Pests Management

Scale Insect

  • Go to Frequently Asked Questions about Scale Insect
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    Coconut Scale Insect is a small, flat, yellowish scale with a semitransparent or whitish, waxy covering.

    Eggs are laid under the scale cover and hatch into a stage called crawlers.

    The crawlers then move out from the scale and wander around the plant, or are dispersed by the wind, on clothing of people, or on the feet of birds and other flying animals.

    The female lays about 90 eggs over a period of nine days. The life cycle takes between 32 to 35 days to complete.

     

    PEST CONTROL MEASURES

    During the early stages of an outbreak, cutting and burning of affected plant parts may be effective.

    Cleansing with soap and water can be done on infested small trees and plants.

    Chemical sprays are only effective on the crawler stage of scales. However, control is difficult on other life stages. Use of appropriate systemic insecticides can be used.

    Pesticides should be used only when parasites are not economically effective. The application of pesticides may kill natural enemies of the scale and result in a resurgence of the pest.

     

    NATURAL ENEMIES

    Many species of predators and parasites have been reported attacking the scale insect.

    Several of these natural enemies have been successfully utilized to control outbreaks of this scale in other countries.

     

    OTHER PLANT HOSTS

    Coconut is the preferred host but also attacks other perennial species including many species of fruit trees, such as avocado, breadfruit, mango, guava, papaya, cocoa, cassava, cotton, oil palm, papaya, rubber, sugarcane and tea.

    This species is highly polyphagous and therefore can easily be re-introduced, even if it is successfully controlled on the primary host crop.

    Quarantine and border surveillance can restrict the pest spread through other host plants and planting materials.

     

     

    Frequently Asked Questions about Coconut Scale Insect Pest

     

    GENERAL QUESTIONS

     

    WHAT IS SCALE INSECT? HOW MANY KINDS ARE THERE?

    Scale insects is one of the leaf sucking family of pests. They can be distinguished from others as armored scale insects. They’re called Armored scales insects because they secrete a waxy round scale like protective canopy (cover) the edge of which is stuck to the surface of the host leaf, thus they are immobile.

     

    HOW DOES SCALE INSECT INFECT AND CAUSE DAMAGE TO COCONUTS?

    The scale insects feed continuously on sap from leaf or twig axils. They are known to infest a stressed host (due to temperature, weather changes etc.). Continuous feeding and exchange of toxins from insect mouth parts destroys the leaves. When infestation is high, the leaf gradually turns yellow, then turns brown, withers and drops.

     

    HOW TO KNOW THE EARLY SYMPTOMS OF CSI?

    Initially few round CSI scales (1-2 mm dia) can be seen on leaves where the crawlers have settled down to feed. These round scales look like a miniature “sunny -side-up” fried egg. They are the initial signs of infestation. They are difficult to notice since the coconut canopy is high above the ground, hence infestation goes unnoticed. However, they can be seen easily in seedlings if present.

     

    IF HOST PLANTS ARE SHOWING THE SCALES, HOW DO WE GET RID OF IT?

    When infestation is detected early (easily possible in seedlings) in form of round scales few in number, it is relatively easy to control. Leaf sampling must be done periodically (every 15 days) and inspected for visible armored scales (and/or soft scales/ mealy bugs).

    If on seedlings they can be physically wiped out from the leaf surfaces with soap/detergent water. If on the palm canopy a timely spray of detergent/insecticide/water or Horticultural oil formulations can be applied at appropriate time. Leaves must be continuously monitored and sprayed again if necessary.

     

    HOW DO WE PROTECT OUR CROP FROM SCALE INSECT?

    Be highly vigilant for the presence of the scale insect on coconut and alternate hosts.

    Sprays work well when eggs hatch and crawlers are emerging out of the protective scales, hence are vulnerable. Time your spraying to coincide with peak in crawler population. Introduce natural predators or parasitoids (specific wasps and beetles) in cases of mild infestations in addition to cleanups.

    Systemic trunk injections with suitable pesticide is preferable in medium or high levels of infestation. Do not transport infested plants and plant parts. Strictly observe quarantine in order to save your farm. Prune and destroy the infested lower leaves to reduce populations.

     

    HOW LONG DOES IT TAKE TO GET RID OF THE CSI?

    In very mild cases of infestation CSI is probably easier to control. Natural predators and basic spraying activities can help do it.

