• In India, whitefly was first recorded on cotton at Pusa (Bihar) during 1905 and assumed the status of a serious pest on cotton in Punjab in the 1930s
• Major outbreaks of whitefly were noticed in different cotton growing states in India namely undivided Punjab (1930-43), Andhra Pradesh (1984-87), Tamil Nadu, Maharashtra and Karnataka (1985-87), Gujarat (1986-87) and Punjab (1996)
• The introduction of synthetic pyrethroids (insecticides) in cotton to control bollworms in early 1980s favoured whitefly multiplication. So it was recommended that pyrethroids should not be used for more than two sprays on desi cotton (arboreum) and more than three sprays on American cotton (hirsutum)
• Economic threshold level (ETL) of whitefly (6-8 adults per leaf in the upper canopy of plant before 10.00 a.m.) was established for application of insecticides for the management of this pest
• Over the years, whitefly has created a niche in agroecosystem and has almost become a pest of regular occurrence in all the cotton growing areas of North-West India

Activity period: May to October

Peak activity period: July to September

Distribution in State

• Whitefly is distributed throughout the northern and western regions of the Indian sub continent and it is very serious pests of American cotton, particularly in dry areas
• In Punjab it occurs frequently in the districts of Bathinda, Fazilka, Mansa, Sri Muktsar Sahib, Faridkot, Sangrur, Barnala and Moga in cotton and other host plants
• Khuhian Sarwar block of Fazilka is generally considered to be the hot spot for whitefly. The whitefly generally observed first in certain pockets of district Fazilka like Khuhian Sarwar, Abohar and Fazilka and spreads further to adjoining regions under favourable weather conditions
• However, moderate incidence of whitefly is recorded in districts like Barnala, Moga, Sangrur and Faridkot

Important Host plants of Whitefly in Punjab

It is a polyphagous pest and feeds on about 600 plant species throughout world.

Field crops: Cotton, moong, mash, soybean, arhar, guar, sarson, toria

Vegetable crops: Brinjal, cucurbits (pumpkin, toria, melon, summer squash), okra, chilli, potato tomato, raddish, cabbage, cauliflower etc.

Weed host plants: Peeli buti (Abutilon spp), Kangi buti (Sida spp), Puth kanda (Achyranthes splendens), Button buti, Makoh, Wild sunflower, Dhatura, Gut putna etc.

Nature of damage

• Both nymphs and adult suck the plant sap by feeding on the undersurface of leaves
• Chloratic spots develop on leaves which drop prematurely. It also cause stunting of plants, shedding of fruiting bodies, bad boll opening and poor quality lint and overall decline in seed cotton yield
• Nymphs and adults also excrete sugary liquid called 'honeydew' on which sooty mold (black fungus) grows. The presence of sooty mold on leaves interferes with photosynthesis and affects the overall health and growth of the plant as well as lint quality
• The attack of whitefly gives the plant a sickly appearance
• Whitefly transmits cotton leaf curl virus and the infected plants exhibit leaf curling, crumpling, vein thickening, cupping and plant stunting etc. causing considerable yield loss

Natural enemies of Insect Pests of Cotton

Besides spiders which catch large numbers of adult whiteflies in their webs, there are eight species of natural enemies (five of predators and three of parasitoids).

• The predatory beetles are Serangium parcesetosum Sicard, Brumoides suturalis (Fab.), Cheilomenes sexmaculata (Fab.), Coccinella septempunctata L. and a neuropteran, Chrysoperla zastrowi sillemi (Esben-Petersen)
• The three parasitoids are Encarsia lutea (Masi), Encarsia sophia (Girault & Dodd) and Eretmocerus sp