CONTROL OF THE
PINK MEALYBUG Maconellicoccus hirsutus
SOURCE: New Pest Response Guidelines - Pink Hibiscus Mealybug
Maconellicoccus hirsutus, USDA-APHIS-PPQ June 1997
The following is a list of suggested treatments that may be applicable under certain
conditions.
1. Biological and cultural controls should play as large a role in program efforts as
possible. It is
worth noting that mortality of larvae in large populations due to parasitization or predation may
be high.
This effect could be enhanced or augmented with other available means such as biopesticides,
mating
disruption, or cultural practices as listed below.
This technique is carried out by USDA, Agricultural Research Service and other agencies,
institutions, and
State cooperators. APHIS, PPQ is active in implementing classical biological control. The need
here would
be to find exotic natural enemies known to attack the PHM, which would be released and
established. This
would provide a permanent self-sustaining suppression of the pest population density below
economic
damage levels.
Individuals of two exotic parasite species and one predator species are currently being used for
control of the PMB: Anagyrus kamali and Gyranusoidea indica and
Cryptolaemus montrouzieri.
(Complete list of potential parasites and
predators)
c. Augmentation of Predators or Parasites in Infested Area(s)
This technique is applied by mass rearing of the most highly efficient parasites or predators for
mass
release in infested areas. It is generally used when natural enemies are absent, occur too late, or
are in
numbers too small to provide effective pest control when needed.
Where the PHM is new or is expected to occur in an area, inoculative augmentation may be
practiced with
the intention of establishing populations of its enemies through subsequent generations for
control.
(Driesche & Bellows, 1996)
Inundative augmentation by flooding a chosen area with large numbers of one or more natural
enemies is
intended to exert rapid control of the pest in the present generation (like a pesticide) and prevent
or bring
down possible damaging host losses.
d. Conservation of Predators and Parasites
This treatment refers to the conservation of natural enemies, native or introduced, through
integrated
procedures, highly selective predator- or parasite-friendly insecticides or techniques, biological
insecticides,
and cultural practices favoring predators and parasites.
(1) Trunk Injection
For woody hosts, trunk injection of selected insecticides will effectively curtail the pest population
attacking an injected host while protecting the predator/parasite population, except those
individuals which
may feed on or parasitize poisoned pests.
(2) Band Treatment
This treatment consists of the free application of insecticide to the tree trunk with a trunk
applicator or
paint brush. It is obviously less selective and somewhat more likely to endanger a
parasite/predator
population. However, the area of application is still out of the way of most parasite-predator and
prey
activity.
e. Chemical Integration
The direct application of selected chemicals to the host which are nontoxic or relatively nontoxic
to selected
parasites or predators which are also released in the area. Pesticides nontoxic to specific parasites
or
predators are listed below:
This treatment refers to augmenting the ability of predators and parasites to attack the host with
greater
efficiency or to be more tolerant of insecticides or other practices through selective breeding of
the most
efficient predators and parasites. Gene manipulation may also be involved. The work of Marjorie
Hoy (now at the University of Florida, Gainesville) in this area on genetic
improvement of natural arthropod enemies is instrumental to the concept, and her expertise
should be
consulted in designing any enablement program.
g. Ant Control
As an adjutant to biological control options, ant control measures may be required to prevent ants
from
protecting the PHM from parasites and predators. There are several types of options, depending
on the
situation.
h. Insecticides
The following are effective against the PHM. Specific information is mentioned, where possible,
under
each insecticide. Some compounds, such as growth regulators, should be preferred if they exhibit
little or
no toxicity towards any predators and parasites that may be present or introduced in an area.
Application of any of these compounds should take into consideration the life habits of the
mealybug to
include by spraying whenever possible and practical, protected habitat such as cracks in the bark,
in
crevices, between fruit clusters, under the calyx of the fruit and even under heavy, sooty-mold
encrustations.
Notes: Foliar applications may need to be mixed with surfactants to
penetrate the waxy covering of PHM,
unless otherwise specified.
The crawler stage is the most susceptible and sprays applied at times of most crawler activity will
be the
most successful in controlling the population.
Hosts with susceptible roots or tubers (potatoes, some grasses, peanuts, beans, cotton) may need
to be treated with granular formulations.
The ovisacs, which contain the eggs, are provided with additional protection as they are
composed of waxy
filamentous secretions and the natural body wax of the mealybug in addition to the sooty-mold.
The above suggests that a drench to the host is the best possible application. Depending on hosts
and
situations involved, however, a drench may not always be possible or practical.
Note: The PHM has demonstrated resistance against chlorinated
hydrocarbons years ago, including DDT
and toxaphene in 1951.