    Medium infestations if promptly attended to by treatments can reduce the pest populations within months. However, comprehensive data for Philippine conditions are still lacking or inadequate.

    A very high infestation may be difficult to eradicate. If coconuts are senile or near-senile, the best bet is to cut, safely dispose and replant the area with recommended varieties of coconut (Livelihood programs for income must be considered for affected farmers while waiting for next harvest…)

    Heightened awareness and strict adherence to quarantine is imperative to contain the pest.

     

    WHAT CAN WE DO ABOUT CASES OF VERY HEAVY INFESTATIONS AND AVOID SUBSEQUENT YIELD LOSSES?

    In cases of heavy infestation, leaf pruning and subsequent fertilizer application and when beyond recovery, replanting with high yielding varieties can be recommended.

     

    WHAT KIND OF INSECTICIDE WILL WORK AGAINST CSI?

    At present no registered insecticide for coconut exists in the country, however, there are insecticides used against scale for other crops, mostly the neo-nicotinoids, these are compounds chemically similar to nicotine, and are green labelled pesticides.

     

    WHAT KIND OF BIOLOGICAL CONTROL IS POSSIBLE?

    In other countries, the biological control agents reported are the coccinellid beetles as predators and wasps which can parasitize the scale insects known as parasitoids and currently, there are four types of predators and two types of parasitoids being mass-reared in PCA- managed laboratories in Lucena City in Quezon, and in Alaminos, Laguna.  There are other laboratories established by BPI and LGUs

     

    WHAT DO WE KNOW ABOUT THE INFESTING SPECIES OF CSI AND ITS LIFE CYCLE?

    The species known is Aspidiotus destructor endemic and a minor pest of coconut ever since, the newly reported, Aspidiotus rigidus, is invasive and causing outbreaks and not known to be present  before in the country, causing severe damage to coconut and mangosteen. They have with a life cycle of 32 days. Female body is highly modified and sedentary under the scale.

    Males develop under the oval scale and emerge with appendages and one pair of wings. They can fly, but are short lived, only to mate and die.

     

     

    TECHNICAL QUESTIONS

     

    HOW DOES CSI INFEST AND SPREAD?

    CSI occurs on a wide range of plant hosts. Infestation on coconut can occur from any nearby host source, where the pest is active, just by gusts of wind which carries and disperses the crawlers.

    Infestation may be connected to weather conditions and host stress.

    It can increase in number dramatically over a short period of time if conditions are conducive. Each female can lay 30 to 100 eggs which are protected under the waxy scale, thus the increase in population can be exponential.

     

    HOW FAST CAN THE CSI SPREAD?

    Studies on pest dynamics in CALABARZON conducted by PCA and collaborating agencies have revealed that, if unchecked, it is possible that from focus of infestation, CSI can spread up to 400 m radius every month depending on wind directions and speeds.

     

    HOW DO WE IDENTIFY THE PRESENCE OF CSI?

    The only way armored scales can be spotted is by regularly sampling a leaf (lower pinna of 9th frond of coconut palm is ideal sample during medium-high infestation) and visually checking for the presence of the typical round and oval scales.

     

    IS IT EASY TO SOLVE THE PROBLEM OF CSI? IF YES, WHY? IF NO, WHY NOT?

    Yes and No.   Scale insects rarely cause a major headache. They have been a minor horticultural problem usually and can be handled by natural predators or simple interventions. However, in the past disasters have been known to occur on a large scale (Indonesia, Fiji, Hawaii, etc) on coconuts due to certain species.

    Yes, the problem may be easier to solve if we are lucky to spot the scales early enough and do not neglect them. Prompt identification and treatment measures are imperative to their control. Prompt action with consistent monitoring is the key.

    No, in complex cases it may not be easy to solve. If the initial out- break goes unnoticed in remote locations in a highly suitable host and climatic conditions, spread can occur rapidly just by wind dispersal.  If noticed but inadequate steps are taken to counter, unforeseen resurgence can occur over a period of time (CALABARZON is a case in point).  Battle will be hard and drastic steps would be needed to save the coconuts.

     

    CAN CSI BE ERADICATED FROM SEVERELY AFFECTED COCONUT FARMS? WHAT ARE THE ODDS?

    It cannot be eradicated but it can be managed by trying to decrease the population level and prevent the infestation to reach the outbreak level and restrict the spread to other non-infested areas.

