Nutrient Deficiences of sunflower

Nitrogen

Little new growth, yellow leaves: this being more pronounced in older leaves. Earlier fall leaf drop. New shoots may be red to red-brown.

Phosphorous

Overall dark green with purple, blue or reddish cast to leaves particularly on underside, veins and stems and some plants respond to lack of P with yellowing. Foliage may be sparse, small and distorted becoming mottled and bronzy with maturity. Excess foliage with no flowers can also indicate lack of P.

Potassium

Sickly looking plants, undersized flowers and seeds, leaves showing marginal and interveinal yellowing. Yellowing starts on older leaves and progresses upwards. Leaves may crinkle, turn brown and roll upwards. Blossoms may be distorted and small. Plant has little resistance to heat, cold and disease problems.

Sulphur

Plants showing paling/yellowing of leaves. Yellowing spreads from the base to the apex. Growth of plants is reduced. The size of capitulum is severely restricted. Inflorescence may remain covered within the bracts. Maturity of flowers is delayed.

Boron

Under severe deficiency at about 3 weeks growth, young and middle leaves of plants develop small chlorotic patches. Cotyledons of these plants become massive and the shoot apex becomes globose and deformed. Later, chlorotic patches become more pronounced and develop orange coloured necrotic areas in young leaves. Shoot apex may turn necrotic and cease to grow. Young leaves show severe curling and distortion. This leads to appearance of side branches bearing small leaves. Eventually all the young leaves turn necrotic. For remedy, give directed spray of 0.2% Borax (2g/l of water) to capitulum at ray floret opening stage.

Calcium

Young leaves are small and distorted with curled back leaf tips. Shoots may be stunted and show some dieback, reduced roots and shoot development. Small distorted leaves near branch tips, and terminal buds blacken and fail to continue to develop and reduces the seed formation.

Zinc

Light yellow stripes along with veins of leaf blade. Under acute condition-vein chlorosis and cessation of growth of terminal bud. Older leaves may show slight chlorosis. Apply foliar spray of ZnSO₄@0.5%.

Iron

Yellowing of young leaves; interveinal chlorosis. Apply foliar spray of FeS₄@0.5%.

IPM for Sunflower

To know the IPM practices for Sunflower, click here.

Source: NIPHM;Directorate of Plant Protection, Quarantine & Storage