Insect Pests of Vegetable, Ornamental and Spice Crops (2+1)

Aphid and Sawfly

1. Rose aphid, Macrosiphum rosaeformis (Aphididae: Hemiptera)

Distribution: In India this aphid has been reported from rose from Punjab, Delhi, Mysore, Andhra Pradesh and Nilgiri hills

Host: Rose

Damage:

• The aphids suck the sap from the tender parts
• Particularly injurious to tender buds, resulting in the disfigurement and withering of flowers
• A black fungus also develops on the honey dew giving ugly appearance to the plant
• Deteriorates the market value the produce.

Identification:

• Small (about 2.5mm long) wingless aphids having large red eyes, black cornicles and a yellowish green tip of abdomen.

Life cycle:

• The pest is active from November to April in North India.
• Nymphal development of non winged forms is in 11-14 days and of winged forms in14-19 days.
• The growth is quickest in March.
• Population starts increasing from November and is highest during March.
• The population starts declining from April as the temperature starts increasing.
• There is an increase in winged forms from December on wards with peak in March (90% alates)
• The pest multiplies most rapidly in late spring and with the increasing in temperature its population declines.

Management:

• The pest can be controlled by spraying the crop with oxy- demeton methyl (0.025%) or phosphamidon (0.03%) or malathion (0.05%) as soon as the attack is noticed.
• Natural enemies like coccinellids, syrphids, chrysopids, etc. also take care of these aphids
• Avoid application of insecticides when these natural enemies are active.

2. Ground nut aphid, Aphis craccivora (Aphididae: Hemiptera)

Distribution: Through out India.

Hosts: Ground nut, rose, Bougainvillea spp and many other plants of economic importance.

Identification: Adults are black or brown with variable size

Damage:

• Both nymphs and adults suck the cell sap from tender plant parts.
• Downward cupping of leaves and premature drop of flowers.

Life cycle:

• The offsprings of winged form may be wingless.
• Reproduction is parthenogenetic and viviparous
• Each female can produce 8-30 young ones in a life span of 10-12 days.
• Nymphs pass through four moults and become adult in 5-8 days.
• Apterous females start producing brood within 24h of attaining the stage.
• Pest breeds throughout the year
• Both alatae as well as apterae forms are present.

Management:

• Same as for rose aphid

3. Rose sawfly, Arge fumipennis (Argidae: Hymenoptera)

Host: rose

Damage:

• Damage is caused by larvae
• feed voraciously on the leaves and cause complete defoliation
• Female makes an ovipositional slit on the stem and side branches with the help of saw like ovipositor

Identification:

• Newly emerged larvae are green in colour with black head and thoracic legs
• The adults on emergence are dull in colour which soon changed into shining black orange in colour.
• Males are lightly smaller in size than females.

Life cycle:

• The pest appears during first week of July with the onset of monsoon and remains active through out the rainy season
• Newly emerged larvae feed on leaves in groups
• Larval development is completed in about 15 days
• Five larval instars.
• Pupate in debris in protected silicon cocoons.
• Papul period lasts for 1-2 days.

Management:

• Apply malathion (0.05%) or carbaryl (0.1%).
• Repeat the spray after 10 days if required.