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===Introduction===
Insect pests and a number of diseases can attack and
damage palms and in extreme cases can kill them.
If the growing point of a palm is invaded by insects
or infected by disease the strength of the palm can be
greatly reduced, and if it is destroyed, the palm will die.
Cycads are less affected by pests and diseases, their tough
leaves are most vulnerable only during the stage that they
are emerging and before they have hardened up.

In the cool climates, attack on palms and cycads by pests
and diseases is not as much a problem as it is in tropical
climates where several generations of insects may breed
within one year and where there are a large number of
diseases that thrive in the warmth and humidity. This is
especially the case with fungal diseases. The cool climates
have the advantage in that during the cooler months many
species of insects go into decline and in some climates are
killed by cold. The marked separation of the seasons arrests
the spread of some diseases and gives one the time to keep
control.

Some pests and diseases are common to most countries, while
each country has some that are common mainly to it Therefore
mention of all of the types is not possible in this section.

===Pests ===
Insects and mites can attack palms and damage the new
growth causing the leaves to look unsightly. Older palms are
not attacked to the same extent as younger ones, or if they
are, the damage is less noticeable.

Insects generally fit into one of two catagories, those that
cause damage by sucking sap from the leaves and those that
cause damage by chewing at the leaves.

====Mealy Bug: ====
These insects are oval in shape, about 2 mm in
size, are grey, pale pink or pale yellow in colour and have a
white wax covering their bodies. They multiply rapidly into
large colonies that can often look like patches of white
fungus and feed by sucking sap from the leaves and stems.
They thrive in warm moist places and can live in the soil or
on the plant. If they affect the bud of a palm, new leaves
may emerge distorted They also have the tendency to colonise
on the underside or in the crown of cycads, again sucking sap.
Sometimes they may be associated with ants who feed on
honeydew that they produce. Mealy bug infestations can be
controlled by spraying with dimethoate.

====Mites And Spider Mites: ====
These sucking insects are usually
invisible to the eye and breed rapidly in warm dry conditions.
They can tend to go unnoticed until signs of their damage are
obvious. They colonize on the underside of palm leaves,
withdrawing the sap causing the leaves to go brown and die.
The European mite and the two-spotted mite are known to
invade not only the leaves but also the bud and crownshaft of
some palms, causing their growth to be arrested. Control is
achieved by spraying with dicofol or other specific miticides
often twice to break the insects breeding cycle.

====Scale: ====
There are many species of these pests that suck sap
from the leaves of palms and cycads. They can vary in shape
and colour and commonly encountered types are oval in shape
with armoured shells and sometimes waxy to touch, usually
visible and do not seem to move about. While many of the
types are specific to certain countries, some species, white
palm scale (Phenacaspis eugeniae), palm scale (Parlatoria
proteus), fern scale (Pinnaspis aspidistrae), soft brown
scale (Coccus hesperidum) and pink wax scale (Ceroplastes
rubens) are known to attack palms and cycads. Their damage is
greatest on palms and can cause yellowing of the leaves with
the infestation of sooty mould in shaded areas. Scale can be
controlled by spraying with maldison or dimethoate.

====Thrips: ====
A number of the species of thrips feed on dead
leaves or decaying matter while some will attack palms
causing considerable damage. They are small in size and
colonize on the underside of palm leaves chewing by rasping
and sucking the sap causing the leaves to develop
silver-white patches. The adults fly from plant to plant, lay
eggs and the young thrips feed on the plant then often move
into leaf litter at the base of the plant, develop into
adults then take flight to lay eggs again. They are
particularly prevalent after warm dry weather. Control by
spraying with dimethoate or maldison.

====White Fly: ====
These insects resemble tiny white moths and some
species attack palms infesting the underside of the leaves
and sucking sap from the plant Small infestations can be
controlled by hosing and if this is not effective it should
be sprayed with dimethoate or demeton-S-methyl.

====Caterpillars Of Butterflies And Moths: ====
Many butterflies and
moths do not feed at all but lay eggs that develop into
larvae and there are a large number of insect larvae referred
to as caterpillars which cause damage to palm leaves or
emergent cycad leaves by chewing or grazing on the foliage.
Many can be picked off the leaves or controlled by spraying
or dusting with carbaryl, maldison or pyrethrum.

Palms with a trunk growth form which are subject to caterpillar invasion can be protected by applying a tree band around the trunk and coating it in horticultural glue.

