Macadamia problem solver & bug identifier Reprint – information current in 2003

REPRINT INFORMATION – PLEASE READ! For updated information please call 13 25 23 or visit the website www.deedi.qld.gov.au

This publication has been reprinted as a digital book without any changes to the content published in 2003. We advise readers to take particular note of the areas most likely to be out-of-date and so requiring further research: • Chemical recommendations—check with an agronomist or Infopest www.infopest.qld.gov.au • Financial information—costs and returns listed in this publication are out of date. Please contact an adviser or industry body to assist with identifying more current figures. • Varieties—new varieties are likely to be available and some older varieties may no longer be recommended. Check with an agronomist, call the Business Information Centre on 13 25 23, visit our website www.deedi.qld.gov.au or contact the industry body. • Contacts—many of the contact details may have changed and there could be several new contacts available. The industry organisation may be able to assist you to find the information or services you require. • Organisation names—most government agencies referred to in this publication have had name changes. Contact the Business Information Centre on 13 25 23 or the industry organisation to find out the current name and contact details for these agencies. • Additional information—many other sources of information are now available for each crop. Contact an agronomist, Business Information Centre on 13 25 23 or the industry organisation for other suggested reading. Even with these limitations we believe this information kit provides important and valuable information for intending and existing growers. This publication was last revised in 2003. The information is not current and the accuracy of the information cannot be guaranteed by the State of Queensland. This information has been made available to assist users to identify issues involved in macadamia production. This information is not to be used or relied upon by users for any purpose which may expose the user or any other person to loss or damage. Users should conduct their own inquiries and rely on their own independent professional advice. While every care has been taken in preparing this publication, the State of Queensland accepts no responsibility for decisions or actions taken as a result of any data, information, statement or advice, expressed or implied, contained in this publication. Brown or dead leaves Chewed leaves Spots on husks or shells Premature nut drop Leafminer damage ...... 8 Twig-girdler damage ...... 10 Spotting bug damage .102-104 Various causes ...... 114 Twig-girdler damage ...... 10 Leaf beetle damage ...... 22 Nutborer damage ...... 106-108 Discoloured husks/shells Felted coccid damage ...... 12 Caterpillar damage ...... 28-32 Husk spot disease ...... 110 Black shells ...... 126 Leaf beetle damage ...... 22 Meat ant damage ...... 78 Scale infestation ...... 116 Pale shells ...... 126 Cicada damage ...... 34 Leaf fall Husk rot disease ...... 118 Thrips damage ...... 128 Heat damage ...... 38 Tree decline ...... 4 Yellow peach ...... 124 Mite damage ...... 130 Herbicide damage ...... 42 Trunk canker disease ...... 4 Adhering husk ...... 136 Spray damage ...... 142 Salt damage ...... 44 Armillaria root rot disease .48 Cornelian butterfly ...... 138 Mealybug infestation ...... 146 Branch dieback disease ..... 50 Kretzchmaria disease ...... 78 Nut stemborer damage .....138 Bacterial wilt disease ...... 52 Twig-girdler damage ...... 140 Damaged kernels Boron toxicity ...... 60 Trunk damage Hail damage ...... 140 Spotting bug damage ...102-104 Frost damage ...... 72 Trunk canker disease ...... 6 Pencilled blue butterfly ...144 Nutborer damage ...... 106-108 Fire burn damage ...... 74 Lichen infestation ...... 62 Mealybug infestation ...... 146 Husk rot disease ...... 118 Hail damage ...... 66 Early germination ...... 120 Distorted leaves Leptocoris bug damage ....148 Frost damage ...... 72 Sigastus weevil damage ...152 Cracked shells ...... 122 Typical symptoms – lack of vigour, yellow leaves, and leaf fall Felted coccid damage ...... 12 Fire burn damage ...... 74 Yellow peach moth ...... 124 (healthy tree on right) Holes in shells Flower thrips damage ...... 16 Graft incompatibility ...... 76 Black shells ...... 126 Broad mite damage ...... 18 Nutborer damage ...... 106-108 Pale shells ...... 126 Aphid damage ...... 20 Brown or dead flowers Rat damage ...... 112 Flower caterpillar damage ..80 Kernel grub damage ...... 132 Glyphosate damage ...... 24 Kernel grub damage ...... 132 Open micropyle ...... 136 gumming Fruitborer damage ...... 26 Raceme blight disease ...... 82 Open micropyle ...... 136 gumming Flower thrips damage ...... 84 Cornelian butterfly ...... 138 Mealybug damage ...... 36 Split or broken shells Twig-girdler damage ...... 140 Spotting bug damage ...... 46 Leaf beetle damage ...... 86 Water stress damage ...... 90 Early germination ...... 120 Green vegetable bug ...... 150 Zinc deficiency ...... 58 Cracked shells ...... 122 Sigastus weevil damage ...152 Extreme boron deficiency ..58 Herbicide spray damage .....90 damage ...... 134 problems & trunk branch leaf, discoloured bark Broad mite damage ...... 92 Miscellaneous split bark suckers Tip borer damage ...... 64 Water stress ...... 142 Mistletoe infestation ...... 64 Frost damage ...... 92 Sticktight nuts ...... 122 Copper deficiency ...... 68 Lace bug damage ...... 98 Prominent suture ...... 148 Vining disorder ...... 70 Aphid infestation ...... 100 Vertical growth disorder .....70 Distorted flowers dead wood Felted coccid damage ...... 88 Chewed flowers Hairyline butterfly damage ...94 Flower looper damage ...... 96 Trunk symptoms – mature tree Trunk symptoms – young tree 6 2 3

Typical symptoms— leaf Tree decline fall, yellow leaves, and twig Cause: Undetermined. Believed to be caused by a combina- dieback tion of factors that lead to a run-down in tree health. These include nutrient deficiencies; low soil organic matter levels; soil erosion, exposing surface roots to desiccation; root death in compacted or shallow soils (heavy clay or rock within 1 m of the surface). Identification: Typical symptoms are leaf fall, yellow or bronzed leaves and twig dieback. Trees may die. Leaves may show a wide range of symptoms but leaf spotting, and yellowing and burning of the leaf margins are common. Typical field symptoms – scorched appearance of new growth Treatment: Prune affected trees to reduce tree size by one- third. Apply a general foliar fertiliser at regular intervals once new leaf growth has occurred. Maintain a layer of mulch 5 cm thick up to and just outside the dripline to help encourage new root growth. Ensure that the mulch is kept away from Close-up of the trunk. Trees may take some time to recover. yellowing and burning of the Prevention: Maintain appropriate levels of soil nutrients by leaf margins using regular soil and leaf analysis. Pay particular attention Fully grown larvae under a blister to phosphorus, calcium and pH. Regularly apply mulch, leaf, branch & trunk problems problems & trunk branch leaf, problems & trunk branch leaf,

particularly where soil erosion or mechanical harvesting problems & trunk branch leaf, ready to pupate exposes surface roots. Consider a perennial ‘living mulch’ such as sweet smother grass in the interrow and tree row areas. Control water flow within the orchard to prevent water flowing down the tree rows, causing soil erosion. Treat and disease problems promptly to maintain trees in a healthy vigorous condition. Regular light pruning of healthy trees Close-up of fully grown larvae encourages vigorous new growth. Avoid planting macada- Close-up of leaf blisters (left), (blister removed) – actual size 4 mias in shallow marginal soils. 5 8 insect mines (right) up to 6 mm long Spots on husks or shells Premature nut drop Trunk canker disease Spotting bug damage .102-104 Various causes ...... 114 Cause: The fungus Phytophthora cinnamomi. Nutborer damage ...... 106-108 Discoloured husks/shells Husk spot disease ...... 110 Black shells ...... 126 Identification: Typical symptoms are lack of vigour, Scale infestation ...... 116 Pale shells ...... 126 Husk rot disease ...... 118 yellow leaves and leaf fall. In advanced cases, twig dieback Thrips damage ...... 128 may also be present, and trees often set a heavy crop of nuts. Yellow peach moth ...... 124 Mite damage ...... 130 Adhering husk ...... 136 Spray damage ...... 142 Trees may die. On the trunks, affected areas (cankers) show Cornelian butterfly ...... 138 Mealybug infestation ...... 146 as dark discolouration of the bark, often with gum or resin Nut stemborer damage .....138 Damaged kernels exuding. If the bark is removed, a brown discolouration of Twig-girdler damage ...... 140 the outer wood is visible. As the disease progresses, deep Hail damage ...... 140 Spotting bug damage ...102-104 Pencilled blue butterfly ...144 Nutborer damage ...... 106-108 furrowed vertical cankers with split bark may extend up Mealybug infestation ...... 146 Husk rot disease ...... 118 from ground level. Suckers may develop from the rootstock, Leptocoris bug damage ....148 Early germination ...... 120 particularly in young trees. Sigastus weevil damage ...152 Cracked shells ...... 122 Typical symptoms – lack of vigour, yellow leaves, and leaf fall Yellow peach moth ...... 124 (healthy tree on right) Treatment: With small cankers, pare back affected bark and Holes in shells Black shells ...... 126 wood with a sharp knife; thoroughly soak trunks with an ap- Nutborer damage ...... 106-108 Pale shells ...... 126 propriate registered fungicide. Some labels recommend the Rat damage ...... 112 Kernel grub damage ...... 132 fungicide be applied in conjunction with a white, water-based Kernel grub damage ...... 132 Open micropyle ...... 136 gumming gumming paint. This helps seal the wound and keep the fungicide in Open micropyle ...... 136 Cornelian butterfly ...... 138 Split or broken shells Twig-girdler damage ...... 140 contact with the tree. Where cankers are extensive, and par- Early germination ...... 120 Green vegetable bug ...... 150 ing back affected bark/wood is impracticable, either spray or Cracked shells ...... 122 Sigastus weevil damage ...152 paint affected areas, or spray affected trees with an appropriate

