Cotton White Fly OR Whiteflies

Cotton Insect Pest WHITEFLIES

Common Name :Whiteflies

 Local Name : Pandhari Mashi

Scientific Name : Bemisia tabaci Genn.

Family : Aleyrodidae

Order : Hemiptera

Pest Category: Sap feeder

             A minor pest in many parts, cosmopolitan occurring as far north as Europe and Japan. An occasional pest that is widely distributed in our country (Bihar, Delhi, Haryana, Punjab, Rajasthan, and Maharashtra). It is a polyphagous pest that feeds on several crops like tobacco, cassava, cabbage, cauliflower, melon, mustard, brinjal, cotton and is important as a vector of leaf curl virus.

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Distribution and status:         India, Sri Lanka, Nigeria, Congo, West Africa, Japan, and Europe,

Host range:                             Cotton, Tomato, Tobacco, Sweet Potato, Cassava, Cabbage, Cauliflower, Melon,.   
                                                 Brinjal, and Bhendi.

ETL:                                          5-10 nymphs / leaf

Description of Insect Stages:

Life Cycle of White Fly in Cotton

Egg: 

          Eggs are yellowish-white laid singly on the undersurface of leaves. They are stalked and sub elliptical in shape.

Nymph: 

             Nymphs are yellowish and brownish, sub elliptical and scale-like. They are found in large numbers on the underside of leaves. Pupae also resemble nymphs in shape and have brownish opercula.

Adult: 

            Adults are tiny and white in color. They have a yellow body dusted lightly with a white waxy powder. Females are 1.1 - 1.2 mm long; males are slightly smaller. Antennae of females are longer than males. Hind legs are larger than the anterior pair of legs. Genitalia of females consists of outer and inner valvulae that are rounded. Parameres of males are extended, narrow and pointed. Large numbers of adults are found in the middle region of the plant.

White Fly in Cotton

Bionomics:

              An adult is a minute insect with a yellow body covered with a white waxy bloom.  Eggs are laid on leaves.  The egg period is three days.  Nymph is greenish-yellow oval in outline, along with puparium on the undersurface of the leaves.  A nymphal period is 5-33 days in summer, 17-73 days in winter.  

Nature of Damage:

         Whiteflies cause damage to cotton plants in two ways firstly by sucking the sap and secondly by excreting honeydew on which sooty mold grows. Damage from direct feeding reduces the photosynthetic activities of the plant and hence the yield. Indirect damage results from lint contamination with honeydew and associated fungi and through the transmission of leaf curl virus disease. Late season severity affects seed development and lint quality.

• Chlorotic spots on leaves.
• Yellowing of leaf leading to dropping of matured leaves.

  

  White Fly on Plant Leave in Cotton
• Vegetative growth is retarded, boll formation hampered.
• Shedding of squares and bolls.
• Bad boll opening in matured bolls and reduces the quality of cotton.
• Severe infestation after boll bursting makes the lint sticky due to the deposition of honeydew.
• It also transmits the leaf curl virus.

Symptoms:

          Leaves curl upwards and the plant vigor reduces. Leaves become shiny with honeydew or darkened by sooty mold growing on honeydew. Lint contamination with honeydew and associated fungi occur during heavy infestations after the boll opening

White Fly Adult Stage in Cotton

Life History: 

         The female whitefly lays the eggs singly on the undersurface of leaves and mostly on the top and middle crop canopy. Each female is capable of laying about 120 eggs. The incubation period varies from 3-5 days during spring and summer, 5-17 during autumn and >30 days during winter. The nymphs after hatching fix themselves to the underside of the leaves and they molt thrice before pupation. The nymphal period varies from 9-14 days during summer, and 17-19 days during winter. The pupal period is 2-8 days. The total life-cycle ranges from 14 to 107 days depending upon the weather conditions. There are about 12 overlapping generations in a year and the pest also reproduces parthenogenetically at times.
Whiteflies have an extremely wide host range.

White Fly Adult Stage in Cotton

          Eggs are laid on the undersurface of tender leaves in group and hatch in 3-5 days. The hatched young ones are called crawlers which are a flat move for a day or two and fix a place for feeding where it spends all its nymphal period. The further molting leads to reduced legs and sticks on to a single place for 9-14 days (summer); it is extended in winter up to 70-73 days. Normally pupal period lasts for 2-8 days with a total life cycle of 14-20 days depending on the weather & even life span extended up to 107 days in winter.

Nature of damage:

• Nymphs and adults suck the sap from foliage.
• They secrete honeydew on which sooty mold develops and interfere with photosynthesis.