    There is some promising outcome at least coming from the active counter measures like leaf pruning, massive spraying of detergent, cochin oil, etc., followed by fertilization, that were conducted during 2012 and 2013 by the PCA in the affected areas of CALABARZON. In some areas, the affected palms are now seem to be recovering with green top young leaves visible. However, it still remains to be established if there has been a drop in the pest populations.

    The use of the systemic insecticide treatments on an area-wide application should be done to drastically lower the pest population at the level that the biocontrol agents can already prevent the increase in pest population and nutritional support to affected trees via fertilizer application to overcome the stress of pest infestation.

     

    HOW DO WE PREVENT THE SPREAD OF THE CSI TO NEIGHBORING BARANGAYS?

    Since wind is a means of dispersal, all neighboring barangays must be made aware of the risk. Vigilance and monitoring becomes imperative and prompt counter measures must be taken when cases are reported.  Information dissemination and public awareness of the devastating effect of the pest should be known to the coconut farmers for early detection and immediate action to avoid the increase in pest population and avert pest outbreaks

     

    HOW DO WE PREVENT PEST OUTBREAKS IN OTHER PARTS OF THE REGION/PROVINCE/COUNTRY?

    No infested material of any sort must be transported out of the affected zone. Quarantine must be strictly followed without fail. All Farmers must be made aware that entry of contaminated material in any form will endanger their own crop and contribute to spread.

     

    WHAT PREVENTIVE MEASURES CAN BE TAKEN TO AVOID INTRODUCTION OF CSI INTO NEW AREAS?

    Quarantine. Quarantine. Quarantine!

    It is better to be safe than sorry.

    It must be made sure that general awareness of the mode of spread and invasiveness of the CSI in order for the farmers to be convinced of the dire situations in case of pest incursion.

    Personnel manning the Quarantine Check-posts should strictly conduct their duties. They must actively safeguard the interests of the country.

    If and when new foci are discovered in other unaffected areas, a proactive approach for affording all protective actions as recommended by the authorities and experts must be promptly established by the Farmers and LGUs of the concerned areas.

     

    WHAT METHODS OF TREATMENT MAY BE EFFECTIVE IN CONTROLLING CSI? WHY?

    In slight infestation,  spraying soapy water/detergent /cochin then the massive releases of biocontrol agents ssuch as predator/parasitoids, this will prevent the increase in pest population

    In moderate infestation, trunk injection of systemic insecticides, as an immediate tactic to kill the current population and prevent further development of new pest generations and follow-up spraying of other contact oil-based or organic insecticides and releases of biocontrol agents after lowering the pest population .

    Leaf pruning of infested leaves and burning, in severe situation, then trunk injection with systemic insecticides, if there is recurrence, spot spraying with cochin or other oil-based sprayable can do the job.  Beyond recovery infested trees, cut and replant with high-yielding and early bearing coconut varieties.

     

    SHOULD WE URGENTLY INVEST ON R AND D TO LEARN MORE ABOUT THIS DEVASTATING PEST?

    Armored scales are very complex and bizarre insects with complicated genetics. Some species have a very high invasive potential, and owing to their size and habit, they are especially difficult to identify for untrained eyes, and hence is a known quarantine nightmare worldwide.

    There is a need to identify and document all the existing armored scale species in the Philippines, and update the existing database in the country. (66 species of Aspidiotus itself are listed until recently in other parts of the world).

    Recent advances in molecular phylogeny methods using DNA analysis approach has thrown light into the complexity of the family of this pest in general.

    Understanding the complex genetics of the local species will open up more avenues of identification, combat and control of invasive pests.

    This will help in preventing future outbreaks in coconuts and in other fruit crops.

     

    WHAT ASPECTS OF THE COUNTERMEASURES MUST BE EMPLOYED URGENTLY WITHIN CALABARZON /OTHER AREAS WHERE FOCI ARE DETECTED TO STOP INFESTATION? WHAT GUARANTEES CAN BE GIVEN FOR THE RESULTS OF SUCH PLANNED ACTION?

    An integrated pest management approach is a must and urgent:

    In severe situation use of systemic pesticide thru trunk injection and spot spraying of oil-based sprayables in case of recurrence.

    In moderate infestation, trunk injection and spraying

    In slight infestation, use of biocontrol agents

    These treated trees should be leaf pruned prior to treatment and should be fertilized after treatment.

