The last or rear of the three body division of an insect.

To have wings.

This development is seen in the more primitive wingless orders

Antennae or feelers are slender jointed sensory organs that appear in pairs on the head of all insects.

To be wingless.

A bristle tip on an antenna normally associated with flies.

A growth regulating compound that is involved in processes such as budbreak, root growth and seed germination.

The control of pests by natural predators, parasites or diseases.

A stem disease in which a dead area is surrounded or accompanied by live tissue.

A cast is depicted by three or four body forms that are found in social insects such as ants or bees.

The lava of a moth, sawfly or butterfly.

A cell is an area that is enclosed by veins on the wings of an insect.

The term chrysalis is used to describe the pupa of many butterflies or moths.

Cockroaches

Order Blattodea

These flattened insects are normally dull brown to black and have long antennae and chewing mouthparts. They may have a full set of wings, short wings or are wingless, normally with a thickened forewing. Normally the female is wingless and the male is winged. They are nocturnal and eating plant or animal material (scavengers). They live in arid to damp tropical regions and found under stones or rotten wood. The eggs are laid in an ootheca that is carried by the female. They have a hemimetabolous life cycle.

Species in Australia 440

A cocoon is a silken case that contains a pupa of several groups of insects including moths.

When leaves and buds loose chlorophyll as a result of a sudden cold snap turning the leaf white or giving it yellow margins.

When an insect has a complete life cycle from lava, which doesn't resemble an adult and transforms through a pupal stage to maturity.

When vegetables such as carrots or tomatoes crack or form splits from excessive rain or excessive watering followed by dry periods. Plant in well drained soils and mulch to avoid drying out.

First nymphal stage of a scale insect.

When seedlings are attacked and killed by a soil borne fungus.

This is a leafless parasitic plant that has long wiry stems that are attached to the host penetrating the vascular system and feeds of its sap. The Cassytha species becomes large and may kill the host by smothering it.

The thickening of the forewings as in beetles or earwigs to protect the membranous hind wings and are not used in flying.

When a parasite lives inside the body of its host.

Insects and arthropods form an exoskeleton which is a tough and jointed covering. It is composed of chitin and must be shed periodically to allow growth.

This is the third of the five segments found on an insect's leg and is normally the largest.

Fern and fern allies

Ferns and fern allies are in the class Pteridophyta, which contains up to 10,000 species that includes a wide range of forms that all reproduced by spores. Generally these plants characteristically grow by unrolling young segments (leaf-like) similar to plants that produce the seeds. Ferns have been recorded since the Paleozoic era and climaxed during the Carboniferous era. Since this time they have decrease their importance in the floral world but the number of species has increased.

Rhizomes

The stems of ferns are known as rhizome and have advantageous roots. These rhizomes vary considerably from wiry to a woody or fleshy and may be long and slender or thick; branched or unbranched. There are short creeping rhizomes, medium creeping, long creeping, erect and tufted with the smaller stems called caudex and large stems known as trunks.

The growing apex and fronds is protected by scales or hairs, which vary in shape and size and may be deciduous or persistent and the scale margins may be entire ciliate or serrated. These characteristics are used as a diagnostic feature to identify species.

Leaves

The upper part of a frond is called the lamina which may be simple or divided with a variable leaflets that may be sessile or stalked. The upper surface of the pinnae or pinnules has various venations from simple to a reticulated network. The leaf stem known as the stipe emanates directly from the rhizome or from an outgrowth known as the phyllopodium and changes name once it reaches the lamina to the rhachis. Divided fronds have a primary rhachis, secondary rhachis or tertiary rhachis and both the stipe and the rhachis have scales or hairs of some description. Fronds may be fertile or sterile and may appear dissimilar and commonly fertile fronds are erect to aid in dispersal of spores.

Spores

The sporangia produce the spores and are released through slits or a specialised ring of cells called the annulus. The variable sporangia are found in groups called sori or are arranged along the veins of the fronds and are rounded or elongated in shape and may be naked (exindusiate) or protected by an outgrowth called the indusia. The released spores are like fine dust commonly brown or blackish.

