Dusky Cotton Bug Life Cycle in Cotton Crop

Dusky Cotton Bug Life Cycle in Cotton Crop

Common Name: Dusky cotton bug 

Local Name: Bhurke dhekun

Scientific Name: Oxycarenus hyalipennis Costa.

Family:  Lygaeidae

Order: Hemiptera

Pest Category: Lint Stainers

Distribution and status:            Africa, Egypt, Indian, China, and the Philippines. Minor pest but regular in occurrence.

Host range:                                Cotton, Bhendi, Hollyhock, and other Malvaceous weeds.

Description of Insect Stages:

Egg: 
          Eggs are cigar-shaped and whitish immediate to oviposition. They turn pale than to pink before hatching.

Dusky Cotton Bug Life Cycle in Cotton

Nymph: 

          Early instar nymph is about 2.5 mm long with its rostrum extending the abdomen. They are orange in color when about to molt. After the first molt, the nymphs become reddish-brown then become darker after each molt.

Adult: 

           Adults are 4-5 mnt elongated with pointed heads, dusky brown with dirty white transparent wings and black spots on the forewing and having deep red legs.

Bionomics: 

            
           The adult is a small flat bug, dusky brown in color.  It lays cigar-shaped, white eggs in clusters of 2-10 within the half-opened bolls, on the bolls, flower or buds.  The incubation period is 6-10 days.  The nymphs undergo five instars.  The nymphal duration is 30-40 days.

Nature of Damage:

                Nymphs and adults suck the sap gregariously from immature seeds that do not ripe, remain lightweight. Adults found in the lint get crushed during ginning emitting a bad odor and stain the lint.

• Nymphs and adults are damaging
• Suck the cell sap from leaves and fruits
• Reduces the vitality of the plants

Symptoms:

              Being associated with the open bolls, they cause a nuisance to workers during cotton picking. Discoloration of the lint with a large number of nymphs and adults of brown to black color is common.

Dusky Cotton Bug Adult Stage in Cotton

Life History:

             Egg and nymphal period last for 7 and 26 days, respectively. Nymphs molt 6 times before reaching the adult stage. Development is completed in 40-50 days. It appears late in the season of the cotton crop.

Seasonal Dynamics of Stainers:

             Red cotton bug appearance on cotton is after the commencement of the first open boll in the cotton fields. the dusky cotton bug appears on cotton is when the majority of bolls on the crop are open. As they occur at the end of the crop season and the loss caused have been minimal, not much attention has been given to the counting their numbers than describing their status as low, medium and high. Usually, the insecticides that were applied during the mid to late seasons against bollworms suppressed their population effectively. However, with the reduced insecticide use against bollworms in the 21 century and the large-scale commercial cultivation of Bt transgenic cotton hybrids has led to an increase in the population of these red cotton bugs. No estimates are available as on date to specify the degree of lint quality loss caused by these red cotton bugs but might deserve attention if their severity rises in the future.

Pest Management Options:

                              The initial population of red cotton bugs has been found to be susceptible to all the insecticides used for pink bollworm control. Since they appear very late in the crop season their management is not attended to. However, with the changing pest scenario on cotton and with the severity of stain on the increasing trend, it is necessary to take proper care with the onset of the population. Dislodging the gregarious population of the stain on the bolls into a vessel containing water with a thin film of kerosene is recommended as the late-season insecticidal application leave residues in the harvested produce besides being uneconomical.

1. Spray phosphamidon 40 SL 600 ml/ha
2. Chlorpyriphos @ 1000ml per 100 litres of water