By Alma L. Tingcang
PAGADIAN CITY -
Aspidiotus destructor, more
commonly known as the coconut scale insect is attacking coconut plants in
Batangas. It is less than 5mm long which secretes a waxy coating for defense
that resembles fish scales. Scale insects multiply faster in hot and dry
weather. Thus, the long dry spell in 2010-2011 that hit Southern Luzon,
particularly Batangas, allowed the scale insects to reproduce faster more
quickly.
The outbreak of the coconut scale insect in Batangas in October 2012 was
attributed to bad agricultural practices such as overuse or misuse of
pesticides on vegetables and fruit trees planted under coconuts. Pesticides
also kill natural enemies and without the natural enemies, insect pests are
free to multiply without control. A single female scale insect can produce as
much as 200-250 offspring, with a life cycle of 30 days.
Coconut is the preferred host of Aspidiotus destructor, although it is
also known to attack many species of fruit trees such as avocado, mango,
mangosteen, guava and papaya.
Its damage to coconut palms result in yellowing of the leaves
progressing to drying and wilting in young and old palms. Later, premature
nutfall occurs resulting to yield reduction. The scale insect also colonizes
the leaves, young and old fruits and petioles.
And the scale insect is now affecting 15 barangays in Basilan making our
area susceptible to infestation.
The Philippine Coconut Authority-IX has
devised ways to combat the onset of the attack through leaf pruning
since it reduces the reproduction of scale insects and prevent its spread to
other areas.
Washing coconut fruits with soap and water-infested fruits intended for
marketing such as buko or mature nuts is advised to remove the insects and
prevent its spread from farm to farm.
Spraying of insecticides and horticultural oils and local quarantine
regulations like avoiding the transport of infested plant parts, coco
planting materials and others that could result in the spread of the pest to
non-outbreak areas would be a wise move.
Another method is fertilizer
application that allows the palm to compensate for the loss in photosynthesis
caused by insect feeding and leaf pruning.
Scale insects having a soft body are susceptible to oil sprays. Instead
of using pesticides, oil sprays can be used but this is applicable only for
seedlings and young palms.
To better combat this infestation, biological control is the long term
solution. There are many known predators such as coccinellid beetles, most
common are chilocorus, pseudoscymnus,
scymnus and telsimia, lacewings and parasitic wasps.
PCA-9 Regional Manager Ralph S. Hamoy said these predators are reared in
a laboratory for eventual release in outbreak areas to augment the present low
levels of natural enemies.
PCA further advises that
palms will need to recover from the coconut scale insect infestation and regain
their former lever of productivity. Intercropping with cash crops and other
perennial crops including livestock integration under coconut is recommended to
sustain farm income and provide alternative livelihood sources while awaiting
recovery in coconut farms. (PIA9)