Animal damage ...... 134 problems & trunk branch leaf, discoloured bark Miscellaneous split bark suckers registered systemic fungicide. Repeat as directed. Water stress ...... 142 problems & trunk branch leaf, Sticktight nuts ...... 122 Prevention: Plant disease-free nursery trees. Avoid planting Prominent suture ...... 148 in soils subject to periodic waterlogging. Where drainage is marginal, plant on shallow mounds with an effective or- dead wood chard surface drainage network. Avoid wounding the trunk, particularly when using slashers. Keep mulch and fertiliser at least 30 cm from the base of the trunk. Before the wet

Trunk symptoms – mature tree Trunk symptoms – young tree season, spray the trunk with a mixture of a copper fungicide 6 7 3 and white, water-based paint to a height of 350mm.

Tree decline Macadamia leafminer damage Cause: Undetermined. Believed to be caused by a combina- Cause: Larvae of the macadamia leafminer Acrocercops tion of factors that lead to a run-down in tree health. These chionosema. include nutrient deficiencies; low soil organic matter levels; Identification: Field symptoms are a ragged and fire- soil erosion, exposing surface roots to desiccation; root death scorched appearance of the new growth flush. Close-up ex- in compacted or shallow soils (heavy clay or rock within amination of affected leaves shows meandering mine tracks 1 m of the surface). of the larvae and leaf blistering, the latter occurring with Identification: Typical symptoms are leaf fall, yellow or more extensive damage. If leaf blisters are moist, removal bronzed leaves and twig dieback. Trees may die. Leaves of the blister will reveal live larvae underneath. Fully-grown may show a wide range of symptoms but leaf spotting, and larvae are up to 6 mm long, pale green to yellow in the earlier yellowing and burning of the leaf margins are common. Typical field symptoms – scorched appearance of new growth stages, and with red bands when ready to pupate. Treatment: Prune affected trees to reduce tree size by one- Damage is most severe in orchards located in elevated re- third. Apply a general foliar fertiliser at regular intervals once gions close to rainforest. new leaf growth has occurred. Maintain a layer of mulch 5 Treatment: Treatment is only necessary on young trees cm thick up to and just outside the dripline to help encourage when more than 60% of inspected terminals are damaged. new root growth. Ensure that the mulch is kept away from Where necessary, spray with an appropriate registered in- the trunk. Trees may take some time to recover. secticide. Older trees can tolerate the damage with minimal Prevention: Maintain appropriate levels of soil nutrients by effect, and do not require spraying. using regular soil and leaf analysis. Pay particular attention Fully grown larvae under a blister Prevention: Regularly monitor young trees so that the to phosphorus, calcium and pH. Regularly apply mulch, leaf, branch & trunk problems problems & trunk branch leaf, problem can be treated before it gets out of hand. Use an particularly where soil erosion or mechanical harvesting problems & trunk branch leaf, problems & trunk branch leaf, ready to pupate integrated pest management (IPM) approach, which includes exposes surface roots. Consider a perennial ‘living mulch’ the use of less disruptive insecticides with minimal impact such as sweet smother grass in the interrow and tree row on beneficial . areas. Control water flow within the orchard to prevent water flowing down the tree rows, causing soil erosion. Treat insect Leafminer has many natural enemies and if these are properly and disease problems promptly to maintain trees in a healthy managed, spraying is generally unnecessary. vigorous condition. Regular light pruning of healthy trees Close-up of fully grown larvae encourages vigorous new growth. Avoid planting macada- Close-up of leaf blisters (left), (blister removed) – actual size mias in shallow marginal soils. 5 8 insect mines (right) up to 6 mm long 9 12 leaf, branch & trunk problems 10 leaf, branch & trunk problems coccid feeding Distortion of young shoots from A heavy coccid infestation the insect. Note the insect faeces Leaves webbed together as a shelter for or leaf whorl (arrowed) Damage first shows at abranch fork (actual size ofadult females up to 1mm) Close-up ofinfestation –magnified Close-up of trunk infestation Feeding damage onolder leaves from its shelter (actual size 25mm) Close-up ofamature larva protruding Close-up ofdamaged leaf whorls male crawlers adult females pupae insecticides withminimal impacton beneficial insects. disruptive less of use the includes which approach, (IPM) before it gets out of hand. Use an integrated treated be pestcan problem the that managementso trees monitor Regularly such materials for the pest. If detected, disinfest before use. orchard on budwood or nursery plants, carefully inspect all Prevention: of thepest. build-up encourage may and enemies natural the destroys chemicals some of use frequent as consultant pest adamia their immediate vicinity. Seek in specialist advice trees from a mac- and trees affected only Spray insecticide. istered reg- appropriate an with trees affected Spray Treatment: may also affect flowers – see symptoms on page 88. from the felty covering of the adults and pupae. The coccid name its gains insect The infested. be also may trunks and mid-vein), brown male crawlers and white pupae. Branches white to grey adult females (generally present along the leaf raised ‘scales’. Depending on the time of year, these may be leaves reveals a large number of small (up to 1 mm across) infestations. Close examination of the undersides of affected heavy by killed be may trees grafted Youngand seedlings feeding leaves, causes older yellow On spotting, occurs. leaf browning leaves and youngest and leaf death. the of distortion stunting extensive shoots, young on feeds coccid Cause: Macadamia twig-girdler damage Identification: dei. Cause: Macadamia felted coccid damage unnecessary. generally is spraying managed, properly are these if and enemies natural many has girdler twig The insects. eficial of less disruptive insecticides with minimal impact on ben- use the includes which approach, (IPM) management pest integrated an Use hand. of out gets it before treated be can Prevention: for nutborerprovideadequatecontrol. is generally unnecessary on bearing trees, as sprays applied be necessary on young trees (up to about five years old), but an appropriate registered insecticide. Specific treatment may justify treatment. Where necessary, spray affected trees with young trees and 20% on mature trees need to be damaged to to warrant treatment. More than 15% of terminal shoots on enough serious is damage the that Treatment:check First may alsoaffect nuts–seesymptomsonpage140. nutborer.macadamia insect of The larvae from distinguish to difficult dots. be dark-brown can of They rows gitudinal lon- and capsule head black a with colour mottled brown a and long mm 25 to up are larvae Mature faeces. larval incorporates that shelter a into together them web larva the and nursery.skeletonised or be field may the leaves in The trees young to confined generally is and whorl leaf or fork branch a at shows first generally Damage Identification: luteotactella. adults adults Larvae of the macadamia twig-girdler macadamia the of Larvae The macadamia felted coccid coccid felted macadamia The nymph As the pest is generally introduced into an an into introduced generally is pest the As Regularly monitor trees so that the problem the that so trees monitor Regularly There is a range of symptoms. When the the When symptoms. of range a is There Eriococcus ironsi- Eriococcus Neodrepta 13 leaf, branch & trunk problems 11 leaf, branch & trunk problems insecticides withminimal impacton beneficial insects. disruptive less of use the includes which approach, (IPM) before it gets out of hand. Use an integrated treated be pestcan problem the that managementso trees monitor Regularly such materials for the pest. If detected, disinfest before use. orchard on budwood or nursery plants, carefully inspect all Prevention: of thepest. build-up encourage may and enemies natural the destroys chemicals some of use frequent as consultant pest adamia their immediate vicinity. Seek in specialist advice trees from a mac- and trees affected only Spray insecticide. istered reg- appropriate an with trees affected Spray Treatment: may also affect flowers – see symptoms on page 88. from the felty covering of the adults and pupae. The coccid name its gains insect The infested. be also may trunks and mid-vein), brown male crawlers and white pupae. Branches white to grey adult females (generally present along the leaf raised ‘scales’. Depending on the time of year, these may be leaves reveals a large number of small (up to 1 mm across) infestations. Close examination of the undersides of affected heavy by killed be may trees grafted Youngand seedlings feeding leaves, causes older yellow On spotting, occurs. leaf browning leaves and youngest and leaf death. the of distortion stunting extensive shoots, young on feeds coccid unnecessary. generally is spraying managed, properly are these if and enemies natural many has girdler twig The insects. eficial of less disruptive insecticides with minimal impact on ben- use the includes which approach, (IPM) management pest integrated an Use hand. of out gets it before treated be can Prevention: for nutborerprovideadequatecontrol. is generally unnecessary on bearing trees, as sprays applied be necessary on young trees (up to about five years old), but an appropriate registered insecticide. Specific treatment may justify treatment. Where necessary, spray affected trees with young trees and 20% on mature trees need to be damaged to to warrant treatment. More than 15% of terminal shoots on enough serious is damage the that Treatment:check First may alsoaffect nuts–seesymptomsonpage140. nutborer.macadamia insect of The larvae from distinguish to difficult dots. be dark-brown can of They rows gitudinal lon- and capsule head black a with colour mottled brown a and long mm 25 to up are larvae Mature faeces. larval incorporates that shelter a into together them web larva the and nursery.skeletonised or be field may the leaves in The trees young to confined generally is and whorl leaf or fork branch a at shows first generally Damage Identification: luteotactella. Cause: Macadamia twig-girdler damage Identification: dei. Cause: Macadamia felted coccid damage adults adults Larvae of the macadamia twig-girdler macadamia the of Larvae The macadamia felted coccid coccid felted macadamia The nymph As the pest is generally introduced into an an into introduced generally is pest the As Regularly monitor trees so that the problem the that so trees monitor Regularly There is a range of symptoms. When the the When symptoms. of range a is There Eriococcus ironsi- Eriococcus Neodrepta 13 leaf, branch & trunk problems 11 leaf, branch & trunk problems 16 leaf, branch & trunk problems 14 leaf, branch & trunk problems Close-up ofadult thrips (highly magnified –actual size less than 1.5 mmlong) Curling and cupping symptom withleaf discolouration Strap-leaf symptom showing significant leaf distortion Latania scale: onleaf (left), on twig (right) (actual size up to 2mmacross) Oleander scale (actual size up to 2mmacross) Macadamia mussel scale (actual size up to 2mmlong) Long soft scale (actual size up to 3mmlong) Macadamia white scale (actual size up to 2mmacross) Identification: combei Cause: Scale insects eficial insects. of less disruptive insecticides with minimal impact on ben- use the includes which approach, (IPM) management pest integrated an Use hand. of out gets it before treated be can problem the that so trees monitor Regularly Prevention: situations, sprayingmaynotbenecessary. these in – rain heavy following significantly reduced often their immediate vicinity (‘hot spots’). Heavy infestations are registered insecticide. Spray only affected trees and trees in Treatment: ers andnuts–seesymptomsonpages84128. readily visible to the naked eye. Thrips may also affect flow- not and mm) 1.5 than less size (actual tiny are thrips Adult and cupping. leaves causing yellow to bronze discolouration with curling significantly stunted and strap-like; and distortion of young be to them causing leaves youngest the of distortion – cur particularly in dry seasons. Two types of symptoms can oc- growth, new damage can which mouthparts, sucking and rasping with insects tiny are thrips Flower Identification: Cause: Flowerthrips(Scirtothripssp.). Flower thrips damage If detected,disinfestbeforeuse. orchard on nursery plants, carefully inspect these on arrival. an into introduced commonly are scales insects. As eficial of less disruptive insecticides with minimal impact on ben- use the includes which approach, (IPM) management pest integrated an Use hand. of out gets it before treated be can problem the that so trees monitor Regularly Prevention: and mayencouragebuild-upofscales. frequent use of some chemicals destroys the natural enemies the as consultant pest macadamia a from advice Seek specialist nuts. and shoots to moving are scales young when periods at targeted be vicinity.should immediate Spraying the in trees and trees affected only Spray insecticide. tered Treatment:affectedSpray regis-appropriate an with trees also affect nuts – see symptoms onpage116. honeydew.Scaleinsectsthe may on feeding present, often are Ants scale. soft long by secreted honeydew on grows occur mostly along the main vein. Black sooty mould often mon on the upper surfaces. Long soft scale and oleander scaleinfest the undersides of leaves but oleander scale is also com- white circular patches to raised elongated lumps. Most scales also infest twigs and branches. Appearance varies from small pidiotus nerii As- ( scale oleander macadamiae ), (Lepidosaphes scale sel ), long soft scale ( Macadamia white scale (Pseudaulacaspis brimble- nymph Spray affected trees with an appropriate appropriate an with trees affected Spray ) andlataniascale (Hemiberlesialataniae A number of scale insects infest leaves; some egg Coccus longulus adult ), macadamia mus- ). 15 17 leaf, branch & trunk problems leaf, branch & trunk problems 20 leaf, branch & trunk problems 18 leaf, branch & trunk problems Close-up ofaphid adults and nymphs (magnified –actual size about 2mmlong) Typical field infestation —note the ants tending the aphids Close-up of the mites (highly magnified –actual size less than 0.3 mmlong) Close-up ofaffected leaves —note that the margins are cupped downwards Typical symptoms –healthy tree onleft; affected tree onright shed skins adults syrphid fly larva–beneficial eggs problem canbetreatedbeforeitgetsoutofhand. Prevention: spots’). (‘hot vicinity immediate their in trees and trees affected spotting for applied bugs are generally effective against broad mite. Spray only sprays required, Where nurseries. Treatment: 92 and130. mite also affects flowers and nuts – see symptoms on pages than less The eye. naked the with – visible not are and – long mm 0.3 small extremely are mites The cupped downwards. margins the with leaves Typical distorted field. are the symptoms in trees young in occurs occasionally and nurseries, in common most is Damage Identification: Cause: Thebroadmite Broad mite damage approach, which includes the use of less disruptive disruptive less of use the insecticides withminimalimpactonbeneficial insects. includes which approach, Prevention: registered insecticide. for other pests. Where necessary, spray with an appropriate chemicals disruptive of use frequent of result the generally are outbreaks Serious control. adequate provide generally Treatment: infest flowers–seesymptomsonpage100. spring. early and also winter may of Aphids months cooler the in common most are Infestations long. mm 2 to up and secretions. honeydew the for soft-bodied black, are Aphids secretions of the aphids. In many cases, ants tend the honeydew aphids the on grows often mould sooty Black tip. ing sucking) damage can cause(sap feeding distortion The ofgrowth. thenew leavessucculent the and on grow- feed they Identification: Aphids typically infest young shoots where Cause: Theblackcitrus aphid Toxoptera citricida. Aphid infestation Treatment is rarely necessary as natural enemies Regularly monitor nursery trees so that the the that so trees nursery monitor Regularly Treatment is generally only necessary in in necessary only generally is Treatment Use an integrated pest management (IPM) (IPM) management pest integrated an Use Polyphagotarsonemuslatus. 19 21 leaf, branch & trunk problems leaf, branch & trunk problems approach, which includes the use of less disruptive disruptive less of use the insecticides withminimalimpactonbeneficial insects. includes which approach, Prevention: registered insecticide. for other pests. Where necessary, spray with an appropriate chemicals disruptive of use frequent of result the generally are outbreaks Serious control. adequate provide generally Treatment: infest flowers–seesymptomsonpage100. spring. early and also winter may of Aphids months cooler the in common most are Infestations long. mm 2 to up and secretions. honeydew the for soft-bodied black, are Aphids secretions of the aphids. In many cases, ants tend the honeydew aphids the on grows often mould sooty Black tip. ing sucking) damage can cause(sap feeding distortion The ofgrowth. thenew leavessucculent the and on grow- feed they Identification: Aphids typically infest young shoots where Cause: Theblackcitrus aphid Toxoptera citricida. Aphid infestation Treatment is rarely necessary as natural enemies Use an integrated pest management (IPM) (IPM) management pest integrated an Use

