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Sunday, December 16, 2012
AAB monitoring device, cultural practices and chemicals for management of mango tree mortality
By Dr. R. D. Khuhro, Dr. S. M. Nizamani, M. M. Jiskani and M. A. Talpur
Faculty of Crop Protection, Sindh Agriculture University Tandojam
Mango, Mangifera indica is one of the important fruits of Pakistan which is exported to many countries such as Dubai, Saudi Arabia, UK, Germany, France, Holland, Switzerland, Italy, Singapore and Malaysia. It is known as “King of Fruits” and is consumed both by poor and rich people in various forms. Mango is grown is tropical and sub-tropical countries of the world. In Pakistan, it is grown on large acreages of Sindh and Punjab provinces. There are numerous varieties of mango, each differing in fruit characters such as taste, flavour, colour, tinge, shape and size which determine the quality of the fruits and market value at home and abroad (Jiskani, 2002).
Mango tree plant suffers from
various insect pests and diseases. Among insects, mango hoppers, fruit flies,
thrips, scales, stem borers, shoot borers and mites are reported (Talpur and
Khuhro, 2003; Soomro, 1988). Similarly, various diseases caused by fungi such as
Fusarium, Aspergillus, Botryodiplodia, Penicillium
and Colletotrichum are also reported on mango (Hafiz, 1986; Ramos
et al., 1991 and 1997; Wagan et al., 200; Al-Adawi, 2005).
During 2002-3 in Pakistan and Sindh, the mango was grown over an area of 102.8
and 46.5 thousand hectares and the production was 1034.6 and 335.9 thousand
tones per hectare, respectively (Agha, 2004). Currently, mango trees are dying
suddenly at the rate of 2-20%, depending upon severity of disease and management
by the owners of mango orchards.
Causes
Asian ambrosia beetle (ABB) is
considered as the primary cause of the mango mortality followed by different
species of fungi. Basically, this is a management problem. The owners of mango
gardens give their gardens on contract and forget about care of the garden
whereas, contractors don’t apply proper fertilizer, cultural and plant
protection practices as per requirement of the gardens. In this way, the problem
of mortality in mango is multiplying. If this, scenario remain constant, we
shall end up with mango cultivation and loose export exchange in next few years.
The mango growers are warned to expend at least 10% of their income on
management operations for the sustainability of mango fruit in their own
interest and country at large; therefore, garden owners must not depend on
contractors.
Characteristics of
AAB
The Asian ambrosia beetle (ABB)
has stout dark reddish-brown body and is reported as pest on broad host range
including woody ornamentals, fruit and nut trees (Atkinson et al., 1988;
Kovach, 1986). Schedl (1962) reported 124 hosts of ABB. The beetle has been
collected and identified from various samples taken from dead or partially dead
mango trees, Shisham, Gold Mohar, Gular, Neem, Eucalyptus, Siris
Albizzia lebbek, rubber plant and Casia fistula from various
ecological zones of Sindh. Only females have wings and disperse with small
movement from infested and dead mango trees, wood logs/pieces and by its own
short movements. These beetles are so tiny that initially attacked trees, don’t
show symptoms. In case of severe infestation, the
small pin head sized holes appear with the inside and outside movement of beetle
on bark. The beetles excavate galleries in the branches, trunks, roots and
twigs. The beetles introduce fungi complex in the mango tree and lay their eggs
in clusters. In some mango trees no holes in bark appear but black spots on the
basal parts of trunks are present. After cutting those barks, the light yellow
paste with bad odour watery secretion flows. The beetles are also present in
infested black basal part of the trunk. The gum like secretion/drops
commonly known as gummosis oozes out from holes of trunks/branches of mango
trees infested with beetle. The “C” shaped, legless, white grubs of beetle are
found feeding on inner darkened portion of barks. From the infested trunk of the mango
tree, the frass of the beetle is pushed out of galleries, in a typical
tooth-pick fashion.
Management:
A. Asian
ambrosia beetle monitoring device
· Various research experiments have
been conducted and are in progress at Sindh Agriculture University, Tandojam
under Mango Research Project sponsored by Higher Education Commission,
Islamabad. On the basis of these preliminary experimental results, it is
suggested that apply sticky traps of 1sq.ft. size by pasting grease on plastic
sheets (coated over cloth) at the rate of 10-15 traps per acre at the height of
1-3 ft from ground level for catching the winged female beetles. It was also
observed that green colour sticky trap attracted more female beetles followed by
black and other colours.
B. Cultural
· Regular monitoring of mango gardens
for bark beetle and development of decline symptoms is compulsory.
· Prune diseased branches along with
4-5 inches of healthy portion with saw and apply bordeaux paste at the rate of
1:1:10 (1kg CuSO4+1kg lime+10 liters of water)on the cut points in
July-August.
· Removal and burning of diseased/dead
mango trees including roots.
· Avoid wounding the trunks and roots
during pruning, inter-culturing and fruit picking. In case of wounds, Bordeaux
paste may be applied.
· Plowing/inter-culturing and other
sanitation practices followed by pruning of gardens in July-August.
· Soil testing is compulsory for
application of proper chemical fertilizers. Zinc sulphate and other macro and
micro nutrients may be incorporated on the basis of soil testing.
· Proper irrigation application as and
when required but not on the basis of availability of water.
C.
Chemical
· Apply Lorsban 40 EC or any other
systemic insecticide in combination with Alliete fungicide just after fruit
setting.
· The same spray may be repeated at
the interval of 15-21 days.
· Apply 3rd spray in
September/October.
Method
of application
· Generally foliar pesticide is
carried out but in this case washing of trunks and branches through spraying or
similar to white wash is suggested.
The same pesticides can also be
applied by drilling followed by injecting in main trunk and its primary branches
deep up to 6".Sorce: http://www.pakissan.com/english/advisory/aab.monitoringm.device.shtml
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