Life cycle

Ferns have two distinct life cycle phases known as the alternation of generations. The haploid gametophyte stage which produces the sexual organs and the diploid stage that produces spores in the sporangia. The life cycle commences when a released spore germinates on a damp, favourable media, normally a rock. It then divides to form a filamentous prothalli and grows to form a heart-shaped structure that is one cell thick with only hairlike root structures and forms a thickened central point called the archegonial cushion.

It is from this point that the female organs grow and the male organs (antheridia) appear along the margins of the prothallus. During wet conditions the male releases sperm, under the prothallus and swim to the archegonia which releases an attractive chemical. The fertilised egg is diploid and develops into a true fern feeding off the prothallus until it develops true roots and can photosynthesise for its food. In time, spores are once again produced on the under surface of the fertile fronds and the cycle starts again.

This is the main part of an antenna.

This is a chemical that is used to control fungal diseases.

This is a bulbous growth on plants that can contain early stages of insects or results from infestation of another plant species.

Girdled or Pot Bound

When a plant remains in a pot too long and the roots form a circular patten. This root patten continues when the plant develops in the ground causing it to stunted and unstable (easy to fall over).

Congregating in groups

This is a fleshy-bodied, sluggish beetle lava that has prolegs and a developed head capsule.

This development is when the immature nymphs resemble the adults

Having six legs.

This development occurs when metamorphosis is observed during the pupal stage.                

This is the sugary liquid that is secreted from insects from the Hemiptera order such as aphids or scale insect. Ants are attracted to this sticky substance and sooty mold forms on it.

The adult stage of an insect.

This is a life cycle where the young (nymphs) have a simular appearance to the adults and develops gradually with out a pupa stage, such as aphids.

The form of an insect between successive moults.

This is the immature insect between egg and pupa.

When a leaf becomes dry, papery and brown, normally shrivelling as a direct result of cold drying winds. This is an environmental problem.

When a plant sheds foliage, normally the inner leaf as in Thuja species where there is little light. Also when a plant is stressed as in drought conditions.

The chewing parts of the mouth (jaws) of an insect.

When an insect changes form as in a pupa to an adult.

Misshapen of vegetables

When poor pollination occurs. This may be improved by growing additional flowers and creating a small pond to attract bees. Certain species may be grown at the edge of the garden for greater exposure.

The immature stage of an insect that resembles an adult except lacking in functional wings.

Cockroaches

Order Blattodea

These flattened insects are normally dull brown to black and have long antennae and chewing mouthparts. They may have a full set of wings, short wings or are wingless, normally with a thickened forewing. Normally the female is wingless and the male is winged. They are nocturnal and eating plant or animal material (scavengers). They live in arid to damp tropical regions and found under stones or rotten wood. The eggs are laid in an ootheca that is carried by the female. They have a hemimetabolous life cycle.

Species in Australia 440

Beetles

Order Coleoptera

These insects are large or small and have a hard body with strong wing cases (elytra). These meet along the midline covering the hind wings that are fan-like and are fold along the body. The abdomen terminates in forceps and beetles have biting and chewing mouth parts. The grub-like larvae may or may not have legs and both adult and larvae are predatory or feed on vegetable material. These insects have a holometabolous life cycle.

Species in Australia 20,000

Springtails

Order Collembola

These small to tiny insects have a forked spring organ that folds under the abdomen and is used for jumping. They have a slender body that is made up of 6-segmented with chewing mouthparts and have antenna. They have adapted to marine environments or moist positions under leaf litter and in the soil, feeding on plant material. These insects have an Ametabolous life cycle.