21 leaf, branch & trunk problems 22 24 leaf, branch & trunk problems leaf, branch & trunk problems leaves lower on the branch are unaffected ‘Witch’s broom’ effect.Note how the Typical distortion ofleaves onabranch Close-up ofadult beetles (actual size about 4mmlong) Typical ‘scorched’ appearance ofaffected leaves becoming hard and leathery Stiffened appearance from leaves orchards adjacenttokikuyupastures. be can treated before it problem gets out of hand. Be the particularly vigilant in so summer, early and spring in rain after particularly carefully, orchards Monitor Prevention: recover. to time some take may trees Heavily-damaged insecticide. registered appropriate an with vicinity immediate their in trees and swarms beetle Treatment:with trees only Spray symptoms onpage86. of beetle activity. The beetles may alsoaffect flowers–see attractive to the beetles and can be used as an early indicator pastures. Cadagi gum ( torelliana ) is particularly similar or kikuyu of largeareas are there where districts in serious more is problem The beetle-free. largely are trees or small groups of trees are heavily infested while adjacent trees individual Often days. 3 to 2 within damage serious spring and summer. Swarms can invade orchards and cause at various times of the year but are most common after rain in mm long. The beetles occur sporadically in plague numbers the middle of each wing cover. Beetles are generally about 4 the base of the wing covers and a similarly coloured spot in are light yellow in colour with a cherry-coloured band across desiccate, leaves ‘scorched’a giving shoots. the to appearance beetles Adult affected The veins. of network a only leaving often leaves, young attack Beetles Identification: (or Monoleptabeetle) Monoleptaaustralis. Cause: Feeding by swarms of the redshouldered leaf beetle Redshouldered leaf beetle damage or useprotectivesleevesonthe trunk. uptake from lower leaves, strip them off when planting out, range. Protect the trees while spraying. To prevent herbicide herbicide at is rates at the it lower end of If the recommended the label mix time. and sprayer knapsack a use planting-out necessary, absolutely near or at particularly trees, young around herbicide Prevention:glyphosate Don’tuse may helpinrecovery. offPruning problem. the of out grow affectedthe branches Treatment: If the damage is not severe, trees will gradually ground. the to leaves close and tissue stem green presence of the of Young trees are particularly susceptible to damage because leathery, givingthegrowthastiffened appearance. broom’. In some cases, the affected leaves become hard and ‘witch’sas known appearance bunched a produces growth part of a branch on a tree shows symptoms. The stunting of small, distorted and often yellow. Often only one branch or Identification: cide ontothefoliageoftree. Cause: Glyphosate herbicide damage Drift or accidental application of glyphosate herbi- glyphosate accidental applicationof or Drift The youngest leaves on an affected shoot are 23 25 leaf, branch & trunk problems leaf, branch & trunk problems 28 leaf, branch & trunk problems 26 leaf, branch & trunk problems 50 mmlong) male case onright (actual size about (actual size about 100 mmlong) and Large bagworm: female case onleft long – actual size oflarva up to 25mm lozogramma) ondamaged leaf Cup mothlarva (Anaxidea produces multiple side shoots Damage to the growing point Rolling and webbing of young leaves size about 60 mmlong) Variegated hairy caterpillar (actual up to 10mmlong) Close-up oflarvae (actual size larva resemble aleaf stripe down the back, which helps the long and 10mmwide.Note the yellow fasciata) –actual size up to 20 mm Macadamia cupmothlarva (Comana Identification: and 32forsymptomsofdamagebyothercaterpillars. cides withminimalimpactonbeneficial insects. disruptive insecti-less of use the includes which approach, gets out of hand. Use an integrated pest management (IPM) trees in the field so that the problem can be treated before it Prevention: also generallyeffective againstorangefruitborer. the field. Where necessary, sprays registered for nutborer are necessary in the nursery and occasionally on young trees in will generally keep it in check. However, treatment may be is rarely necessary, as sprays applied for macadamia nutborer Treatment: the singleshootrequiredforgrafting. the in development of multiple side shoots near the tip, results instead of point growing the to damage nurseries, In down thelengthofbody. running stripes brown to two with colour, in brown greenish-brown and long mm 10 to up are larvae Fully-grown tunnels arecompletelyfreeofinsectfaeces. other moth and butterfly larval tunnels, the orange fruitborer to form silken tunnels or shelters for the larvae. Unlike many Identification: Cause: Larvaeoftheorangefruitborer Orange fruitborer damage cides withminimalimpacton beneficial insects. disruptive insecti-less of use the includes which approach, gets out of hand. Use an integrated pest management (IPM) trees in the field so that the problem can be treated before it Prevention: generally effective againstcaterpillars. sprays registered for nutborer and fruitspotting bug are also necessary,Where field. the in trees young on occasionally and nursery the in necessary be may treatment However, borer and fruitspotting bug will generally keep them in check. lars is rarely necessary, as sprays applied for macadamia nut Treatment: In bearing trees, leaves throughtoraggedholesandpatchesinleaves. pest, but may range from complete defoliation of the young ( caterpillar hairy variegated lozogramma terflies including cup ( but- and moths of range a of (larvae) Caterpillars Cause: Caterpillar damage –1 In bearing trees, , ag bgom ( bagworm large ), Regularly monitor trees in nurseries and young Regularly monitor trees in nurseries and young Leaf symptoms vary widely depending on the Young leaves are rolled and webbed together Comana

specific treatment for caterpil- specific treatment for this pest Oiketicus

fasciata and Anaxidea ). See pages 30 pages See varia). miserana.

elongatus ), and and ), 29 27 leaf, branch & trunk problems leaf, branch & trunk problems 32 leaf, branch & trunk problems 30 leaf, branch & trunk problems long) Brown tufted caterpillar ondamaged leaf (actual size ofcaterpillar up to 25mm Doubleheaded hawk mothlarva (actual size up to 120 mmlong) (actual size up to 30mmlong) Bizarre looper viewed from above Note that colour may vary according to diet Pencilled blue butterfly larva on adamaged leaf (actual size up to 16mmlong). Right: mature larva. Note that larva is now brown incolour and up to 50 mm long satiny-black incolour with transverse white bands, and are up to 25mmlong. Brown looper. Left immature larvae onadamaged leaf. Note that larvae are the typical looping body motion Bizarre looper; side view showing Identification: and 32forsymptomsofdamagebyothercaterpillars. cides withminimalimpacton beneficial insects. disruptive insecti-less of use the includes which approach, gets out of hand. Use an integrated pest management (IPM) trees in the field so that the problem can be treated before it Prevention: generally effective againstcaterpillars. sprays registered for nutborer and fruitspotting bug are also necessary,Where field. the in trees young on occasionally and nursery the in necessary be may treatment However, borer and fruitspotting bug will generally keep them in check. lars is rarely necessary, as sprays applied for macadamia nut Treatment: In bearing trees, leaves throughtoraggedholesandpatchesinleaves. pest, but may range from complete defoliation of the young ( caterpillar hairy variegated Identification: Cause: Larvaeoftheorangefruitborer Orange fruitborer damage lozogramma terflies including cup moths ( but- and moths of range a of (larvae) Caterpillars Cause: Caterpillar damage –1 cides withminimalimpactonbeneficial insects. disruptive insecti-less of use the includes which approach, gets out of hand. Use an integrated pest management (IPM) trees in the field so that the problem can be treated before it Prevention: also generallyeffective againstorangefruitborer. the field. Where necessary, sprays registered for nutborer are necessary in the nursery and occasionally on young trees in will generally keep it in check. However, treatment may be is rarely necessary, as sprays applied for macadamia nutborer Treatment: the singleshootrequiredforgrafting. the in development of multiple side shoots near the tip, results instead of point growing the to damage nurseries, In down thelengthofbody. running stripes brown to two with colour, in brown greenish-brown and long mm 10 to up are larvae Fully-grown tunnels arecompletelyfreeofinsectfaeces. other moth and butterfly larval tunnels, the orange fruitborer to form silken tunnels or shelters for the larvae. Unlike many In bearing trees, , ag bgom ( bagworm large ), Regularly monitor trees in nurseries and young Regularly monitor trees in nurseries and young Leaf symptoms vary widely depending on the Young leaves are rolled and webbed together Comana

specific treatment for caterpil- specific treatment for this pest Anthela Oiketicus

fasciata and Anaxidea ). See pages 30 pages See varia). Isotenes miserana.

