ལ༌ཡོངས༌ ོ་ཤིང༌ ང༌ ོབས༌ ེ་བ། · (quadraspidiotus...
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�ལ༌ཡོངས༌�ོ་ཤིང༌�ང༌�ོབས༌�ེ་བ།National Plant Protection Centre
Department of Agriculture Semtokha: Thimphu
San Jose Scale(Quadraspidiotus perniciosus )
Ento, leaflet 18
NPPC
Produced by:
Entomology Unit National Plant Protection Centre
Semtokha, Thimphu
Control measures: Badly affected twigs or branches
should be pruned and burnt
The most effective control for this pest is the use of Tree Spray Oil (TSO) in winter
TSO should be sprayed towards the end of February. Sticking to this pe-riod is important as TSO will cause phytotoxicity if sprayed later when the green buds have emerged.
The recommended dosage for TSO is: 30 ml of TSO in 1 litre of water OR 1 litre of TSO mixed with 35 litres of water. The above mixture should be sprayed thoroughly to a run off. A good coverage to all the twigs, branches and trunk is essential, making sure that the spray penetrates into the cracks.
Contact us:National Plant Protection Centre
Department of AgricultureMinistry of Agriculture and Forests
Semtokha, ThimphuP O Box: 670
Tel: +975-02-351016/351665Fax: +975-351656
Email: [email protected]: www.nppc.gov.bt
SJS on the stem
San Jose scale crawler
The Pest OrganismSan José Scale is scientifically belongs to the family of armoured scales. The tiny circular, greyish scales are just visible to the unaided eye. These insects are protected by thick, waxy, protective scale. San José Scale is an important localized pest in apple, often induced by indiscriminate use of pesticides. It has been recorded from all the apple-growing areas in Bhutan, but with varying degrees of infestation in different localities
Adult male San Jose Scale are minute, winged insects, about 1 mm long and golden brown in color .Female San Jose Scale do not deposit eggs, but rather produce live crawlers within 4 to 6 weeks following mating. A female may produce crawlers for 6 to 8 weeks at a rate of about 10 per day.
Life cycle The adult is a small insect that lives beneath a conical grey shell. Eggs are laid under the shell. During spring the young crawlers emerge from the shelter of the shell and find new locations on which to settle. In these new locations, they secrete a shell and do not move again. Young scales often settle on leaves and fruits initially and when older move to permanent locations on twigs. They are only mobile during the first few instars, the crawler being the dispersive stage.
The adult females are all permanently fixed to the plant tissue by their needle-like mouthpart. Twigs and branches may become completely covered with scales. This will lead to die-back of the affected parts and will ultimately cause decline of the tree. On fruits, the feeding site is, surrounded by a red circular spot. These spots are particularly noticeable on green or yellowish parts of the apple.
Adult San Jose Scale