Species in Australia 215

Earwigs

These nocturnal insects have flattened elongated bodies with prominent forceps at the end of the abdomen. These are used for offence or defence by being raised and opened when the insect is alarmed. The greatly thickened forewings form a protective cover over the hindwings that are complexly folded along the body. Some species are wingless, but all exercise parental care over the eggs and young. During daylight Earwigs take shelter under debris, stones or bark and feed on plant and animal material with chewing mouth parts. These insects have a Hemimetabolous life cycle.

Species in Australia 60

Campodeids, Japygids

These are small white eyeless hexapods that are elongated and terminating with 2-long cerci (Campodeids) or stout forceps (Japygids) simular to Earwigs. The abdomen segments other than the terminal one have small appendages. They are found in moist situations in leaf litter, under bark or in the soil and generally are not classed in Insecta.

Species in Australia 32

Flies, Mosquito

This large order includes active insects that generally have one pair of obvious wings. The hindwings form small club-like structures called halteres. These parasitic or gall forming insects feed off plants or animals and have sponging and sucking or occasionally piercing and sucking mouth parts. The variable legless larvae may be aquatic and may or may not have a head capsule. Examples are mosquito or a maggot. These insects have a Holometabolous life cycle.

Species in Australia 6,500

Web Spinners

These small narrow insects have elongated dark bodies and live in groups. The females are wingless and the short lived males may be winged or attracted to light. Nymphs are simular to the wingless adults and spin silken galleries in rock crevices, tree trunks or among leaf litter. The silk is produced from the swollen front tarsi (5^th segment of the leg).

Species in Australia 65

Mayflies

These small delicate insects are short lived and have large broad forewings with the hindwings reduced or absent. They are dull coloured with large eyes, small antennae and are recognisable by 2 or 3 long (tails) filaments or caudal appendages on the abdomen. They rest on leaves during the day swarming at dusk and are found around water. The nymphs are aquatic with lateral abdominal gills and have 3 (tails). These insects have a Hemimetabolous life cycle.

Species in Australia 125

Bugs, Cicadas, Aphids, Scale Insect, Leaf Hoppers

This variable group of insects have mouthparts with a cylindrical rostrum that encloses a slender stylet for piercing and sucking plant or animal fluids. The forewings are membranous and thickened or may be absent. In some cases the insect is wingless, legless and immobile as in a mature scale insect. The nymphs resemble the adults and may live under ground. These insects have a Hemimetabolous life cycle.

Species in Australia 3,700

Bees, Wasps, Ants, Sawflies

This large order consists of hard-bodied insects that have membranous wings and biting and chewing mouthparts. Most have waists between forebody and hindbody except sawflies and often have a stinger. All ants, bees and certain wasps are social, living in colonies of a few individuals to large numbers, with castes for division of labour. The adults are parasites, gall makers or free living and the grub-like larvae are normally legless with a head capsule. These insects have a Holometabolous life cycle.

Species in Australia 9,000

Termites

These soft bodied insects are social and have several castes wingless solders and workers. The reproductive castes have wings to help in dispersal after which they lose there wings for mating and establishing new colonies. They have chewing mouth parts and feed on wood, grass or organic material and are a serious pest. They build earthen nests above or below the ground or in trees and decaying wood. These insects have a Hemimetabolous life cycle.

Species in Australia 200

Moths, Butterflies

This large order consists of various size insects all with wings that are covered in scales or hairs. They have mouth parts that form a siphoning, coiled sucking tube (haustellum) for feeding on nectar. The larvae are soft bodied (caterpillars) commonly with 4 or 5 pairs of pro legs and head capsule. These feed on plants with their chewing mouth parts. Butterflies are distinguished by club antennae and female moths have filiform (thread-like) antennae. The male have plumose (feather-like) antennae. These insects have a Holometabolous life cycle.

Species in Australia 11,250

Preying Mantids

These medium to large insects are predators with triangular heads with large eyes and raptorial forelegs which hold live prey for eating. They have chewing mouth parts. Females have wings that are reduced or absent and the males have fully functional wings, often attracted to light. Males may look different to the females of the same species. The nymphs are simular to the wingless adults. These insects have a Hemimetabolous life cycle.