     

     

    Brontispa

     

    The Brontispa popularly known as Coconut Leaf Beetle is an invasive pest that causes serious damage to both young and mature coconuts and ornamental palms, drying the young shoots and eventually killing the whole tree.

    Both larvae and adults are destructive, inhabiting the developing and unopened spear leaves of the coconut where they feed on the leaf tissues.

    Damage palms appear burnt at a distance.

    Affects all coconut stages in almost all coconut growing areas in the country

     

    NATURE OF DAMAGE

    The larvae and adult Brontispa live in the still-folded heart-leaf of preferably young palms, feed on the mesophyll of both surfaces of the closely oppressed leaflets, gnaw long incissions in the tissues leaving longitudinal white streaks.

    The narrow feeding scars enlarge to form irregular, brown blotches as the frond opens. The brown areas usually shrivel and curl, giving the characteristics scorched, ragged appearance.

    When the insects are numerous, the incisions are so close to one another that whole of the attacked part of the leaflets are similarly injured, and photosynthesis is reduced to zero.

    Severe attack by Brontispa can destroy palm leaves, restricts  growth and significantly reduce coconut yields.

     

    LIFE STAGES

    EGG (3-7 days)

    • Flat, surrounded by debris and excrement, laid in rows of 2 to 4 (sometimes singly)
    • 1.4 mm long,  0.5 mm wide

    LARVA (23-54 days)

    • Whitish when newly hatched later turned yellowish white with prominent caliper-like hooks at the hind end.
    • 8-10 mm long, 2 mm wide

    PUPA (4-6 days)

    • Limited movement, found in between surface of leaflet.
    • 9-10 mm long; 2 mm wide

    ADULT (60-220 days)

    • Two  colored, orange/ brown thorax  and brown to dark elytra
    • Nocturnal
    • Found in unopened leaflet
    • 120 eggs on the average
    • 7.5-10 mm long, 1.5-2 mm wide

     

    HOST RANGE

    Coconut*, Royal Palm*, Areca Palm, Betel Nut, Sago Palm, California Fan Palm, Mexican Fan Palm, Chinese Fan Palm, Fox Tail Palm, Alexandra Palm, Dwarf Date Palm, Nipa, Oil Palm, Nicobar Palm, Carpentaria Palm, Fish Tail Palm, Bottle Palm, Ivory Nut Palm, Several Cycads (*Preferred hosts)

     

    BIOLOGIGAL CONTROL AGENTS

    ENTOMOPATHOGENS (FUNGUS). Infect  the larva, pupa and adult of Brontispa

    • White Muscardine Fungus Beauveria bassiana
    • Green Muscardine Fungus Metarhizium  anisopliae

    PREDATORS. A general predator that preys on young larva  of the Brontispa

    • Earwig  (Chelisoches  morio)

    EGG PARASITIODS. Attack the eggs of the Brontispa. Solitary parasitoid (one parasitoid wasp develop inside a host egg)

    • Ooencyrtus sp.
    • Haeckeliana sp.

     

    LARVAL PARASITOID. Attacks the larva of the Brontispa. Gregarious parasitoid (many parasitoids develop inside a host larva)

    • Asecodes sp.

    PUPAL PARASITIOD. Attacks pupa of the Brontispa. Gregarious parasitoid (many parasitoids develop inside a host pupa)

    • Tetrastichus sp.

     

    OTHER CONTROL MEASURES

    Mechanical Control. Prune infested  leaves and destroy beetles especially in nursery seedlings and young  plantings

    Cultural Control. Plant covercrops, other leguminous crops and banana under coconut to enhance population of parasitoids and  predators (earwig) as they feed on nectars of these crops

    Chemical Spraying. Chemical spraying may be done on a case to case basis (feasible  only in nursery seedlings and young plantings) but not compulsory  especially when  the  biological control agents are numerous enough to minimize pest population.  This may not be feasible on tall palms.

    Trunk Injection. This can be done as an emergency measure to control Brontispa for tall and mature palms.

     

    FACTORS GOVERNING ABUNDANCE

    Large-scale availability of 2-3 year old coconut palms attracts the pest.

    Dry periods favour the development of Brontispa populations.

    The palms grown in poor soil, infested by aleurodids and other pests, inadequately maintained, etc., were more susceptible to attack of Brontispa.

    Poorly-grown palms with a less compact heart are more susceptible to Brontispa attacks.

    Strong monsoon winds are considered to reduce the influence of parasitoids and predators, which triggers the pest attack.