Wheat Vegetative Stage

First irrigation should be given at this stage because the CRI stage starts and the CRI stage is most important stage for irrigation. It has been found that each week delay in 1^st irrigation from CRI stage results in yield reduction of 83-125 kg per acre. 

Remaining quantity of Nitrogen should be applied at the time of crown root initiation. CRI (crown root initiation) stage of wheat starts and this is the most important stage of wheat crop. At this time farmer has to be very careful about water management because any shortage of moisture at this stage results in less tillering, formation of small eartheads and great reduction in yield. 

As post emergence weedicide, use 2, 4-D @ 1 ml per ltr of water for controlling broadleaf weeds in standing crops. Timing of application of 2, 4-D is critical to avoid injury to wheat. The critical period for 2,4-D applications is after wheat is Fully tillered but before Jointing Stage. Application before full tillering stage and after jointing stage may cause harm to the crop.

       Spraying of weedicide in wheat crop     Weedicide 2,4-D

The pre-dominant weeds associated with wheat crop are Anagallis arvensis (Krishananeel), Argemone mexicana (Satyanashi), Asphodelus tenuifolius (Piazi), Avena ludoviciana (Jangli Jai), Cannabis sativa (Bhang), Carthamus oxycantha (Pohli), Chenopodium album (Bathu), Cirsium arvense (Kateli), Convolvulus arvensis (Hirankhuri), Cornopus didymus (Pitpapra), Euphorbia jelioscopia (Dudhi), Fumaria parviflora (Gajri), Lathyrus aphaca (Matri), Malva parviflora (Gogisag), Medicago denticulata (Maina), Malilotus alba (Metha), Phalaris minor(Mandushi/Gulidanda), Poa annua (Poa ghas), Polygonum plebejum (Raniphul), Polypogon monspeliensis (Lomar ghas), Rumex retroflex (Jangli palak), Spergula arvensis (Bandhania), Vicia sativa (Chatri/Gegla). Phalaris minor is the major weed of wheat in rice wheat system. Sometimes its population is so high (2000-3000 plants / m2) that farmers are forced to harvest the wheat crop as fodder. Isoproturon (Arelon) was recommended for the control of Phalaris minor.

Some Useful Hints 

Do’s-

Spray the herbicides, both pre and post emergence, when there is sufficient moisture in the soil. Spray the post-emergence herbicides when phalaris minor is at 2-3 leaf stage. Spray on clear and sunny days only when the leaves are dries. Use only flat fan nozzle especially for fenoxaprop. Remove phalaris minor before seed setting and use as fodder. Ensure complete coverage of the field. 

Don’ts- 

Do not use Sulfosulfuran in mixed cropping system of wheat and mustard or other crops. Never apply these post emergence herbicides by mixing with sand, urea or soil. Do not mix Clodinafop and Fenoxaprop with 2,4-D.

Gujhia Weevil (Tanymecus indicus)

Identification: Weevils are earthen grey about 6.8 mm in length and 2.4 mm in width and Larvae are fleshy and creamy white. The pest is active from June to December and undergoes larval or pupal diapause during rest of the year in the soil.

Nature of Damage

Only adults feed on leaves and tender shoots of the host plants. They cut the germinating seedlings at the ground level. Often the crop is re-sown. The damage is particularly serious during October-November when the rabi crops are germinating. 

Management of Gujhia Weevil

Cultural Control: 

• Plough the fields in summer to expose and kill the pupae of Gujhia Weevil by Sun light and heat. 

Chemical Control: 

• Seed treatment with Chlorpyriphos 20 EC @ 4.5 ml per kg of seed. 
• Mixing of dust like Lindane 1.3 D @ 25-30 kg/ha in soil before sowing. 
• Foliar spray with Chlorpyriphos 20 EC @ 2-3 ml/litre of water as and when infestation is noticed in the field.

Leaf Rust (Brown)

Symptoms: 

The first symptom of the disease is the appearance of minute, round, orange sori, irregularly distributed on the leaves, rarely on the leaf sheath and stem. The sori turn brown with maturity.

Management of Leaf Rust (Brown)

Chemical Control:

• Seed dressing with Plantvax @2.5 g/kg of seed.
• Foliar Spray with Plantvax 20 EC @ 2 ml/lit of water OR
• Propiconazole 25 EC @ 1 ml/lit of water OR 
• Zineb 75 WP OR Mancozeb 75 WP @ 2 g/lit of water to control the leaf rust of wheat. 

• Apply 20-25kg/ha nitrogen for better growth and development of wheat crop.
• Irrigation should be given at this stage because of tillering stage starts.

Aphid (Opalsiphum maidis)

Identification: Aphids are small, soft-bodied, pearl-shaped insects that have a pair of cornicles (wax-secreting tubes) projecting out from the fifth or sixth abdominal segment. Aphids are yellowish green, grey green or olive green with a white waxy bloom covering the body.

Nature of Damage

The nymphs and adults suck the sap from plants, particularly from their ears. They appear on young leaves or ears in large numbers during the cold and cloudy weather. 

Management of Aphid

Cultural Control: 

• The crop sown before 20^th october escape the damage. Apply recommended dose of fertilizers.

Mechanical Control: 

• Destroy the affected parts along with aphid population in the initial stage.

Biological Control:

• Releases of bio agent Chrysoperla carnea @ 50,000/ha two times at weekly interval when aphid infestation is noticed.

Chemical Control: 

• Foliar spray with Imidacloprid 17.8% @ 0.25 ml/lit of water OR Dimethoate 30 EC @ 1 ml/lit of water.

Black or Stem Rust

Symptoms: 

Symptoms are produced on almost all aerial parts of the wheat plant but are most common on stem, leaf sheaths and upper and lower leaf surfaces. Uredial pustules (or sori) are oval to spindle shaped and dark reddish brown (rust) in color. The pustules are dusty in appearance due to the vast number of spores produced. Spores are readily released when touched.

Management of Black Rust

Cultural Control: 

Avoid late sowing as late sown crop is more exposed to rust damage. Balanced application of nitrogenous fertilizers lesser the occurrence. 

Chemical Control: 

• Spray with Plantvax 20 EC @ 2 ml/lit of water followed by two sprays with the Zineb or Mencozeb 75 WP @ 2 g/lit of water adding 0.1 % Sandovit (spreader-sticker) for better results. 
• Give first spray when rust pustules are seen in the last week of January or first week of February. 
• Give the second spray 10 days after the first spray. Give third and fourth sprays at an interval of 14 days if required.