(1). Aldicarb
One application in soil of granular formulation at 50 gms per vine protects
grape bunches. However,
residues in bunches were not determined.
(2). Citrus Oil
Citrus oil was found to be 95 percent effective against the lst stage of the citrus mealybug
(Planococcus citri) at a rate of 74.8 L/ha. The authors suggested citrus
oil + chlorbenzilate at 2.24 kg Al/ha to control both citrus mealybug and citrus rust mite on citrus
and
to time the application for the first nymphal stage and yet be relatively safe to the natural enemy
complex. It is not known how the PHM will respond to this treatment.
(3). Dichlorvos
Dichlorvos is applied at a rate of 0.2 percent in combination with fish
oil rosin soap at a rate of 25 g/L
in a spray formulation.
(4). Safer BioNeem
This is a new botanical growth regulator with Azadirachtin as the active ingredient.
Generally, apply
8 oz. of product per 3,000 sq ft. It is not known how PHM will respond to this
treatment.
(5). Garlic Barrier®
This is a new botanical repellent for which mealybugs are listed as a target insect. Dilute
product in
water at a ratio of 100 product: 1 water. Use a fine spray mist by air or on the ground. One
application should be applied early in the season and three more about 3-4 weeks apart.
Advantages
are safety, low cost, and lack of odor. Disadvantages are unknown effect on the PHM and
repellent
effect to the PHM predator and parasite complex.
i. Cultural Control
(1). Bird predation
Should a resident bird population appear to effectively reduce the numbers of a targeted
pest, then the
bird population in question should be disturbed as little as possible. If it is felt desirable, the birds
can
be encouraged to increase in numbers through provision of food during winter months, the
protection
of nesting sites, and the discouragement of various bird predators or possibly, of diseases.
(2). Patch Complex
A variation of the above, especially for biological forest protection, involves the
employment of patch
complexes in which a number of areas are set up inside the entire control area to promote certain
ecological situations advantageous for control within the economic constraints of a program.
Inside
the patch (or area), a complex of increased natural diversity is encouraged. Methods include the
introduction of underwood species, increasing the provision of nesting sites for birds and the
encouragement or discouragement of ant colonies depending on their perceived role in either
protecting
or preying on the mealybug or natural enemies.
(3). Host Destruction
In situations with a very limited infested area and when the hosts are all herbaceous,
vinelike or
decumbent, consideration may be given to host destruction by herbicides; disking or plowing; and
removal and burial or incineration. In cases of such destruction, all host material must be
completely
destroyed.
(4). Sanitation
Sanitation in nurseries, farms, gardens, and other establishments where hosts are present
will be
carried out within the core and buffer areas. While it is impossible to completely clean out an
infestation by this means, the mealybug population can be reduced through trimming and pruning
of
twigs, leaves, branches, fruiting areas and even removal of plants, especially seriously affected
ones.
Whole trees, as the single most serious source of continued widespread infestations, should be
carefully cut to avoid scattering ovisacs and crawlers. In general, any cutting and pruning should
not
be done when strong winds or breezes are present as this will also scatter the various life stages of
the
mealybug while the work is going on.
Sanitation will also consist of the following measures, to be applied depending on the
circumstances
and equipment available.
(a) Burning of Debris
When PHM infested host material is collected, it may be piled into heaps and
burned if local
ordinances permit. The residue can be disked under or otherwise buried in an approved landfill.
Care should be taken not to unduly disturb ovisacs or crawlers which could result in scattering
eggs or crawlers so that they escape destruction.
(b) Animal Food
Some kinds of host material may be used as animal food. Any residue will be
disposed of by
burning or burial at an approved landfill. Unless food is processed, care should be taken not to
unduly disturb ovisacs or crawlers which could result in scattering eggs or crawlers so that they
escape destruction.
(c) Bagged and Buried
PHM infested host material may be collected in suitable containers and transported
to an
approved landfill. Care should be taken not to unduly disturb ovisacs or crawlers which could
result in scattering eggs or crawlers so that they escape burial.
(d) Vehicle/Outdoor Object Inspection/Cleaning
Vehicles, trucks, wagons, outdoor furniture, containers, and other things left
outdoors, that are
used in host fields, stands, orchards, woods, or yards within the regulated area must be inspected
to ensure that accidental movement of ovisacs, crawlers, or other life stages does not occur.
Cleaning consists of the removal and destruction of any ovisacs and mealybugs found, including
any substrate, such as leaves, twigs, flowers, buds, fruit on which they may occur.
(e) Host Inspection/Cleaning
In cases of limited infestations, an inspection of hosts or nearby nonhosts may turn
up suspect
ovisacs, crawlers, or other life stages. Cleaning the trunks and stems can do much to reduce the
infestation especially if done in autuirm after harvest time for the following year.