Species in Australia 120

Scorpion Flie

This is a small group of predacious insects with a slender body that may have an up-turned abdomen and long slender legs. The slender wings are membranous and the head is elongated between the eyes. It has chewing mouth parts that form a beak. They feed on the flower nectar in damp areas or catch other insects on the wing. The caterpillar-like larva lives in damp places and pupates under ground. These insects have a Holometabolous life cycle.

Species in Australia 64

Dobsonflies, Alderflies

These medium size insects are sluggish and found near streams in cool coastal regions. They have long flexible abdomens and wings with dark spots, and veins without end-twigging (simular to Lacewings). The larva are predaceous and aquatic, recognisable by the gills along there abdomen. These insects have a Holometabolous life cycle and have chewing mouthparts.

Species in Australia 16

Lacewings, Ant-lions

These small to large insects are fragile and weak fliers with a narrow body and are attracted to light. They have membranous wings (lace-like) with dense network of veins. The larvae are predaceous with curved or grooved mandibles (chewing mouth parts) through which they suck the juice of the prey and may be found in conical pits as in Ant-lions. These insects have a Holometabolous life cycle.

Species in Australia 400

Dragonflies, Damselflies

These slender small or large, strong flying insects have wings with numerous cross veins at right angles to the body. The compound eyes are large and the antennae are short. The nymphs are aquatic predators and seize pray with an extensible 'mask' and adults catch prey on the wing. These insects have a Hemimetabolous life cycle and have chewing mouth parts.

Species in Australia 250

Grasshoppers, Crickets

This group of medium to large insects are normally herbivorous with chewing mouth parts and have enlarged hind femur used for jumping or digging. Some species are wingless others have forewings that form a cover over the folded hindwings. The nymphs are simular to the adults. These insects have a Hemimetabolous life cycle.

Species in Australia 1,500

Stick Insect

These medium to large, very slender insects resemble the twigs or leaves of the host plant as they are camouflaged. Normally the females are wingless and the males are sometimes winged, these are found higher up in the plant. During the daylight they remain motionless and feed at night on foliage, with chewing mouthparts. The dark oval eggs are laid in the canopy of the host plant then fall to the ground, and the nymphs appear simular to the adults. These insects have a Hemimetabolous life cycle.

Species in Australia 132

Biting Lice, Parasitic Lice

These flattened wingless insects are parasites with chewing or blood sucking mouthparts. The life cycle takes place on the host with the eggs laid in the feathers of birds or the fur mammals and causing great irritation. These insects have a Hemimetabolous life cycle.

Species in Australia 210

Stone Flies

These medium size dull coloured insects have slender bodies with smaller hindwings that have an anal lobe. The wings fold flat over the body when at rest and they have long antennae. The adults are commonly found along creeks or around water and the nymphs are aquatic with gills. These insects have a Hemimetabolous life cycle.

Species in Australia 90

Class Protura

These small hexapods which are insect-like have elongated bodies with 12-abdominal segments and no eyes or antennae. They live in moist positions under leaf litter or in the soil and are not commonly seen.

Species in Australia 30

Book Lice, Psocids

These small insects have chewing mouthparts that have been modified for rasping. They may be winged or wingless and have slender 4-segemented antennae. Some form colonials and have different castes within the nest and most commonly known for damaging stored products or books in libraries. The nymphs look simular to the adults. These insects have a Hemimetabolous life cycle.

Species in Australia 120

Fleas

These insects are wingless with compressed bodies and are blood sucking ectoparasites on birds and mammals with the adults having piecing and sucking mouth parts. The grub-like larvae seldom lives on the host and tends to dwell in dust or sand being free-living scavengers. Under the favourable conditions they appear in plague proportions and the adults can spend some time off the host. These insects have a Holometabolous life cycle.

Species in Australia 75

Stylops

The small order consists of tiny winged males and wingless females that are parasites, on other insects. The short lived male, has modified forward wings (rod-like) and the large rear fan-shaped wings. Its eyes are berry-like and antennae are flabellate with up to 4 prongs, very obvious. These insects have a Holometabolous life cycle and the females normally do not leave there host.