elongatus ), and and ), 29 27 leaf, branch & trunk problems leaf, branch & trunk problems 32 leaf, branch & trunk problems 30 leaf, branch & trunk problems Right: mature larva. Note that larva is now brown incolour and up to 50 mm long satiny-black incolour with transverse white bands, and are up to 25mmlong. Brown looper. Left immature larvae onadamaged leaf. Note that larvae are long) Brown tufted caterpillar ondamaged leaf (actual size ofcaterpillar up to 25mm Note that colour may vary according to diet Pencilled blue butterfly larva on adamaged leaf (actual size up to 16mmlong). Doubleheaded hawk mothlarva (actual size up to 120 mmlong) (actual size up to 30mmlong) Bizarre looper viewed from above the typical looping body motion Bizarre looper; side view showing cides withminimalimpactonbeneficial insects. disruptive insecti-less of use the includes which approach, gets out of hand. Use an integrated pest management (IPM) trees in the field so that the problem can be treated before it Prevention: generally effective againstcaterpillars. sprays registered for nutborer and fruitspotting bug are also necessary,Where field. the in trees young on occasionally and nursery the in necessary be may treatment However, borer and fruitspotting bug will generally keep them in check. lars is rarely necessary, as sprays applied for macadamia nut Treatment: In bearing trees, leaves throughtoraggedholesandpatchesinleaves. pest, but may range from complete defoliation of the young bleheaded hawk moth ( terflies including bizarre looper ( but- and moths of range a of (larvae) Caterpillars Cause: Caterpillar damage –2 Identification: for symptomsofdamagebyothercaterpillars. 32 and 28 pages See absimilis). (Candalides butterfly blue cides withminimalimpactonbeneficial insects. disruptive insecti-less of use the includes which approach, gets out of hand. Use an integrated pest management (IPM) trees in the field so that the problem can be treated before it Prevention: generally effective againstcaterpillars. sprays registered for nutborer and fruitspotting bug are also necessary,Where field. the in trees young on occasionally and nursery the in necessary be may treatment However, borer and fruitspotting bug will generally keep them in check. lars is rarely necessary, as sprays applied for macadamia nut Treatment: In bearing trees, leaves throughtoraggedholesandpatchesinleaves. pest, but may range from complete defoliation of the young Identification: 30 forsymptomsofdamagebyothercaterpillars. and brown looper (Lophodes sinistraria). See pages 28 and terflies including brown tufted caterpillar (Olene but- and moths of range a of (larvae) Caterpillars Cause: Caterpillar damage –3 Regularly monitor trees in nurseries and young Regularly monitor trees in nurseries and young Leaf symptoms vary widely depending on the Leaf symptoms vary widely depending on the Coequosa

specific treatment for caterpil- specific treatment for caterpil- Eucyclodes

triangularis

pieroides ), and pencilled mendosa), ), dou- 33 leaf, branch & trunk problems 31 leaf, branch & trunk problems 36 leaf, branch & trunk problems 34 leaf, branch & trunk problems at alater stage Close-up of the twig damage affected by cicada egg-laying Affected tree showing branches Stunting of the growing point from mealybug damage from mealybug feeding Distortion of the growing point branches and trunks ofaffected trees 20 mmlong), are often attached to the Shed nymphal cases (actual size about cicadas on twigs Egg-laying slits madeby female (Cryptolaemus montrouzieri) a larva of the predatory ladybird (actual size about 4mmlong) and Close-up ofmealybugs –magnified adults & nymphs predator with minimalimpactonbeneficial insects. proach, which includes the use of less disruptive insecticides Prevention: Use an integrated pest management (IPM) ap- use ofdisruptivechemicalsforotherpests. control. Serious outbreaks are adequate generally provide the generally result ofenemies frequent natural and sporadic Treatment:are outbreaks as necessary Treatmentrarely is insect mayalsoaffect nuts–seesymptomsonpage 146. secretions. honeydew the on grows often The mould Sooty Ants often tend the mealybugs for their honeydew secretions. thin coatingofgreyish-whitemealywax. a by covered and body, the from extending filaments thin with long, mm 4 about oval-shaped, are mealybugs Adult stunting of the shoot and the formation of a rosette of leaves. and eventually, permanent damage to the tip. This results in leaves youngest the of distortion in results Feeding points. Identification: Cause: Thehibiscusmealybug Mealybug damage ventative measuresareconsideredpractical. pre- no sporadic, generally is damage the Prevention:As warrant treatment. Treatment: to thebranchesandtrunks. attached skins shed the tree. emergingleave the The adults the roots. When nymphs mature, they exit the soil and climb When the eggs hatch, the nymphs enter the soil and feed on and die,arealsomoresusceptibletowinddamage. splinter may branches (ovipositor). These apparatus laying deposits eggs in slits cut in the branches by its spear-like egg- emerge in orchards during summer. After mating, the female Identification: Cause: Adultcicadas (Psaltodasp.). Cicada damage Damage is not generally serious enough to to enough serious generally not is Damage Mealybugs congregate near the growing growing the near congregate Mealybugs Large numbers of adult cicadas often often cicadas adult of numbers Large Maconellicoccushirsutus. 37 35 leaf, branch & trunk problems leaf, branch & trunk problems 38 40 leaf, branch & trunk problems leaf, branch & trunk problems Typical symptoms ona shoot, showing the overall pale-green colour Leaves sometimes show anuneven yellow bleaching Bleaching of young leaves from heat stress Typical heat damage symptoms associated with advanced nitrogen deficiency than the interveinal areas. The lower leaf is beginning to show the bronzing Close-up of affected leaves. Note that the veins may be distinctly lighter in colour Leaf burning from hot dry winds Close-up ofaffected leaves ventative measuresareconsideredpractical. pre- no sporadic, generally is damage the Prevention:As warrant treatment. Treatment: to thebranchesandtrunks. attached skins shed the tree. emergingleave the The adults the roots. When nymphs mature, they exit the soil and climb When the eggs hatch, the nymphs enter the soil and feed on and die,arealsomoresusceptibletowinddamage. splinter may branches (ovipositor). These apparatus laying deposits eggs in slits cut in the branches by its spear-like egg- emerge in orchards during summer. After mating, the female Identification: Cause: Adultcicadas (Psaltodasp.). Cicada damage Damage is not generally serious enough to to enough serious generally not is Damage Large numbers of adult cicadas often often cicadas adult of numbers Large 35 leaf, branch & trunk problems 38 40 leaf, branch & trunk problems leaf, branch & trunk problems associated with advanced nitrogen deficiency than the interveinal areas. The lower leaf is beginning to show the bronzing Close-up of affected leaves. Note that the veins may be distinctly lighter in colour Typical symptoms ona shoot, showing the overall pale-green colour Typical heat damage symptoms Leaves sometimes show anuneven yellow bleaching Bleaching of young leaves from heat stress Leaf burning from hot dry winds Close-up ofaffected leaves where available,helpstominimisedamage. irrigation, and windbreaks of use appropriate The areas. Prevention: not appeartosignificantly affect nutyieldorquality. Treatment: None is practicable. Short-term heat stress does from theremainingskeletonoftree. emerges flush new The off. drop eventually and burnt be In young trees exposed to hot dry winds, all the leaves may recent growthflush. leaf. Damage is generally confined to the leaves of the most whole a of death the to through margins leaf of death the Hot dry conditions may cause leaf death. This may vary from caused bycoldweather(seepages72–73). yellows winter of those to similar be may Symptoms 781. is generally confined to highly susceptible varieties such as Damage mottling. and bleaching yellow uneven an to ing tree condition, leaf symptoms vary from a complete bleach- on Depending leaves. young the of bleaching a cause may temperatures high varieties, susceptible In Identification: (heat stress)andhot,dryconditionsdamage). Cause: Heat stress anddamage fertilisers tomaintainappropriatenitrogenlevels. Prevention: ply fertiliserasrecommendedbytheresults. Treatment: Do a leaf analysis to check nitrogen levels. Ap- deficiency, leavesmaybecomebronzedincolour. youngest leaves are generally affected. In advanced nitrogen the only where stress, heat from problem the distinguishes our. Symptoms first appear on the older leaves. This generallyIdentification: Cause: Insufficientnitrogenavailabletothetree. Nitrogen deficiency High temperatures (over 35°C) during leaf growth