Life Cycle and Management strategies of Cucurbit Fruit Fly
Dr. Hadi Husain Khan1, Dr. Anjani Kumar2, Dr. Mohd. Monobrullah3, Habibul Haque4, Nirmal Chandra Ghose5 & Mofiul Islam6
1Research Associate, ICAR-DRMR-APART, Dhubri -783324 (Assam), India.
2ICAR-Agricultural Technology Application Research Institute, Zone – IV, Patna- 801506 (Bihar), India.
3Principal Scientist, Division of Crop Research, ICAR-RCER, Patna- 800014 (Bihar), India.
4District Agricultural Officer-Cum-Project Director, ATMA, Dhubri – 783324 (Assam), India.
5SDAO (HQ)-Cum-Nodal Officer, ICAR-DRMR-APART, Dhubri – 783324 (Assam), India.
6Deputy Project Director, CSS-ATMA, Dhubri -783324 (Assam), India.
Cucurbit Fruit fly, Bactrocera cucurbitae (Diptera: Tephritidae) is the most problematic insect of the cucumber group plants (cucurbits), which includes cucumber, bitter gourd, pumpkin etc. Cucurbits are infested by several insect pest which are considered to be the significant obstacles for economic production. Among them cucurbit fruit fly is serious pest responsible for considerable damage of cucurbits vegetables (Butani and Jotwani 1984). The cucurbit fruit fly can attack about 16 different types of cucurbit crops. Yield losses due to fruit fly infestation vary from 19.19 to 69.96 percent in different fruits and vegetables. (Kabir et. al. 1991). It attacks young and older stages. Maggots are found in infected fruits, which mean the fruits cannot be eaten. The female flies insert egg in to the young fruit. Hatching out from the egg, the larvae start feeding internal tissue of the fruit making the fruit for unsuitable for human consumption. The larvae remain inside the infested fruits. The female adult visit cucurbit fruits only to lay the eggs and the leave the fruits soon after egg laying.
Life Cycle :
The adult females lay eggs on the flowers as well as on fruits of the cucurbits crops. The females fly inserts its ovipositor in to the flowers or fruits and lay eggs by forward and backward movement of the abdomen. Eggs are laid singly or in clusters of four to ten. The number of eggs laid by an average female varies from 42-58. The eggs are white, cylindrical and slightly curved on one side and measure 1.3 mm in length and 0.4 mm breadth. The eggs incubation period varies from 18 hour in the summer season, the females lay eggs during the day under shaped condition, but they prefer evening to avoid strong sunshine.
Soon after hatching from the eggs, the young larvae, commonly called maggots, bore into the flower buds or in to the fruits and start feeding. The maggots become full-fed in about three days in the summer and two weeks in the winter. The full-fed maggots are 9-10 mm long and 2 mm broad across the thorax and are cream or pale white in color. The larval period lasts for 7-14 days.
The fully develop maggots come out from the fruit through one or two exit holes made in the fruit and pupate half to 3-inches deep in the soil depending upon the nature of the soil. The pupa is barrel shaped, light brown or pale in color. It is 11 segmented, measuring 5.5 mm in length and 2.0 mm in breadth. The pupal period is 5-8 days in the humid summer season and about three weeks in the winter months.
The adults emerge usually in the morning between 6-9 in the summer and 8-11 in the cooler months. The adult fruit fly in reddish brown with lemon yellow in clock having curved vertical marking on the thorax and fuscous shading on the outer margin of the wings. The female is easily distinguished by the presence of a tapering abdomen ending in a pointed ovipositor. The adults are active and capable of breeding throughout the year except during the cooler months of November, December and January when it is very cold. The fruit fly has several generations in a year.
Nature of Damage Fruit fly damage starts from March and ends in August or September. Female flies lay eggs inside the fruit. The eggs hatch and the maggots damage the fruit. Numerous maggots may be seen within infected fruits. After 7 to 10 days the maggot will drop onto the soil and pupate. The adult fly is pale yellow to brown with transparent wings that each have 2 spots on. Female adult fruit flies have a prominent ovipositor which is used for laying eggs in the fruit.
a. Maggots feed on the pulp of the fruits.
b. Oozing of resinous fluid from fruits.
c. Distorted and malformed fruits.
d. Premature dropping of fruits and also unfit for consumption.
1. Collect damaged fruits regularly and destroy them in a deep hole or soak in water mixed with a chemical insecticide.
2. Use of cue lure trap for cucurbit fruit fly.
3. Prepare a food bait to control the flies. Take yellow crushed ripened pumpkin and apply drops of Malathion 50 EC 0.1 % solution over it and keep it in different places on the ground near the crop.
4. Cover young fruits with newspapers or waste clothes initially if cultivating a small area or in a kitchen garden. The fly will not go into the shaded area under the newspaper or cloth so this will prevent the fly laying eggs.
5. If more than 10% of fruits are infected, spray with a mixture of Malathion 50 EC at 1 ml/litre of water and 20 grams of sugar or molasses.
6. Do not harvest within 7 days of spraying.
7. Treat the soil with Malathion 5 % powder 20 kg per during winter.
8. Deep ploughing in winter is recommended as this will damage pupae in the soil.
1. Butani, D. K. Jotwani, M. G. insects in vegetables. Periodical Experts book Agency. Vivek-Vihar, Delhi, India, 1984, 69-79.
2. Kabir, SMH, Rahman, R., Molla., MAS. Host plants of Dacinae fruit flies (Diptera: Tephritidae) of Bangladesh. Bangladesh. J Entomol. 1991: 1:60- 75.