Factors responsible for the incidence:

Generally infests the crop from November to February. The temperature around 30 ºC and high humid situations help multiplication of the pest. Dry season favors the incidence, but they disappear rapidly with the onset of rain.

Seasonal Dynamics: 

           The period of activity of whiteflies lasts from the emergence of seedling to the full-grown crop. During the end of the cotton season, the adults migrate to other crops such as crucifers, cucurbits, and malvaceous plants. They migrate to new season cotton crop as soon as it is in the field. High temperature and scanty rainfall situations aggravate the severity of the pest.

Pest Management Options: 

              Whitefly management should be achieved when their populations are at low levels through cultural practices. Maintenance of good field sanitation by destroying and removing the crop residues, and weeds is an effective practice against whiteflies. Growing vegetables in short periods and allowing maximum time between host crops of whitefly reduces its pest status on cotton. Combination of cultural practices and need-based insecticidal applications keep a check of whitefly populations. Repeated applications of insecticides during early and mid seasons lead to a resurgence of whiteflies, and hence a highly judicious chemical application is a must. Neem oil (1%), fish oil resin soap (2.5%) and neem seed kernel extract (NSKE) 5% give effective control of whiteflies. Triazophos 40 EC @ 600 g a.i./ha, Ethion 50 EC @ 1000 g a.i./ha and Acetamiprid 20 SP @ 30-40 g/ha is effective against whiteflies. More than 25% of leaf coverage by the whitefly pupae on the undersurface of leaves of middle plant canopy and flight of white adults visible on a single stroke of the plants should be used to decide the insecticidal applications. The severity of whiteflies is seen after the crop growth crosses 10 nodes on the main stem. Therefore, the amount of spray fluid while spraying the insecticides should be greater than 250 l/ha using power sprayers. Proper coverage of underside of leaves during the insecticidal sprays effectively reduces the whitefly population.

Management

1. Use white fly tolerant varieties like LK 861, Amravathi, Kanchan, Supriya, LPS 141
2. Treat 100 kg seeds with Imidacloprid 48 FS 500-900 ml or Imidacloprid 70 WS 500-1000 g Thiamethoxam 30 FS 1.0 L I or Thiamethoxam 70 WS 430 g


1. Timely sowing with recommended spacing, preferably wider spacing is essential, avoid late sowing.

2. Avoid the alternative cultivated host crops of the Whitefly (Brinjal, Bhendi, Tomato and Tobacco) in the vicinity of the Cotton crop.

3. Grow cotton only once in a year either in winter or summer season in any cotton tract.

4. Adopt crop rotation with non-preferred hosts such as sorghum, ragi, maize, etc., to check the build-up of the pest.

5. Remove and destroy alternate weed hosts like Abutilon Indicum, Solanum nigrum from the fields and neighboring areas.

6. Follow judicious Irrigation Management and Nitrogenous Fertilizer application to arrest the excessive vegetative growth and pest the buildup.

7. Monitor the activities of the adult whiteflies by setting up yellow pan traps and sticky traps at 1-foot height Also monitor through in situ counts.

8. Collect and remove whitefly infested leaves from the plants and those which were shed due to the attack of the pest and destroy them.

9 Spray NSKE 5% and neem oil 5 ml or fish oil rosin soap at 1 kg / 40 L of water (or) in combination with a recommended dose of insecticide (2 ml/L).

10. The use of synthetic pyrethroids should be discouraged/minimized to 2-3 sprays in cotton to avoid the problem of whitefly.

11. Avoid repeated spraying of synthetic pyrethroids.
Spray any of the following insecticides with 500 L water/ha.

·         Acetamiprid 20 SP 100 g	·         Fenpropathrin 30 EC 250-340 ml
·         Azadirachtin 0.15% 500-1000 ml	·         Fipronil 5 SC 1.5-2.0 L
·         Azadirachtin 5% 750 ml	·         Imidacloprid 17.8 SL 100 -125 ml
·         Bifenthrin 10 EC 800 ml	·         Profenofos 50 EC 1.0 L
·         Buprofezin 25 SC 1000 ml	·         Thiacloprid 21.7 SC 500-600 ml
·         Clothianidin 50 WDG 40-50 g	·         Thiamethoxam 25 WG 100 g
·         Diafenthiuron 50 WP 600 g	·         Triazophos 40 EC 1.5-2 L
·         Ethion 50 EC 1. 5-2.0 kg	·         Verticillium lecanii 1.15 WP 2.5 kg
·         Methyl demeton 25 EC 500 ml	·         Quinalphos 25 EC 2 .0 L
·         Phosalone 2.5 l/ha

White Fly OR Flies Live Video - https://www.agritechguru.com/2019/11/cotton-insect-pest-whiteflies.html