Pigeon Pea (Arhar) (Cajanus cajan L. Millsp.)

Pigeon pea commonly known as red gram or arhar is a very old crop of this country. After chickpea, arhar is  the second most important pulse crop in the country. It accounts for about 11.8 per cent of the total pulse area and 17 per cent of total pulse production of the country. It is a rich source of protein and supplies a major share of the protein requirement of the vegetarian population of the country. It is mainly eaten in the form of split pulse as 'dal'.

Pigeon pea contributes about 15 per cent in total pulse area as well as production of India.

ORIGIN AND HISTORY

Although Pigeon pea has been cultivated in India for more than three thousand years and is one of the most widely grown pulse in the country. It has been reported to occur in wild state in Africa, in the upper regions of the river Nile and coastal districts of Anjola. It seems that Africa is the probably place of origin and the plant might have been introduced into India by ancient traders trading on the route between Zanzibar, India and Ceyclon.

AREA AND DISTRIBUTION

Pigeon pea is grown through out the tropical countries of the world especially in the more arid regions in Africa, West Indies, Ceyclon, Australia and Malaya.

It is one of the most widely cultivated waste crops of India next to chick pea. It is grown over an area of 3.5 million hectare with a production of 2.8 million tones. The crop is extensively grown in Maharashtra, Uttar Pradesh, Madhya Pradesh, Karnataka, Andhra Pradesh and Gujarat. The state of Uttar Pradesh has a unique distinction of contributing about 20 per cent of the total pigeon pea production in the country.

CLASSIFICATION

   Numerous types of cajanus are known, differing in height, habit, time of maturity, color, size and shape of pods and seeds. All these cultivated types fall into two groups.

1. Cajanus Indicus var. bicolor: This group includes generally late maturing varieties, having all bushy plants, flowers yellow, purple streaked, pods dark colored each with four or five seeds. The standard which is the largest of the five petals in the flower, possesses red veins on the dorsal side.
2. Cajanus indicus var. flavus: This group includes early maturing varieties having smaller plants, yellow flowers, plain pods with two or three seeds.

All the types under both the groups have 2n = 22 chromosomes

Diseases

Wilt

This disease is caused by a fungus, Fusarium oxyporum f. sp. Udum, which survives in off season on plant trashes in the soil.

The leaves of the affected plants become yellowish in color, then drop and finally the whole plant dry out. These types of symptoms can be easily confused with shortage of moisture in the soil though there is plenty of moisture in the soil where these symptoms develop. The disease in fact can be diagnosed by seeing the black streaks on the wood after removing the outer epidermal strip from the major roots.

Control Measures

It is difficult to control the disease due to the soil borne nature of the causal fungus. However, its incidents can be reduced considerably by taking certain precautions. Thses include following a three to four year crop rotation, taking a mixed crop of jowar and arhar and collecting and burning the plant trasnes left after harvesting. Best control is to plant disease resistant varieties like Amar, Azad, Asha (IPCL-87119), Maruthi, C-11, BDN-1, BDN-2, NP-5 etc.

Stem Rot

This disease is caused by fungus Phytophthora dreschsleri var. cajani. The disease affected plants show formation of brown to dark brown lesions on the stem near the soil surface. Theses lesins rapidly girdle the whole stem because of which the plant starts drying. It may be noted that the symptoms can be confused with symptoms of the wilt disease. But this disease can be differentiated from wilt by examining the roots which remain healthy in this case. Also, plants affected by stem rot can not ne easily pulled out.

Control Measures

• This disease can be controlled by planting resistant varieties.
• There should be good drainage in the fields and the plants should be protected from stem injury.
  

Cankers

Several types of cankers are found on red gram. These are caused by fungi like Dilopodia cajani, colletotrichum cajani and Macrophoma cajanicola. The disease affected plants show formation of cankers on stem and twigs. The plant part may break at such places.

Control Measures

      In case of severe intensity of this disease, the crop should be sprayed with Mancozeb 75 WP at the rate of 2.5 kg per hectare. A suitable crop rotation should be followed if the cankers are a problem in the same field every year.

Sterility Mosaic

It is caused by sterility mosaic virus. It is an important disease of pigeon pea. The virus is spread from plant to plant under field conditions through Eriophyid mite.