A strain of Bacillus thuringiensis (Bt) marketed by Yates as 'Dipel' provides targeted organic caterpillar control, killing caterpillars which eat leaves sprayed with the Bt solution while not harming beneficial insects.

====Other Chewing Insects: ====
Grasshoppers, locusts, earwigs,
beetles and their larvae can attack palms at certain times of
the year. They can be controlled with an insecticide such as
carbaryl or other types depending on the type of insect and
the country. Snails and slugs will attack some species of
palms, particularly ''Chamaedorea species'', moving up the
stems to feed on the leaves. They can be physically removed
or prevented by the use of metaldehyde or methiocarb pellets.

====Borers And Termites: ====
These insects are known to cause damage
to palms and cycads. Borers can bore holes in the trunks of
palms causing visible damage but do not threaten palms
particularly if they are healthy. Termites can cause major
damage to palms, attacking from below the ground and are
difficult to control In areas where they are prevalent,
prevention by destroying their nests is the best means before
they affect a plant They will also invade cycads that are
unhealthy, attacking the roots and trunks. Slaters behave
similarly, attacking unhealthy cycads, feeding on their stems
and any rot that may have developed.

===Diseases ===
Diseases are often difficult to identify and it is
common to mistake a nutrient deficiency as a symptom of a
disease. Cycads are relatively free from diseases and are
mainly susceptible to root rot if they are grown without good
drainage. Those diseases that commonly affect palms are
usually fungal or bacterial in type although viruses are also
known. Diseases can be spread by soil insects and human
contact and when they do occur it is important to burn any
infected parts of the plant once removed and avoid replanting
where a soil disease is known to be present. If potting soil
used to raise seedlings is infected because the seedlings
died from obvious signs of fungal attack wilt or rot, that
soil should not be reused for a new batch of seedlings
because it is likely that the disease will invade the new
seed or plants.

====Damping-Off: ====
This disease can be common for newly germinated
palm seedlings that are being raised in a greenhouse which is
warm, moist and has insufficient ventilation. The seedlings
may readily rot either soon after they germinate and before
they emerge or after they have totally emerged. Clean pots,
soil and seed will help to eliminate and prevent the spread
of organisms responsible for damping-off. Good ventilation
should be provided and in addition, fungicide sprays such as
benomyl or maneb can be used to reduce fungi.

====Bud Rot: ====
In palms, this term has also been used to mean Core
rot and Crown rot. The symptoms include wilting, yellowing
and finally death of the terminal bud of the palm, the
growing point, therefore death of the palm. Bud rot is caused
by fungus or bacteria entering the crown of the palm and the
infected tissue becomes a gelatinous mass. It can be caused
from physical damage as from hurricanes which damage the
growing point of the palm or from excess water sitting in the
crown allowing the entry of pathogens. It has also been
caused by insect damage to palms, such as severe attack by
mites that suck the sap from the plants, weakening their
growth so that new growth is also weak and fungi can enter.
It can be prevented after physical damage, or if it is
detected in its early stage, by pouring a solution of a
systemic fungicide such as benomyl or a general fungicide
such as copper oxychloride into the growing point.

====Wilt Diseases: ====
A fungal disease identified as Fusarium wilt
(''Fusarium oxysporum'') a soil inhabiting fungus that enters the
plant through the roots attacked 15% of the 3000
''Phoenix Palms'' in San Diego, USA in the early 1980s,
causing first the lower leaves to wilt and the palms to die.
Other palms such as

'' Syagrus romanzoffiana''
and ''Washingtonia species'' were immune to the disease
and not affected. Fungi of this type can remain in the soil
for a number of years developing in warm weather and can be
spread by tools and shoes. It can affect other palms planted
in similar localities and it is transmitted by pruning; all
tools should be sterilized between pruning trees.

====Root Rot: ====
Diseases in this class are caused by the fungi
''Phytophthora'' particularly in cold wet and soggy soils. Leaves
of the plant begin to turn yellow and it may survive to
warmer months to die in hot weather. ''Phytophthora cinnamomii''
or cinnamon fungus can attack ''Syagrus rornanzoffiana''
in soil that is too heavy and with poor drainage. If a plant
has suffered and died from this disease, it is important not
to replant in the same position unless the soil is treated
with metalaxyl. All parts of a diseased plant should be
removed from the site and buried or burned. Root rot has been
known to affect ''Washingtonia filifera'' in Arizona
during the 1930's causing a number of palms to die.

