggs in cracks or bruises in the bark4 ,the larvae which hatch from these eggs feed during the remainder of the season and pass the winter4 ,there is only one generation each year4 ,illustration3 ,figure #bb4 ,adult twig girdler and characteristic injury to twig4 ,control4--,the beetles are attracted to trees or areas of trees in a devitalized condition1 induced by transplanting1 drouth1 sunscald1 bruises or poor growing conditions4 ,the trees must be kept in a healthy1 vigorous condition by proper fertilization and watering4 ,on young or transplanted trees1 wrapping the trunks in early spring before the adults appear is the only effective control known for these insects4 ,injury can be prevented by thoroughly wrapping the entire trunk from ground level to the branches with heavy paper or other wrapping material4 ,the wrapping should be tied securely with twine and should be maintained on the tree for #b years4 ,regular observations should be made to see that the twine does not girdle the tree4 ,in older trees1 the borers can be removed with a sharp knife4 ,care should be taken to injure as little of the healthy wood as possible4 ,if the wound is extensive1 it should be trimmed and then painted with a commercial tree paint or with a mixture of one part creosote and three parts coal tar4 ,dead and dying limbs and trees should be removed from the orchard each year and burned before the following spring4 ,if they are not burned1 the borers in them may mature and re-infest surrounding trees4 ,commercial tree borer preparations are of little value in controlling this insect4 ,,obscure ,,scale ,the obscure scale1 ,chrysomphalus obscurus 7,comst471 is a pest of considerable importance1 particularly in the more arid portions of the ,state4 ,the tiny insect under its scale covering sucks the sap from the limbs and branches1 causing them to lose their leaves and die back from the tips4 ,the tree is so devitalized by the feeding of this insect that it is made vulnerable to attack by wood borers4 ,the scale covering over a full-grown female is about one-eighth inch long and is usually dark gray1 and closely resembles the bark of the tree4 ,infested limbs appear to have had wood ashes sprinkled over them1 ,figure #bc4 ,numerous pits appear in the bark where the insects feed1 producing a roughened appearance4 ,illustration3 ,figure #bc4 ,severe infestation of obscure scale on a pecan twig4 ,the winter is passed by the female scales under their coverings on the bark4 ,eggs laid in the spring hatch into tiny1 salmon-colored crawlers which move about for a short time1 then settle down and insert their beaks4 ,while they are feeding1 a scale covering develops which is made up of secreted wax and cast skins4 ,the females never move again from the spot they have selected1 but the adult males develop wings and emerge from their scale coverings to mate with the females4 ,only one generation is produced each year4 ,control4--,when damaging populations develop1 a spray application of #c gallons of #ig percent miscible dormant oil per #ajj gallons of water during the dormant season will keep this pest under control4 ,application of ,fungicides and ,insecticides ,when possible1 fungicides for disease control and insecticides for insect control should be combined in the spray tank and applied to the trees in one operation4 ,the spray materials should be applied evenly and thoroughly to all the leaf and nut surfaces to provide a chemical barrier to disease organisms and insects4 ,do not neglect the tops of the trees4 ,diseases and insects can harbor and multiply in all unsprayed areas of the tree4 ,thorough coverage with spray materials is essential for effective control4 ,as a guideline1 apply approximately #a gallon of spray mixture for each foot of tree height4 ,apply #bj gallons to a #bj-;foot tree and #dj gallons to a #dj-;foot tree1 etc4 ,spray ,equipment ,various types of spray