Species in Australia 95

Thrips

These insects have narrow elongated dark bodies, less than 12mm (¼in) long, with slender fringed wings. The lighter coloured nymphs are simular to the wingless adults and both have stylet-like mouth parts to rasp and suck the plants juices. Some insects are predaceous and others are commonly found in leaf litter, under bark, in flowers, on leaves or forming galls. These insects have a Hemimetabolous life cycle.

Species in Australia 300

Silverfish

These are flattened, agile insects that are covered in silvery scales with long antennae and three slender filaments (tails). They feed on starch or are scavengers that avoid daylight and are not normally seen, they live under leaf litter or stones. These insects have an Ametabolous life cycle and have chewing mouthparts.

Species in Australia 23

Caddis Flies

These small brown moth-like insects have hairy or scale covered wings and very long antennae. The aquatic larvae construct cases from plants, sticks or small pebbles using webbing and are identified by its pair of abdominal prolegs. Adults are normally found around creeks or ponds and are attracted by light. These insects have a Holometabolous life cycle. The lava has chewing mouth parts and the adults have "siphoning" mouth parts.

Species in Australia 260

This is a tubular structure on a female insect that is used to deposit eggs. In some species it is concealed while on others it is long and obvious.

The production of fertile eggs with out male fertilisation involved.

Disease producing (pathogen)

This is an elongated mouthpart of a sucking insect such as the coiled tubular mouth parts of moths or butterflies.

The short appendages on the abdomen of certain caterpillars that act as legs.

The beak-like mouthparts for piercing and sucking as found in bugs or refer to the snout of weevils.

The first basal segment of an antenna.

When the inside of a leaf becomes waterlogged as a result of a slowdown of transpiration. This normally occurs during long wet periods when the leaf is unable to dry out. The leaf becomes blackened and dies.

Boron

This element is involved in flowering and fruiting processes. It is also involved in germination, cell division and carbohydrate metabolism. It is not mobile and is normally seen in young tissue.

Symptoms of Deficiency

The stems produce shortened internodes and become thickened, tough and brittle. The leaves smaller, deformed and stiff and some species upper leaves turn yellow. The plant may loose geotropic response and grow sideways rather than up and side shoot production is increased. Petioles, midribs, stems and root storage organs may develop cracks that become corky.

Possible Cause

Insufficient fertiliser with Boron added to soil or the pH is too high. Leaching of the soil or high calcium levels reduce the availability of Boron.

Similar symptoms may result from calcium, copper and zinc deficiency or pesticides, phototoxicity and nematodes, which cause corkiness in storage roots.

Toxicity from Excessive Use

It is commonly found in excess when foliar sprays are used.

Plant Symptoms

The older leaves form marginal scorching and turn brown to black. The leaves may also form interveinal spotting or become thick and cupped.

Possible Cause

Application of foliar sprays or water that contains boron. Soil mixes that contain boron such as sawdust from boron treated timber or wast material that contains boron.

Calcium

This element is required in cell wall structure and also acts as a detoxifying agent for micronutrients and organic acids such as oxalic acid.

It is not mobile and is normally seen in young tissue.

Symptoms of Deficiency

Generally a deficiency of calcium causes young leaves to become pale green and cupped either convex or concave. The terminal leaves are stunted and the margins or apex becomes blackened causing the shoot tips to die. This blacking can also occur in the flower buds, and flowers fail to open. Petals and stems develop water-soaked areas that eventually cause them to collapse. Certain species develop yellowish spots that enlarge becoming necrotic causing the leaf to fall. These symptoms tend to progress from the base of the plant upwards.

Possible Cause

Calcium deficiency may result from the lack of lime or dolomite in the soil or after a heavy application of potassium or ammonium fertiliser.