leaf during 35°C) (over temperatures High Do regular leaf and soil analysis and apply apply and analysis soil and leaf regular Do Avoid highly susceptible varieties in hotter hotter in varieties susceptible highly Avoid Affected leaves are an overall pale-green col- 39 41 leaf, branch & trunk problems leaf, branch & trunk problems 42 44 leaf, branch & trunk problems leaf, branch & trunk problems Severe salt damage in nursery plants Typical field symptoms. Note the severe marginal burn Close-up of two examples ofdamage Typical damage to the lower leaves in applicationtechnique. a pressure gauge to monitor pressure, and instruct operators shielded machinery,calibrate nozzles, flood Use or fan low-pressure use risk. the low minimise will (removing branches) trees hanging of Skirting conditions. windy ing dur- herbicides applying Avoid foliage. with contact any Prevention: Treatment: leaves closesttotheherbicidespraypath. spots and burnt areas. Damage generally occurs on the lower Identification: diquat andparaquat/diquatmixtures. paraquat, include herbicides Desiccant foliage. to applied Cause: Desiccant herbicide spray damage over-fertilising, especiallyinyoungplants. avoid to carefully very rates fertiliser Calculate levels. salt planting macadamias, do a soil analysis to check underlying ter with a salt level of less than 1.2 dS/m is preferred. Before Prevention: affected plants. re-pot nursery, the in occurs problem the If source. water another use damage, salt confirms analysis water If zone. root the of out salt the leach to heavily Waternecessary. if re-adjust and rates fertiliser Check water. irrigation and been investigated. Get an analysis done on soil, plant tissue has problem the until fertilisers apply not Treatment:Do in nurseryplants. may also be pale in colour. The problem is commonly seen marginsleaf leaves. the older leaves of younger ing The brown- distinct a is symptom typical The Identification: use ofsaltyirrigationwaterortheover-use offertilisers. Cause: Salt damage High salt levels in the root zone. Caused by either the Damage from desiccant herbicide accidentally accidentally herbicide desiccant from Damage Notreatmentispossible. Thoroughly test irrigation water before use. Wa- Apply herbicides very carefully, avoiding avoiding carefully, very herbicides Apply Affected leaves show a variety of brown brown of variety a show leaves Affected 43 45 leaf, branch & trunk problems leaf, branch & trunk problems 48 leaf, branch & trunk problems 46 leaf, branch & trunk problems base ofa tree (soil removed) ‘Shoestrings’ of the fungus at the Affected tree withhealthy tree on the right Typical symptoms showing the collapse of the shoot at the point offeeding long (excluding antennae) Nymph –actual size about 10mm long (excluding antennae) Adult bug –actual size about 12 to 15mm of a tree Mushrooms of the fungus at the base growing under the bark coloured fungus (arrowed) Large root showing the cream- 48 leaf, branch & trunk problems 46 leaf, branch & trunk problems base ofa tree (soil removed) ‘Shoestrings’ of the fungus at the Affected tree withhealthy tree on the right long (excluding antennae) Nymph –actual size about 10mm Typical symptoms showing the collapse of the shoot at the point offeeding long (excluding antennae) Adult bug –actual size about 12 to 15mm of a tree Mushrooms of the fungus at the base growing under the bark coloured fungus (arrowed) Large root showing the cream- Cause: Cause: Bananaspotting bug damage on beneficialinsects. impact minimal with insecticides disruptive less of use the includes which approach, (IPM) management pest grated inte- an Use orchard. the of parts these in only necessary be may spraying cases, some In spots’. ‘hot known or est rainfor- to adjacent areas in first Monitor hand. of out gets trees in the field so that the problem can be treated before it Prevention: page 102. on symptoms see – nuts attacks also bug The insecticide. field. Where necessary, spray with an appropriate registered grafting is necessary) and occasionally on young trees in the in the nursery (where the maintenance of a single shoot for necessary be may treatment Specific damage. tip prevent to sufficient generally are protection nut for applied sprays essential The treatment. specific justify to sufficient rarely Treatment: to rainforest. The bugoccursinQueenslandonly. (excluding antennae).long Damage mm is 15 worse in to orchards 12 adjacent about are Adults build. in slender and shape in rectangular somewhat winged, brown, to green a pair of large black spots on the abdomen. Adults are light orange-red with a distinctive light-red stippling surrounding The shoot collapses at the feeding point and dies. Nymphs larly are in late summer and early autumn after the nuts mature. Identification: lutescens. and majorrootsareremovedbeforeplantingmacadamias. Prevention: the plantingsitebeforere-planting. possible. This limits further spread, and allows treatment of remove the tree together with as many of the major roots as If decline of the tree is well advanced, it is probably best to Treatment: of thetree(generallypresentduringcoldwetweather). the base of the tree; honey-coloured mushrooms at the base strands of the fungus (called ‘shoestrings’) in the soil around neath the bark of the crown and larger roots; black, cord-like be-just growth cream-coloured fungal – symptoms lowing can be diagnosed by the presence of one or more of the fol- disease The dieback. twig and growth stunted leaves, dead Identification: Cause: ThefungusArmillarialuteobubalina Armillaria root rot disease The bananaspotting bug bug bananaspotting The There is no effective treatment for affected trees. In bearing trees, damage is insignificant and is On newly cleared ground, ensure all tree stumps Regularly monitor trees in nurseries and young Affected trees slowly decline, with yellow or The bug attacks young lush shoots, particu- Amblypelta lutescens lutescens Amblypelta . 47 49 leaf, branch & trunk problems leaf, branch & trunk problems 52 leaf, branch & trunk problems 50 leaf, branch & trunk problems dark lines inwood removed. Note narrow branch canker withbark Close-up ofDothiorella Affected tree showing the diseased branches amongst otherwise healthy foliage a branch Close-up ofPinks disease fungal growth encircling tissues water conducting discolouration of tree showing the of anaffected the basal trunk Cross-section of leaves and death of rapid browning showing the Affected tree Identification: solanacearum. as manyarehostsforthedisease. appropriate, mounding. Keep broadleaf weeds under control, terlogging by ensuring adequate surface drainage and, where soils. marginal Avoidshallow in wa- macadamias planting crops such as tomato, potato, capsicum and eggplant. Avoid into sites that have recently grown bacterial wilt susceptible Prevention: very quickly. Treatment: There is no practical treatment, as the trees die to waterlogging. subject soils marginal shallow in common more is disease may exude from the affected tissues on the cut surface. The water conducting wood can be seen. A slimy bacterial ooze the of discolouration watersoaked brown, to grey a across, quickly, but remain on the tree. When the lower trunk is cut Cause: Bacterial wilt disease to dryoutafterrain. density to increase air canopy movement Reduce and assist orchards. the lowerbetween canopy moving when chinery ma- pruning Disinfect branches. of wounding unnecessary Avoid stress. moisture or nutrient frost, heat, to exposed not are branches that so vigour tree Maintain Prevention: per-based fungicide. cop- registered appropriate an with affectedarea the Spray mastic. grafting or paint plastic water-based with wounds all Seal mould). or wood discoloured for (look infection the below point a at limbs affected out Treatment:Prune trees subjecttoshadingfromadjacentforest. disease is more common in wetter, humid areas and in large white and the affected bark often cracks and peels off. Pinks turns it ages, growth the limbs. As affected of bark the on seen. With Pinks disease, a thin, be pink may fungallines narrow growthin wood developsthe of discolouration purple edge of the infection. When the bark is peeled away, a normal brown-with a slight water soaked appearance at the leading Dothiorella canker, the bark of affected limbs is darker than foliage. The leaves stay attached to the affected branch. Withhealthy otherwise the amongst conspicuous very branches healthy sheen. They eventually dry out, making the diseased branches. Leaves of affected limbs first look pale and lack a Identification: and Corticiumsalmonicolor (Pinksdisease). Cause: Branch dieback disease The fungi The h bacterium The Where possible, avoid planting macadamias macadamias planting avoid possible, Where Leaves on affected trees brown and die die and brown trees affected on Leaves The disease generally affects individual individual affects generally disease The

