Management of Whitefly

A. Non-chemical control measures

• Monitoring and scouting for insect-pests at weekly intervals from February onwards on alternate hosts i.e. weeds and cultivated crops
• Whitefly also attacks other alternate host crops like brinjal, cucurbits (kheera, tar, chappan kadu, wanga), potato, tomato, okra, moong, mash and guar. Regular surveillance should be done from February onwards for timely management on these crops
• Eradicate the weeds like kanghi buti, peeli buti, puth kanda, button buti, wild sunflower, makoh, dhathura, congress grass growing on field bunds, waste lands, road side and irrigation channels/canals to avoid further spread of whitefly to cotton fields
• It has been observed that initially whitefly incidence is established in the form of hot spots in selected villages. A regular surveillance mechanism throughout the cotton growing areas of the states will help in early detection of these hot spots and timely remedial measures in such areas will help to check its build up
• Grow only recommended varieties/hybrids of cotton. Prefer to grow desi cotton (arboreum) in the area of high infestation of whitefly and leaf curl
• Complete the sowing from 1^st April to 15^th May
• Following the recommended row-to-row spacing of 67.5 cm and plant-to- plant of 75 cm for Bt cotton. In densely sown crop, plant attains more height and creates favourable micro-climate for buildup of whitefly population. It also hampers the insecticidal control operations as the insecticide fails to reach the target site
• Applying recommended dose of fertilizers on soil test basis. The application of Muriate of Potash (MoP) @ 20 kg per acre minimizes the whitefly incidence and four sprays of potassium nitrate (NPK 13:0.45) @ 2 kg/acre at weekly interval starting from flower initiation improves the health of the crop
• Applying first irrigation 4-6 weeks after sowing depending upon soil type and last irrigation by end September
• Extensive monitoring for whitefly in the cotton fields grown near the orchards
• Deploying the low cost yellow sticky traps @ 40 per acre during initial phase of the cotton crop to check early infestation of whitefly
• Extensive campaign should be followed at village level for effective management of whitefly

B. Chemical control measures

• Strictly follow Economic Threshold Level (ETL) and spray insecticides when whitefly population reaches 6 adults per leaf in the upper canopy of plant before 10 a.m. or when honeydew appears on 50 per cent of plants
• First two sprays should be done at 5-7 days interval with Nimbecidine/Achook @ 1.0 litre/acre in 125-150 liters of water to manage whitefly and to conserve the natural enemies
• The cotton field adjoining to orchards with very high population of whitefly adults should be sprayed with Diafenthiuron 50 WP (Polo/Craze) @ 200 g/acre and after 5 days, spray Pyriproxyfen 10 EC (Lano) @ 500 ml/acre OR Spiromesifen 240SC (Oberon) @ 200 ml/acre
• In fields, where adult population of whitefly has crossed ETL (6 adults/leaf), spray Flonicamid 50WG (Ulala) @ 80 g/acre OR Diafenthiuron 50 WP (Polo/Craze) @ 200 g/acre OR Ethion 50 EC (Fosmite/E-mite/Volthion) @ 800 ml/acre OR Triazophos 40 EC (Sutathion/Marktriazo) @ 600 ml/acre. If again whitefly crosses ETL, spray Pyriproxyfen 10 EC (Lano) @ 500 ml/acre OR Spiromesifen 240SC (Oberon) @ 200 ml/acre
• In fields, where nymphal population is high and honey dew (shining of leaves) symptoms have appeared, spray Pyriproxyfen 10 EC (Lano) @ 500 ml/acre OR Spiromesifen 240SC (Oberon) @ 200 ml/acre followed by spray of Flonicamid 50WG (Ulala) @ 80 g/acre OR Diafenthiuron 50 WP (Polo/Craze) @ 200 g/acre
• Avoid using synthetic pyrethroids (cypermethrin, fenvalrate, deltamethrin), acephate and Pride (acetamiprid) to minimize resurgence of whitefly
• Through coverage of plants with insecticides is essential to check the multiplication of whitefly. The recommended insecticides should be sprayed using 125-150 litres of water per acre with manually operated knapsack sprayer
• Community approach should be adopted at village level for the application of insecticides (the pesticide to be applied at all farmers fields of the village on the same day)
• The same insecticide should not be sprayed repeatedly

Economic Threshold Level for Whitefly

If Whitefly population is <4.0 adults per leaf in the upper canopy of plant before 10.00 AM

Regular monitoring of whitefly be done

If Whitefly population is 4.0 to 6.0 adults per leaf in the upper canopy of plant before 10.00 AM

First two sprays should be done at 5 days interval with Nimbecidine /Achook @ 1.0 litre/acre in 100-150 liters of water to manage whitefly and to conserve the natural enemies

If Whitefly population is >6.0 adults per leaf in the upper canopy of plant before 10.00 AM

Use the recommended insecticides as per the case mentioned above in the whitefly management strategy.

Information about the effect of insecticides on adults and/ or nymphs is summarized below:

Pesticide application technology

• Cleaning the spray tank properly before and after the use
• The recommended insecticides should be sprayed using 125-150 litres of water per acre with manually operated knapsack sprayer and 75 litres with the tractor mounted sprayer
• Use fixed type hollow cone nozzle for knapsack sprayer