The affected plants become light greenish in color which can be easily differentiated from dark green healthy plants. Leaves are reduced in size. Affected plants remain stunted and branch profusely, as a result of which they appear bushy. No flowers and fruits are borne on such affected plants resulting in total loss of yield. Sometimes only a few branches in the plant are affected others remaining healthy. In such cases the yield reductions are patial. The virus is not seed borne.

Control Measures

• Plant resistant varieties like Pusa-885, Asha, Sharad (DA-11), Narendra-Arhar-1, Bahar etc.
• Control mites by spraying 0.1% Oxydemton methyl (Metasystox). Start spraying as soon as first affected plants are seen in the field. Three to four sprays are needed to control the mites.

Insect Pests

Pigeon pea crop is attacked by a number of insect pests. The important ones are given below:

Pod Borer

This is widely distributed and is the most injurious pest of early and medium maturing varieties. The larvae, after hatching, feed on tender leaves and twigs but at pod formation they puncture pods and feed on developing grains. The caterpillars are green with dark brown, grey lines along the sides of the body.

Control Measures

• The caterpillar should be picked by hand after shaking the plants and destroyed in the early stages of attack.
• Spray the crop with 1.5 litre Endosulfan 35 EC or Monocrotophos (Nuvacron) 36 per hectare in 1000 litres of water.

Tur Pod Fly

It is an important pest of Pigeon pea causing more severe damage in medium and late maturing types. The eggs are laid in tender pods. As the larvae grow and feed on the seeds, damage becomes more conspicuous and distinct. Stripes can be seen on the surface of the affected grains, while the attacked pods are somewhat twisted of deformed. In case of severe damage, as many as 80 per cent pods and 60 per cent grains may be damaged.

Control Measures

      The pests can be controlled by spraying the crop with 1.5 litres of Endosulfan 35 EC or Monocrotophos (Nuvacron) 36 EC in 1000 litres of water per hectare.

Plume Moth

      This is a serious pest of Pigeon pea. The larvae damage seeds as well as cause flowers, buds and pods to drop. The caterpillar is greenish-brown in color and fringed with short hairs and spines. It also enters into the pod and feeds on developing grains.

Control Measures

Spray the crop with Endosulfan 35 EC (1.5 millilitre in 1 litre of water) at the rate of 800-1000 litres per hectare.

Hairy Caterpillar

Three species of hairy caterlpillars may cause damage to early crop of arhar by eating away the green water of the leaves. The adult moth of these caterpillars lay eggs in large clusters and the young larvae are also congregated. The red hairy caterpillar may damage the crop at seedling stage.

Control Measures

Collect and destroy the eggs and young larvae. The young caterpillars can also be killed by dusting 2% Mythyl parathion at the rate of 25-30 kg per hectare. For full grown caterpillars spray Endosulfan #% EC at the rate of 1.5 litres in 1000 litres of water per hectare.

Leaf Hopper

The adult and nymphs of this green hopper suck the juice from the larvae. Generally the insects sucks sap from the lower surface of the leaves but also occasionally from the upper surface. As a result of sucking the sap, the leaves turn brown and curl from the edge. In severe cases, they show symptoms of 'hopper burn' and ultimately dry up.

Control Measures

Give basal application of Phorate (Thimet) 10 % granules at the rate of 10 kg per hectare or Disulfortan 5% granules at the rate of 20 kg per hectare at the time of sowing. Spraying with Monocrotophos 36 EC (1 millilitre in 1 litre of water) also controls the insect effectively.

Bean Fly

It is a sporadic type of pest. The larva enters into the stem and causes plants to wilt or young plant to die. In case of severe infestation, there may be considerable damage.

Control Measures

Application of systemic soil insecticide as used in case of leaf hopper provides adequate protection to the crop.

Galerucid Beetle

It is an important pest of arhar. It avoids sunlight and causes more damage during dusk and night. It hides under debris and loose soil during the day time. The adult beetle stipples the leaves with small and more or less circular holes. In severe cases, the leaf area is very much destroyed on account of feeding by the beetles and this adversely affects the vigour and growth of the plant.

Control Measures

A basal application of Phorate (Thimet) 10% granules at the rate of 10 kg per hectare has proved very effective for the control of this pest.