Dothiorella ribis Dothiorella

Ralstonia (syn (syn (Dothiorella canker), canker), (Dothiorella Pseudomonas ) 53 leaf, branch & trunk problems 51 leaf, branch & trunk problems 56 leaf, branch & trunk problems 54 leaf, branch & trunk problems Close-up ofaffected leaves – severe deficiency inleaf at right Yellow mottling symptom. Note the green ‘iron spots’ ‘X-ray’ effect where the veins remain dark green the older leaves remain green Symptom inanursery plant showing the yellowing of young leaves. Note that green leaves remain the youngest leaves while in the older yellowing showing Affected shoot to dryoutafterrain. density to increase air canopy movement Reduce and assist orchards. the lowerbetween canopy moving when chinery ma- pruning Disinfect branches. of wounding unnecessary Avoid stress. moisture or nutrient frost, heat, to exposed not are branches that so vigour tree Maintain Prevention: per-based fungicide. cop- registered appropriate an with affectedarea the Spray mastic. grafting or paint plastic water-based with wounds all Seal mould). or wood discoloured for (look infection the below point a at limbs affected out Treatment:Prune trees subjecttoshadingfromadjacentforest. disease is more common in wetter, humid areas and in large white and the affected bark often cracks and peels off. Pinks turns it ages, growth the limbs. As affected of bark the on seen. With Pinks disease, a thin, be pink may fungallines narrow growthin wood developsthe of discolouration purple edge of the infection. When the bark is peeled away, a normal brown-with a slight water soaked appearance at the leading Dothiorella canker, the bark of affected limbs is darker than foliage. The leaves stay attached to the affected branch. Withhealthy otherwise the amongst conspicuous very branches healthy sheen. They eventually dry out, making the diseased branches. Leaves of affected limbs first look pale and lack a Identification: and Corticiumsalmonicolor (Pinksdisease). Cause: Cause: Branch dieback disease The fungi The The disease generally affects individual individual affects generally disease The

