Okra (Abelmoschus esculentus) is an annual vegetable crop grown in tropical and subtropical regions. Specific varieties are grown even in lower hills with moderate climate. Tender, green fruits are cooked in curry and soup. The root and stem are used for clearing cane juice in preparation of ‘gur’. High iodine content of fruits helps control goitre while leaves are used in inflammation and dysentery. The fruits also help in cases of renal colic, leucorrhoea and general weakness. In India, the crop has not adapted as leafy vegetable as in Far East countries. It has yet multiple uses. The dry seed contains 13–22% good edible oil and 20–24% protein. The oil is used in soap, cosmetic industry and as vanaspati while protein is used for fortified feed preparations. The crushed seed is fed to cattle for more milk production and the fibre is utilized in jute, textile and paper industry. Uttar Pradesh, Bihar and Orissa are major okra-growing states in India.

Major Insects and  Management

Leafhopper - Amrasca biguttula biguttula:

Symptoms

This pest attacks the crop at its early stage of growth. Small, greenish leaf hoppers; nymphs and adults are found on the underside of the leaves. The adults and the nymphs suck the cell sap from the leaves. As a result the leaves curl upwards along the margins and have a burnt look which extend over the entire leaf area. The affected plants show a stunted growth.

Control:

Soil application of Carbofuran 3 G (1 kg a.i./ha) at the time of sowing effectively controls the pest. Spraying the crop with Monocrotophos (0.05%) at fortnightly intervals starting with the appearance of the pest provides a good control.

Shoot-and fruit- borer - Earias vittella:

Symptoms:

The incidence of fruit borers usually occurs during humid conditions after the rainfall. The adult female lays eggs individually on leaves, floral buds and on tender fruits. Small brown caterpillars bore into the top shoot and feeds inside the shoot before fruit formation. Later on they bore into the fruits and feed within. Bored fruits have larvae inside or filled with excreta. Affected fruits become unfit for consumption.

Control:

The infested fruits and shoots should be removed regularly and buried deep in the soil. Spraying with Quinalphos 25 EC (2 ml/litre of water) or Carbaryl (4 g/litre of water) effectively controls the pest. Before spraying all the affected plant parts should be removed.

White fly - Bemisia tabaci:

Symptoms:   

The milky white minute flies; nymphs and adults suck the cell sap from the leaves. The affected leaves curl and dry. The affected plants show a stunted growth. White flies are also responsible for transmitting yellow vein mosaic virus. Losses may be even 80–90%.

Control:

Soil application of Carbofuran (1 kg a.i./ha at the time of sowing and 4-5 foliar sprays of Dimethoate (0.05%) or Metasystox (0.02%) or Nuvacron (0.05%) at an interval of 10 days effectively controls the whitefly population.

Aphids  : Aphis gossypii:

Symptoms :    

Colony of aphids on young leaves and fruits can be seen.

Control:

Destroy affected parts as soon as infestation is noticed. Apply Monocrotophos, Phosphamidon, Dimethoate, Methyl demeton (0.05%) 20 and 35 days after sowing. Repeat again, if necessary.

Mites Tetranychus cinnabarinum:

Symptoms :

The infestation of mites is mostly observed during the warm and dry periods of  the season. Nymphs and adults suck cell sap and whitish grey patches appear on leaves. Affected leaves become mottled, turn brown and fall.

Control:

Spraying with Wettable Sulphur 80 WP (2 g/ litre of water) or Dicofol 18.5 EC (2.5 ml/litre of water) or wettable sulphur (2 kg/ha) effectively control the mites. 

Okra Stemfly Melanagromyza hibisci:

Themaggots of this fly attack 15-30 days old plants causing nodulated galls and swellings. At later stages, the maggots of this fly damage the petioles resulting in complete defoliation of the affected plant.

Control:

Application of Carbofuran or Phorate @ 1 kg a.i./ha protects the main stem from the pest attack during the seedling stage.

Root-Knot Nematode Meloidogyne incognita:

The root-knot nematode enters the roots causing characteristic root knots or galls. The aerial symptoms consist mainly of stunted plant growth and yellowing of leaves. Nematode attack in the seedling stage leads to pre- and post-emergence damage resulting in reduced crop stand.

Control:        

Cultural control methods such as rotation with non-host crops such as cereals, fallowing and deep ploughing 2-3 times in summer months is recommended. Application of Nemagon (30 litres/ha) with irrigation before sowing is recommended to protect the seedling in its early stage of plant grow

Conclusion:

Farmers grow okra to produce the pods which they utilize as a vegetable or sell to earn income. It can be concluded that since the insect species found damaging okra pods in this study affected the yield of okra directly; they were among the most serious pests of the crop. It can also be concluded from this study that insect pest species can cause over 80% pod damage on highly susceptible cultivars. Therefore it is recommended that pest control measures should be applied to prevent serious damage on okra pods. The varietal differences in susceptibility can be utilized to select those cultivars that were least susceptible for use by farmers in an integrated pest management strategy against specific species.

References

Dabire-Binso, C.L., Ba, M.N., Some, K. and Sanon, A. (2009) Preliminary studies on incidence of insect pests of okra, Abelmoschus esculentus (L.) Moench in central Burkina Faso. African Journal of Agricultural Research 4:1488-1492..

Singh, R. and Joshi, A.K. (2003). Pests of okra (Abelmoschus esculentus Moench.) in Paonta Valley, Himachal Pradesh. Insect Environment 9:173-174.

Soares, J.J., Silva, M.S., Melo, R. and De, S. (2006). Effect of planting date on the production and occurrence of pests in the cotton (Gossypium hirsutum). Acta Scientiarum-Agronomy 28:337-343.

Sumathi, E. (2007). Seasonal incidence of sucking pests and fruit borers of bhendi. Journal of Ecobiology 19:15-8.

Munthali, D. C. and Tshegofatso, A. B. (2013). Major insect pests attacking okra; Abelmoscus esculentus (L) Moench, in Sebele.Bots. J. Agric. Appl. Sci. 9 (Issue2) xx-xx.


Authors:

*Mahendra. K. Choudhary, Dr. Kavita Aravindhakishan1 R. K. Jat2 and N. Jat2

1College of Horticulture & Forestry, Jhalawar

2Rajasthan College of Agriculture, Udaipur

Maharana Pratap University of Agriculture & Technology,

Udaipur- 313001, Rajasthan, India.

*Email of corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.