machines for application of fungicides and insecticides to pecan trees are available4 ,the spray machines employ either a high pressure hydraulic pump1 high pressure centrifugal pump or low pressure high air velocity systems4 ,all the machines are portable and are equipped with a gasoline engine or operate from a truck or tractor power takeoff shaft4 ,for pecan spraying1 a tank having a minimum capacity of #cjj gallons is desirable4 ,the pump should deliver #bj to #cj gallons per minute and maintain a pressure of #djj to #fjj pounds per square inch while operating4 ,a spray gun which is adjustable to produce a mist spray for spraying small trees or the lower canopy of large trees and a narrow stream that will reach the tops of tall trees is essential4 ,for safety and durability high pressure rubber hose having an inside diameter of three-fourths inch should be used with all high pressure spray machines4 ,literature ,cited #a;,bilsing1 ,s4 ,w41 #aiaf2 ,life history of the pecan twig girdler4 ,journal ,econ4 ,ent4 #i3aaj-aae4 #b;,bilsing1 ,s4 ,w41 #aibg2 ,studies on the biology of the pecan nut casebearer4 ,texas ,agricultural ,experiment ,station ,bulletin #cdg1 #ga pp4 #c;,bilsing1 ,s4 ,w41 #aida2 ,an economical method of removing ,spanish moss 7,tillandsia usenoides7 and ,ball moss 7,tillandsia recurvata7 from trees4 ,texas ,agricultural ,experiment ,station ,progress ,report #gdg4 #d;,dobbins1 ,traber ,norman1 #aicb2 ,the biology of the pecan phylloxera4 ,master's ,degree ,thesis1 ,texas ,a4 and ,m4 ,college4 #e;,dorman1 ,harvey ,s41 #aicd2 ,the life history of the yellow pecan aphid ,monellia nigropunctata ,granovsky4 ,master's ,degree ,thesis4 ,texas ,a4 and ,m4 ,college4 #f,king1 ,d4 ,r4 and ,david ,w4 ,rosberg1 #aiee2 ,experiments for the control of pecan insects and diseases1 #aied4 ,texas ,agricultural ,experiment ,station ,progress ,report #aghf4 #g,king1 ,d4 ,r4 and ,david ,w4 ,rosberg1 #aief2 ,control of ,tetranychus hicoriae ,mc,g4 on pecans4 ,journal ,econ4 ,ent4 #di 7#c73djd-e4 #h,nickels1 ,c4 ,b41 #aieb2 ,control of the pecan weevil in ,texas4 ,journal ,econ4 ,ent4 #de 7#f73 #ajii-aajj4 #i,osburn1 ,m4 ,r41 ,a4 ,m4 ,phillips1 ,william ,c4 ,pierce1 and ,john ,r4 ,cole1 #aied2 ,insects and diseases of the pecan and their control4 ,,usda ,farmers ,bulletin #ahbi1 #ef pp4 #aj,rosberg1 ,david ,w41 #aiej2 ,control of pecan diseases in #aiej4 ,texas ,agricultural ,experiment ,station ,progress ,report #accj4 #aa,rosberg1 ,david ,w4 and ,d4 ,r4 ,king1 #aied2 ,pecan disease and insect control experiments in ,texas1 #aiec4 ,texas ,agricultural ,experiment ,station ,progress ,report #afga4 ,your ,county ,,extension ,,agents ,illustration3 ,extension agents can furnish you the latest information on farming1 ranching and homemaking4 ,they represent both ,the ,texas ,a4 ,m4 ,college ,system and the ,united ,states ,department of ,agriculture in your county4 ,most county extension agents have their offices in the county courthouse or agriculture building4 ,they welcome your visits1 calls or letters for assistance4 ,this publication is one of many prepared by the ,texas ,agricultural ,extension ,service to present up-to-date1 authoritative information1 based on results of research4 ,extension publications are available from your local agents or from the ,agricultural ,information ,office1 ,college ,station1 ,texas4 ,cooperative ,extension ,work in ,agriculture and ,home ,economics4 ,the ,texas ,a4 ,m4 ,college ,system and ,united ,states ,department of ,agriculture cooperating4 ,distributed in furtherance of the ,acts of ,congress of ,may #h1 #aiad1 as amended1 and ,june #cj1 #aiad4 #aj,m-#c-ei4 ,reprint4 ,transcriber's ,notes --,silently corrected a few typos4 --,retained publication information from the printed edition3 this e,book is public-domain in the country of publication4 --,in the text versions only1 text in italics is delimited by underscores4