Introduction to major field crops (1+1)

Plant Protection

Insect Pests

Bihar Hairy Caterpillar: The crop is damaged by young larvae which feed gregariously on the undersurface of the leaves. In later stage, caterpillar defoliates the complete plants. The insects can be controlled by spraying Endosulfan 35 E.C. at0.2 per cent or Dimethoate 30 E.C. 0.1 per cent.

Capitulum Borer: The insect directly damages the developing seeds and causes enormous loss to yield. Two sprays of Endosulfan (0.05 %) at 25 and 40 days after sowing is advisable for the effective management of capitulum borer.

Root Weevil: Damage is caused by both grubs and adults. The adults of the insect feed on foliage whereas grubs feed on roots which cause mortality of the plants. Soil application of insecticide at the time of last ploughing helps to control the pest. Any of the Chlorinated hydrocarbons e.g. Lindane (3.5 kg a.i./ha), Heptachlor (1.5 kg), Dieldrin (1.0 kg) or Toxaphane(0.25kg) may be used to control this pest.

Diseases
Alternaria Leaf Blight: It is a destructive disease cause reduction in seed and oil yield.Mancozeb at the rate of 0.30 per cent sprayed at 7-10 days interval is effective in controlling this disease.


Fig: Alternaria Leaf Blight.

Rust: Reddish brown pustules appear on the lower surface of the young leaves and later spread over entire vegetative surface. Dusting of elemental sulphur at 15 kg/ha or spraying of any Organosulphurs (Zineb 0.4%),Mancozeb (0.15%),Ziram0.15 %) are highly effective in managing the disease. Sunflower hybrids viz. MSFH-1, 6, 8, 9, 10, BSH-1, VSF-1 and 2 are fairly resistant to rust in India.


Fig: Rust.

Charcoal Rot: The disease incidence, increases due to low soil moisture at flowering accompanied by high temperatures above 30°C for prolong period. Seed treatment withThiram at 2-4 g/kg seed helps in minimizing seed borne inoculum.

Head Rot: Kharif crop is more susceptible to the infection. At first brown irregular water soaked spots appear on the surface of the head near the stalk and gradually spread to the head causing rot of the head. This can be controlled by spraying Mancozebat 0.2 per cent during head emergence.




Fig: Head Rot.