1. Fruit flies:
- Important species:
- Bactrocera cucurbitae
- B. tau
- Family: Tephritidae
- Order: Diptera
- Distribution: India, Pakistan, Myanmar, Malaysia, China, Formosa, Japan, East Africa, Australia, Mauritius, Bangladesh, Sri-Lanka, Indonesia, Thialand, Philippines, Taiwan etc.
- Host plants: Melons, gourds, tomato, chillies, guava, citrus, pear, fig, cauliflower, cotton, sunflower, lettuce and other cucurbits.
Damage:
- The larvae feed inside the fruits
- Fruits become unfit for consumption and drop prematurely
- The young fruits can be destroyed in a few days,
- Older fruits show less symptoms, but on split opening, a mass of maggots in pulp is found
- In melons the infestation sometimes reaches up to 100 per cent
- Infested fruits are also attacked by microbes
Identification
- The maggots are apodous, dirty white
- Full grown maggot measures 9-10 mm in length and 2 mm in breadth
- The adult flies are reddish brown with lemon yellow marking on the thorax
- Fuscous areas on the outer margins of their wings
Life cycle
- Adult longevity is 14-54 days
- Each female on an average lays 58-95 eggs
- The incubation period is 1-9 days
- Larval period extends from 3 days in summer to 21 days in winter
- Pupal period is 5-9 days in summer and may be extended upto 30 days in cold weather
- Total life cycle is completed in 12-34 days
- There are several generations in a year
Salient features
- The flies hibernate during winter months
- Become active in hot weather and breed during monsoon.
- After mating it takes few days for eggs to mature inside the body
- Lay eggs inside the fruits singly or in groups of 4-10
- Freshly hatched maggots bore into the pulp forming galleries.
- Full grown maggots come out of the fruits and drop to the ground and pupate in the soil at a depth of 1.5-15 cm
Management
- Collection and destruction of infested fallen fruits regularly
- Frequent raking of the soil under the vine
- Ploughing the infested field after the crop is harvested
- Bait spray or bait stations
- Attractants/ lures
2. Hadda beetles:
3. Red pumpkin beetle, Aulacophora foveicollis (Chrysomelidae: Coleoptera)
- Distribution: Tropical, sub-tropical and temperate regions of the world
- Hosts: Cucurbits.
Damage:
- Both grubs and beetles are damaging
- Grubs feed on underground plant parts
- Beetles damage cotyledons, flowers and tender leaves
- Adults are very destructive particularly during the initial stage of crop growth
- Some times resowing is required
Identification:
- Adults are orange coloured, 6-8 mm long with black ventral surface clothed with hairs.
Life cycle
- Each female can lay 150-300 eggs
- The egg, larval and pupal period varies from 6-15, 13-25 and 7-17 days, respectively
- Total life cycle is completed in 1-2 months
- There are 3-4 generations in a year
Salient features
- Lay eggs, singly or in clusters of 8-9, in moist soil around the base of the plants
- Pupation takes place in oval, water proof earthen cells in the soil.
- Adults hibernate during winter in the soil
- Beetles resume activity during March and remain in the field till October
- Peak activity is in April-June
- September onwards, the population starts declining.
Management:
- After the crop is over, plough the field deep to kill the grubs present in the soil.
- Collection and destruction of adult beetles reduces the population.
- Spray of carbaryl 0.1% or malathion 0.05%.
4. Blister beetles
- Discussed under okra/ bean
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