Similar symptoms may result from frost damage causing the leaf margins to burn, excessive heat, pesticide damage or deficiency in Boron and Manganese.

Toxicity from Excessive Use

Calcium toxicity is rare.

Plant Symptoms

High levels of soluble calcium can occur in low pH soils and may induce magnesium deficiency.

Possible Cause

Excessive application of lime or gypsum.

Copper

This element is found in many plant enzyme systems including the process of photosynthesis and respiration. It is not mobile and is normally seen first in young tissue.

Symptoms of Deficiency

Generally affected plants are stunted with the young leaves becoming twisted or crinkled, particularly terminal leaves that are small and have dead apexes. Below the dead growing tips multiple budding may occur giving a Witches Broom appearance. Lower mature leaves generally remain healthy and unchanged.

Possible Cause

Insufficient fertiliser with Copper added to soil or the pH is too high. Copper may also be less available if a high phosphorus, manganese, zinc or iron content is in the soil.

Similar symptoms may result from soil deficient in calcium, zinc and boron.

Toxicity from Excessive Use

Copper toxicity may occur when soil mixes are composed poorly, particularly when the soil is too acid.

Plant Symptoms

Plants may become stunted and the leaves may become burnt as a result of excessive copper.

Possible Cause

Excess copper commonly occurs after the application of copper based fungicides or from excessive copper foliar fertilisers.

Iron

This nutrient is required in the production of chlorophyll and other enzyme systems. It is not mobile and is normally seen in young tissue.

Symptoms of Deficiency

Initially interveinal chlorosis occurs on young leaves with the veins remaining green. Leaves including the veins tend to become yellow, then a uniform cream colour. New leaves tend to be stunted and in extreme cases brown necrotic areas occur. This deficiency will not cause leaf deformity.

Possible Cause

This is trace element is commonly deficient in ornamental plantings and generally indicates a very high pH level, particularly in soilless media. Insufficient iron added to the media or high Phosphorus levels also results in deficiency.

Similar symptoms may result from Manganese deficiency or the application of pesticides

Toxicity from Excessive Use

Excessive iron is commonly associated with foliar sprays, but soil toxicity is rare.

Plant Symptoms

Iron toxicity is normally seen as a manganese deficiency.

Possible Cause

Excessive use of iron, particularly as iron sulfate in soilless media or the application of acidifying fertiliser to the soil.

Magnesium

This element is the central atom in the chlorophyll molecule and is essential in certain enzyme reactions as a phosphate carrier.

Symptoms of Deficiency

As this element is highly mobile throughout the plant and older leaves show symptoms first with interveinal chlorosis, or bronze-yellow discolouration along the margins towards the apex. This discoloration can be seen on the lower leaves forming arcs towards the base of the leaf forming a 'V' shape at the apex. The apex is the first to die followed by the base.

There are variations of symptoms such as pigmentation and a rusty-brown necrosis occurring on the leaf with a simular pattern or the main veins remain green, or in legumes the margin remains green.

Possible Cause

Insufficient Magnesium in the soil may result from adjusting the pH with lime rather than dolomite. The deficiency may also result for excessive potassium applications or high sodium levels in irrigation water and is more pronounced in adverse climatic conditions such as, very wet or dry and cold weather.

Similar symptoms may result from virus infections or Manganese deficiency but these normally start at the leaf apex and usually on the lower leaves.

Toxicity from Excessive Use

It is not commonly found in excess but plants that are under a high fertiliser regime are susceptible.

Plant Symptoms

If magnesium is added to the soil with out the addition of calcium the plant may become deficient in calcium.

Possible Cause

Excessive application of magnesium to the soil in relation to other elements.

Manganese

This element is an activator for enzymes that are involved in oxidation-reduction reactions, controlling oxygen production in photosynthesis and production of plant oils. It is not mobile and is normally seen in young tissue but may be found on older leaves in some plant species.

Symptoms of Deficiency

Interveinal chlorosis on new leaves with all veins including the smallest remains green resulting in a very reticulated pattern. Interveinal and marginal areas may also turn yellowish or white and chlorotic areas can form tiny black spots.