Cycads suffering from root rot should be dug out and washed
to remove all the soil. Any areas of rot should then be
removed with a sharp knife back to uninfected tissue and the
damaged area soaked in a strong solution (5g per litre) of
benomyl for at least 24 hours. The number of leaves should be
reduced and the cycad placed in a dry shady place for around
two weeks to allow it to callous and seal the wounds. It can
then be planted in well drained medium, watered and allowed
to dry out between each watering until signs of new growth
appear.

====Sooty Mould: ====
These black fungi can cover the leaves of palms
and cycads and have the appearance of soot The mould grows on
excretions of aphids, mealy bugs and some scale and it is
often called 'honeydew'. It may fall onto the plant from
taller trees infected by these insects. Although it does not
damage plants, it lowers their efficiency to use light and
photosynthesise. The remedy is to remove the source of the
insects producing the 'honeydew' and the mould will disappear.

====Rust: ====
Rusts are caused by fungi and are evident as yellow or
orange spots on the surface of the leaves. They do not
usually cause a more serious problem than to detract from the
overall appearance and can be treated by spraying with copper
oxychloride.

====Lethal Yellowing: ====
This disease was first reported in the
1800's and started to become widespread in tropical areas of
the Caribbean and Florida in the 1970's when it affected
Coconut Palms and had a devastating effect on coconut
production. It spread to Texas in 1978 affecting
''Phoenix Palms'' in the Lower Rio Grande Valley then
extended into Mexico. It was estimated that it spread at the
rate of 1-3 miles per month. It is caused by mycoplasma-like
organisms being carried from tree to tree by insects known as
planthoppers who inject the microbes from their saliva,
infecting palms as they feed on their leaves. New populations
of insects then pick up the disease from infected palms and
pass it on to others. Lethal yellowing generally kills a palm
within five months. First the leaves turn yellow and fall
until the bare trunk is left. The symptoms can be suppressed
by boring a hole in the trunk of a palm and filling it with a
tetracycline antibiotic. The treatment must be repeated every
four months as the disease reoccurs as soon as the treatment
is discontinued. The main method to prevent the disease from
depleting palms from an area is to introduce species
resistant to it. Coconut Palms are being replaced with
species resistant to Lethal yellowing.

===Chemicals For Pest And Disease Control ===
All chemicals for the control of pests and diseases should
be handled in accordance to the manufacturers directions and
should not be intermixed or stored mixed unless otherwise
advised. Their toxicity warnings should be heeded and the
appropriate protection used when they are being handled and
sprayed.

The following table lists the chemicals mentioned in the
section 'Pests and Diseases' giving some of the Trade names
used by manufacturers.

<br>

<center>
<table width=80% border=5 cellpadding=10><tr>
<td width=30%><b> Chemical Name</b>
<td width=70%><b> Trade Names</b>
<tr><td style="padding:5px">benomyl	<td style="padding:5px">Benlate&reg;, Tresan&reg;
<tr><td style="padding:5px">carbaryl	<td style="padding:5px">Carbaryl&reg;, Septan 80&reg;, Sevin&reg;, Bugmaster&reg;
<tr><td style="padding:5px">copper oxychloride	<td style="padding:5px">Cop-ox&reg;, Copperox&reg;, Cobox&reg;, Cupravit&reg;
<tr><td style="padding:5px">demeton-S-methyl	<td style="padding:5px">Metasystox&reg;
<tr style="padding:5px"><td>dicofol			<td style="padding:5px">Kelthane&reg;
<tr><td>dimethoate		<td style="padding:5px">Rogor&reg;, Roxion&reg;, Perfekthion&reg;
<tr><td>maldison		<td style="padding:5px">Malathion&reg;, Malathon&reg;
<tr><td>maneb			<td style="padding:5px">Manzate D&reg;
<tr style="padding:5px"><td>metalaxyl		<td style="padding:5px">Ridomil&reg;
<tr style="padding:5px"><td>metaldehyde		<td style="padding:5px">Defender&reg;, Snail & slug Killer, Blitzen&reg;</td></tr>
</table>
</center>

<br>

===Extracted from: ===
'''Palms & Cycads Beyond the Tropics''', Keith Boyer.

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