Jasmine is an important flower crop grown on a commercial scale. It is often seriously affected by a mosquito like insect called the blossom midge.
Due to its attack, the base of the flower buds get swollen, deformed, discoloured into pink or purple colour and drops prematurely.
Pest biology
About 100 minute eggs are deposited into the open tips of young flower buds by the adult female. Within 24 hours maggots emerge from the eggs and move into the buds.
With their rasping mouth parts as they feed the open flower buds, the larvae inject some toxic substances which induce swelling, malformation and colour change of the blossom.
The colour of the maggot ranges from white in the early sage to pink in the later stage.
Maggots mature in 5 to 7 days inside the buds and flip into air to exit the flower buds and burrow into the soil for pupation by spinning a cocoon.
Pupal period
Pupae are light yellow in colour. The pupal period ranges from 12 to 21 days according to the environmental conditions.
Adult midge emerges from the soil surface in due course of time but survive for only 4 days.
Entire life cycle is completed in 21 to 28 days under optimum conditions.
Management methods
Collect and destroy fallen and discoloured flower buds.
Maintain sanitation of the jasmine garden with good drainage facilities.
Avoid planting of alternate host plants such as tomato, brinjal and bitter gourd around the main cropped area.
Rake the soil to kill the pupae in the ground. Prune the bushes during winter.
Setting of light traps or sticky traps would also be helpful in controlling this pest.
Spraying of monocrotophos 36 WSC or profenofos 50EC at 2 ml/lit, acephate 75 SP or carbaryl 50WP at 2gm/lit and neem seed kernel extract 5 per cent.
Soil application of carbofuron 3G at 30kg/ha Drenching the soil surface with chlorpyrifos 20EC at 5ml/lit may also prove effective.
J. Jayaraj & S. Manisegaran,Agricultural College and Research InstituteMadurai