Possible Cause

Insufficient fertiliser with Manganese added to soil particularly in mixes that have a peat base. A high pH level or high phosphorus, iron, copper or zinc also inhibits the availability of Manganese.

Similar symptoms may result from iron deficiency which has less greening of minor veins or Magnesium deficiency which only occurs on older leaves.

Toxicity from Excessive Use

Manganese toxicity is found in acid soils and soilless media particularly where pine bark is included in the mix.

Plant Symptoms

Brown to black spots appear on the lower leaves causing them to fall. Leaves may also become cupped or have marginal chlorosis, particularly on the young leaves.

Possible Cause

The use of barks that are high in manganese in soil mixes, particularly when the mix is steam sterilised or waterlogged. Excessive application of manganese fertiliser or acidifying fertilisers.

Molybdenum

This element is required in very small amounts and is involved in converting nitrate to nitrite as the first step towards protein production. It is not mobile and is normally seen first in young tissue, but symptoms may be seen on mature leaves of some plant species such as Euphorbia pulcherrima.

Symptoms of Deficiency

Leaves are affected in several ways, including becoming generally thick, leathery or with thickened margins. They may also curl up or downwards and in certain species the mature leaves turn yellow with the margins becoming scorched. This is a direct result of nitrate build-up.

Possible Cause

Insufficient Molybdenum available in the soil or the pH is too low.

Similar symptoms may result from deficiency in boron, copper and zinc. Insects or mite infestations may also cause simular symptoms.

Nitrogen

This nutrient is essential to plant growth and is an important component of proteins, amino acids, enzymes and chlorophyll.

Symptoms of Deficiency

As this element is highly mobile throughout the plant and older leaves show symptoms first. Leaves become pale green to yellowish then completely yellow before turning brown and falling from the plant. This chlorosis normally forms pattens associated with the veins and is some cases the mid rib turns purplish.

Possible Cause

Generally it is a result of a lack of nitrogen available in the soil. This can be attributed to insufficient nitrogen fertiliser or soil that has been leached from well-drained soil mixes. The nutrient may also be unavailable in waterlogged soils.

Similar symptoms may result from sudden cold weather, nematodes attacking the roots, waterlogged soils, excessive light or root temperature and mild sulfur deficiency (more obvious on new growth).

Toxicity from Excessive Use

The most common problem from excessive use of nitrogen is Ammonium ion toxicity.        

Plant Symptoms

Initially the roots die followed by rapid wilting of the upper part of the plant or the entire plant collapses. Interveinal chlorosis and marginal necrosis occurs on the leaves followed by premature leaf fall.

Possible Cause

Excessive application of ammonium based fertiliser containing more than 35% of nitrogen. Ammonium toxicity may also be attributed to poor nitrifying conditions such as poor aeration and cold conditions.

Storage of media that contains slow release fertiliser over a long period or the use of semi composted material that contains excessive urea leads to toxicity.

Phosphorus

This nutrient is essential in compounds that transfer or store energy that enables enzyme reactions to occur such as protein synthesis.

Symptoms of Deficiency

As this element is highly mobile throughout the plant the older tissue show symptoms first. The leaf surface loose sheen and appearing on the underside are bluish, red or yellowish pigments that tend to be along the veins. The older leaves fall prematurely and young leaves become stunted. Simular symptoms may be caused by cold weather, root problems or too much or too little moisture.

Possible Cause

Generally the result of a lack of phosphorus in the soil from under fertilising or excessive use of microorganisms in the soil.

Similar symptoms may result from cold weather, root problems or diseases and extremes in moisture.

Toxicity from Excessive Use

Toxicity commonly occurs to plants that require a low phosphorus soils such as Australian native plants, (Banksia, Protea and Grevillea species).

Plant Symptoms

The margins on young and old leaves turn brown or black resulting in leaf burn, eventually the leaf falls. It also induces zinc, copper, manganese deficiencies that are pronounced when the pH is between 5 and 7.