Dothiorella ribis Dothiorella (Dothiorella canker), canker), (Dothiorella

51 leaf, branch & trunk problems 56 leaf, branch & trunk problems 54 leaf, branch & trunk problems Close-up ofaffected leaves – severe deficiency inleaf at right the older leaves remain green Symptom inanursery plant showing the yellowing of young leaves. Note that ‘X-ray’ effect where the veins remain dark green Yellow mottling symptom. Note the green ‘iron spots’ green leaves remain the youngest leaves while in the older yellowing showing Affected shoot over-liming andoveruseofphosphorusfertilisers. fertilisers in accordance with the results. This will help avoid Prevention: or sulphateofammonia. sulphur elemental either applying by soil the acidify test), water (1:5 7.0 above is pH soil the If soil. the to sulphate determine if the soil is deficient in iron. If so, apply ferrous appear in time without further treatment. Do a soil analysis to ing or overuse of phosphorus fertilisers, symptoms may dis- symptoms. However, where the problem is due to over-lim- the of severity the reduce to used be can sulphate ferrous soluble or chelate iron either of sprays Treatment:Foliar all cases,theoldestleavesremaindarkgreenthroughout. and the next oldest leaves are yellow with green midribs. In In nursery plants in pots, the growth tip is brown and stunted tissue remain green.Inseverecases,nutsarealsoyellow. the where effect veins major and midrib the and yellows veins the ‘x-ray’ between an to mottling yellow Identification: May alsobeaprobleminalkaline(highpH)soils. fertiliser.phosphorus of overuse or over-liming by caused Cause: Iron deficiency levels. magnesium and pH soil appropriate maintain to fertilisers Prevention: oxide. magnesium apply Otherwise test). water (1:5 5.0 than less is pH soil the and low are both levels magnesium if and calcium dolomite Apply levels. magnesium and calcium and pH soil check to Treatment:analysis soil and leaf Do shaped bandofgreentissue. tree’‘Christmas a producing green, remain tissue adjacent and veins the cases, severe but all In margins. the towards out extending veins, the between occurring yellowing with Identification: Cause: Insufficientmagnesiumavailabletothetree. Magnesium deficiency Insufficient iron available to the tree. Generally Generally tree. the to available iron Insufficient Do regular leaf and soil analysis and apply apply and analysis soil and leaf regular Do Do regular leaf and soil analysis and apply apply and analysis soil and leaf regular Do Symptoms first develop in older leaves leaves older in develop first Symptoms Field symptoms vary from an overall overall an from vary symptoms Field 55 57 leaf, branch & trunk problems leaf, branch & trunk problems 60 leaf, branch & trunk problems 58 leaf, branch & trunk problems Field symptoms in anursery tree Typical symptoms of severe damage Extreme boron deficiency –note the split veins and dead growing point leaves at the end of shoots Zinc deficiency –clusters of stunted burn and interveinal yellowing tree showing the uneven marginal Close-up of symptoms inanursery stunted leaves Zinc deficiency –close-up of cording toleafandsoilanalysisresults. during orchard preparation and then at regular intervals ac- trees the under ground the to boron Apply levels. nutrient monitor to analysis soil and leaf regular Do Prevention: on ratesandapplicationprocesses. also apply a soil application of boron. Seek specialist advice solution, permanent a Solubor.For of spray foliar a Apply Treatment: formed with splits in the veins. The growing tip may die. leathery,and hard mal-Identification: are leaves Affected Cause: Extreme boron deficiency leaf andsoilanalysisresults. to according annually then and preparation orchard during trees the under ground the to zinc Apply levels. nutrient monitor to analysis soil and leaf regular Do Prevention: spray zincsulphateheptahydratetothespringleafflush. Apply zinc to the ground under the tree. In severe cases, also Treatment: away fromtheleafmargins. show an interveinal yellow mottling, which initially develops ends of the shoots (known as ‘rosetting’). The stunted leaves resulting in the formation of clusters of stunted leaves at the Identification: Cause: Insufficientzincavailabletothetree. Zinc deficiency spray itontothesoilsurface. in solid form. The best way is to mix the boron in water and quantities involved, this is very difficult when applying boron boron to the soil, apply it very evenly. applying Because of the small When recommendations. analysis soil and leaf Prevention:carefully,very rates Calculate boron on based trees willeventuallygrowoutoftheproblem. potting medium. Provided the damage is not too severe, field boron out of the root zone. Where possible, the replant in a leach new to heavily water plants, nursery In Treatment: Again, theveinsremaingreen. burn. marginal the without yellowing, severe show erally upward as the marginal burning progresses. Field trees gen- curl may Leaves green. dark remain veins The yellowing. interveinal associated marginalwith uneven leaves of burn an is common most the plants, nursery In situation. the on Identification: A range of symptoms may occur, depending fertiliser. Cause: Boron toxicity Extremely low levels of Excessive use or uneven application of boron boron of application uneven or use Excessive Get a leaf analysis done to confirm the diagnosis. Get a leaf analysis done to confirm the diagnosis. The deficiency causes restricted shoot growth

