Management of watermelon aphids
MELON APHID, Aphis gossypii, is a predominant aphid species, which attacks watermelon during spring time.
Melon aphids occur in clusters near the terminal growing points of the developing vines and congregate on the lower surface of the leaves. They feed by sucking the sap from the leaves and cause curling of leaves. Infested leaves appear wrinkled. Severe damage results in stunted plant growth, yellowing and wilting of the entire plant.
Sooty mould
They secrete a large amount of honeydew upon which sooty mould growth occurs. This growth disrupts the photosynthetic activity, which in turn reduces the yield.
Greenish brown female aphids reproduce at the rate of about 22 young ones per day. Green colour nymphs mould four times a day at each stage lasting 1-3 days. Adult melon aphids are soft bodied and pear shaped. It takes about 7 to 9 days to complete the entire life cycle.
Pest management
Remove the alternative host plants. Infested crops should be destroyed immediately after harvest to prevent dispersal of aphids.
Crops that are grown down-wind from infested fields are especially susceptible because of aerial passive dispersal.
Setting up of yellow sticky trap at 50 numbers per hectare in the field will check the aphid menace and also help in monitoring the pest.
Spraying dimethoate 30 EC at 2 ml per litre of water or methyl demeton 25 EC at 2 ml per litre of water or endosulfan 35 EC at 2ml per litre of water at 30, 45 and 60 days after sowing will protect the crop.
V.RADHAKRISHNAN
K. NATARAJAN & L. ALLWIN
Tamil Nadu Agricultural University,Coimbatore
Tamil Nadu
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