Possible Cause

When soluble phosphorus levels are high in the soil or commonly in soilless media where little phosphorous fixation occurs.

Potassium

This element is found abundantly in the plant aiding in enzyme systems such as photosynthesis, respiration and carbohydrate metabolism. It is also responsible for neutralising the organic acids in the plant.

Symptoms of Deficiency

As this element is highly mobile throughout the plant and older leaves show symptoms first, with chlorosis occurring between the veins and along the margins. Necrosis may appear at the leaf apex or on the margins and progresses towards the base. Leaves may also show no signs or symptoms and turn from green to brown.

Simular symptoms may result from the leaf drying out, wind damage, salt toxicity or excessive boron.

Similar symptoms may result the plant drying out or becoming too cold, wind damage, excessive salt in the soil, boron toxicity and certain pesticides.

Toxicity from Excessive Use

Excessive potassium is more commonly found in cut flower production or in container plants.

Plant Symptoms

Excessive potassium induces salt damage or calcium and magnesium deficiencies.

Possible Cause

Excessive application of fertiliser containing potassium, particularly liquid fertilisers.

Sulfur

This nutrient is a part of certain amino acid that form bonds which join strings of amino acids into proteins. It is not mobile and is normally seen in young tissue first unless the plant is nitrogen deficient. In this case the symptoms may be seen throughout the plant.

Symptoms of Deficiency

Generally younger leaves become yellowish or turning entirely golden yellow. They may also become cupped and deformed with interveinal chlorosis.

Possible Cause

Generally the result of a lack of sulfur in the soil due to insufficient fertilising or unavailability because of waterlogging.

Similar symptoms may result from mild nitrogen deficiency or iron deficiency, but in this case the veins remain green longer.

Toxicity from Excessive Use

Sulfur toxicity commonly occurs when applied to lower the pH of the soil, especially in potted plants.

Plant Symptoms

Soil may become very acid, which induces manganese toxicity. Waterlogged soils with high sulphur content induce copper, iron, zinc and manganese deficiency.

Possible Cause

Excessive applications of sulphur or sulfates such as ammonium sulfate and iron sulfate. It may also occur from irrigation water that is high in sulfates.

The Element Calcium

This element is required in cell wall structure and also acts as a detoxifying agent for micronutrients and organic acids such as oxalic acid.

It is not mobile and is normally seen in young tissue.

Zinc

This element is involved in hormone synthesis and in the enzymes that control carbon fixing in photosynthesis. It is not mobile and is normally seen in young tissue.

Symptoms of Deficiency

Generally a deficiency of Zinc causes young leaves to become smaller and particularly narrow giving them an elongated appearance. It also shortens the internodal distance producing leaves that appear to be arranged in rosettes and veins may become shortened causing the leaf to become twisted, or distorted forming a 'C' shape. Other symptoms include numerous side shoots towards the top of the branches, interveinal whitish necrosis and bronze coloured spotting on older leaves.

Possible Cause

Generally Zinc is unavailable in the soil as a result of high pH or high levels of excessive Phosphorus, particularly in high pH soils.

Similar symptoms may result from deficiency in Boron, Copper, Manganese or Calcium.

Toxicity from Excessive Use

Zinc toxicity may occur when soil mixes are composed poorly, particularly when the soil is too acid.

Plant Symptoms

Excessive zinc may induce iron deficiency and stunting or slow growth of the plant. Leaves may also become damaged.

Possible Cause

Zinc toxicity may appear in water that has been stored in galvanised tanks or associated with galvanised fittings.

The centre segment of the three body divisions of an insect. The wings and legs are appendages of the thorax.

When the twigs at the end of the branches turn brown in late winter, resulting from heavy snow and cold temperatures.

On the underside of the body.

Bearing live young.

When a plant is unable to supply enough water to the leaves, due to the soil being frozen. Normally occurring during warm early spring.