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Plant Health Brief
A Publication of the Agri-Food & Veterinary Authority of Singapore
May 2014
Comments:: The overall average thrips population was
almost the same- 7 thrips/trap as of April 14. One of
the farms recorded high incidence of thrips in all the 4weeks surveyed while the thrips incidence in all other
farms did not show much variation. Compared with the
same month last year, the population had changed
significantly downwards from around 14 thrips/ trap in
May 13 to around 7 thrips/ trap in May 14.
Comments:. The overall average Diamondback moth (DBM)
population has increased from around 22 moths/trap in April
14 to about 27 moths/trap in May 14. All the 4- farms in
Sungei Tengah area and one farm in LCK area have
recorded high counts of DBM. Compared with the same
month last year, the population was found to have increased
significantly from around 8 moths/trap in May 14 to 27
moths/trap in Mar 14.
SPIRALLING WHITEFLYALEURODICUS SP ON BUTTERCUP
TREE- COCHLOSPERMUM
foliage which causes premature dropping of leaves.
Direct feeding damage, even during heavy infestations, is
unlikely to kill plants. Indirect damage is due to the
accumulation of honeydew and white, waxy material
produced by the whiteflies (Fig.2) . The white waxy
material produced by the nymphs is scattered by the
wind and creates an unsightly nuisance. The honeydew
is fed by other insects and also serves as a substrate on
which sooty mold grows which blackens the leaf,
decreases photosynthesis activity and vigor and often
causes disfigurement of the host . The third type of
damage is the ability of this insect to act as a vector for
many viral diseases in plants. There are four immature
stages. The first three are referred to as “larvae” and are
continuous feeders. The first larval stage, called a
"crawler", is the only immature stage that is capable of
active movement. All other immature stages are
sedentary. The final and fourth immature stage is
considered the pupa of this species. This stage feeds
during the earlier stage and undergoes internal tissue
reorganization before molting into the adult. The pupal
RELIGIOSUM
Aleurodicus sp commonly called as the spiralling
whitefly has been recorded on more than 100
species. It is common to find this pest attacking many
vegetable, ornamental, fruit and shade tree crops
Specific plants that are attacked include, banana,
citrus, coconut, eggplant, guava,
mango, palm,
papaya, pepper, plumeria, poinsettia, rose etc., The
spiralling whitefly is a native to Central America and
the Caribbean region. Cochlospermum religiosum –
known as buttercup tree (Fig 1-2) was recently found
seriously infested with Aleurodicus sp . The spiralling
whitefly causes three types of damage such as direct
damage, indirect damage and virus transmission.
Immature and adult stages of whiteflies causes direct
feeding damage by piercing and sucking of sap from
stage serves as the basis for most of the taxonomic
PEST INTERCEPTIONS (MAY 2014)
identification. The pupal stage lasts for 10 to 11 days There was no pest interception for the month of May
with temperatures ranging from 20 to 39 deg C. The 2014.
adult whiteflies are similar in appearance to many
PESTICIDE INFORMATION
other species of whiteflies. They are white and quite
small, 2-3 mm in length and coated with a fine dust- COMMON NAME Diflubenzuron
TRADE NAME
Diflubenzuron 48% EC
like waxy secretion. Coccinellid beetles, and parasitic
wasps were used as bio control agents . Periodic
TYPE
Insecticide
fertilization of plants to improve plant vigor will help as
CHEMICAL
Belongs to benzoylurea group
the pest will attack only unhealthy hosts. Insecticides
NATURE
such as abamectin should be used.
FORMULATION
Soluable Concentrate
PROPERTIES
Inhibits chitin synthesis and
interferes with the formation of
insect cuticle. Non systemic insect
growth regulator with contact and
stomach action. Acts at the time of
insect moulting or at hatching of
eggs.
USES
Effective on a wide range of leaf
eating insects . Also controls larvae
of flies, mosquitoes, grasshoppers
and migratory locusts. Used as
ectopaarsiticde on the sheep for
control of lice, fleas and blowflies
larvae.
TOXICOLGY
Mammals: Oral LD50 for rats :
Around >4640 mg/kg
Fig.1.Spiralling whiteflies- Aleurodicus sp on Cochlospermum
Fish: Very mildly toxic to fishes and
religiosum
non- toxic to bees and predatory
insects .
DOSAGE
Around 0.25 ml to 1 ml/lit.
WITH-HOLDING
2-weeks
PERIOD
CONTACT US
Fig.2. A close up view of the spiralling whiteflies-Aleurodicus sp
on Cochlospermum religiosum
Please report any unusual occurrence of pests and
diseases (new or severe occurrence) to Plant Health
Laboratory, AVA. It would help to protect our plant
industry and the garden city from new invasive pests or
diseases. Please provide the location, plant hosts
attacked and suspected pests or diseases to our officers
to follow-up and confirm the situation if required You can
report
your
observations
through:
Email:
[email protected] or Telephone: 63165168
or 188 or Fax: 63161090 or
Visit us at:
http://www.ava.gov.sg/AgricultureFisheriesSector/Pl
antHealthServices/PlantHealthLabServices/index.htm