boron available to the tree. 59 61 leaf, branch & trunk problems leaf, branch & trunk problems 62 64 leaf, branch & trunk problems leaf, branch & trunk problems Tip borer damage to the growing point Lichens ona trunk Algal leaf spot Close-up ofmistletoe infestation 62 64 leaf, branch & trunk problems leaf, branch & trunk problems Close-up ofmistletoe infestation Tip borer damage to the growing point Lichens ona trunk Algal leaf spot lichens causenopermanentdamage. Prevention: permanent damage. Treatment: Treatment is not necessary as lichens cause no and fogregularlyoccur. mists where regions elevated in orchards old in more common are They trunks. tree and branches the on growths irregular greyish-green as appear Lichens Identification: association betweenalgaeandfungi). Cause: Lichen infestation leaf spotcausesnopermanentdamage. Prevention: causes nopermanentdamage. spot leaf algal as necessary not is TreatmentTreatment: leaves ageanddropoff. the until remain they leaf, the to damage permanent no do and superficial are spots the Although surface. leaf upper Identification: The algae produce distinct grey spots on the leaf surface. Cause: Algal leaf spot Prevention: There are no available preventative measures. clumps. Treatment: lower canopy. the in limbs main on growing found commonly are which tletoes should not be confused with natural epiphytic ferns, Mis- flowers. and branches leaves, own their produce they there, From stream. tree’ssap the to connect and branches Identification: Cause: Infestationbyplant-parasiticmistletoes. Mistletoe infestation cides withminimalimpactonbeneficial insects. disruptive insecti-less of use the includes which approach, gets out of hand. Use an integrated pest management (IPM) trees in the field so that the problem can be treated before it Prevention: tipborer. sprays registered for nutborer are generally effective against and occasionally young trees in the field. Where necessary, Treatment: insect mayalsoaffect nuts–seesymptomsonpage138. new leaf flushes, especially in late summer and autumn. The Identification: Cause: Thenutstemborer Tip borer damage Saprophytic (non-pathogenic) algae growing on the Growth of lichens (organisms that are a symbiotic a are that (organisms lichens of Growth Preventative measures are not necessary as algal Treatment may be necessary in the nursery nursery the in necessary be may Treatment Preventative measures are not necessary as as necessary not are measures Preventative Regularly monitor trees in nurseries and young Cut off and destroy accessible mistletoe mistletoe accessible destroy and off Cut The insect causes death of the growing tips on Mistletoe seeds germinate on macadamia macadamia on germinate seeds Mistletoe Paranepsia amydra. 63 65 leaf, branch & trunk problems leaf, branch & trunk problems 68 leaf, branch & trunk problems 66 leaf, branch & trunk problems Close-up ofan affected shoot end of the shoot Typical symptoms showing the long willowy growth and upward curling at the Hail damage to trunk symptoms Manganese toxicity – typical deficiency (‘Christmas tree’ effect) margin) combined withmagnesium Manganese toxicity (dark spots around Prevention: There arenopracticalpreventativemeasures. trunk cankerinfection. subsequent against trunk the protect may sprays fungicide Treatment: hailstone impact.Seepage140fornutdamagesymptoms. against protection limited provides foliage the because age dam- trunk to prone more are Youngshape. trees and size varying of marks’ ‘pock brown of consist and tree the of Identification: Cause: Impactdamagefromhailstones. Hail damage at 6.5orabove(1:5watertest). pH soil maintain soils, manganese high In levels. nutrient monitor to analysis soil and leaf regular Do Prevention: test). water (1:5 6.5 to pH soil raise to dolomite or lime Apply Treatment: deficiency. magnesium with combination in occurs often toxicity The yellow margin towards their tip, with many small dark spots. Identification: (1:5 watertest). 6.5 below falls pH when levels manganese high with soils Cause: Manganese toxicity copper deficiency. of likelihood the reduces generally control spot husk for sprays fungicide based copper of use The levels. nutrient monitor to analysis soil and leaf regular Do Prevention: by thesoilanalysisresults. deficient, apply copper sulphate to the soil at rates determined spray. Get a soil analysis done to check soil copper-based copper levels. a If of application foliar a Treatment: Apply confused withtheviningdisorder–seepage70. be sometimes can deficiency Copper soils. sandy in likely more is problem The distorted. and small be may leaves upward. grow to Terminalattempting tip shoot the through downwards under the weight of foliage. The twisting follows problem is caused by the weakness of the shoot,The trees. whichyoung in bends particularly ‘vine-like’, and twisted is Identification: caused bylowlevelsofcopperinthesoil. Cause: Copper deficiency High uptake of manganese from the soil. Occurs in Insufficient copper available to the tree – generally There is no practical treatment, although copper Get a leaf analysis done to confirm the diagnosis. The newly formed flush of affected branches Symptoms are typically confined to one side Affected leaves have an irregular pale pale irregular an have leaves Affected 69 67 leaf, branch & trunk problems leaf, branch & trunk problems 70 72 leaf, branch & trunk problems leaf, branch & trunk problems Abnormal vertical growth disorder odwn aae(itrylos Foliage symptoms of freezing damage Cold wind damage (winter yellows) Vining disorder ringbarked becomes effectively how the trunk (right) –note later symptoms falling off; bark splitting and (left) –note the early symptoms freezing damage: Trunk symptoms of Prevention: There arenopracticalpreventativemeasures. trunk cankerinfection. subsequent against trunk the protect may sprays fungicide Treatment: hailstone impact.Seepage140fornutdamagesymptoms. against protection limited provides foliage the because age dam- trunk to prone more are Youngshape. trees and size varying of marks’ ‘pock brown of consist and tree the of Identification: Cause: Impactdamagefromhailstones. Hail damage at 6.5orabove(1:5watertest). pH soil maintain soils, manganese high In levels. nutrient monitor to analysis soil and leaf regular Do Prevention: test). water (1:5 6.5 to pH soil raise to dolomite or lime Apply Treatment: deficiency. magnesium with combination in occurs often toxicity The yellow margin towards their tip, with many small dark spots. Identification: (1:5 watertest). 6.5 below falls pH when levels manganese high with soils Cause: Manganese toxicity copper deficiency. of likelihood the reduces generally control spot husk for sprays fungicide based copper of use The levels. nutrient monitor to analysis soil and leaf regular Do Prevention: by thesoilanalysisresults. deficient, apply copper sulphate to the soil at rates determined spray. Get a soil analysis done to check soil copper-based copper levels. a If of application foliar a Treatment: Apply confused withtheviningdisorder–seepage70. be sometimes can deficiency Copper soils. sandy in likely more is problem The distorted. and small be may leaves upward. grow to Terminalattempting tip shoot the through downwards under the weight of foliage. The twisting follows problem is caused by the weakness of the shoot,The trees. whichyoung in bends particularly ‘vine-like’, and twisted is Identification: caused bylowlevelsofcopperinthesoil. Cause: Copper deficiency High uptake of manganese from the soil. Occurs in Insufficient copper available to the tree – generally There is no practical treatment, although copper Get a leaf analysis done to confirm the diagnosis. The newly formed flush of affected branches Symptoms are typically confined to one side Affected leaves have an irregular pale pale irregular an have leaves Affected 69 67 leaf, branch & trunk problems leaf, branch & trunk problems 70 72 leaf, branch & trunk problems leaf, branch & trunk problems Abnormal vertical growth disorder odwn aae(itrylos Foliage symptoms of freezing damage Cold wind damage (winter yellows) Vining disorder ringbarked becomes effectively how the trunk (right) –note later symptoms falling off; bark splitting and (left) –note the early symptoms freezing damage: Trunk symptoms of Prevention: There are no available preventative measures. Treatment: There isnoavailabletreatment. trees takeontheappearanceofpoplartrees. same age. Flowering and nut production cease. When severe, upright branching, and are taller than unaffected trees of the Identification: Cause: Unknown. syndrome) Abnormal vertical growth disorder (tall tree close planting. avoid situations, these In areas. foggy cool, in 508, variety the particularly macadamias, planting AvoidPrevention: the tree. of aesthetics the improve will branches affected pruning Treatment: the Atherton Tableland. on Malanda example for situations, light) (low foggy and The problem seems more common at higher altitudes in cool ternodes, also bushy. Affected branches are non-productive. leaves on affected branches are small and because of short in- branches, sometimes up to a metre in length. Sometimes the Identification: The disorder causes abnormal long, slender Cause: Unknown. Vining disorder before the frostseason mayhelpreduce damage. areas. applied lower sprays to Anti-transpirant flow can air cold so rows tree Plant passed. has frost of risk the after rugated cardboard, aluminium foil or grass/straw). Remove trunk before winter with insulatingthe materialwrapping loosely (newspaper,by trees cor- young Protect areas. frosty in trees planting Avoidautumn. late in fertiliser nitrogen Prevention: With young trees in colder areas, do not apply ference is affected, replanting is usuallynecessary. with water-based plastic paint. If more than half the circum- it seal then fungicide copper a with area affected the spray If less than half the circumference of the trunk is damaged, recover. Where trunks are damaged, remove the generally loose bark. will only) symptoms (foliage damage freezing mild and damage Treatment:wind cold by Treesaffected lying partoftheorchard,wherecoldairpools. lowest the in occurs usually Damage dies. it cases most in splitting of the bark on the trunk. This ringbarks the tree, and browning and death of the young leaves, causes and where severe, temperatures freezing from Damage appearance. rubbery hard a develop and bleached then yellow become It is most common in colder production areas. Young leaves flushes induced by fertilising in late autumn (winter yellows). from cold winds may occur in young trees on winter growth Damage symptoms. of types two Identification: are There trees canwithstandshortperiodsoffrostto-6°C. Older trees. young damage will -1°C Temperaturesbelow Cause: Cold weather/frost damage Damage from cold winds or freezing temperatures. There is no available treatment, although although treatment, available no is There Affected trees appear to have excessive excessive have to appear trees Affected 73 leaf, branch & trunk problems 71 leaf, branch & trunk problems 76 leaf, branch & trunk problems 74 leaf, branch & trunk problems Chimera (genetic mutation) over-growing scion Graft incompatibility –rootstock regrowth Trunk symptoms. Note the sucker of young trees Typical fire burn damage inarow the right side facing the fire front Note how the damage is more severe on Close-up ofdamage from radiant heat. the burnt trunk Brown nodules (callus tissue) forming on growing rootstock Graft incompatibility – scion over- enough towarrant anypreventativemeasures. Prevention: Treatment: There isnotreatment. unlike mostnutrientdisorders. the variegation of leaves is completely unrelated to the veins, patterns of variegation are a common symptom. In this case, branches on the tree will be normal by comparison. Irregular Other variation. colour and distortion including symptoms Identification: Cause: Geneticmutationinabranchonthetree. Chimera ing theuseofrootstocksknowntocauseproblems. Prevention: show obvioussymptomsofdecline. little apparent ill-effect from the problem, while others may Treatment: swelling point. the rootstock. Cracking of the bark sometimes occurs at the over-growing and swelling scion the involves second The involves the rootstock swelling and over-growing the scion. Identification: rootstock. Cause: Graft incompatibility trees, particularlybeforethehighfire-risk period. young trees. Avoid build-up of dry organic material around able), and keep dry mulch such as husks or straw away from interrow areas mown and watered (where irrigation is avail- keep risk, fire high of periods During damage. major from heat and fire resistant, may help shield the macadamia trees more are which trees, mango of border a possible, be may chard. In forested situations where only minimal firebreaks or-the effectivearound firebreak an Prevention: Maintain plastic paintorgraftingmastic. water-based with wounds all seal damaged, partially are trees are best removed and the sites replanted. Where trunks recover.not will These tree the damaged, severely is trunk the if However recover. generally will tree the branches, Treatment: If the damage is confined to just the leaves and from therootstock. (callus tissue) form on the burnt areas. Sucker growth occurs causing bark splitting and ringbarking. Later, brown nodules fires, front. ground or Trunksgrass by damaged mostly are fire the facing tree the of side the on severe generally more is Damage branches. and leaves of death and scorching of through radiant heat from fires. This causes varying degrees occurs generally damage branch and Leaf Identification: burn fire actual around thetree. from and vicinity near the in fires from heat radiant from both damage, heat to susceptible highly Cause: Fire burn damage Heat from bush and grass fires. Macadamias are are Macadamias fires. grass and bush from Heat Incompatibility between the scion wood and the the and wood scion the between Incompatibility There is no available treatment. Some trees show There is little that can be done apart from avoid- The problem is sporadic and not significant significant not and sporadic is problem The Two types of symptoms may occur. The first Affected leaves may show a range of of range a show may leaves Affected 77 leaf, branch & trunk problems 75 leaf, branch & trunk problems 80 flower problems 78 leaf, branch & trunk problems eeeydmgdflwrrcmsEggs on the buds and on the bud stalks Severely damaged flower racemes Meat ant damage to leaves raceme (actual size about 12 mmlong) A larva feeding amongst the flower buds ofa the areas ofdecayed wood Kretzchmaria disease inroot. Note the thin black lines (arrowed), which bound (actual size about 7mmlong) Adult mothat rest onaflower